气体流量单位换算

我是做LED灯饰方面的.我需要了解哪方面的知识呢 LED照明基础知识LED照明：1.“LED的寿命都是100,000小时”是实验室数据吗?灯具的寿命应以灯具所有部件中寿命最短的部件为限?那么中高档的LED灯具的使用寿命基本上是多少小时?2.LED是冷光,3.LE 得心应手成语接龙 啊神翻译是什么 Questions 26 to 30 are based on the following passage.Some futurologists have assumed that the vast upsurge(剧增)of women in the workforce may portend a rejection of marriage.Many women,according to this hypothesis,would rather work than marry.The 英语阅读题目～急T T 英语阅读理解急John,David and James were three brothers.Every year on their mother's birthday,they sent her expensive presents.They liked to show her how rich they were.The oldest brother,John,decided to give his mother a perfect (完美) prese 假如从地球表面向下挖,挖到美国人是头先出来还是脚先出来.（我说的是假如）求大神帮助 圆的面积和长方形的面积相等如果长方形的长6.28cm,求圆的面积,是多少平方厘米? 英语翻译UNIT GOALS-\x09Use must,have to,and have got to to show something is necessary-\x09Use must not an cannot to show something is prohibited-\x09Choose between have to and have got to-\x09Use do not have to to show something is not necessary 天气寒冷,下起大雪对外放热吗? he tried in vain to comfort her.I could see worry etched on his face as well...he tried in vain to comforther.I could see worry etched on his face as well,a deep brotherly concern forhis now missing friend. 一篇英语阅读分析.选T.F的Mr.King lives in a city.He has some shops and so he makes a lot of money.His son,Mike,studies in a middle school.The boy likes everything but he does not like studying.He doesn’t listen to his teachers in class and 英语翻译只知道是圣经的句子, tried to face any danger.什么意思? 什么叫剧烈反应?剧烈反应一定会放热吗? 为什么大天朝的死亡人数不会超过三十五人 在推导圆的面积公式时,将圆等分成若干（偶数）份,拼成一个近似的长方形,已知长方形的长是6.28cm,圆的面积是多少? 在推倒圆的面积公式时,将圆等分成若干份,拼成一个近似的长方形.已知长方形的长是6.28厘米,圆的面积是多少 一列火车从甲地到乙地,若提高速度百分之20,则所用的时间减少百分率约是多少?（精确到千分位） 求英语演讲稿一篇(高一)大约一分钟就可以 ,讲叙中西文化理解 ,以茶与咖啡作为媒介 沿着这条弯曲的小路走,能到李红家.改疑问句 英语翻译非常感谢您对我公司的信任、现将贵公司的需求报价如下,以供参考!※以上材料提供材质质量保证书；确切订购数量、重量、价格、约定项目均已签约合同条款为准!※ 以上价格为美 英语翻译尽量的精简标准哦~“据统计2090年,最后一直浣熊死于皮草猎人之手 人们为了纪念这种因奢华皮草时尚儿牺牲的动物特制了大小1：1,并且用钮扣作为眼睛的浣熊标本,告诫世人--皮草时 用一根4米的绳子围一颗树的树干一圈,余下0.86米.这棵树树干直径有多少米?急用! my sister seems to have lots of stress的同义句八个空的 最好是有关于经济的~时间3分钟左右 关于高一政治的自由演讲,大家帮我确定下选题说是有关政治学、经济学、哲学的都可以，但是要尽量贴近生活的~ 如图,用与竖直方向成30度角的力F将重为10N的物体推靠在光滑的竖直墙上,求当物体沿着墙匀速滑动时,推力F 讲理想的就好了27号之前才要哦要做成ppt的模式啊有的可以发到awasdf123456@foxmail.com 沿着这条小路,能到金明家 改为设问句怎么改 请问解析信号的瞬时频率与实信号的瞬时频率的关系?我的QQ号：369737942