What is the difference between 21 79 and 21 901

What version of the human education version is 30 yuan.

If it is the same brand of mountain bike, the same brand of transmission, 21-speed and 24-speed without considering other configurations, the main differences are as follows:

The first is whether the shifting is flexible. You may not feel it on a normal road, but you can feel it when you step on an uphill road.

Second, there is a difference between the 21-speed and the 24-speed finger pluck and model. The more advanced the better, and the more reasonable the design.

In ordinary use, especially on urban roads, both transmissions are about the same, nothing is noticeable. If you're on a mountain trail and have a lot of uphill climbs, the 24-speed transmission has a clear advantage.

The 21-speed is 3*7, the 24-speed is 3*8, and the transmission option is larger. Theoretically, 24 to 21 is faster at the same cadence. But in fact, the high gear ratio pedal is very heavy, and the cadence will naturally decrease, and the cadence will decrease, and the speed will naturally decrease, and the theoretical speed cannot be reached.

Parameters: 21 speed chainring 48 38 28 flywheel 14 2824 speed chainring 42 32 22 flywheel 11 30 (11 32) The number of chainrings divided by the number of flywheels is the transmission ratio.

21-speed maximum gear ratio, minimum gear ratio 1

24-speed maximum gear ratio, minimum gear ratio.

The 24-speed has a larger or smaller gear ratio than the 21-speed, which can make you run more and run with less effort. Because the 24 chainring is not the same as the 21, a smaller chainring can get a lighter gear ratio, which is a great advantage when climbing.

Force. The 24-speed car can achieve the gear ratio even when using the 2*1 gear ratio, and if the flywheel is 11 32 car, it can reach the gear ratio of 1, (the minimum gear ratio of the 21-speed is 1). Therefore, the advantage of the 24-speed car over the 21-speed car is not only in the fastest gear, but more in the slowest gear, and it is easier and more powerful to walk on mountain roads.

Mountain bike speed gear ratio, let's talk about the personal understanding of the difference between 21 speed, 24 speed, 27 speed, please advise: first look at the parameters 21 speed chainring 48-38-28 flywheel 14 2824 speed chainring 42-32-22 flywheel.

Of course there is a difference, just like a car, there are five speeds in forward gears, and there are six speeds. The 21-speed cassette ranges from 14 to 34 teeth and tends to be slower rides such as hill climbing. The 24-speed and 27-speed wheels range from 11 to 32t or 34t, and the 27-speed has an extra gear level compared to the 24-speed, resulting in more refined and precise shifting.

Long distance riding doesn't require too much speed, so 21 speed is fine, but if you have more silver, you can still use a higher flywheel.

The 18-speed is 3*6, and the 18-speed acceleration is relatively fast, but due to the lack of rear flight, the speed change is not delicate. The 24-speed is 3*8, and the speed is not as good as the 18-speed, but the speed is delicate. Moreover, the 3*8 gear can accelerate downhill, and in the same way, the last gear (3*9) of the 27-speed is generally used for downhill.

Hanging a block to start on flat ground is not good for the knee and is easy to injure.

Of course, there are, it's more precise, and this is a change in speed.

It's not the same, it's better to go or not.

Theoretically, as long as the gear ratio and cadence are the same, the speed is the same, so there is no difference between the top speed of the 8-speed and the 9-speed. But in reality the 9-speed is definitely faster than the 8-speed because they are very different.

Suppose that two other cars with the exact same configuration, one with DEORE transmission and one with XTR transmission, let the same rider ride the same way on a stretch of road, will the speed be the same? There's no doubt that the XTR is faster, although both the Deore and XTR are 9-speed.

What I want to say is that there are differences in workmanship, material and weight between different levels of accessories, and the differences in several details add up to a clear difference in overall performance, so don't just look at the number of teeth, after all, the 8-speed transmission is only entertainment-grade.

1. The calculation method of grade point is different, and the common calculation method of most colleges and universities in China is: grade point = score 10-5, credit grade point = credit * grade point = credit * (score 10-5) (more than 90 points are calculated as 90 points).

