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概率论与数理统计（英文要点·大一大二）
核心内容
Basic Concepts:
In this course, I mainly learned conditional probability multiplication formula(条件概率计算方法), geometric probability model(几何概型), and mathematical statistics(数理统计).
Explanation of Concepts:
Conditional probability multiplication formula:
P(AB)=P(B)P(A|B) P(AB) is equal to P(B) times P(A|B)(the probability of A given B).
P(AB) is the probability that event A and event B happen together.
P(B) is the probability that event B happens.
P(A|B) is the probability that the event A happens, when the event B has already happened.
So by this formula, we can get the probability of any part in the formula if we know the other two parts.
Geometric probability model:
We can use some geometric methods to solve the probability problem. If there are two variables, 0<x<1, 0<y<1, then we want to know the probability of x+y<1. It’s a geometric probability model.
First , we should change the form of the inequality.
x+y<1 changes into y<1-x.
Then we know that what we want is the part beneath the line of y=1-x.
And considering the conditions 0<x<1 and 0<y<1, we can draw a diagram.
So the square is the area of 0<x<1 and 0<y<1, and the line through point (1,0) and (0,1) is the line of y=1-x, and the shadow area S is the area of y<1-x, we can get from the diagram that the area of S is half of the area of the square. So the probability of x+y<1 under the condition of 0<x<1,0<y<1 is 1/2.
According to the example, we can know that if we use the geometric probability model, we can solve some kinds of probability problem very easily.
Mathematical statistics:
Mathematical statistics is to collecting, processing and analysising the data, which is get form the tests and experiments. And then we can get some regular conclusions. For example, if we throw a dice for 20 times,
number 1 2 3 4 5 6 times 2 4 1 3 3 7 Then we can see the results clearly by this chart and we can get the average number and other things, like
The average of the number we got is
The variance(方差) is
The standard deviation(标准差) is the square root of the variance
Of course , if we throw the dice for many times and there are no problem with the dice, the probabilities of each number appearing are equal, and are all 1/6.
参考：来源：大一大二资料（英文.doc｜专业：机械工程｜课程：概率论与数理统计
机械原理（英文要点·大一大二）
核心内容
Basic Concepts:
In this course ,we learned about the structure analysis of planar mechanism(平面机构结构分析), planar linkage mechanism(平面连杆机构), the cam mechanism(凸轮机构) and its design, gear mechanism(齿轮机构), gear trains(轮系) and calculation of its transmission ratio.
Explanation of Concepts:
Machinery（机械） include machine（机器） and mechanism(机构).
Structure analysis of planar mechanism:
In this chapter, i learned the lower pair(低副), the higher pair(高副) and degree of freedom of planar mechanism.
Direct contact and the movable connecting of two components is called kinematic pair.
Surface contact kinematic pair is called the lower pair. The revolute pair(转动副) and the sliding pair are lower pair.
Point contact and line contact kinematic pair is called higher pair. The gear pair and cam pair are higher pair.
The formula of the degrees of freedom of planar mechanism is
n —— the number of components, which can move;
—— the number of the lower pairs;
—— the number of the higher pairs.
For example,
This is a cam mechanism. It is composed of two moving parts, the A is push rod and the B is cam. The 1 is a sliding pair and the 3 is a revolute pair, they are all lower part. But the 2 is a line contact kinematic pair, it is a higher pair. So the degree of freedom is
When we calculate the degree of freedom, we should pay attention to three mechanisms.
local degree of freedom(局部自由度)： the degree of freedom which is unconcerned with the main movement is called local degree. When we calculate the degree of freedom of mechanism with local degree, we should delete the local degree first.
Compound hinge(复合铰链)：there are three members(构件), two of them have revolute pairs with the third one. When this happens, the number of the revolute pairs is the number of the members minus one.
Virtual constraint(虚约束)：we can regard
the virtual constraint as the repeated constraint,
it is existing for ensuring the strength of
the mechanism. When we calculate the degree
of freedom, we should ignore the virtual constraint.
Low pair replaces the high pair(高副低代):
For solving the problem conveniently, we can replace the high pair with the low pairs. But the degree of freedom, instantaneous velocity and instantaneous acceleration of the replacing institution must be the same as the primary institution.
Look at the above picture , the original mechanism is composed of two wheels, the kinematic pair between the two wheels is a line contact kinematic pair. It is a high pair. And we can replace it with the planar linkage mechanism. The length of the O1O2 is equal to the sum of r1 and r2.
Planar linkage mechanism :
I learned about the crank rocker(曲柄摇杆) , crank block(曲柄滑块) and the condition of the sum of the bar length(杆长之和条件).
The condition of the sum of the bar length:
The sum of the length of the shortest bar and the longest bar is not larger than the sum of two other ones.
If a revolute pair wants to be a full rotation pair , the nearest bar must be the shortest and these 4 bars must meet the condition of the sum of the bar length.
If the institution meet the condition:
If the shortest bar is the rack(机架), it is double crank mechanism.
If the nearest bar of the shortest bar is the rack ,it is crank rocker mechanism.
If the bar against the shortest bar is the rack, it is double rocker mechanism.
If the institution can not meet the condition of the sum of the bar length, then it is always a double rocker mechanism, no matter which bar is the rack.
Geometric features of planar linkage mechanism:
Extreme position angle(极位夹角)：
In the process of cranks rotation, there are twice that the crank and the bar next to it on the same line. The angle between the crank at these two times is called the extreme position angle. The two places of the crank is called the extreme position(极限位置). And extreme position angle is in the range [0°,180°].
The pressure angle and the transmission angle(压力角和传动角)：
The pressure angle: the acute angle(锐角) between the direction of force F and the direction of the velocity of the follower is named pressure angle. Like the angle α.
The transmission angle is the complement angle(余角) of the pressure angle. Like the angle γ.
The larger the transmission angle is , the better for the institution. Because
The γ is changing with the movement of the bars, but for keeping the transmission work well, we usually keep the γ more than 40°.
