商用冷柜制冷系统换装环保冷媒及制冷循环特性分析

减少温室气体排放使得替代冷媒R134a也将受到管制或禁用。本文以R600a/R290混合比例各为50%的碳氢冷媒替代传统的R134a冷媒,重点讨论换装碳氢冷媒在商用冷柜制冷系统中的循环过程,并通过试验数据分析商用冷柜在使用R600a/R290碳氢冷媒后的性能。     

半封闭活塞式压缩机工质替代后的改进方向

采用R404A、R134a替代R22后,半封闭活塞式制冷压缩机润滑油采用POE油更适宜;压缩机的铝制活塞需要进行阳极氧化以提高耐磨性能和化学稳定性,同时相关密封材料需要进行材质替代;压缩机本体电机的清洁度和系统对水分及其残留物的要求都比R22制冷剂有所提高,R134a、R404A系统水分和杂质的控制是一重要指标,对于制造工艺提出了更严格的要求。     

离心式冷水机组长时间停机后跑油分析

分析了某款使用R134a冷媒和POE合成冷冻润滑油的离心式冷水机组在长时间停机后产生失油现象的原因,作了理论分析和实验验证,并且从应用上提出了一些解决办法。     

New Insights into the Major Drug Target of H7N9 Human Infecting Inl uenza Virus

<正>Between February and March of 2013,the source of avian-origin H7N9 human infection was discovered in Shanghai and Anhui,China.Prior to this,H7N9 has only exhibited characteristics of a low pathogenic avian infl uenza virus,carried by chickens with no known cross-species transmission.By the end of August 2013,Chinese mainland reported a total of 134 confi rmed cases of H7N9 human infections across12 provinces and 42 cities,resulting in 45 deaths.In October and November,Zhejiang Province found three new cases and Guangdong found one case of human infection,suggesting the possibility of a comeback in the fall and winter seasons.Researchers led by Prof.GAO Fu(George Fu Gao)at the Institute of Microbiology,CAS and Beijing Institutes of Life Science,have made progress on understanding     

对待臭氧,莫要一概而论

正新闻事件:日前,全国首例因违法使用消耗臭氧层物质(ODS)构成环境污染罪并判处刑事处罚的案件在浙江省湖州市宣判。湖州市德清明禾保温材料有限公司法定代表人祁某某因违法使用三氯一氟甲烷(CFC-11,俗称氟利昂)生产组合聚醚,被地方法院以环境污染罪判处有期徒刑10个月。     

循环形式对工质热力循环性能影响的分析

在双级压缩中,5种工质表现出和单级压缩中相近的趋势,其中R600同样质量单位制热量较高。且与单级压缩相比较,5种工质的COP值都有所提高,其中R134a、R245ca、R245fa提高幅度较大,因此,中高温热泵使用这三种工质时,适宜采用双极压缩的型式。     

通过一个重要不等式的探索来培养学生能力

给出了不等式a12+a22≥2a1a2的拓展结论,并举例说明了它们的应用.     

CAS,BHP-Billiton to deepen cooperation

On 12 April, CAS and BHP-Billiton, a Melbourne-based company of diversified resources, held a special workshop on cooperation in Beijing. CAS Vice President LI     

冰箱用蒸发器换热性能和压降实验研究

为了评估不同工况下冰箱换热器的性能,以R134a为工质以开发的冰箱换热器性能测试系统为平台,研究不同工况下换热器的换热性能和压降。测试蒸发器为全铝翅片管式风冷蒸发器。实验研究的制冷剂质量流量范围为0.75～2.04g/s,蒸发压力为0.13～0.26Mpa,蒸发干度分别为0.2、0.3、0.4、0.5。实验表明干度和饱和压力对蒸发器的换热性能和压降有较大影响.     

空气源热泵机组液体融霜过冷方式研究

电动热泵系统是建筑物供暖、供热水的高效清洁技术装备,特别是气候寒冷地区的中心城市,使用电动热泵带来的节能减排效果尤其明显。本文以制冷剂R22和R134a为工质,将液体过冷对热泵制热性能的影响进行理论分析,结果表明:增加过冷度可以增加热泵的制热量同时提高制热COP。提出一种利用液体融霜过冷的空气源热泵系统,并对其正常制热和融霜过冷过程进行分析。     

S100A12's Application Value in the Assessment of Severe Acute Pancreatitis's Severity and the Evaluation of Curative Effect

S100A12 plays a key role in regulating the inflammation.It is mainly expressed in neutrophils.In early acute pancreatitis,neutrophils are activated and release a large number of cytokines and inflammatory medium—this is a central link of the systemic inflammatory response caused by severe acute pancreatitis.S100A12 could real-timely reflect the severity of acute pancreatitis and can be used for monitoring the development and prognosis of the disease.     