2. The main directions of the two are different:

The main direction of the grade point system is the implementation of the grade point system, which is one of the important supporting measures for the implementation of the credit system and a method of evaluating academic performance.

The focus of credit grade points is the credit system, which is to use credits and grade points as the unit of calculation to measure the quantity and quality of students' learning, and to obtain a certain number of credits and average grade points as the standard for graduation and obtaining degrees, and to implement a variety of educational specifications and a more flexible teaching management system. Calculating GPA is calculating the average number of grade points for credits.

Passing the exam determines whether you can get credits, and the grade point depends on your test score.

If you fail the exam, then you will not be able to earn credit for the course and your GPA will be recorded as 0, which will be detrimental to your overall grade point! So how did you come up with your GPA? To illustrate to you with a simple example-

English score: 75 points, GPA, 10 credits; Ideology and politics 90 points GPA 4 credits 2, assuming a total of two courses, then the final grade point should be (, the average score can be as high as a score.

Please note here that the level of "GPA" is related to your future scholarship evaluation, joining the party, research insurance, studying abroad, etc., so please try to maintain a high GPA, which is very helpful to you. In addition, if you do not plan to do these things in the future, then please at least ensure that the "GPA" is not lower, otherwise you will lose the right to apply for a bachelor's degree (that is, after graduation, you only have a graduation certificate, no degree certificate).

Regarding "credits", please check the "teaching plan" issued by the teacher at the time of admission, which is very detailed for the course arrangement of each major you are studying, and will also clearly list the corresponding credits of each course; In school, as long as you pass the exam, you can get all the "credits" of this course, so you can only graduate if you complete all the credits, otherwise the school will give you a certificate of completion, not a graduation certificate! Therefore, if you want to graduate successfully, you must not fail the course; If you accidentally hang up, then you must pass the make-up exam.

The difference between MD786CHA and MD792CHA is that the color is different;

The MD786CH A is the gray version of the iPad Air.

The MD792CH A is the Silver version of the iPad Air.

The biggest change to the iPad Air is its overall design, which is more biased towards the iPad mini, making the iPad Air incredibly thin and lightweight. Thanks to the unibody design of the aluminum, the body is only millimeters thin.

Hello,The MD786CH A is the 32GB WiFi version of the iPad Air.

MD792CHA is the 32GB WiFi+3G version of iPad Air, which can be plugged into a 3G** card for Internet access.

Trisomy 18 and trisomy 21 are both genetic disorders, both of which have an extra chromosome.

e69da5e6ba9062616964757a686964616f31333431373266, general developmental retardation, abnormal delay in growth rate, intellectual disability.

The difference is: the number of chromosomes is not the same.

Trisomy 18 is an extra set of 18 chromosomes in the body.

Trisomy 21 is an extra chromosome of the body's 21 chromosomes.

Second, the name of the disease is different.

Trisomy 18 is also known as Edwards syndrome.

Trisomy 21 is congenital stupidity or protruding tongue-like dementia.

3. There is a difference in appearance characteristics.

Trisomy 18: posterior skull protrusion, small cranial deformity, droopy and deformed ears, abnormal microjaw deformity, small oral cavity, cleft lip, cleft jaw, nasal tip facing up, wrinkles (cracks) of the eyelids, wide space between the eyes, ptosis of the upper eyelids, overlapping and twisted fingers, hypoplasia (or complete disappearance) of the thumb, hypoplasia of the nails, webbing between the second and third toes, and inward curvature of the feet.

Trisomy 21: round face, flat head, small eye cleft, lateral slanting, protrusion, medial canthal fold, flat nasal bridge, wide eye distance, small mouth, protruding tongue, folded upper edge of both ears. Short stature, loose ligaments in the joints of the limbs, and excessive flexion of the joints.

The face is round and flattened (see figure), the eyes are small, the outer slanted is slanted, the eyeball protrusion, the medial canthal fold, the bridge of the nose is flattened, the distance between the eyes is wide, the mouth is small, the tongue is protruding, and the upper edge of the pinna is folded. Short stature, loose ligaments in the joints of the limbs, joints can be excessively bent, about one-third of the children have other deformities such as congenital heart disease, due to low immune function, susceptible to infectious diseases, the incidence of leukemia is 10-30 times higher than that of normal children.