The dead point position(死点位置):
In this picture, the follower and the next bar is on the same line, the transmission angle is zero, this position is called the dead point position. We should avoid institutions to start at the dead point position ,because this moment the Ft is zero.
The cam mechanism and its design:
Classification of cams according to the shapes:
Dish cam wedge cam(translating cam) cylindrical cam (盘形凸轮) (移动凸轮) (圆柱凸轮)
The follower motion law(从动件运动规律):
The angle AOD(>180°) is called near angle of repose(近休止角).
The angle B’OB is called motion angle for rise travel(推程运动角).
The angle BOC is called far angle of repose(远休止角).
The angle COD is called motion angle for return travel(回程运动角).
This is the diagram of the motion of the follower , h is the distance of the follower moving.
The design of the dish cam:
If we know the base circle and the follower motion diagram, we can design the cam contour. Like the left picture.The base circle is given and the line of follower is through the center of the base circle. If we know the diameter of the wheel on the follower and the follower motion diagram , we can find out the theoretic contour curve. Then we can get the actual contour curve.
Gear mechanism:
I learned types of gears , involute gear（渐开线齿轮） , the size of the standard gear, the transmission ratio of the gears.
The ratio of instantaneous angular velocity(瞬时角速度) of the two gears is called transmission ratio（传动比）.
There are circular gear and non-circular gear.
External meshing gear mechanism and internal meshing gear mechanism.
The external meshing gear mechanism. in this mechanism ,the two meshing gears rotate in opposite directions
The internal meshing gear mechanism. in this mechanism ,the two meshing gears rotate in the same direction.
Pinion and rack mechanism. In this mechanism, it can transform the rotate movement into the linear movement.
Space gear mechanism. In this mechanism, it can change the rotating plane of the rotate movement.
Worm gear mechanism. In this mechanism, it can change the rotating direction of the rotate movement. And the transmission ratio of this mechanism can be very large.
I also learned that the ratio of instantaneous angular velocity of the two gears is called transmission ratio.
And the relative velocity instantaneous center is called meshing pitch point(啮合节点).
The moment locus(瞬心) of pitch point on the gear is called pitch circle(节圆).
Transmission ratio :
the are the pitch circle radius.
The involute gear: choose a point on a straight line, then make the line rotate around a circle, the counter of the point is a involute. The pressure angle of the involute gear never change.
The correct meshing condition of the gear transmission is the modulus(模数) and the pressure angle of two gears must be equal.
Basic parameters of standard gear:
modulus（模数）: it is a very basic parameter of the gear. m for short.
the p is the tooth pitch(齿距). Tooth pitch is equal to the sum of tooth thickness and space width.
For determining the gear geometrical size of each point, we choose a circle as the standard of the calculation, this circle is call the reference circle(分度圆).
name symbol formula Pitch diameter
(分度圆直径) d
Addendum
（齿顶高） Dedendum
(齿根高) whole depth
（齿全高） h Tip diameter
(齿顶圆直径） Root diameter
(齿根圆直径)
Pitch(齿距) p Tooth thickness
(齿厚) s space width
(齿槽宽) e Base diameter
(基圆直径)
Centre-to-centre spacing
(中心距) a Bottom clearance
(顶隙) c z is the tooth number(齿数).
is the addendum coefficient(齿顶高系数), the standard one is 1, the short one is 0.8.
is the bottom clearance coefficient(顶隙系数)， the standard one is 0.25, the short one is 0.3.
x is the modification coefficient, if the gear is not modified, x=0.
the standard of the pressure angle is 20 degree.
In order to prevent the undercutting(根切) when the gears are meshing, the tooth number must larger than 14.
Gear failure form:
1,tooth breakage(轮齿折断); 2, tooth surface wear(齿面磨损);
3,tooth surface pitting(齿面点蚀);4,tooth surface gluing(齿面粘合).
Gear train and its transmission ratio:
The classification of gear train:
There are two types of gear trains, ordinary gear train and epicyclic gear train（周转轮系）.
The ordinary gear train: each axes of the gears are fixed.
The epicyclic gear train : exist axes of the gears are not fixed. Like the gear4.
The transmission ratio of fixed axis gear train:
The product of teeth number of all driven gears(从动轮齿数乘积)
iAB= -------------------------------------------------------------------------------
The product of teeth number of all driving gears（主动轮齿数乘积）
For example,
The gear 1 is the driving wheel, so the 2 is the driven wheel, then the 2’ is the driving wheel ,the 3 is the driven wheel. According to the formula we can get:
As for the direction of the rotate of the gears , we can analysis each pair of gears to get it.
If the gear train is a epicyclic gear train, then we want to find out the transmission of the gear train ,we can just add a im, which is a relative transmission ratio of the planet wheel. Then we can bring the im into the formula, we can get the final transmission ratio.
参考：来源：大一大二资料（英文.doc｜专业：机械工程｜课程：机械原理
机械基础综合实验（英文要点·大一大二）
核心内容
Basic Concepts:
In this course , we have made experiment in the lab of our school, the topic of the experiment is to measure the geometric parameter of the turning tool.
Explanation of Concepts:
The aim of the experiment
Learn the method of measuring the geometric parameter of the turning tool and using of the measuring device;
Enhance the definition and understanding of tool geometry;
Draw the mark angle of the 45° external circular tool.
2. The content and requirements of the experiment
(1) Measure the rank angel(前角) ,clearance angle(后角), major cutting edge angle(主偏角), minor cutting edge angle(副偏角)，tool cutting edge inclination（刃倾角）.
(2) Everyone measures two cutting tool, one is 45°external circular tool, another is cutting off tool.
(3) according to the result of the measuring, draw the angle diagram of the 45° external circular tool.
3. Device
CLY-1 type angulometer of the cutting tool(车刀量角仪).
The structure and working principle of the angulometer of the cutting tool
When manufacturing the cutting tool, we all regard the plane which is parallel to the bottom of the cutting tool rod as the base plane. So when we measuring the cutting tool , we should also be based on the bottom.
