[middle -aged and elderly sports shoes] How do the elderly choose sports shoes

Elderly sneakers are particular about the choice of sports shoes

When testing the shoes, you should use your feet to the ground, adopt an upright posture, and use your thumb to move up and down. It should not be too large or too small. If you choose a high -top shoes, it is best to use squat posture to confirm whether to grind your toes after the shoe.The widest part of the shoes should be consistent with the widest part of the feet to ensure that the shoes are curved with the toe joints when the front foot is strong.

Try to penetrate both feet, and if there is a large and small situation, the larger feet should be prevailed.After trying on your feet, get up and walk around to determine if you are comfortable for your feet.

Try to penetrate the sports socks, reserve space on the front end of the toe, the length of the shoes is 2 to 3 cm longer than the feet. The reserved space of the toes and the toe can avoid the bruises and swelling of the feet.Dry.

The breathability of sneakers is very important, allowing the foot to breathe and breathable.

Pay attention to strong and stability at the heel.The heel of the jogging shoe should be wide and stable, and there should be lining tongue under the shoelaces, so as to protect the back and extended tendon.The soles should have a soft sandwich to absorb the impact effect.

sports shoes must have good non -slip properties.

Note that when Running and playing shoes, you can't wear the same shoes. For example, when Running and walking, you need to choose shoes with a certain degree of flexibility. When playing, you need to choose shoes with high shoe and a certain stability to prevent shoes to prevent a certain stability to prevent them from preventing it.Sprake on the ankle.When Running, you must wear thick -bottomed sneakers, which can reduce the vibration of the brain and reduce the occurrence of exercise damage.

When performing long -term exercise, it is best not to wear new shoes, let alone wear too hard or too slippery shoes to exercise, and it is easy to fall.

1. How much is skiing gloves?

The price of ski gloves varies from factors such as brands, materials, and functions.Generally speaking, the price of ordinary ski gloves ranges from tens of yuan to hundreds of yuan, while high -quality professional ski gloves are higher.Some well -known Ski glove brands, their products are usually ranging from hundreds of yuan to thousands of yuan.Of course, if you buy second -hand ski gloves or discounted promotions, the price may be lower.

In general, the price of ski gloves is not the only factor that determines its quality. Therefore, when purchasing, you need to comprehensively consider many factors, such as brand reputation, material, function, size and your own budget.

2. Where to buy ski gloves

ski gloves can be purchased on various channels, including physical stores, e -commerce platforms, and online brand official website.

1. physical store:In many large shopping malls and Outdoor shops, there are special Ski equipment areas, which contain ski gloves of various brands.Field trials can better choose gloves that are suitable for your own hands and needs.

2. E -commerce platform:E -commerce platforms such as Taobao, Jingdong, and Tmall have a large number of ski gloves.You can choose the right style and brand through screening conditions, and compare the evaluation and price of different products.

3. Online brand official website:Many Ski -equipment brands have their own official websites that can buy ski gloves directly on the official website.The official website usually has more styles and sizes to choose from, and has complete after -sales service.

No matter which kind of purchase channels are selected, you need to pay attention to checking the quality and function of the product, and read the product description carefully before use to ensure that ski gloves can meet your needs.

[Telescope parameters] Astronomical Telescope optical parameters explain in detail how to see the astronomical Telescope parameter

The caliber of the objective mirror (D)

The diameter of the objective mirror is the most important parameter of the Telescope. Generally, it refers to the effective diameter, that is, the diameter of the light, that is, the diameter of the incident pupil of the Telescope. It is the main symbol of the Telescope conservation, not the diameter of the glass of the lens.Generally, it is represented by an inch (in) or millimeter (mm). The larger the diameter, the more light it collects, and the better the brightness and sharpness of the imaging.

(Note: 1 in = 25.4 mm)

Cumping (Ji Guangli)

This is the ability to collect light compared with the eyes to collect light compared to the eyes.It is directly proportional to the area of the caliber.First, the caliber (unit: mm) of the Telescope is divided by 7mm (the size of the eyes of the young people's eyes), and then the obtained commercial Square is the result of the light.For example, the light power of the 8 -inch Telescope is 843 ((203.2/7) = 843).

