不同应变率加载下硅的高压相变行为

高压相变是凝聚态物理、地球与行星科学、材料科学等领域关注的核心问题之一,而加载应变率是相变动力学过程的重要影响因素。由于动态加载下物质相结构原位诊断技术的不足以及宽广加载应变率下物质高压相变系统实验研究的缺失,难以开展基于原子尺度物理机制的相变动力学过程建模和数值模拟研究。由于硅的高压相极其丰富,且拥有大量亚稳相,动力学因素在其高压相变过程中发挥着至关重要的作用,因此,硅是研究高压相变动力学的理想材料,对普适相变动力学过程的理论建模具有重要意义。以硅为例,介绍其在准静态、中等应变率和高应变率加载下的相变行为,探讨加载应变率对其高压相变行为的影响。

3D modeling for effect of tool eccentricity on coupled thermal and material flow characteristics during friction stir welding

A novel three-dimensional numerical model is proposed to investigate the effect of tool eccentricity on the coupled thermal and material flow characteristics in friction stir welding(FSW) process.An asymmetrical boundary condition at the tool-workpiece interface,and the dynamic mesh technique are both employed for the consideration of the tool eccentricity during tool rotating.It is found that tool eccentricity induces the periodical variation of the heat densities both at the tool-workpiece interface and inside the shear layer,but the fluctuation amplitudes of the heat density variations are limited.However,it is demonstrated that tool eccentricity results in significant variation of the material flow behavior in one tool rotating period.Moreover,the material velocity variation at the retreating side is particularly important for the formation of the periodic characteristics in FSW.The modeling result is found to be in good agreement with the experimental one.

Observations on breeding behavior of the White-eared Night Heron(Gorsachius magnificus) in northern Guangdong, China

The White-eared Night Heron (Gorsachius magnificus) is a Class II protected species in China. It is difficult to observe in the field and its population is small. The present study reports a new distribution site in Nanxiong County, in northern Guangdong Province, where observations of an active nest were made from 4 May to 14 July 2012, the first time consecutive observations have been made for a period of more than two months. The adults flew away from the nest at night, with a peak at 19:00-20:00 and returned in the mornings with a peak at 04:30-05:30. The peak time for feeding young was at 05:00-05:30, accounting for 26.5%of total feeding activities. No feeding occurred from 10:00 to 16:00. The results of our study of its behavior explain why the White-eared Night Heron is usually observed in the evening just before dark, or in the morning before sunrise, at least during the breeding season. There were about 67 days from hatching to fledging, longer than the fledging time of most heron species. This study is the first to cover the entire period of parental care and fills a gap in previous knowledge.

期行

亲爱的读者朋友,经过近半年来广大新课程实验教师与我们的共同努力,2003年“新课程优秀教学设计与课例研究专辑”(初中部分)终于和大家见面了。本专辑共分三个部分:第一部分是北京教育科学研究院原副院长文教授撰写的《关于教学设计的若干思考》。文章强调了:当前,我们应该对教学设计有一个新的、全面的认识,教学设计其实是一种教学构想,是以问题为核心的。它在课堂教学中具有许多变数和不确定性,需要教师随时调整教学设计思路,采取应变策略应对新发生的各种问题,真正达到有效教学的目的。第二部分为“课例研究”,由一段引言和四个课例组成,涉及初中数学、化学和科学等学科。细读这些课例,能让我们初步感知:怎样进行课例研究?怎样基于真实情境进行“问题—解决”教学?教师该为学生的探究提供怎样的支持?教师如何引发和应对学生提出的问题?进而思考:什么样的探究是基于学科本质的、真正意义上的探究?怎样区别实质探究和形式探究?等等。第三部分为“教学设计”,由16篇文章组成,涉及初中语文、数学、科学、物理、化学、历史与社会、历史、地理、思想政治、艺术和综合实践活动等学科。这些教学设计是本刊在近几个月里从所征集的近千篇新课程优秀案例中遴选出来的,它从一定层面上反映了不少实验教师经过近两?

Row-action SAGE algorithm for PET image reconstruction

The one-block version of ordered subsets (OS) techniques was used to accelerate the convergent rate of the space-alternating generalized expectation-maximization (SAGE) algorithm. The new row-action SAGE (RA-SAGE) algorithm processed projections in sequentially orthogonal order which reduced the dependency among the projections and speeds up the convergences. Additionally, the over-relaxation parameter in the direction defined by the RA-SAGE algorithm was also applied to obtain fast convergence to a globally maximum likelihood (ML) solution. In experiments, the RA-SAGE algorithm and the classical SAGE algorithm were compared in the application to positron emission tomography (PET) image reconstruction. Simulation results showed that RA-SAGE had better performance than SAGE in both convergence and image quality.