The working principle : all the geometric parameter are measuring in the coordinate planes(坐标平面) of the cutting tool, include base plane（基面）, cutting plane (切削平面), orthogonal plane(正交平面).
The step of the experiment
Measuring the angle in base plane Pr
There are major cutting edge angle Kr(主偏角) and minor cutting edge angle K’r(副偏角) in the base plane. First , we should put the tool on the shoe plate next to the guide block, and che tool nose(刀尖) towards to the front plane of the measuring pointer. Adjust the shoe plate to make the major cutting lip(主切削刃) next to and parallel with the front plane of the measuring pointer, and now read the reading on the dial scale 1. The reading is the degree of the major cutting edge angle Kr. Then adjust the shoe plate again, to make the minor cutting lip(副切削刃) next to and parallel with the front plane of the measuring pointer, now read the reading on the dial scale 1. The reading is the degree of the minor cutting edge angle K’r.
Measuring the angle in orthogonal plane Po
Rank angle γ0 : put the tool on the shoe plate next to the guide block. Then make the bottom of the measuring pointer contact with the rake face(前刀面), now the reading on the dial scale 2 is the angle of the rank angle.
Clearance angle α0 : put the tool on the shoe plate next to the guide block. Through adjusting the shoe plate and the handwheel , make the minor flank is parallel to the front plane of the measuring pointer. Then read the reading on the dial scale 3. Then the reading of the dial scale 3 is the degree of the clearance angle α0.
Measuring the angle in cutting plane (Ps)
There are only the tool cutting edge inclination(刃倾角) λs in the cutting plane. First , we should make the major cutting lip is next to and parallel to the front plane of the measuring pointer. Then adjust the measuring pointer to make the bottom of it is parallel to the major cutting lip. Then read the reading on the scale 2. The reading is the degree of the tool cutting edge inclination（刃倾角）.
参考：来源：大一大二资料（英文.doc｜专业：机械工程｜课程：机械基础综合实验
电工技术与电子技术基础（英文要点·大一大二）
核心内容
Basic Concepts:
In this course, I learned Kirchhoff’s law(基尔霍夫定律), two models of the power supply（两种电源模型）, Thevenin’s theorem（戴维宁定理）, Norton’s theorem（诺顿定理） and series connect and Parallel connect of resistances（电阻的串并联）.
Explanation of Concepts:
Kirchoff’s law:
There is a Kirchhoff’s current law(基尔霍夫电流定律) and a Kirchhoff’s voltage law（基尔霍夫电压定律）.
Kirchoff’s current law:
At one time and at any mode in an electrical circuit , the sum of currents flowing into that mode is equal to the sum of current flowing out of that mode.
Left is an electrical circuit. There are two power supplies and three resistances. Then I3=I1+I2, the current flowing through R3 is equal to the sum of current flowing through R1 and R2.
Kirchhoff voltage law:
At one time, and along one certain direction , the sum of the electrical voltage around any closed network is zero.
When the voltage goes down , it is positive. When the voltage goes up , it is negative. We calculate the voltage along the direction of anticlockwise like left picture. And we can get U1-U2+U4-U3=0.
Series connect and parallel connect of resistances:
The the equivalent resistance(等效电阻) of the series resistors(串联电阻) is equal to the sum of the resistances which are in series. Like left picture, R=R1+R2.
The equivalent resistance of the parallel resistors(并联电阻) is equal to the reciprocal of the sum of the reciprocal of the resistances which are in parallel. Like left picture,
Two models of the power supply:
I learned two models of the power supply, the voltage source model and the current source model.
Any source supplies have electromotive force(电动势EMF) and internal resistance(内部电阻). We often separate them when we calculate.
The voltage source model:
The A is the ideal voltage source, the voltage of it is always E.
The B is the internal resistance, and the resistance of it is R0.
The RL is the load resistance, it is like the power consumption elements.
The I is the current in this electrical circuit.
Above is the voltage source model. The ideal voltage source and the internal resistance are in series. The voltage of this kind of power supply is U=E-R0I.
The current source model:
In this model, the A is the current source, and the current of it is always Is. The R0 is the internal resistance, and it is parallel with the current source. The RL is the load resistance. The U is the load voltage . The current through RL is I=IS-U/R0.
These two kinds of model can transform into each other.
The Is is equal to E/R. We can use this kind of change to solve problem more conveniently.
Is=E/R
Thevenin’s thorem:
The active two-terminal network(有源二端网络)：it is part of the circuit which contains the power source. It can be simple or complicated.
The thevenin’s thorem is that any combination of voltage sources, current sources and resistors with two terminals(终端) can be equivalently replaced(等效替代) by a single ideal voltage source and a single series internal resistance.
The Norton’s theorem:
Any active two-terminal network can be equivalently replace by an ideal current source in parallel with a single internal resistor R.
These two theorems are convenient for us to solve the circuit problem and to calculate.
参考：来源：大一大二资料（英文.doc｜专业：机械工程｜课程：电工技术与电子技术基础
财务管理
核心内容
财务管理：CAPM模型
会计学：会计六要素，资产，负债，所有者权益，收入，费用，利润
The six elements of accounting, assets, liabilities, owners' equity, income, expenses, and profit
创新创业：这个课我们看了一些公司的创业视频，例如阿里巴巴，阿里巴巴的创始人马云第一次接触互联网就看到了这个商机，他要用电子商务，用互联网来赚钱。他和他的团队制造精美的网站，去找投资，去其他网站发广告营销，去做B2B的演讲说B2B会改变人们的生活，就这样马云吸引到了媒体和投资者的关注，后来企业越做越大，他还推出了淘宝，支付宝等
In this class we watched videos of companies starting up, such as Alibaba, Alibaba's founder Jack Ma saw the business opportunity of the Internet, he wanted to use e-commerce and use the Internet to make money. He and his team made beautiful websites, looking for investment, to other websites to send advertising and marketing, make B2B speeches saying that B2B would change people's lives, and in this way Ma attracted the attention of the media and investors, and later the business became bigger and bigger, he also launched Taobao, Alipay, etc.