Focus (F)

The distance from the lens (or main reflector) to the focus, usually the unit is millimeter (mm).Generally speaking, the longer the focal length of the Telescope, the larger the magnitude, the larger the size of the imaging, but the smaller the field of view.For example, compared with a Telescope with a focal length of 1000mm, the magnitude and field range of the 2000mm focal length Telescope are 2 times and 1/2 of the former, respectively.If you do nt know the focal length, you only know the Focal Ratio, you can get the focal length by calculating: the caliber (the unit is MM) by the coke ratio is the focal length.For example, a lens with a diameter of 8 inches (203.2mm) and a coking ratio is F/10, and its focal length is 203.2 x 10 = 2032mm.

Relators (A) and Jiao Bi (1/A)

The ratio of valid diameter D to the focal length F is called relative diameter or relative aperture A, that is, A = d/f.This is a sign of the light mirror light power, so sometimes A is light power.Comet, nebula or galaxy, etc. The imaging illuminance of the surface celestial body is proportional to the Square (A2) of the relative caliber; the so -called linear celestial imaging illumination and relative caliber D (D2/f) of the so -called linear celestial body imaging such as meteor or artificial satellite (D2/F)Propopy.Therefore, when making celestial photography, pay attention to choosing a suitable A or Coking 1/A (that is, F/D. The camera is called the number or coefficient of the aperture).

Distinguish

For the Telescope, it refers to Dawes Limit.That is, the ability to separate two stars with a very close distance, the unit is angle seconds 1 (sex of Arc).The resolution ability is directly related to the caliber, that is, the greater the diameter, the better the resolution ability.The theoretical resolution ability of the Telescope is 4.56 Apart from the diameter (unit: inches) of the Telescope.For example, the resolution ability of a Telescope with a diameter of 8 -inch is 0.6 (4.56/8 = 0.6).However, the discerning ability is also related to the atmosphere and the visual acuity of the observer.

Contrast

Observe low -contrast objects, such as the moon and the planet, we expect the highest imaging contrast.The Newton Telescope and reflection refraction Telescope have a secondary reflex mirror (or auxiliary mirror), which blocked the launch light of some main reflective mirrors.Unless more than 25% of the main reflectors are blocked, the contrast of imaging will not be greatly affected.In order to calculate the secondary blocking rate, the formula (Pi) R can be used to calculate the area of the primary and secondary reflex lenses.Then it can be eliminated.For example, if the diameter of the 8 -inch Telescope is 2 inches, the blocking rate is 11.8%:

8 -inch main area = (pi) r = (pi) 4 = 50.27

2 -inch secondary area = (pi) r = (pi) 1.375 = 5.94

The blocking rate = 5.94 is 11.8% of 50.27

Observation conditions (atmospheric disturbances) are the most important factor affecting the contrast and planet details.

Airy Disk Brilliance Factor

When you look at the stars with a good Telescope, you don't see a bigger image.This is because the distance from the stars to our distance is too far (so that the light emitted is parallel light, and it is directly gathered in the focus of the plane), so even if it is enlarged many times, the stars should look like light spots, not, not, notLight spots or light balls.However, if the Telescope mirror is enlarged to the multiple of the 60 -diameter size (unit: inch), if you look closely at this time, you will find that there is a halo around the stars.The physical characteristics of the lapse and light.For further observation, when the stars are located in the middle of the Telescope vision, two phenomena will appear in the magnifying star map: a bright area in the middle, called Eli spot, and a weak ring surrounded by or or a series of surrounds.Diffraction ring.

When you increase the size of the caliber, the Eli spot will become smaller.The brightness of Eli (the image brightness of the light source star) is proportional to the four squares of the diameter size.Theoretically, when you double the diameter of the Telescope, its resolution ability will double, and its collection of light will increase by 4 times.But more importantly, you can also turn the area of the Eliga into 1/4 times, thereby turning the brightness of the astrology into 16 times.

Out of light

The output of the Telescope refers to the diameter of the round beam of the eyepiece, and the unit is MM.In order to calculate the pupils, the caliber (unit MM) can be divided by the magnification of the eyepiece.For example, a magnification of a Telescope with a diameter of 8 inches (203.2mm) with a 20mm eyepiece mirror is 102, then its pupil is 2mm (203.2/102 = 2mm).Alternatively, you can also get the focal length of the eyepiece to get the pupil size with the coking of the Telescope.

