四重

Carl Sagan has entertainingly described this phenomenon, musing about the destiny of bacteria that reproduce by dividing into two every 15 minutes. Says Sagan:"That means four doublings an hour, and 96 doublings a day. Although a bacterium weighs only about a trillionth of a gram, its descendants, after a day of wild asexual abandon, will collectively weigh as much as a mountain...in two days, more than thesun - and before very long, everything in the universe will be made of bacteria." Not to worry, says Sagan: Some obstacle always impedes this kind of exponential growth. The bugs run out of food, or they poison each other, or they are shy about reproducing in public.

Carl Sagan 曾经开玩笑地解释这种现象，假设有一种细菌每15分钟可以分裂一次，亦即代表每一小时复制四次，一天可复制96次，虽然单一个细菌其重量只有一兆分之一公克重，但是只要经过一天无止尽的无性生殖，其重量可能会比一座山还重，经过两天后，甚至会比太阳还重，要不了多久所有的宇宙都将由这种细菌所组成，不过 Sagan 又说，大家不必担心，上天一定会安排障碍来阻止其倍数成长，有可能他会耗尽食物，或是毒死自己，或是有可能羞于在大庭广众之下复制。

Carl Sagan has entertainingly described this phenomenon, musing about the destiny of bacteria that reproduce by dividing into two every 15 minutes. Says Sagan:"That means four doublings an hour, and 96 doublings a day. Although a bacterium weighs only about a trillionth of a gram, its descendants, after a day of wild asexual abandon, will collectively weigh as much as a mountain...in two days, more than the sun - and before very long, everything in the universe will be made of bacteria." Not to worry, says Sagan: Some obstacle always impedes this kind of exponential growth.

Carl Sagan 曾经开玩笑地解释这种现象，假设有一种细菌每 15 分钟可以分裂一次，亦即代表每一小时复制四次，一天可复制 96 次，虽然单一个细菌其重量只有一兆分之一公克重，但是只要经过一天无止尽的无性生殖，其重量可能会比一座山还重，经过两天后，甚至会比太阳还重，要不了多久所有的宇宙都将由这种细菌所组成，不过 Sagan 又说，大家不必担心，上天一定会安排障碍来阻止其倍数成长，有可能他会耗尽食物，或是毒死自己，或是有可能羞于在大庭广众之下复制。

The use of spherical coordinates triple integral calculation IV Application Multiple Integral Weight points at geometry, physics applications.

利用球面坐标计算三重积分第四单元重积分的应用重积分在几何、物理中应用。

There have been caught in Walden pickerel, one weighing seven pounds —— to say nothing of another which carried off a reel with great velocity, which the fisherman safely set down at eight pounds because he did not see him —— perch and pouts, some of each weighing over two pounds, shiners, chivins or roach, a very few breams, and a couple of eels, one weighing four pounds —— I am thus particular because the weight of a fish is commonly its only title to fame, and these are the only eels I have heard of here;——also, I have a faint recollection of a little fish some five inches long, with silvery sides and a greenish back, somewhat dace-like in its character, which I mention here chiefly to link my facts to fable.

在瓦尔登湖中，捉到过梭鱼，有一条重七磅，且不去说那另外的一条，用非常的速度把一卷钓丝拉走了，渔夫因为没有看到它，估计它稳稳当当有八磅的重量，此外，还捉到过鲈鱼，鳘鱼，有些重两磅，还有银鱼，鳊鱼（学名Leueiscus Pulchellus），极少量的鲤鱼，两条鳗鱼，有一条有四磅重，——我对于鱼的重量写得这样详细，因为它们的价值一般是根据重量来决定的，至于鳗鱼，除了这两条我就没有听说过另外的，——此外，我还隐约记得一条五英寸长的小鱼，两侧是银色的，背脊却呈青色，性质上近于鲦鱼，我提起这条鱼，主要是为了把事实和寓言连接起来。

The paper focuses on the tetraploidy black locust on Loess plaeatu of West Shanxi province, applys steady state promoter method and image processing technology to study the days transpiration water consumption in different weather ,different seasons and different site conditions,has primary analysis on the impact of environment on the transpiration and carries on the calculation to the tetraploidy locust tree by the single leaf water consumption to the single tree water consumption in CaiJiachuan watershed; Uses fast weighing method to measure and analyze the transpiration water consumption of five different herbs under the tetraploidy black locust forest (Capillary Wormwood,Vanilla,Agropyron Sristatum , Common Sowthistle and Medicago Sativa) in short time, in the same and different growcrop,and calculates the average transpiration water consumption per square metres ;the soil colome weighing method was used for determining diumal variation quantity of soil moisture evaporation, analyzing the dynamic variation and caculating the total quantity of soil evaporation water consumption from May to August ; then 5 kind of suppositions about the types of surface vegetation coverage are proposed in experimented site and the total evapotranspiration water consumption are calculated under 5 suppoitions ,aim at providing preliminary theoretic basis for ascertaining the transpiration water consumption of tetraploidy black locust forest,controling standing forest density and optimizing the forest grass deploy on loess plaeatu of west Shanxi province .