100分的科目caring for life-first aid and self rescuer：这门课主要就是看视频，如果你连续20天每天都在看这门课的视频并完成相应的作业，就会得到一个不错的分数。
This class is mostly about watching videos. If you watch the videos in this class every day for 20 days constantly and complete the corresponding homework , you will get a good grade.
How to make cpr and artificial breathing
参考：来源：财务管理.docx｜专业：物流管理｜课程：财务管理
电子技术（英文要点·大一大二）
核心内容
Basic concepts:
In this course , I learned diode(二极管), triode(三极管), basic amplifying circuit(基本放大电路) and basic logic gate circuit(基本逻辑门电路).
Explanation of Concepts:
Diode and triode:
Diode:
Semiconductor(半导体): there are two types of semiconductor, N-type semiconductor and P-type semiconductor.
N-type semiconductor: usually we put some phosphorus(P磷) into the silicon(硅) crystal. There are five electrons in the outside of the P. And there are four electrons in the outside of the silicon. So the fifth electron of the phosphorus isn’t stable. So there are many free electrons in the N-type semiconductor.
P-type semiconductor: usually we put some boron(B 硼) into the silicon crystal.
There are three electrons in the outside of the B . And there are four electrons in the outside of the silicon. So there are many holes in the p-type semiconductor and other electrons will flow to fill the holes. Then the current can come into being.
The surface of the N-type semiconductor and the P-type semiconductor is called P-N junction(PN结).
If we add the forward voltage on the P-N junction, then the free electrons of N-type semiconductor will flow to the holes of P-type semiconductor, then the P-N junction is conducting.
But if we add the backward voltage on the P-N junction , then the P-N junction is not conducting.
Above is the principle of diode. If we add the electrode lead on P-N junction. It’s the diode.
This is the volt-ampere characteristics curve(伏安曲线). We can see, the forward voltage is conducting and the backward voltage is not conducting. But if the backward voltage is too large, the diode will be breakdown(击穿), and the it will be conducting. The minimum voltage when the diode is breakdown is called the breakdown voltage. And we can see , there is a dead zone voltage.
When the voltage is lower than the dead zone voltage , the diode is not conducting as well.
Triode:
The triode has amplified action(放大作用). There are two types triodes: N-P-N type and P-N-P type. Following is the basic structure.
The N-P-N type is used more. IC=βIB, β is only a ratio. As for the N-P-N type, the voltage of the base is highest, the emitter is the lowest. But the P-N-P type ,the voltage of the emitter is the highest, the base is the lowest.
Basic amplifying circuit:
Usually we use a voltage source represent the AC(alternating current) signal source. Left picture is the common-emitter AC amplifying circuit diagram. We use the current amplification function of the triode.
The collector voltage Ucc supplies the energy for the output signal and makes sure the collector junction on reverse bias(反偏).
The collector load resistance Rc turns the current change into the voltage change to realize the voltage amplification.
Bias resistance RB makes the emitter junction forward bias(正偏), and supplies the suitable base current(基极电流) IB.
The coupling capacitance (耦合电容)C1 and C2 make the signal source, amplifying circuit and the load resistance no DC(direct current直流) link and make sure that the AC signal can get through the circuit.
Application: audio power amplifier(扩音器)
Basic logic gate circuit:
The logic circuit belongs to the digital circuit(数字电路). And what we learned before is artificial circuit(模拟电路).
The difference between digital circuit and artificial circuit is the signal of artificial is continuous changing in time and numerical value. But the signal of digital circuits is not continuous changing, it is the pulse signal(脉冲信号). It is “1” or “0” to judge the connect or disconnect.
Following are some basic logic gate circuit.
Logic gate AND-gate OR-gate NOT-gate NOT-OR gate NOT-AND
gate symbol formula Y=A·B Y=A+B Y=Ᾱ Y=
And there are some calculate laws of the logic gate,
Crossover law(交换律):
Binding law(结合律):
Distribution law(分配律):
The truth table for AND-gate:(Y=A·B)
A B Y 1 1 1 1 0 0 0 1 0 0 0 0
参考：来源：大一大二资料（英文.doc｜专业：机械工程｜课程：电子技术
生物科学学科总览（思维导图）
核心内容
【APS 生物科学学科思维导图笔记】
【一、学科总览】
本笔记整合生物科学专业核心课程：免疫学、分子生物学、微生物学、生物化学、细胞生物学、遗传学、无机及分析化学、有机化学、物理学基础及配套实验。
【说明】本合并稿实际仅含免疫学、分子生物学、微生物学、生物化学四门课程要点，其中「生物化学」正文在【4.】处被生成过程截断。本次已按课程拆分到生物科学专业下各自课程条目，其余课程内容见各课程对应的思维导图条目与英文背诵稿。
参考：来源：APS 学科思维导图.zip｜专业：生物科学｜课程：APS 学科思维导图｜原合并稿卷首 + 【一、学科总览】拆分
机械设计课程设计（英文要点·大三大四）
核心内容
Major: Mechanical Design, Manufacturing and Automation
The third year
Basic concepts:
This course is the course exercise of the Mechanical Design, it is to design a two stage reducer.
Explanation of concepts:
01905The steps of design:
Make the requirements clearly: We should make the requirements clearly. The requirements are:a、this is a two stage reducer of a winding drum(卷筒), the speed of the winding drum is 1.2m/s, force of it is 2.7kN, diameter of it is 320mm. And we should choose the Y type three phase asynchronous motor(三相异步电机), and it should be closed type(封闭式).
Calculate the basic data of the reducer: we have know the basic requirements of the reducer, then we should calculate the basic data, like the power of the reducer, the transmission ratios and the torque of the axes. The design have given to my teacher after the course exercise, so i can’t find the date of this part. But i can present you some key data of this part. The transmission ratio between the motor axis and the first gear axis is 3. The transmission of the gear axes is 13.50. The three phase asynchronous motor I chose is the Y132S1-2 type, the speed of it is 3000r/min, and the working speed is 2900r/min.