Magnification

The amplification multiple is one of the most important parameters of the Telescope.The magnification of the Telescope is actually the ratio of the focal length of two independent optical systems -telescopic mirrors and the used eyepiece.

The focal length (unit: MM) of the Telescope mirror can be obtained by the zoom distance (unit: MM) of the eye mirror to get the magnitude of the Telescope.For example, the focal length of the Telescope with a model C8 is 2032mm. If you equipped with a 30mm eyepiece, the magnifying rate is 68X (2032/30 = 68)..Because the eyepiece is replaced, the Telescope can have different magnification as needed.

In actual use, the Telescope has an upper and lower limit amplification rate.This is determined by the characteristics of optical and eyes.In ideal, the maximum magnification available for the Telescope is about 60 times its diameter size (unit: inch).If the increase rate exceeds this upper limit, the image often becomes dim, and the contrast is reduced.For example, the maximum magnifying rate of a Telescope with a diameter of 60mm (that is, 2.4 -inch) is 142X.When the magnification continues to increase, the sharpness and details of the image will decrease.The higher magnification is usually used for the observation of the moon, planets and Gemini stars.Those manufacturers who call the 60mm caliber Telescope can reach 375 or even 750, which is actually misleading consumers.In the evening, the lower limit of the long mirror amplification rate is 3 to 4 times the caliber.The lower limit during the day is 8 to 10 times the caliber.If the amplifier rate is lower than this lower limit, due to the projection of the secondary reflex mirror or oblique mirror, a black spot will appear in the center of the reflection refraction Telescope or Newton Telescope.

Extreme stars, etc.

On the sunny night, use Telescope to observe the darkest star near the ceiling, etc., called the extreme star (MB). Extreme stars and other effective caliber, relative caliber, the absorption coefficient of the objective mirror, and the atmospheric absorption of the atmospheric mirrorThe system is related to various objective factors such as the brightness of the sky background, and it is also related to the visual sensitivity of the observer.The experience expression given by different authors is slightly different.The simpler estimate is MB = 6.9 5LGD. D is used in CM as a unit. For photographic observations, extreme stars, etc. are also related to dew time and negative characteristics.There is a commonly used experience formula: MB = 4 5LGD 2.15LGT type T is the limit exposure time, regardless of the negligent law of mutual failure, and does not consider the impact of urban lighting.The convenient method of testing the limited star of the Telescope is to use the standard star of the target star in the central government of the Star Group, or use the standard star of the Arctic Star (NPS) to estimate or calculate.

Diffraction limit (Ruili judgment)

Near the focus, the residual wave of the split Telescope is far less than 1/4 of the incident light wavelength.Such a Telescope is suitable for an astronomical Telescope.Near the focus of the combination optical system, the wave image difference of separate optical components must be less than 1/4.When the wave ahead of the wave is reduced (1/8 or 1/10 wavelength), the optical quality will be greatly improved.

Close focus

This refers to the nearest distance you can see clearly in the near -land observation task.

Field angle ()

The sky areas that can be used by the telescopic mirror directly in the eyes of the observer are called the field of view or field angle ().The viewing field of the Telescope is often determined during design.The refraction Telescope is restricted by the limitation of the image and is restricted to the viewing angle. The reflection Telescope or refractive Telescope is often influenced by the sub -mirror size and restricted the viewing angle.However, for celestial photography, the field may also be restrained by the size of the receiver.The viewing rate of the Telescope is inversely proportional. The larger the magnitude, the smaller the view.

When the value of the unknown field, you can measure it by itself.Met the stars near the Equatorial Eachi with a Telescope, adjust the instrument, and make the star statue pass in the center of the field.The instrument does not move (without turning instrument clock), record the time interval of the star through the field of view, set to T seconds, the redttire of the star body is , the viewing angle is = 15tcos

Optics

Ivability is all factors that cause imperfections.There are several aberrations in the Telescope design, without the so -called perfect optical system.Optical design engineers must be able to balance all kinds of aberrations to get the desired design results.Here are some different looking portraits in different Telescopes:

Polysis: It often appears on the objective mirror that reflects the Telescope because the lens cannot focus on the light of different wavelengths (color) to focus.As a result, there was a circle of halo around the bright objects.This phenomenon often worsen when the sensitivity and diameter increase.