Travel time and alternative configurations analysis for automated storage/retrieval systems based on geometrical method

In order to evaluate the efficiency of the automated storage/retrieval system(AS/RS)accurately,and compare different layouts of the AS/RS using mean travel time,under randomized storage conditions,an exact,geometry-based analytical model is presented.The model can be used to compute the expected single-command and dual-command travel time for a storage/retrieval(S/R)machine which can travel simultaneously horizontally and vertically as it moves along a storage aisle.The rack may be either square in time or non square in time.Additionally,the alternative layouts of the AS/RS and travel-time models are examined.Comparing with setting the I/O point at the left-lower corner of the rack,setting the I/O point at any point at the vertical edge can help enhance the efficiency of the AS/RS.

Analysis of distance headway

By means of the relationship between speed and distance headway, this paperattempts to directly determine the road capacity based on a new concept. At first it makes acomprehensive analysis of distance headway, including safe distance headway and desired one. Theformer is decided by the demand for the degree of safety, and the latter depends on the motorists'behavior, i.e. the model of traffic flow. Both of them are functions of speed. According to thecharacteristics of their curves, we can find a crossing point that is the capacity of a roadsegment. This capacity represents the maximum flow rate meeting the minimum safety requirement.

Anti-periodic traveling wave solution to a forced two-dimensional generalized KdV-Burgers equation

The anti-periodic traveling wave solutions to a forced two-dimensional generalized KdV-Burgers equation are studied. Some theorems concerning the boundness, existence and uniqueness of the solution to this equation are proved.

Long term behavior of self-compacting reinforced concrete beams

Tests were carried out on 8 self-compacting reinforced concrete(SCC) beams and 4 normal reinforced concrete beams. The effects of mode of consolidation,load level,reinforcing ratio and structural type on long term behavior of SCC were investigated. Under the same environmental conditions,the shrinkage-time curve of self-compacting concrete beam is very similar to that of normal concrete beam. For both self-compacting reinforced concrete beams and normal reinforced concrete beams,the rate of shrinkage at early stages is higher,the shrinkage strain at 2 months is about 60% of the maximum value at one year. The shrinkage strain of self-compacting reinforced concrete beam after one year is about 450×10-6. Creep deflection of self-compacting reinforced concrete beam decreases as the tensile reinforcing ratio increases. The deflection creep coefficient of self-compacting reinforced concrete beam after one and a half year is about 1.6,which is very close to that of normal reinforced concrete beams cast with vibration. Extra cautions considering shrinkage and creep behavior are not needed for the use of SCC in engineering practices.

Laboratory Investigation of Disintegration Characteristics of Purple Mudstone under Different Hydrothermal Conditions

Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory conditions of typical purple mudstone from the Tuodian group of Jurassic red beds(J3t) in Tuodian Town,Shuangbai county,Yunnan Province of southern China.The fresh mudstone was subjected to alternating applications of water,heat and hydrothermal interaction during five treatments:wetting-drying(WD),saturation(ST),refrigeration-heating(RH),a combination of wetting-drying and refrigeration-heating(WDRH),and a combination of saturation and refrigeration-heating(STRH).Each treatment was run in twenty-four cycles.The results showed that there are three types of disintegration:collapsing disintegration,exfoliation disintegration and imperceptible disintegration.The cumulative disintegration rate(percentage of cumulative disintegrated mass to the initiative sample mass passed through a 2 mm sieve) produced a 'S'-shape function when related to treatment cycle time and closely fit a logistic model(R2 > 0.99).The rank order of the cumulative disintegration rate resulting from the five treatments was as the following:WDRH > STRH > ST > WD > RH.Because of alternating periods of moisture and dryness,WD caused the most disintegration,while RH alone resulted in imperceptible disintegration.Additionally,there was a negative correlation between the disintegration rate of each treatment cycle(percentage of disintegrated mass to the treated sample mass) and treatment cycle number.There was a positive correlation between this rate and temperature change under moist conditions,indicating that a change in temperature greatly accelerates the disintegration of parent rock when water was supplied.

Collaborative Problem in Multi-agent System

In the MAS, system goal task can be decomposed into many transactions, which will be achieved by special agents distributed in different physical space. Due to complex coupling relations among transactions, transactions may form Waiting-Circle resulting in deadlock. Concerning the problem, this paper proposes two theorems developed for Waiting-Circle detection in transaction set and ensures the implement of goal task decomposition result. Furthermore, Circle-First Search is put forward to search all of the Waiting-Circle, which prnvide the basic guideline for decomposing goal task again and eliminate Waiting-Circle.