本文以两种不同立地条件下的四倍体刺槐林为研究对象，采用了气孔计法对蔡家川流域生长季内不同天气状况下(典型晴天、阴天和半阴天)四倍体刺槐日蒸腾耗水规律、不同季节(生长季初期、中期和末期)的蒸腾耗水规律、两种不同立地条件下四倍体刺槐蒸腾耗水比较以及影响四倍体刺槐蒸腾耗水的环境因子进行初步研究分析，并对四倍体刺槐由单叶耗水量向单株耗水量进行推算；采用经典快速连续称重法对四倍体刺槐林地生长的主要5种草本植物(白蒿、香青兰、冰草、苦苣和苜蓿)短时段内蒸腾耗水规律、不同生长季内蒸腾耗水规律、同一生长季不同种类草本植物蒸腾耗水量进行了比较分析，并且采用面积与重量比的方法推算出了单位面积四倍体刺槐林地几种主要草本植物平均蒸腾耗水量：采用土柱称重法测定了5月份～8月份土壤水分蒸发昼夜变化量、对试验期内土壤蒸发量动态变化作了分析、推算出了试验地5月份～8月份土壤蒸发耗水总量；对试验地地表植被覆盖类型提出了5种假设，推算出5种假设的情景下蒸散耗水总量，旨在为晋西黄土区四倍体刺槐林蒸腾耗水量的确定、林分密度调控以及林草优化配置等提供初步的理论依据。

Xinquan HuTwo new chiral backbones R-- and S--2-amino-2"-hydroxy-4,4",6,6"-tetra methyl-1,1"-biphenyl were synthesized via nitration, diazotation/iodination, Ulhnann coupling, selective reduction, diazotation/hydrolysis, hydrogenation and resolution from 2,4-dimethyl-aniline in seven steps.

以2，4-二甲基苯胺为起始原料，经过硝化反应、重氮化碘代反应、Ullmann缩合反应、选择性双硝基单还原反应、重氮化水解反应、催化氢化反应和拆分，首次合成了--2-氨基-2'-羟基-4，4'，6，6'-四甲基-1，1'-联苯和--2-氨基-2'-羟基-4，4'，6，6'-四甲基-1，1'-联苯两个对映体。

For example, digital load cell, digital weighing apparatus, dynamic railroad track scale (the study task of national planning committee), electronic scales adjustment device and so on. All those reflected the preeminent technical brainstorm ability of it.

进入2000年以后，四十四所在立足优势技术的基础上又紧跟技术发展潮流开发出了智能称重传感器，数字式衡器，动态轨道衡，称重校验装置等高新技术产品，体现了超强的技术攻关能力。

Has been the development of the tourist attractions are: Chuanzhen large water along the Yellow River Gorge Scenic Area, the Gorge reservoir area, Gap power plant, water of the Yellow River Chuanzhen rabbit island, water re-Chuan Zhen Ping horticultural field of agricultural tourism, cut-long four-shan, four North Long Ping agriculture Tourism, Silver Dragon's four resorts, the four-long Yellow River shipping terminals, four Dragon King Le Grand Courtyard farm tourism, silver high-tech industry park, such as the People's Square.

目前已经开发的旅游景点有：水川镇大峡沿黄风景旅游区，大峡库区、大峡电厂、水川镇黄河玉兔岛、水川镇重坪园艺场农业观光、四龙剪金山、四龙北坪农业观光，白银公司四龙度假村、四龙黄河航运码头、四龙王家大院农家乐旅游、白银高新技术产业园、人民广场等。

Centrifuging method was used to determine soil water characteristic curves of four undisturbed soils different in bulk density, and through the experiment, surfaces depicting quantitative relationship between mass water content, pressure head and bulk density in the four soil samples were obtained.

用离心机法测定了四种原状土壤不同容重下的土壤水分特征曲线实测点，从实验上获得了四种原状土壤的质量含水量、吸力和容重三者间定量关系曲面。

Firstly it takes for example the lack and loss of taking student as the main of education in such respects as seeking short-term success and quick profits and attending to trifles and neglecting essentials in siting Chinese teaching goal; paying too much attention to the basic knowlegde and skill and ignoring the humane intension; stressing teacher" s instruction to student"s participation; the long unimplemented position of student as main body in teaching relation.

本文对此从以下四个方面进行了论述：首先从当前中学语文教育的现状出发，列举了主体性教育缺失的四种现象，主要有在语文教育目标的定位上急功近利，舍本求末；在语文教学内容上重&双基&教学，忽视人文性内涵；在语文教学的方法上重教师讲授轻学生的主动参与；在师生关系上学生主体地位没有真正得到落实。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。