THSCAN Large Container Stationary Inspection System in Service

The “Tongfang Weishi” (THSCAN) LargeContainer Stationary Inspection System was putinto operation at the customs of Ningbo andGuangzhou recently.Those are two cities on thecoastline of Zhejiang and Guangdong Provinces.　 Developed by the Tsinghua Tongfang Company,the system is especially designed to combatsmuggling activities at the customs.It can easilydetect materials in cargoes with X- ray radiation.2 1 sets of the container scanner system have beenput into service at customs in C…     

家园合力培养幼儿良好文明礼仪行为习惯

教师每天都要用文明的语言和幼儿打招呼,如“早上好”、“下午好”、“再见”,幼儿帮你做事后主动说：“谢谢!”幼儿不小心踩到自己的脚上后,马上说：“没关系。”等等。在教室、走廊等墙面上,布置一些礼貌交往的儿歌并配上相适应的图片,例如：早上见到老师时,互相说声“早”,晚上回家时互相说“再见”,有事求人说声“请”,得到别人帮助说“谢谢”等等。因此,在培养幼儿说话有礼貌时,教师要多多的给予幼儿鼓励和表扬。     

A robust photocatalyst for ^1O2-mediated oxidation of cyclopentadiene based on silica-supported platinum （Ⅱ）terpyridyl complex

The oxo-functionalization of hydrocarbons is themost important type of reaction in organic chemical productions. Among various oxidizing reagents, more andmore studies have focused on the employment of molecular oxygen as oxidizing species in order to realize innovative and economically advantageous process, and at thesame time, move toward a “sustainable chemistry”.     

I am not asleep

When a group of women got on the bus,every seat was already occupied(占据)．The conductor noticed a man who seemed to be asleep,and feared he might miss his stop,he nudged(用肘轻推)him and said,“Wake up,sir!”“I am not asleep．”the man answered．“Not asleep?But you have your eyes closed．”“I know．I just hate to look at ladies standing up beside me in a crowded car．”     

The analysis of the legislation on health and safety in Britain

Health and safety is an integral feature of work and employment relations. The consequences of ill-health and danger have an untold impact on workers,on their personal life,on those who enter employment settings,and on the provision of services and goods. In a variety of ways,people attempt to establish minimum standards of danger and hazard to deal with these consequences in their workplace. This essay will firstly review and assess the important issues in the development of the legislation on health and safety at work in Britain,and then analyze the recent situation on health and safety at work in Britain according to some statistics and examples. Finally,it will conclude that Business will benefit from good management of health and safety at work.     

Spatiotemporal characteristics of freezing and thawing of the active layer in the source areas of the Yellow River （SAYR）

Based on the analysis of data on temperatures and moisture of soils in the active layer at four different permafrost sites in the source areas of the Yellow River(SAYR)in 2010–2012,the freeze–thaw processes of soils in the active layer were compared and contrasted for understanding the spatiotemporal variations.At the four studied sites,the thickness and mean annual temperature of permafrost are different.The temperatures at the top of permafrost(TTOP),i.e.,the maximum depth(s)of seasonal frost and/or thaw penetration,are-1.9°C at the Chalaping site(CLP),-0.9°C at the site on the southern bank of the Zhaling Lake(ZLH),-0.4°C at the Maduo Town site(MDX),and 1.1°C at the site on the northern bank of the Eling Lake(ELH).Differences in the mean annual ground temperature of permafrost and TTOPs may be responsible for the differentiations in the freeze–thaw processes of soils in the active layer.With rising TTOPs,the ground thawing started earlier:CLP in early June,ZLH in late May,MDX in early May,and ELH in mid-April,while the freezing began later:CLP in early October,ZLH in early to midOctober,MDX in mid-October,and ELH in the mid-to late October.With increasing TTOPs,the freeze-up periods for permafrost sites were shortened:202 days at CLP,130 days at ZLH,100 days at MDX,and the period of complete thaw was 89 days at ELH.At the CLP and ZLH sites,the two-directional ground freezing(downwards from ground surfaces and upwards from the permafrost table)and thawing finished in the same year,but the ground freezing at the MDX continued to the end of the nextJanuary,with very slow freezing rates in the end.At the ELH site,ground freezing kept on until early May when thawing began on the surface,and upward and downward thawing became increasingly stable in late June to early July.At each site,with rising TTOPs,the downward freezing accelerated in comparison with the upward freezing,and with an increasing proportion of downward frozen depth,and with the larger ratios of freezing to thawing duration.In summary,the patterns of thawing and freezing processes in the active layer in the SAYR differ from those in other parts of the Qinghai–Tibet Plateau to a noticeable extent.     

游乐园

l、小魔术师拿着一个玩具小喇叭,用嘴吹出“嘟嘟”的声音。接着神秘地说:“用嘴吹喇叭你一点也不奇怪,但我今天要用我的神耳朵来吹喇叭我的耳朵可是非同一般的!”     