Ball difference: Make light through different caliber angles through the lens (or transmitted from the mirror) cannot focus on the same point on the axis.It makes the image of the stars not look sharp, but a vague light spot.

Comet: It is mainly related to the parabolic reflection Telescope, which affects the imaging of the external axis, and it is often more obvious at the edge of the field of view.The image of the stars looks like a V -shaped pattern.For high -quality instruments, the smaller the Jiao Bi, the more obvious the comets on the edge will be, but there will be no comets in the center of the field of view.

Portrait: The aberration is stretched from the horizontal position to the vertical position on both sides to the vertical position at the best focus point.This is often caused by poor production or assembly errors.

Field song: It refers to the plane formed by the precise focus of light, but a curved surface.The center of the noodles may be sharp and accurate, but the edges are not focused or opposite.

1. Is there a shelf life?

There is a shelf life of the alarm. If a Positive umbrella is used normally, it can be used for 2-3 years.The sun umbrella is baptized in the sun every day. Over time, the materials will have a certain wear. Once the sunscreen coating is worn and damaged, the effect of sunscreen will be greatly reduced.If the rain is rained in the middle, the sunscreen coating of the Parasol will be aging faster.After 2-3 years, the Parasol can also be used as an umbrella.

2. How to maintain a sun umbrella

1. The main function of the Solar umbrella is to block the ultraviolet rays. The fabric of the Solar umbrella is very fine and contains small particles, so it is best not to use a brush to brush, just wipe it with water or wet towel.Dry the ventilation place, (it is best not to put it under the sun) and wait for drying, then gently remove the soil, then wash it with detergent, and then rinse with water and dry it.

Remember: Do not brush it hard with a brush, otherwise it is easy to break after drying!And don't let the umbrella stand stick to water, otherwise rust can not be used!

2. Prepare two fresh lemon and squeeze the juice.Then drip it on the rusty umbrella rack, wipe it gently, rub it a few more times until the rust is removed, and then wash it with soapy water.

Tips: This method is suitable for using a deep -colored Solar umbrella, because lemon juice will leave a faint yellow!

3. When using a Parasol, try not to use it when you sweat.If the Parasol is dipped in water, wipe it in time.It is best not to use a Parasol when it rains, because this will reduce its sunscreen effect!

Remember: Don't put it away immediately when you just use the Parasol. This will make the umbrella surface aging and crispy!

1. How to place the Flower stand

1. Porch partition

Modern families use soft partitions in the living room, restaurants, or porchs, but although soft partitions such as glass and bead curtains increase the indoor permeability, it will inevitably look monotonous.Therefore, the Flower stand was placed at the entrance at the porch to increase creativity and aesthetics.

2. Corner

Whether it is the corner of the door or in other corners of the living room, a retro -shaped iron Flower stand can be placed.

3. Under the wall wall

If the wall designed by the photo wall is blank, it is definitely the best choice to put a Flower stand.

4,Both sides of the TV Background wall

In addition to the above matching methods, the interior can also be placed on both sides of the TV Background wall. If the style of the Flower stand can be consistent with the TV background wallpaper wallpaper, the effect will be better.It is also possible to choose to place next to the sofa, but people often walk around the sofa, pay attention to safety.

Second, the living room Flower stand placed Feng Shui

1. Don't just right to the door

Try to avoid the appearance of the door when placing a Flower stand in the living room, otherwise it will easily lead to worse Feng Shui in the home, affecting the normal development of our normal life and fortune.

2. Don't place it at the aisle

When we are placing a Flower stand, we must also avoid placing the aisle, because there is a channel for the crowd, and if it is placed on the aisle, it is easy to scrape the flowers.

3. Do not have edges and corners in the Flower stand

When the Flower stand is placed in the living room, be careful not to have corners, because the living room is where there are many crowds. If the Flower stand with edges and corners is likely to scratch people and bring bloody disaster to the home.