Choose belt of the belt transmission: according to the basic data we have got, we can choose the belt of the belt transmission. First the belt transmission ratio is 3, and then we can decide the diameter of the pulleys. The process of choosing the pulleys is mainly according the standard requirements. In another word, it is chose through look-up table. All the data of the pulleys and the belt has standard, we just have to choose the fit ones. Finally, the first pulley’s diameter is 90mm, the second one is 270mm. And we choose the Z type belt, and using 3 belts. The distance of two pulleys is 700mm.
Calculate of the gears: first we should make sure the transmission ratio of the first stage and the second stage of the gear transmission. According to the formula , we can get that the first stage transmission ratio is 4.27, and the second stage is 3.16. Then we can choose the number of the tooth of the gears. Then we should find out if the endurance bending strength and the Contact fatigue strength meet the requirement. If it is OK, then we can continue to calculate the next gear. Finally, the data of the gears is: z1=25, z2=104, a1=135mm, b1=65mm, b2=60mm,α=20°; z3=30,z4=91, a2=155mm,b3=85mm,b4=90mm,α=20°. And the modulus is 2.
We design the shape of the axes: we have get the data of the gears, then we can use look-up table to find the data of the axes, I can’t find the data about the axes now.
At last we have to choose the auxiliary equipment, such as the air hole bolt, the flow nipple, the bearing and the coupling.
All the things have been chosen, then we should draw the assembly drawing and write the instructions of the two stage reducer.
参考：来源：大三大四专业课资料（英文.docx｜专业：机械工程｜课程：机械设计课程设计
专业导论（英文要点·大三大四）
核心内容
Basic concepts:
This course is mainly about the introduce of our major, it is for telling us what we are learning for , what we can do after graduation, and the future of our major. There is nothing important.
参考：来源：大三大四专业课资料（英文.docx｜专业：机械工程｜课程：专业导论
免疫学
核心内容
· 抗原（Antigen）基本特性
· 免疫原性（immunogenicity）：抗原分子刺激机体产生抗体和/或致敏淋巴细胞的特性，又称免疫原生性（诱导免疫应答的能力）
· 抗原性（antigenicity）：又称反应原性，抗原分子与抗体或致敏淋巴细胞发生特异性结合的特性
· 异物性：抗原与机体自身正常组织物质不同；异物性越大，免疫原性越强
· 分子量：一般需 10 kDa 以上；分子量越大，免疫原性越强
· 化学组成与结构复杂性
· 分子构象与易接近性
· 物理状态：颗粒性抗原 > 可溶性抗原
· 抗原的免疫原性条件：异物性、分子大小、化学组成、结构等
· 抗原的特异性（antigenic specificity）：某一特定抗原只能与相应抗体或致敏淋巴细胞结合
· 抗原决定簇（epitope / antigenic determinant）
· 概念：抗原分子中决定抗原特异性的特殊化学基团，是与 TCR/BCR 及抗体特异性结合的基本单位
· 类型：构象表位（conformational epitope）与顺序表位（线性表位）
· 分类：依化学组成、依与载体的结合方式等
· 半抗原（hapten）与载体（carrier）：半抗原为小分子物质，只有反应原性而无免疫原性；与大分子载体结合后获得免疫原性
· 共同抗原（common antigen）与交叉反应（cross reaction）：两种不同抗原分子间存在相同或相似表位，可与同一抗体结合，称交叉反应
· 常见抗原：异嗜性抗原（Forssman 抗原）、同种异型抗原、自身抗原、肿瘤抗原
· ABO 血型系统（ABO blood group system）：红细胞血型系统之一，分 A、B、AB、O 四型；抗体分抗体 α、抗体 β（另有"天然抗体"论述）
· 抗原的分类
· 依来源：完全抗原（complete antigen）/半抗原
· 依是否依赖 T 细胞：胸腺依赖性抗原（TD-Ag）/胸腺非依赖性抗原（TI-Ag）
· 依与机体亲缘关系
· 抗体（antibody）
· 概念：机体在抗原刺激下由浆细胞产生的、能与相应抗原特异性结合的免疫球蛋白
· 结构：两条相同重链（H）和两条相同轻链（L）借二硫键连接成 Y 形；分可变区（V 区）与恒定区（C 区）
· 抗体与免疫球蛋白：抗体主要是丙种（γ）球蛋白，电泳主要位于 γ 区带
· 免疫球蛋白类别：IgG、IgM、IgA、IgD、IgE 五类
· 各类免疫球蛋白的生物学功能
· 抗原性质：由化学组成与结构决定
· 抗体结构要点：两条臂上有 2 个抗原结合部位
· 免疫系统组成
· 免疫器官：中枢（骨髓、胸腺）；外周（淋巴结、脾、黏膜相关淋巴组织）
· 免疫细胞：T/B 淋巴细胞、抗原提呈细胞、巨噬细胞等
· 免疫分子：抗体、补体、细胞因子
· 免疫应答类型：固有免疫（innate immunity）与适应性免疫（adaptive immunity）
· 免疫应答基本过程：抗原识别 → 淋巴细胞活化增殖 → 效应阶段
· 免疫学检测技术：抗原抗体反应、凝集反应、沉淀反应、ELISA 等
参考：来源：免疫学.png｜专业：生物科学｜课程：免疫学
工程热力学（英文要点·大三大四）
核心内容
Basic concepts:
In this course, i learned the zero law of thermodynamics, the first law of thermodynamics, the nature of the ideal gas and the thermal process, the second law of thermodynamics, the basic way of heat transfer and so on.
Explanation of concepts:
Basic concepts:
Heat engine: which can transform thermal energy into mechanical energy of the machine, such as steam engine, internal combustion engine and jet engine.
The zero law: if each of the two objects is in thermal balance with the third object, then the two objects must also be in thermal balance.
Thermal balance: when the heat transfer between the two objects, after a time , the two will reach the same temperature, then they are in heat balance.
