Pollution inside homes and other buildings kills more than 4 million people each year．Many people die as a result of breathing smoke or from cooking over wood﹣powered of coal﹣powered stoves．

    One way to reduce the number of deaths is through cooking equipment powered by the sun．Crosby Menzies，a solar power expert in a South African company，described his latest solar cooker called the“Sol.4”，”It is four square meters of mirrors，six to eight meters in length．It is quite a large cooler．”

    The“Sol.4”works by reflecting （反射）light from the sun off large mirrors．The mirrors direct （把…对准）the light at a cooking pan．Then the light heats the pan with solar energy．Within two minutes，the pan is hot enough to cook sausages and onions．In just four minutes，water can be boiled．That is as fast as cooking with natural gas or electricity．

    The cooker is also much“friendlier”than other models because people do not have to stand in the sun to use it．And people can prepare meals without having to collect firewood or spend money on coal．Suchindividualswould be less likely to have breathing illnesses from harmful smoke．

    At present，the cooker only works when the sun is shining．But engineers are working on a way to make it work without sunlight．

    Each cooker costs about $2000，which is a large amount of money for most Africans．To solve that problem，Crosby Menzies has crated a non﹣governmental organization called solar Cookers for Africa．It plans to raise money through donations to provide poor people with solar cooking equipment．

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    On a very hot day，it can be hard to know what to do to feel good．If we run around，we may feel dizzy and sick to our stomachs．This is because our body can't get rid of the extra heat．However，if we just sit and do nothing，we may feel restless and bored．Are there things we can do to feel good when we are hot? Yes! Playing in water is one way to feel cooler．Of course，people with a pool，river，lake or ocean nearby can play in the water very conveniently．People don't have these can still play in water too．Taking a cool bath or shower can feel good on a hot day．On hot days，you can lose two gallons(加仑)of water in one day，so many doctors agree that you should try to drink at least 16 glasses of water to keep the water balance in your body． Mixing a little juice into your water is a good way to help you drink plenty of water．The food we eat also makes a difference in how we feel in the heat．Cold foods，such as ice cream and drinks with some ice can cool down our bodies．Fruits and vegetables are easy for the body and refreshing．Plan a healthy menu for a hot day．

    How much sleep do we need? We are all different. Some people need only three hours of sleep a night. Others need ten hours of sleep a night. Most Americans sleep an average(平均) of seven to eight hours a night. After the age of fifty, the average sleeping time goes down to 6.5 hours a night.

    Most people have a bad night when they cannot fall asleep(睡着). The name of this problem is called insomnia.

    This isn't a new problem .Many famous people in history had insomnia .Some of these people had special ideas to make them sleep .Benjamin Franklin, the famous inventor had four beds. He moved from one to another to fall asleep .King Louis XIV(国王路易十四)of France had four hundred and thirteen beds and hoped to fall asleep in one of them .Mark Twain, the famous American writer, had a different way. He lay on his side across the end of his bed.

    April 22 is Earth Day. Everyone on Earth should care about and protect the earth!

    The earth has warmed by about 1°F (华氏度) over the past 100 years, but why and how? Well, scientists are not quite sure. Maybe the earth gets warmer and warmer on its own. But many scientists say that people are doing many things which makes the earth warmer. First, greenhouse effect (温室效应) is a very important reason for the change of the earth. People give out too much energy into the air every year. It makes the earth warmer. Climate (气候) change is another important reason. Sometimes it becomes too hot and sometimes too cold. Sometimes there is too much rain and sometimes too little. The change of the climate makes the earth warmer. In turn, the warmth of the earth changes the climate, too.

    When the earth becomes warmer, there may be more rain and a rise in sea level. It will affect the growth of plants, animals and people. On a Pacific island, 100 people have to move to higher ground because the sea is rising. These people can no longer live on the coast. Before that, two islands without people went underwater in 1999. Scientists say that the seas can rise by nearly one meter by 2100.

    People can affect the earth's air, land and water. As for us, we can do many things to protect the earth. For example, we can use fridges less. We can tell more people about protecting the earth.

    Virtual (虚拟的)reality is a way to create a computer-made environment that brings the user into a virtual world. If you ever have put on a VR headset, you would know exactly what I am talking about. From an experiential view we do understand the idea, but what about the technical backend that goes into making it all possible? In this blog, we will understand the technology behind virtual reality and the basic terms about the development of a virtual ecosystem for a VR headset.

    The primary subject of virtual reality is simulating (模拟)the vision. Every headset is to perfect their method to create an immersive (浸人式)3D environment. Each VR headset puts up a screen or two in front of eyes, keeping the user away from any interaction with the real world. Two autofocus lenses (自动对焦镜片)are generally placed between the screen and the eyes that change based on eye movement and positioning. The vision appears on the screen either by using a mobile phone or HDMI line connected to a PC.

    To create a truly immersive virtual reality, there are certain requirements a frame rate (帧 率)of at least 60 fps, a refresh rate and at least 100﹣degree field of view (though 180 degrees is perfect). If either of these doesn't work according to the standards, the user will experience too big of a time difference between their actions and the response from the screen. We need the response to be less than 20 ms (1/1000 second) to fool the brain which is achieved by joining all the above in the right proportion (比例).Another matter that needs to be looked at here is to prevent netsickness because of the differences between the frame rate and refresh rate.

    Apart from the image, there are certain other things that go into creating an immersive VR experience, holding the user's attention completely in the virtual environment. For example, sound effects, when put with the image, can create very attractive effects. By using a headphone and 3D sound effects, the user can totally believe in the virtual environment. While perfecting sound effects, proper care needs to be taken about the consistency (一致)between the pictures and the sound. If you start playing frightening music in the background of a happy scene, it will just put the user off.

    In future, we will see rapid progress in creating a truly immersive digital experience. With leading players like Google, Microsoft, Oculus, and HTC making great efforts to improve the capabilities (性能),we are not far from achieving a virtual reality that would feel so much better than the real world. If you would like to develop a VR app for your business, then feel free to get in touch. With over 10 years of experience in mobile technologies, we can make every dream a reality.