Situation and Development Prospect of Uranium Resources Exploration in China

History of uranium exploration and the general situation of identified uranium resources in China are introduced briefly in the paper, and the feature of uranium resources is summarized as “a large number of deposits, good ore processing properties and centralized occurrence” which should be considered as the advantages. In accordance with the fact that the exploration level of uranium resources is quite low in China, it is pointed out that exploration investment must be intensified from now on to identify more uranium concentrated bases which occurring of middle to large size uranium deposit in order to meet the demand of natural uranium from nuclear power sector. Besides, major scientific and technological achievements on uranium exploration during the past fifty years are elaborated in the paper. According to the exploration ability and uranium resources potential in China, it is believed that uranium exploration can realize the goal of “getting break through both at home and abroad” and meet the requirement of nuclear industry to uranium resources in China by carrying out the uranium resources exploration strategy of “rooted in domestic and opening up abroad”.     

Grain boundary segregation of minor arsenic and nitrogen at elevated temperatures in a microalloyed steel

Auger electron spectroscopy (AES) was used to investigate the grain boundary segregation of arsenic and nitrogen in a kind of microalloyed steel produced by a compact strip production (CSP) technology at 950 to 1100℃, which are similar to the hot working temperature of the steel on a CSP production line. It was discovered that arsenic segregated on grain boundaries when the steel was annealed at 950℃ for 2 h. When the annealing temperature increased to 1100℃, arsenic was also found to have segregated on grain boundaries in the early annealing stage, for instance, within the first 5 min annealing time. However, if the holding time of the steel at this temperature increased to 2 h, arsenic diffused away from grain boundaries into the matrix again. Nitrogen was not found to have segregated on grain boundaries when the steel was annealed at a relatively low temperature, such as 950℃. But when the annealing temperature increased to 1100℃, nitrogen was detected to have segregated at grain boundaries in the steel.     

Growth behavior of electroless copper on silicon substrate

The growth behavior containing deposit morphology, growth rate, activation energy, and growth mechanism of copper on silicon substrate, especially at the initial stage, in the electroless plating process was studied. Copper was deposited on the surface of the silicon substrate in an electloless plating bath containing formalin (CH₂O 37vol%) as a reducing agent at a pH value of 12.5 and a temperature of 50-75℃. The copper deposit was characterized using a field emission scanning electron microscope and transmission electron microscope. The results showed that after the activation process, nanoscale Pd particles were distributed evenly on the surface of the silicon; in the deposition process, copper first nucleated at locations not only near the Pd particles but also between the Pd particles; the growth rate of electroless Cu ranged from 0.517 nm/s at 50℃ to 1.929 nm/s at 75℃. The activation energy of electroless Cu on Si was 52.97 kJ/mol.     

Physiological Defense Mechanism of Ligularia intermedia Against UV—B Radiation on Dongling Mountain

Liguloria intermedia growing at different altitudes were used to investigate the mechanism of ultraviolet (UV)-resistance on physiological aspects in the field. The tests compared the absorbance of the UV-absorbing compound, the content of chlorophyll a, chlorophyll b, and carotenoids, and the activities of peroxidase (POX) and superoxide dismutase (SOD) in Ligularia intermedia growing at three different altitudes on Dongling Mountain in northern China. There were no significant differences between the plants growing at 1160m and 1820m. However, all of these factors increased dramatically at 2190m. The results indicate tha tthe UV-resistance of the plants mainly depends on the mechanism of filtering the radiation and preventing the reactive oxygen species (ROS) damage produced by UV-B.     

欧洲实验动物福利前景

The use and welfare of laboratory animals in research are major issues in modern society. Both widespread public concern on welfare of animals and continuously increasing demands on quality of both animals and of biomedical research make the issues urgent and complex. As a result the use of laboratory animals is experiencing turmoil of rapidly changing regulations both at European and at international level.     

An ERP study on shift of spatial attention resulting from number processing

Using the “stimulus-delay-target” experimental model, the brain mechanism of visual-spatial attention shift after number processing was conducted on 13 participants by using event-related potentials (ERP) technology. Results show that influence of the number processing on the spatial attention is indexed by the P3 component; parietal lobes at both sides may be the main neural substrate for number processing and spatial attention, and the numerical-spatial interaction mainly occurs in the response selection stage.     

An ERP study on shift of spatial attention resulting from number processing

Using the “stimulus-delay-target” experimental model, the brain mechanism of visual-spatial attention shift after number processing was conducted on 13 participants by using event-related potentials (ERP) technology. Results show that influence of the number processing on the spatial attention is indexed by the P3 component; parietal lobes at both sides may be the main neural substrate for number processing and spatial attention, and the numerical-spatial interaction mainly occurs in the response selection stage.     