The first law: when the heat energy and other forms of energy transfer to each other. The total amount of the energy is conservation in this process.
The essence of the first law is the energy conservation law. The expression of the closed system first law of thermodynamics: Q-W=ΔU
It means that the energy enter the system - the energy leave the system = the change of the energy stored in the system
The second law:
Clausius stated(克劳修斯表达): it is impossible to remove heat from low temperature object to high temperature object without causing other change.
Kelvin Planck(开尔文-普朗克表达): it is impossible to take heat from a single heat source and to make it fully converted to work and not to have other effect.
The second law of thermodynamics illustrates the direction, condition and limit of the thermal process in the nature. And it illustrates that the perpetuum mobile of the second kind(第二类永动机can abserb heat energy from single heat source and convert it into mechanical energy 100%) is impossible.
Cannot cycle:
P is the pressure;
V is the volume;
T is the temperature;
S is the entropy(熵) J/K;
Carnot cycle consists of two reversible constant temperature processes（可逆定温过程） and two reversible adiabatic processes(可逆绝热过程):
1-2 constant temperature heat absorption (定温吸热);
2-3 adiabatic expansion (绝热膨胀)3-4 constant temperature heat release (定温放热)
4-1 adiabatic compression (绝热压缩)
The heat efficiency is according to the T1 and T2, and it is none of business of the nature of working medium(工质).
T1: the high temperature heat source.
T2: the low temperature heat source.
T1>T2 the efficiency is always less than 1.
T1=T2 ,ηc=0 so the temperature difference is the requirement when the heat energy transfers to the mechanical energy.
Carnot theorem:
All the heat engines working in the same heat source of high temperature and low temperature heat sources have the same thermal efficiency, it is nothing to do with the work medium;
The thermal efficiency of any irreversible heat engine(不可逆热机) is less than a reversible engine working in the same high temperature and low temperature heat sources.
We know the condition of the heat energy transforming to the mechanical energy and how to improve the heat efficiency.
Basic modes of heat transfer:
Heat conduction(热传导): it is caused by the thermal motion of atoms between objects. It is a heat transfer phenomenon. Such as shaking hands.
Heat convection(热对流): it is caused by the relative displacement of objects. Such as the heat exchange between the indoor and outdoor air.
Heat radiation(热辐射): it is caused by the internal thermal motion of atoms and radiate to the outside. Such as the micro-wave oven. It is use the heat radiation.
参考：来源：大三大四专业课资料（英文.docx｜专业：机械工程｜课程：工程热力学
机械设计（英文要点·大三大四）
核心内容
Basic concepts:
In this course, i mainly learned fatigue strength of mechanical parts, mechanical connection, mechanical transmission and bearing.
Explanation of concepts:
Fatigue strength of mechanical parts:
Left is the material fatigue curve.
σmax is the max stress the material holds.
N is stress-number of cycles at the σmax.
People get this curve from lots of experiments. And we can know that we should keep the stress of the material less than the σmax.
For improving the fatigue strength: a、reduce the stress force; b、choose the material with high fatigue strength; c、improve surface quality of parts.
Mechanical connection:
Mechanical connection includes thread connection, key connection.
As for the thread connection, before it works, there should be a pretightening force(预紧力).
Almost all the thread connection should be tightened when we want to use it. So before the thread connection is in the working bearing load, it will be under a force, the force is called pretightening force.
The amount of the pretightening force:
As for the carbon steel(碳钢): F0≤(0.6~0.7)σsA1.(Q235 σs=235MPa)
As for the alloy steel(合金钢): F0≤(0.5~0.6)σsA1.
The σs is the bolt material yield limit(螺栓材料屈服极限).
The A1 is the bolt danger cross-sectional area(螺栓危险截面面积).
The thread includes internal thread and thread connection. And the thread connection includes bolt connection(螺栓连接), double-screw bolt(双头螺柱连接), screw connection(螺钉连接). The thread connection is used for fixing the part which don’t have relative movement.
Tensile strength of bolt danger cross-sectional area(螺栓危险截面抗拉强度):
F0 is the pretightening force.
The d1 is the minor diameter of the bolt.
The [σ] is the Reference tensile strength(参考应力强度).
Key connection(键连接):
There are mainly five kinds of keys: multiple spline(花键), flat key(平键), woodruff key(半圆键), taper key(楔键) and tangent key(切向键).
multiple spline flat key woodruff key
taper key tangent key
Multiple spline: usually used on the interference fit of the gear and the shaft or the coupling and the shaft.
Woodruff key: just like the flat key. But it may make the strength of the shaft low, usually used in some situation transmit small force.
The key connection usually is used to realize the circumferential(周向) fixed between the shaft and the wheel hub to transmit torque(转矩).
Rivet connection(铆接):
Advantage:Process equipment is simple, impact resistance, solid and reliable.
Welding connection(焊接):
Advantage: High strength, simple process.
Cementing connection(胶接):
Advantage:simple process.
Mechanical transmission(机械传动):
Mechanical transmission includes belt transmission, chain transmission, gear transmission and worm transmission(蜗杆传动).
Belt transmission(<7):
Advantage: simple construction, steady transmission, low cost, it has
buffer(减震) which can absorb vibration.
Disadvantage: it has elastic slipping phenomenon(打滑现象) and affect the
transmission efficiency.
Chain transmission(<7):
Advantage: no slipping phenomenon, keep accurate transmission ratio,
compact construction, lower pressure, install easily, can work
in some bad circumstance, such as high temperature or welt.
Disadvantage: the two wheels’ direction must be the same, and the axis of
the two wheels must be parallel, easy to wear and has some
noisy, can’t be used in the wide range ,load change and
high speed transmission.
Gear transmission(single stage<6; double stage=6~30):
Advantage: efficient, compact structure, work reliably, long lifetime, the
transmission ratio is stable.
Disadvantage: high accuracy of manufacture and install, high cost, it is not
suitable for the long transmission distance.
