环境背压对多孔式喷油器雾化形态特征影响的数值解析

本文旨在通过数值模拟方法解析缸内直喷汽油机(GDI)多孔喷油器在不同环境背压条件下喷雾的形变特性及其影响机制。首先基于喷油器参数在Converge软件中建立了定容弹喷雾模型,进而根据高速摄影和相位多普勒粒子测试仪(PDPA)的试验结果对模型的喷雾宏观形态、贯穿距以及索特平均直径(SMD)进行了验证,在此基础上对0. 1,0. 5和1MPa环境背压条件下的喷雾形态变化进行了详细研究。研究结果表明:随着背压增加,油束被挤压并向喷油器中心轴线方向收缩,且贯穿距减小;由于油束对容弹内气流的冲击作用使得油束外边缘出现强烈的空气卷吸效应,致使在喷雾油束末端的液滴随气流向上回卷,且背压越高油束末端边界越不清晰;在喷雾压力场及速度场的分析中发现,由于喷雾内部区域压力低于外部,导致外部气流向内部冲击挤压油束,使得喷雾宽度减小,油束间相互作用增强,从而出现喷雾形变。

土壤环境背景点位布设思路与方法

土壤环境质量状况不仅关系到农产品的安全,也关系到人类健康和国民经济发展。监测和评价土壤污染状况,首要任务是确定具有代表性的土壤环境背景点并监测其化学组成和元素含量水平。本文通过梳理并分析国内外土壤环境背景点布设方法的特点,提出了基于3S(遥感技术,remote sensing, RS;地理信息系统,geography information systems, GIS;全球定位系统,global positioning systems, GPS)技术的土壤环境背景点位布设思路与方法:首先对土壤环境干扰源进行分类,并对不同土壤环境干扰源的缓冲区距离进行详细的论述,在此基础上获得土壤环境背景区;其次明确基本样品数量的测算方法;再者提出网格法布设土壤环境背景点。该方法适用于全国尺度或区域尺度下土壤环境背景点的布设,可为我国土壤环境背景点的布设工作提供技术支撑。

“玉兔二号”复杂月背环境休眠与唤醒控制方法

针对复杂地形与中继通信等多约束条件下“玉兔二号”巡视器休眠与唤醒控制问题,提出了复杂月背环境休眠与唤醒规划控制方法。通过巡视器单目相机序列成像的天际线感知方法实现了周围地形的遮挡情况分析,基于巡视器姿态预测方法计算了巡视器给定位置的可休眠姿态及控制策略,提出了可休眠性指标与可视化综合分析方法以辅助寻找备选休眠点,并设计了休眠唤醒在轨工作模式。将其应用到“玉兔二号”在轨控制中,实施情况说明了控制方法的正确性和工作模式的有效性。

喷油压力及背压对丁醇柴油喷雾影响的模拟及验证

为深入了解丁醇柴油的喷雾特性,该文根据喷雾可视化试验结果,利用AVL Fire软件建立了耦合喷嘴内流动的丁醇柴油喷雾模型,并依据试验结果证明了模型的准确性。通过该模型研究了喷油压力、背压和掺混比对丁醇柴油喷雾的影响,计算了各种因素对混合燃料的油束发展、喷雾贯穿距、索特平均直径(sauter mean diameter,SMD)、速度场和浓度场的影响。结果表明:随喷油压力和背压的变化,正丁醇体积分数为25%的丁醇柴油混合燃料(记为N25)的油束形态基本不变;随喷油压力的升高,N25的贯穿距增加,SMD减小,油束和环境的卷吸增强,油束中心速度和轴线附近浓度均增加;随背压的升高,N25贯穿距减小,SMD在喷雾初期稍降,喷雾中后期基本不变,油束中心的速度降低,浓度增加;随正丁醇掺混比的增加,贯穿距和SMD均逐渐降低;随环境温度的升高,贯穿距增加,SMD在温度由293.15 K升高后明显降低,而后随温度升高变化不大。该文的研究分析了多种因素对丁醇柴油喷雾的影响,为其作为替代燃料的应用提供了理论支持。

深海保压取样模拟测试装置的设计与应用

为了对赋存于高压低温环境下海洋天然气水合物资源进行精准评价并掌握其储存情况,在钻探取样时需尽可能地保持水合物原始赋存状态。为提升保温保压工具的可靠性和成熟度,作者设计了深海保压取样模拟测试装置,模拟测试装置包括顶驱钻机、大通径钻杆、BHA、岩样筒、带压打捞装置等,以便在实验室条件下,模拟实际作业环境及过程,进行取样器投放及打捞、循环、工具旋转及钻进、井筒加背压及工具带压打捞等过程的测试,进而有效评价取样工具的可靠性和技术性能。通过应用,测试装置能够有效发现被测试工具的不足,进而促进工具的改进和性能提升,大大减少海试次数及时间,从而降低工具研制费用并加快工具研制进程。

