如图所示的实验,是我们在学习分子动理论时做过的一些实验:
图a:浓硫酸铜溶液与清水开始界面十分清晰,几天之后,两种液体混合均匀了;
图b:玻璃板的下表面接触水面,发现拉力大于玻璃板的重力;
图c:水和酒精充分混合后的总体积小于混合前水和酒精的总体积;
图d:将红墨水滴入水中,可以看到它在水中扩散开来;
图e:将两个底面干净、平整的铅块紧压在一起,两个铅块就会结合在一起,下面吊一个较重的物体也不会将它们拉开.
2013年7月12日,中国人民银行公布2013年前二季度金融统计数据报告。6月末,本外币贷款余额72.87万亿元,同比增长15.1%。人民币贷款余额68.08万亿元,同比增长14.2%,分别比上月末和上年末低0.3和0.8个百分点,增速放缓。居民储蓄存款增速减缓,主要是因为( )
①通胀预期导致居民储蓄意愿降低
②超低位存款利率使居民储蓄收益降低
③我国经济快速发展,居民收入不断增加
④投资方式多元化促成储蓄存款分流
人的性染色体存在于( )
The following is a selection of the 2017 summer programs offered at colleges and universities around the world.
Hong Kong Polytechnic University: Kowloon, Hong Kong
July 26-31
PolyU is offering a 5-dayprogram for Grade 10 or 11 students wishing to explore the field of engineering and understand various engineering disciplines.We are looking for 6-8 students from the same high school to join the program, along with 1-2 accompanying teachers.Students can enjoy a special program fee of $200 (all-inclusive).The said fee is ignored for teachers.
Program Contact Email: denquiry@polyu.edu.hk
Queen's University: Kingston, ON
August 13-18
The Summer Enrichment Experience at Queen's gives students the opportunity to learn beyond the school classroom with engaging and challenging courses, motivating them to explore and apply new knowledge.After the experience, students will return to school with renewed energy, and excitement for learning.
Program Contact Email: linda.lamoureux@queensu.ca
University of Missouri: Columbia, MO
July 13-28
The Career Exploration Summer Program is a 2-week program in which Explorers experience a taste of various 21st century career paths.The program includes professional site visits to Fortune 500 companies, nonprofit organizations, and U.S. Government Buildings.Social activities include free time at the on-campus Student Recreation Center, watching professional sports teams, and exploring new places during program field trips.
Program Contact Email: mucoemie@missouri.edu
虹吸雨水收集系统是在缺水地区利用一些技术手段将屋顶的大气降水进行回收、处理、再利用的一种良性系统。读虹吸雨水收集系统示意图(图5),回答下列各题。