Worm transmission(15~60):
Advantage: it can achieve large transmission ratio, compact structure,
steady transmission fewer noise.
Disadvantage: there is some slipping at the mashing point, easy to wear
lower efficiency.
Bearing(轴承):
It can support mechanical rotary body, reduce the friction, ensure the accuracy of its rotation.
According to the difference nature of friction, the bearing includes sliding friction bearing and rolling friction bearing.
Sliding friction bearing includes radial bearing(向心轴承) and thrust bearing(止推轴承).
The radial bearing is under radial load. Thrust bearing is under axial load.
Application of the sliding friction bearing: high rotate speed, large impact or vibration, in the water or some other circumstances, such as using in the combustion motor aircraft engine, radar.
The structure of the rolling friction bearing includes inner ring, outer ring, rolling body and holder.
The rolling bearing has low friction coefficient, less start resistance. It is standardization.
So the selection, maintain, lubrication are convenient. Is is widely used in common machine.
There are two sealing method: contact sealing(接触式密封), such as sealing ring. Non-contact sealing(非接触式密封), such as gap sealing(间隙密封).
The lifetime calculation formula of rolling bearing:
: the lifetime , the unit is 10^6 round
C: basic rated dynamic load (基本额定动载荷)
P: equivalent dynamic load(当量动载荷)
ε：just a coefficient, as for the ball bearing it is 3, non-ball bearing it is 10/3.
If the we have to consider the temperature, the formula is
The ft is the temperature coefficient, it can be found in the standard table.
参考：来源：大三大四专业课资料（英文.docx｜专业：机械工程｜课程：机械设计
单片机原理（英文要点·大三大四）
核心内容
Basic concepts:
In this course, i mainly learned the structure of single chip computer and some basic program of AT89S51.
Explanation of concepts:
Single chip computer is a microcomputer. It has CPS(central processing unit), RAM(random access memory 快取记忆体), ROM(read only memory 只读记忆体), parallel input/output interface(并联I/O接口), serial input/output interface(串联I/O接口), timer(计时器), counter(计数器), interrupt system(打断系统) and system bus(系统总线) on the semiconductor silicon wafer(硅片).
Characteristics of the single chip computer: it is small in size, have lower price, has convenient application and it is stable and reliable.
The single chip computer has wide application. It is used in many electronic products, robots and cars. It has automatic control function by the finished program which is stored in the chip.
Structure of single chip computer:
The Watch dog timer: it is a timer, when the SCM work normally, this timer will be reset after a constant certain time, when the program don’t work normally, it won’t be reset, and it will overflow, and make the program restart. Just like feed a dog.
Timer: to generate precision time pulse to delay or something else to start the period event and count the impulse signal.
In this course, i also learned a little assembly language, but just the very easy part, because we seldom use it.
Here is a simple program in assembly language:
Hexadecimal(16进制) binary system(2进制) decimal (10进制)
START： MOV A,#00H --- #:immediate data H: hexadecimal
MOV R1,#10 ---assign 0 to A and assign 10 to R1
MOV R2,#00000011B ---assign 03H to R2
LOOP： ADD A,R2 ---assign the sum of R2 and A to A
DJNZ R1,loop ---DJNZ: R1 minus 1 and don’t jump if
it is not 0, continue the loop, if
the R1 is 0, next step
NOP ---it means do nothing and go next,
just for holding time, and waiting
for the next order
HERE： SJMP HERE
grade operation code operation date
(标号) (操作码) (运行数据)
Above is a simple circulate program of the single chip computer. It can be used to delay.
参考：来源：大三大四专业课资料（英文.docx｜专业：机械工程｜课程：单片机原理
免疫学实验
核心内容
· 实验一：单向免疫扩散（Single Radial Immunodiffusion, SRID）
· 实验目的
· 了解单向免疫扩散的合成方法及基本原理
· 用于检测标本中抗原的含量（定量）
· 试剂与器材
· 诊断血清（抗体，免疫血清）
· 牛血清白蛋白（Bovine Serum Albumin, BSA）——标准抗原
· 三羟甲基氨基甲烷（Tris）、氨基甲烷、氯化钠、盐酸（1 mol/L HCl）——缓冲液体系
· 琼脂糖（Agarose）、载玻片、打孔器、微量加样器、恒温水浴箱、湿盒
· 实验步骤
· 制备琼脂糖板：将琼脂糖配制成 1.5% 浓度，加热溶解后冷却至 50℃
· 打孔：在琼脂糖板上打孔
· 加样：向孔中加入抗原标本（如 BSA，浓度示例 2.20 mg/mL）
· 反应与温育：抗原向含抗体的凝胶中扩散，形成沉淀环
· 关键原理
· 抗原在含定量抗体的琼脂糖凝胶中单向扩散，形成以孔为中心的沉淀环
· 沉淀环直径与抗原浓度成正比，可用于定量检测
· 实验二：ABO 血型鉴定（ABO Blood Group Typing）
· 实验目的
· 学习 ABO 血型鉴定的原理和方法
· 实验原理
· 血型即红细胞膜上特异抗原的类型
· ABO 血型系统：红细胞膜上含 A 和 B 两种抗原，根据是否含 A、B 抗原分为 A、B、AB、O 四型
· 分型血清：抗 A 分型血清（含抗 A 抗体）与红细胞上的 A 抗原结合；抗 B 分型血清（含抗 B 抗体）与红细胞上的 B 抗原结合
· 凝集反应（Agglutination）：颗粒性抗原（细菌、细胞等）与相应抗体（凝集素）结合，或可溶性抗原（凝集原）与相应抗体结合，产生肉眼可见的凝集小块
· 分型判定（正定型，即检测红细胞膜上是否含 A、B 抗原）
· O 型：无 A 抗原，无 B 抗原；血清中有 A 抗体、B 抗体
· A 型：有 A 抗原，无 B 抗原；血清中无 A 抗体，有 B 抗体
· B 型：无 A 抗原，有 B 抗原；血清中有 A 抗体，无 B 抗体
· AB 型：有 A 抗原，有 B 抗原；血清中无 A 抗体、无 B 抗体
· 实验器材和药品
· 镜架夹具、脸盆、生理盐水、试管、滴管、竹签、玻片、记号笔、一次性采血针、75% 酒精
· 实验步骤（玻片法）
· 取玻璃片一块，用干净纱布擦拭干净；在玻璃片两端用笔标记 A、B
· 用消毒采血针取血
· 用竹签两头分别混合，搅匀
· 静置
· 2 min 后肉眼观察，判断是否出现凝集颗粒或边缘凝集现象
· 判定血型：根据是否凝集判断血型
· 易考点与关键术语
· 凝集反应（Agglutination）：颗粒性抗原 + 抗体 → 肉眼可见凝集块
· 凝集原（Agglutinogen）：可溶性抗原
· 凝集素（Agglutinin）：相应抗体
· 正定型（Forward typing）：检测红细胞膜上 A、B 抗原
· 单向免疫扩散（SRID）：沉淀环直径与抗原浓度成正比，用于定量
· 琼脂糖浓度：1.5%；冷却温度：50℃
· 温育时间：2 min（ABO 玻片法观察时间）
参考：来源：免疫学实验.png｜专业：生物科学｜课程：免疫学实验
材料成型技术基础（英文要点·大三大四）
核心内容
Basic concepts:
In this course , i mainly learned about the metal structure and metal crystal, casting(铸造) ,metal plasticity(金属塑形成性) and joint forming.