Temperature dependence of niobium superconducting nanowire single-photon detectors in He-3 cryocooler

Performances of superconducting nanowire single-photon detectors （SNSPDs） based on low Tc mate- rials strongly depend on the operating temperatures. We have fabricated infrared-sensitive niobium SNSPDs based on doped niobium （Nb＊） films and measured them in He-3 cryocooler. The critical current approaches to the de-pair- ing current at 0.3 K. Therefore, with the decrease in tem- peratures, we have observed a monotonous increase of count rate at the wavelength of 1,521 nm and exponential decrease of dark count rate at all bias currents. The possible origin of dark counts for doped Nb devices is also discussed.     

Non-Fourier heat conduction study for steady states in metallic nanofilms

As a fundamental theory of heat transfer, Fourier’s law is valid for most traditional conditions. Research interest in non-Fourier heat conditions is mainly focused on heat wave phenomena in non-steady states. Recently, the thermomass theory posited that, for steady states, non-Fourier heat conduction behavior could also be observed under ultra-high heat flux conditions at low ambient temperatures. Significantly, this is due to thermomass inertia. We report on heat conduction in metallic nanofilms from large currents at low temperatures; heat fluxes of more than 1×1010 W m 2 were used. The measured average temperature of the nanofilm is larger than that based on Fourier’s law, with temperature differences increasing as heat flux increased and ambient temperature decreased. Experimental results for different film samples at different ambient temperatures reveal that non-Fourier behavior exists in metallic nanofilms in agreement with predictions from thermomass theory.     

Multi－proxy evidence for late Pleistocene－Holocene environmental change in arid Central Asia： An overview of the RACHAD 2001 symposium

This special issue of Chinese Science Bulletin arose from a symposium entitled “Abrupt Environmental Changes in Arid Asia——History and Mechanisms” (RACHAD 2001) held at Lanzhou University in October 2001. This international event was attended by over 70 scientists from Australia, China, Germany, India, Mongolia, Russia, the UK and the USA. More than fifty papers were given over a three-day period on all aspects of the mechanisms and history of environmental change in Asia’s drylands. Most of the papers presented in the symposium are the preliminary results of the INQUA working group called “Rapid Climatic Changes in the Central-Asia’s Drylands” (RACHAD).......     

全球招聘新闻

正博士后[美国]University of Texas at Austin University of Texas at Austin opens a full-time postdoctoral position in the Dr.Dawit Kidane Laboratory with the College of Pharmacy,Division of Pharmacology and Toxicology.Research in the laboratory focuses on DNA damage response and genomic     

Erosion-corrosion and its mitigation on the internal surface of the expansion segment of N80 steel tube

We investigated erosion-corrosion(E-C) and its mitigation on the internal surface of the expansion segment of N80 steel tube in a loop system using array electrode technique, weight-loss measurement, computational-fluid-dynamics simulation, and surface characterization techniques.The results show that high E-C rates can occur at locations where there is a high flow velocity and/or a strong impact from sand particles, which results in different E-C rates at various locations.Consequently, it can be expected that localized corrosion often occurs in such segments.The E-C rate at each location in the expansion segment can be significantly mitigated with an imidazoline derivative inhibitor, as the resulting inhibitor layer significantly impedes the electrochemical reaction rate.However, we found that this inhibitor layer could not effectively reduce the difference in the erosion rates at different locations on the internal surface of the expansion segment.This means that localized corrosion can still occur at the expansion segment despite the presence of the inhibitor.     

Expression of Smad2 and Smad4 in rhesus monkey endometrium during the menstrual cycle and early pregnancy

Expression of Smad2 and Smad4 mRNAs in the endometrium of rhesus monkey on Days 8, 20 and 28 of the normal menstrual cycle and on Days 12, 18 and 26 of early pregnancy was detected using in situ hybridization. The results showed that Smad2 and Smad4 mRNAs were mainly localized in luminal epithelium and glandular epithelium. The expression of Smad2 mRNA in glandular epithelium was sustained at moderate level on Days 8, 20 and 28 of the menstrual cycle, while the expression of Smad4 gradually increased with the menstrual cycle. Both Smad2 and Smad4 mRNAs in functionalis glandular epithelium were expressed at the highest levels on Day 12 of early pregnancy, while in basalis glandular epithelium the most abundant expression of both Smads occurred on Days 12 and 18 of pregnancy. On Day 26, both Smads mRNAs were expressed at the lowest levels either in functionalis or in basalis. The data suggest that the epithelium is the major compartment where TGF-βs/activins exert their biological effects via Smads, and that Smad4 may play a role in the maintenance of endometrial gland function during secreting period of the menstrual cycle. During lacunar stage of early pregnancy, Smad2 and Smad4 are implicated in the tissue remodeling of endometrial functionalis and basalis, and during early villous stage both Smads are functional primarily in basalis.