Globular adiponectin induces differentiation and fusion of skeletal muscle cells

The growing interest in skeletal muscle regeneration is associated with the opening of new therapeutic strategies for muscle injury after trauma, as well as several muscular degenerative pathologies, including dystrophies, muscu- lar atrophy, and cachexia. Studies focused on the ability of extracellular factors to promote myogenesis are therefore highly promising. We now report that an adipocyte-derived factor, globular adiponectin （gAd）, is able to induce mus- cle gene expression and cell differentiation, gAd, besides its well-known ability to regulate several metabolic func- tions in muscle, including glucose uptake and consumption and fatty acid catabolism, is able to block cell cycle entry of myoblasts, to induce the expression of specific skeletal muscle markers such as myosin heavy chain or caveolin-3, as well as to provoke cell fusion into multinucleated syncytia and, finally, muscle fibre formation, gAd exerts its pro- differentiative activity through redox-dependent activation of p38, Akt and 5＇-AMP-activated protein kinase path- ways. Interestingly, differentiating myoblasts are autocrine for adiponectin, and the mimicking of pro-inflammatory settings or exposure to oxidative stress strongly increases the production of the hormone from differentiating cells. These data suggest a novel function of adiponectin, directly coordinating the myogenic differentiation program and serving an autocrine function during skeletal myogenesis.

Control of Spiral Waves and Spatiotemporal Chaos by Exciting Travel Wave Trains

Spiral waves and spatiotemporal chaos usually are harmful and need to be suppressed. In this paper, a method is proposed to control them. Travel wave trains can be generated by periodic excitations near left boundary,spiral waves and spatiotemporal chaos can be eliminated by the trains for some certain excitation periods. Obvious resonant behavior can be observed from the relation between the periods of the trains and excitation ones. The method is against noise.

Graph Description by the Chromatic Polynomials

By means of the chromatic polynomials, this paper provided a necessary and sufficient condition for the graph G being a mono-cycle graph（the Theorem 1）, a first class hi-cycle graph and a second class bicycle graph（the Theorem 2）, respectively.

English professional football players concussion knowledge and attitude

Background： Concussions are a common pathology in football and multiple misconceptions exist amongst the players and managers. To address these misconceptions, and potentially reduce concussion associated sequela, effective educational interventions need to be developed. However, the current knowledge and attitude status must be ascertained to appropriately develop these interventions. The purpose of this study was to assess the concussion knowledge and attitude of English professional footballers. Methods： Twenty-six participants from one English Football League Championship club completed the study. A mixed methods approach included the Rosenbaum Concussion Knowledge and Attitudes Survey （RoCKAS） and a semi-structured interview. The RoCKAS contains separate knowledge （055） and attitude （15-75） scores and was followed by a semi-structured interview consisting of concussion knowledge, attitude, and behavior related questions. Results： The mean score on the RoCK.AS knowledge was 16.4± 2.9 （range 11-22） and the attitude score was 59.6 ± 8.5 （range 41-71）. The interview responses identified inconsistencies between the RoCKAS and the intended behaviors, endorsing multiple concussion misconceptions, and revealed barriers to concussion reporting. Conclusion： The results of this study suggest that Championship Level English footballers have moderate concussion knowledge, safe attitudes, and good concussion symptom recognition when assessed with pen and paper questionnaires. However, within the semi-structured interview many respondents reported unsafe concussion behaviors despite accurately identifying the potential risks. Further, multiple barriers to concussion reporting were identified which included perceived severity of the injury, game situations, and the substitution rule. These findings can help form the foundation of educational interventions to potentially improve concussion reporting behaviors amongst professional footballers.

Effects of photoperiod on daily activity rhythm of juvenile sea cucumber, Apostichopus japonicus (Selenka)

In nature, Apostichopus japonicus exhibits a behavioral characteristic of emerging at night and sheltering during the day. Hence, it was commonly believed that longer and darker light conditions are better for a population of A. japonicus. In aquaculture situations therefore, animals have commonly been cultured without lighting, especially during juvenile-hatching culture. However, how the length of darkness each day affects .4.japonicus and what the mechanism is of behavioral response of A. japonicus to different photoperiods remain unclear, and are specifically addressed in this study. We applied nine photoperiod treatments （light：dark （LD） cycles at 0：24, 3：21, 6：18, 9：15, 12：12, 15：9, 18：6, 21：3, and 24：0 under 500Ix） to 60 individuals （29.73±0.23 g） per treatment （with 3 replicates）. The enviroramental conditions were set as： water temperature = 16.9±0.3℃, dissolved oxygen〉6.0 rag/L, ammonia〈0.3 mg/L, pH=7.8-8.2, and salinity=30-32. Under experimental conditions of continuous darkness as well as continuous light, cyclic nocturnal activity patterns of A. japonicus （viz. the animals emerged and fed at night and sheltered during the day） were observed. However, they spent more and less time, respectively, moving and feeding under continuous darkness and continuous light, than those under a natural light cycle. Under photoperiods with 6-12 h of light, the animals showed one sheltering behavior transition and two emerging behavior transitions. These behavior transitions appeared to be governed by some internal physiological factors and induced by daily light variation. The behavior of the animals was significantly affected by different photoperiods, and the distribution rate （DR） of the animals emerging at ＂daytime＂ increased with lengthening ＂light time＂ （except for the LD 3：21 cycle）. We also found that there was no significant difference in mean DR per day under LD cycles of 6：18, 9：15, 15：9, and 12：12. Mean DRs per day were significantly lower for these photoperiods, than for those under LD cycles of 0：24 and 3：21, and significantly higher than for those under LD cycles of 18：6, 21：3 and 24：0. These results imply that 6-15 h light per day were the similar photoperiods to natural sunlight. From the viewpoint of activity and feeding behaviors, these might be the optimal photoperiods for rearing A. japonicus.