Explanation of concepts:
The metal structure and metal crystal:
This part is introduced in《chemistry of engineering》in detail.
Casting:
Casting is pouring the melt metal into casting mould(铸模) and after cooling we can get the workpiece with certain shape, size and performance. It is a forming method.
Advantage of the casting: low cost, the shape and size of the casting workpiece
is not restricted.
Disadvantage of the casting: misrun(浇铸不满), contraction cavities(缩孔), pore(气孔), flaw of tissue looseness(组织松散), there may be some sinkhole(沉孔), the quality is unstable and the efficiency is low.
The higher the casting temperature is, the better the liquidity(流动性) is. And the liquid metal will fill the mould better.
The pressure is stronger, the liquid will fill the mould better.
Contraction cavity: in casting solidification process(铸造凝固过程), because fo the poor feed, the holes came into being. It often appears in the final solidification parts. When the metal solidification temperature range is wide, it is easy to appear contraction cavity.
The solution of the contraction cavity: we can make the solidification in a certain direction in the mould and add the pressure to feeding to reduce the shrinkage cavity.
Sometimes, there casting stress(铸造应力) in the casting. So we can design the casting structure reasonably or use stress relief annealing.
The air hole is for letting the air in the mould go out.
The pouring gate is the way that the melt metal go into the mould.
We have practiced the casting in the engineering training.
Cast riser(冒口): to prevent misrun and make the contraction cavities into the riser.
Investment moulding(熔模铸造)：using wax make the model like the workpiece, then use mud wrap up the model, then dry it , then the dry mould is baked into a ceramic mould(陶模), after baking, the wax model will disappear, only left the ceramic mould, then casting through the sprue gate we left.
Lost foam casting(消失模铸造):use the wax make the model, brush the fire proof dope on the model, then put it into dry sand, casting under the negative pressure, make the wax model gasify and the melt metal occupy the space of the model, then cool it down.
The metal plasticity:
The metal plasticity include forge(锻造) and stamping(冲压).
The advantage of the plasticity: high material utilization(高材料利用率), high production efficiency(高生产效率).
The principle of plastic forming is the relative sliding in lattice(晶格) between atoms due to the large shear stress.
Free forge: simpleness, be in common use, directly economic, make the billet(坯料) deformation directly. And it is suitable for the single-piece production and small-lot production. The commonly used basic working process of the free forge include:
Die forge: forge which is using the die. It has some advantages , such as high efficiency, high precision(精度). But it is high cost ,too. One of the upper die and the lower die is often fixed, and another one can move.
Stamping: make the sheet metal separation or form. Usually the thickness of the workpiece is less than 4mm.
The advantage of the stamping: easy and simple to handle, high productivity, high material utilization.
The stamping mainly includes three methods: blank(落料), punching(冲孔) and bend(折弯).
The difference between blank and punching: the blank needs the falling part, but the punching needs the remaining part.
Joint forming:
Joint forming is a type of connection of components. Such as welding, glue joint and mechanical connection.
Welding: use the heat energy of the pressure, use or not use the filling material(填充材料) to connect the parts.
Welding mainly includes:
Melt welding(熔焊): melting the metal to connect parts together;
Press welding(压焊): using pressure and temperature to connect the parts;
First using pressure to squeeze the weldments together and close, then the electrode will generate current and the current will go through the weldment, the resistance of the weldment is very big, and it will generate a great amount of heat to melt part of the weldments and joint them together.
Braze welding(钎焊): using the brazing filler metal fill the gaps, the metal has
lower melting point.
Braze welding includes two kinds of welding method, one is the soldering(软钎焊), usually the melting temperature of the alloy is lower than 450℃, the strength of the joint is low. And the other one is brazing(硬钎焊), the melting temperature of the alloy is higher than 450℃, the strength of the joint is high, usually higher than 200MPa. Using to connect the workpieces which bear large force or working in high temperature.
Because of the welding temperature of the brazing welding is not too high, so the joint usually smooth and the tissue and the performance change very little, the deformation of the workpiece is small. Usually used to some place high precision, micro size, complex structure, such as the vacuum vessel and hard allow tool.
Carbon dioxide protection welding: using the carbon dioxide as the protection gas. It is more safe , and can exhaust the air.
Glue joint: use glue to connect the workpieces. It has high production efficiency and low cost.
Mechanical connection: this part is introduced in 《principle of mechanical》
It is easy to repair.
参考：来源：大三大四专业课资料（英文.docx｜专业：机械工程｜课程：材料成型技术基础