Why does shape memory alloy have memory ability?
It starts with its microstructure. When a metal is solid, its atoms are always arranged in a regular way, forming a lattice. Under different conditions, such as temperature, metal may have a different structure, in which case it is said to be in a different phase. The change from one phase to another is called a phase transition. The properties of a metal change during a phase transition. The temperature at which a metal transforms is called the transition temperature. The difference between a shape memory alloy and other metals is that the phase transformation process in a shape memory alloy is reversible under certain conditions.
Why do so many people like rimless glasses?
Rimless glasses are lighter because they have no frame and are made of memory titanium alloy, which greatly relieves the pressure on the bridge of the nose and eyes and makes them more comfortable to wear. And because there are no frames to tie them down, the wearer has a wider view. Rimless glasses style is more diverse and stylish. They are rich in color, so loved by young eyeglasses.
What Strength Reading Glasses Do I Need?
What strength reading glasses do I need? You can choose the reading glasses strengths by age or you can also perform a reading glasses test. If you are aging from 40 to 44, the +0.75 to +1.00 dioptre power is recommended. If you are aging from 45 to 49, the +1.00 to +1.50 dioptre is recommended. Age from 50-54, recommended power is +1.5 to +2.00 dioptre. Age from 55-59, recommended power is from +1.50 to +2.25 dioptre. Age from 61-65, recommended power is from +2.25 to +2.50 dioptre.
If you find two different strengths of reading glasses are available, choose the lower power because too strong strength can cause discomfort compared to weaker powered glasses and can even lead to nausea and dizziness.
So, if you need a pair of reading glasses, try Koalaeye Optical, which is an online glasses store. It provides all kinds of eyeglasses, sunglasses and frames. You can choose the satisfied one from here.
Choose high-quality lenses.
As resin lens technology becomes more and more mature now, resin lens has gradually become popular, so the use of resin lens is the trend. Now resin coated lenses are very popular now. There are anti-reflection films and hard films (anti-wear films) anti-UV films. Anti-reflection film can improve the transmittance of light, making people see more clearly, at the same time, because it can reduce the reflection, the lens is more beautiful in appearance. Hard coating films can effectively protect the lens surface from wear and tear and can resist the damage of hard objects, to prolong the life of the lens. UV-resistant films block the harmful ultraviolet rays of sunlight. For example, the UV400 lens is good for engineers who work outdoors for a long time.
The extraction of titanium
Nowadays, the commonly used extraction method is the reduction method of titanium tetrachloride. Compared to copper and zinc, although high in content, much more expensive. On the other hand, China is the country with the largest reserves of titanium, and a large number of steel mills with perennial overcapacity began to produce titanium, so the price of titanium fell year after year.
Distinguish true and false myopia firstly.
Children's eyesight is not good for many reasons, excluding organic reasons. Hyperopia, myopia, astigmatism, and other refractive error factors can cause. False myopia, called modulatory myopia on medicine, is caused as a result of eye ciliary muscle overregulation. False myopia is in ciliary muscle paralysis, and the degrees disappear after putting pupil to remove adjustment.
How to buy contact lenses online?
Choose well-known brands.Nowadays, the contact lens brands in the market are mixed, with the proliferation of inferior products, but there are still some authoritative and well-known ones, like Johnson & Johnson, Bausch & Lomb, which are products recognized by most users, and you can rest assured to buy them.