Shanghai's Fashion During Republic Period

The goal of this research is to describe and analyze Shanghai’s fashion during Republic Period. Shanghai’s fashion during Republic Period plays a special role in fashion history of China and Shanghai history. In the paper, three aspects including the fashion centre of China as well as Far East, men’s fashion and women’s fashion in Shanghai are discussed. The style, textiles, color, decoration and combination of clothing are described. Many costumes from the Clothing Museum at Donghua University and private collections as well as some historical writings, photographs and publications are elucidated and corroborated to give a more detailed description about Shanghai’s fashion during that period.Here are some tentative conclusions. Firstly, Shanghai had always been the fashion center in China even Far East during Republic Period. Modeng was the main reflection of Shanghai fashion. Secondly, the traditional clothing exerted less influence and was less widely used, some kinds and combinations were out of fashion gradually. The fashion was described to be highly stylized, exquisite and concise. Thirdly, the influence of Western Style was further greater. The fashion in Shanghai was almost synchronous with fashion of Paris. Some western clothing was directly used in daily life and the elements of Western Style had an increasingly wide utilization. Fourthly, the New Chinese Style whose representatives were Qipao and Zhongshan Zhuang appeared and popularized in Shanghai. The fashion of Qipao changed frequently. Finally, the fashion in Shanghai called Shanghai Style could be summarized fashionable, exquisite, rapidly changeable, which is harmonious of both ancient and modern, Chinese and foreign.

Advances in Technology for Preparation of Acetylene via Partial Oxidation of Natural Gas

This article introduces the latest advances achieved by the Sichuan Vinylon Plant in the fields of maintaining the stable operation of acetylene reactors, extending the operating cycle of production equipment, adaptation to the composition of different natural gas feeds and enlarged scale of production facilities. And a forward-looking idea on next step of technology for manufacture of acetylene from natural gas has been set forth.

Ontogenetic development in the morphology and behavior of loach(Misgurnus anguillicaudatus) during early life stages

Loach （Misgurnus anguillicaudatus） is a commercially important fish in China and an ideal aquaculture species. However, culturists experience high larval and juvenile mortality during mass production. To provide insight into ways to improve larviculture techniques, we describe the morphological characteristics and behavior of loach during the larval and early juvenile stages. Yolksae larvae ranged from 2.8 to 4.0 mm body length （BL） between days 0 to 4; preflexion larvae ranged from 3.6 to 5.5 mm BL between days 4 to 6; flexion larvae ranged from 4.8 to 8.1 mm BL between days 5 and 14; and post-flexion larvae ranged from 7. l to 15.7 mm BL between days 11 to 27; the minimum length and age of juveniles was 14.1 mm BL and 23 d, respectively. Loach are demersal from hatch through to the early juvenile stages. A suite of morphological characteristics （e.g., external gill filament and ventral mouth opening） and behavioral traits have developed to adapt to demersal living. We observed positive allometric growth in eye diameter, head length, head height, and pectoral fin length during the early larval stages, reflecting the priorities in the development of the organs essential for survival. Our results provide a basis for developing techniques to improve the survival of larval and juvenile loach during mass production.

A successful mountain rescue operation in Yushu Earthquake

On April 14, 2010, an earthquake reaching 7.1 Richter scale struck Jiegu Town of Yushu. More than 2 698 people were confirmed dead, and 12 135 were injured, of which 1 434 were severely injured. Rescue operation was carried out soon after the disaster; however, the rescue teams face great challenges of altitude hypoxia, freezing temperature and very bad weather. Thus, 1 434 severe injuries were rapidly transported airlifted to hospitals in Xining and neighboring provinces for effective treatment. The extremity trauma （49.9 % ） was the most common patteru of injuries. Asphyxia （40.8 % ） was by far the most important reason for death. A high incidence of acute altitude illness in the lowland rescuers was a special medical problem during the highest earthquake in Yushu. We have learned more lessons from Yushu Earthquake.