21 trisomy bai

The syndrome is DOWN syndrome DU (DS), also known as congenital stupidity, which is a disease caused by the aberrations of the chromosomal body structure.

The karyotype of the Hui person is A47, xx(xy), +21, that is, there is one more chromosome 21 than the normal person. The main thing is that he is born a fool, has a flat face, is stunted, and can only survive until 20-24 years old.

Trisomy 18 (Edwards syndrome) is the second most common chromosomal tribody sign after congenital stupidity. Generally, it is easy to die early, mental retardation, finger remnants and other symptoms.

These are the more common chromosomal abnormalities of the fetus, and there is no way to carry them out.

Down's screening is a detection method that measures the concentration of alpha-fetal protein and chorionic gonadotropin in maternal serum by sampling the serum of pregnant women, and calculates the risk factor of giving birth to a Down syndrome by combining the expected date of delivery, age, weight and gestational age of the pregnant woman at the time of blood collection.

Serum AFP and HGG can also screen for high-risk pregnant women with neural tube defects, sosomy 21, sosomy 18, and sosomy 13 syndrome.

What is the difference between body and trisomy 21?

My pregnancy test detected trisomy 18 with a score of 1:250 is high risk (reference value is 1:350), but I found that many pregnant women were tested.

To apply for the transfer of a motor vehicle to registration, the following documents need to be submitted: a motor vehicle driving license.

The driver's license is the "license certificate" for the driver to drive on the road: the person who is allowed to learn to drive a motor vehicle according to the law, after studying, mastering the knowledge of traffic laws and regulations and driving technology, and passing the examination of the management department, the legal certificate of permission to drive a certain type of motor vehicle is issued. That is, it is a legal credential for a driver who drives on the road;

The motor vehicle driving license is a legal document that allows a motor vehicle to drive on the road in China, and it is a legal certificate for a motor vehicle;

Both documents are required for the car to hit the road, and both are indispensable.

There are two differences between a driving license and a driver's license, and the differences are as follows:

The driver's license is a document that proves that the holder has driven the corresponding model, and the content on it has the driver's license number, valid as scheduled, and the type of quasi-driving.

The driving license is a valid document to prove the corresponding vehicle, which has the license plate number, the name of the owner, and the vehicle model. Engine chassis number, etc.

The driver's license is a document that indicates that there is a corresponding model of driving, and the driving license indicates the valid document of the vehicle. Driving licenses and license plates are a must for vehicles to be on the road.

To apply for motor vehicle transfer registration, the "Motor Vehicle Driving License" must be submitted

The difference between a motor vehicle driver's license and a motor vehicle driving license.

1) "Motor Vehicle Driver's License".

The "Motor Vehicle Driver's License" is a license required by motor vehicle drivers in accordance with the law, and the contents on it include name, gender, date of birth, nationality, address, identification number, date of initial license, and quasi-driving type code.

2) "Motor Vehicle Driving License".

The "Motor Vehicle Driving License" is a legal document that allows motor vehicles to drive on the road, which includes the license plate number, vehicle type, owner, address, nature of use, brand model, vehicle identification number, etc.

3) The "Motor Vehicle Driving License" is a document that proves that the holder has driven the corresponding model, and the "Motor Vehicle Driving License" is a valid document to prove the corresponding vehicle.

The above information is in**Regulations for the Implementation of the Road Traffic Safety Law of the People's Republic of China

What is the difference between a driving license and a driver's license?

The driver's license is a record, some information of the driver, and the driving license is a record of vehicle information, and the traffic police will generally ask you to show these two certificates, because the traffic police are indispensable to deal with some violations. Article 8 of the Road Traffic Safety Law The State implements a registration system for motor vehicles. Motor vehicles can only be driven on the road after being registered by the traffic management department of the public security organ.

If a motor vehicle that has not yet been registered needs to be temporarily on the road, it shall obtain a temporary license plate. Driving licenses and license plates are a must for vehicles to be on the road.