Quantum Communications

正Major AchievementsHallmark Advances during the Period of the 12~(th) National Five-Year Plan"It will confirm China’s ascent in the field,from a bit-player a little more than a decade ago to a global powerhouse:in 2016,ahead of Europe and North America,China plans to launch a satellite dedicated to quantum-science experiments,"commented science writer Zeeya Merali in a feature report published in December2012 in Nature,after introducing the ambitious plan of     

Structures of Human P2Y_(12) Receptor Key to Next Generation of Antithrombotic Drugs

<正>An international team led by scientists at the Shanghai Institute of Materia Medica(SIMM),CAS has characterized the detailed structure of a receptor that plays a key role in platelet activation and blood clotting.The work has implications for treatment of cardiovascular and other diseases.In a pair of papers published by the journal Nature on May 1st,the scientists provide a detailed map of P2Y12R,a human Gi protein-coupled receptor,in the antagonist and agonist bound states.The antithrombotic drug target has a market of several billion U.S.dollars."This new work will not only deepen the understanding of activation of this receptor super-family,but will also provide invaluable insight into the improvement and development of P2Y12 drugs targeting cardiovascular and other diseases,"said team leader ZHAO Qiang,professor at SIMM."I am particularly proud of the high quality international collaboration among China,USA,and     

日本千叶县发现高辐射土壤疑来自福岛“黑雨”

据英国广播公司报道,日本政府文部科学省周日（10月23日1在东京郊外的千叶县柏市调查一个被发现高辐射的地点。这个被检测出高辐射的空地距离地面30公分的土壤里,含有高浓度铯134和铯137元素,平均每公斤土壤含27．6万贝克勒尔（Bq）。铯134和137也是福岛核事故散发的主要辐射元素。     

Basic Research Objectives Reaffirmed

As a national institution for scientific research and a component of the national innovation system, CAS should and must make key contributions to the great national rejuvenation of the country. Keeping this in mind, CAS has developed four developmental targets for its basic research. This was revealed at a CAS conference on basic research held June 11-12 in Beijing.     

A stand-alone power system to integrate wind, wave and solar energy

On 12 October, 2007, an agreement on the construction of a stand-alone renewable energy (RE) system at the Dangan Island was inked between the CAS Guangzhou Institute of Energy Conversion (GIEC) and the Wanshan Exemplary Marine Development Zone in Zhuhai, a coastal city in south China's Guangdong Province.     

可微分的n元函数极值点判定

众所周知 :可微分函数 z=f( x,y)在 ( x0 ,y0 )处取得极值 ,则 ( x0 ,y0 )必是驻点 ,但驻点是否是极值点需用以下定理判定 :定理 :设函数 z=f( x,y)在点 P( x0 ,y0 )的某一邻域内具有一阶和二阶连续偏导数。又设 f′x( x0 ,y0 ) =0 ,f′y( x0 ,y0 ) =0 ,a11=f″xx( x0 ,y0 ) ,a12 =f″xy( x0 ,y0 ) ,a2 2 =f″yy( x0 ,y0 )。D=a11a2 2 - a12 2 ,则 :( i)若 D>0 ,则当 a11<0 (或 a2 2 <0时 ,函数 f( x、y)在点 P取得极大值 ,而当 a11>0 (或 a2 2 >0 )时 ,函数 f( x、y)在点 P取得极小值。( ii)若 D<0 ,则点 P不是 f( x,y)的极值点。( iii)…     

Microbial Carbon Sequestration in the Ocean: The Big Role of Small Bugs in Mitigating Global Climate Change——An Interview with Prof. JIAO Nianzhi

Ocean is the largest carbon reservoir on Earth. By taking up about one-third of all human carbon emissions, it has effectively reduced atmospheric carbon dioxide and eased global climate change. Scientists have studied extensively on the mechanisms of C02 absorption in the ocean, or the so-called ＂carbon pumps＂, from physical to chemical and biological pumps. Microbes, traditionally regarded as organic matter decomposers, had been long neglected until a few years ago Prof. JIAO Nianzhi from Xiamen University proposed the concept ＂microbial carbon pump （MCP）＂ illustrating that these tiny marine inhabitants are also producers of refractory dissolved organic carbon, a persistent form of matter which can be stored in the ocean for thousands of years and thus constitute an ideal carbon pool. Today, the MCP concept has been widely accepted as a promising sequestration strategy, and Prof. JIAO is working hand in hand with scientists from all over the world under the Scientific Committee on Oceanic Research （SCOR） Working Group 134 to better understand how to use these magic creatures for preserving carbon in the deep blue.     

CAS Scientist Awarded Tyler Prize for Environment Achievement

Prof. Liu Dongsheng (Tungsheng Liu), a CAS member and professor at CAS Institute of Geology and Geophysics, has been awarded the 2002 Tyler Prize for Environment Achievement. He shared a cash prize of $200,000 with the other laureate, Dr. Wallace S. Broecker from Columbia University, the US, and received a gold Tyler Prize medallion on April 12.     

Strive to Be a Powerhouse in China＇s S＆T Development——2010 Annual Meeting of CAS in Beijing

The 2010 annual conference of CAS opened on January 25 in Beijing. The three-day meeting reviewed the work of CAS over the past year and made arrangements for its tasks in the year ahead, with a focus on planning for the 12th fiveyear period （2011-2015） and the initiation of Innovation 2020 on a trial basis.