背压对液氨制冷系统用安全阀技术性能指标影响的讨论

目前,国内安全阀型式试验装置无带背压型式试验系统,针对有背压的封闭式安全阀仍采用不带背压型式试验装置(排放为大气压)进行型式试验;在日常校验中,氨制冷用安全阀校验环境是大气环境下校验,使用环境为带背压排放环境。这样,由于使用与校验环境条件的不同造成整定压力等技术参数的偏差。以上两个原因造成在设计、制造、型式试验以及以后的使用监管环节都存在安全阀使用的风险,本文就可能存在的风险进行研究分析。

Correlation Between the Animal Community Structure and Environmental Factors in Dongbei Cave and Shuijiang Cave of Guizhou Province

Mollusks, arthropods and chordates which were visible to the naked eye were observed and collected in Dongbei and Shuijiang caves of Libo county five times between February and July from 2002 to 2005. Four hundred and forty samples from Dongbei Cave were classified into three phyla, five classes, 10 orders, 20 families and 39 species or groups of species. Four hundred and ninety-eight samples from Shuijiang Cave were classified into three phyla, six classes, 11 orders, 20 families and 25 species or groups of species. Six animal communities were identified in the light belt of the two caves according to their species types and numbers of individuals in the light belt of two cave. The communities which have the highest values of species richness community diversity, maximum diversity, evenness, dominance and community similarity are respectively： B （4. 1059）, H （2.4716）, B （3.3322）, E （0.9042）, C （0.3442） and A - C （0. 5251）. The community diversity and correlation of environmental factors were also studied. The temperature, humidity, content of CO2 and N2, content of organic matter and some inorganic salts in soil were analyzed by Pearson correlation. The results showed that the content of organic matter in soil is positively related to species number, species richness and maximum community diversity, with correlations of 0. 885, 0.909, 0. 868 respectively （two-tailed significance test, P ≤ 0. 05）, and significantly positively related to diversity, with the coefficient of 0.611, （two-tailed significance test, P ≤ 0. 1）. This suggests that the content of organic matter in soil is one of the important elements influencing the community variation of cave animals. Outside the cave, temperature and humidity are important factors impacting on community diver- sity. As the temperature in all seasons in the cave is stable and the humidity is always high （above 90% ）, the temperature and humidity have weak correlation to community diversity in caves.

Design of a 6.25 Gbps backplane SerDes with adaptive decision feedback equalization

A 6.25 Gbps SerDes core used in the high signed based on the OIF-CEI-02.0 standard. To speed backplane communication receiver has been decounteract the serious Inter-Syrmbol-Interference （ISI）, the core employed a half-rate four-tap decision feedback equalizer （DFE）. The equalizer used the Signsign least mean-squared （SS-LMS） algorithm to realize the coefficient adaptation. An automatic gain control （AGC） amplifier with the sign least mean-squared （S-LMS） algorithm has been used to compensate the transmission media loss. To recover the clock signal from the input data serial and provide for the DFE and AGC, a bang-bang clock recovery （BB-CR） is adopted. A third order phase loop loek （PLL） model was proposed to predict characteristics of the BB-CR. The core has been verified by behavioral modeling in MATLAB. The results indicate that the core can meet the specifications of the backplane receiver. The DFE recovered data over a 34＂ FR-4 backplane has a peak-to-peak jitter of 17 ps, a horizontal eye opening of 0.87 UI, and a vertical eye opening of 500 mVpp.

Research on College English Teaching Model Based on Multimedia and Network

Based on multimedia and network environment, college English teaching mode can effectively improve the teaching environment of traditional English teaching and students, and expand the capacity of English classroom information, and enrich the students’ English culture background. Therefore, as a teacher, we should first of all make efforts to learn new knowledge and teaching methods to improve our English professional quality. Strengthening the multimedia, network technology and educational psychology research, and put themselves in the teaching position. In addition, the college English teaching model based on multimedia and network environment can cultivate students’ independent thinking, autonomous learning, analysis and problem - solving ability, and promote the high efficiency of college English teaching.

Locating Power and Decision-Making： Social Production of Space in Juiz de Fora, Brazil

This paper aims to discuss how the shaping of a city, Juiz de Fora, in Brazil, has resulted from the power of location of some social agents and from their disputes on the production of space. First, it introduces the concept of social production of space, emphasizing the role of social agents in urban processes. Then, it presents specific aspects of the history of Juiz de Fora＂ its origins and how social agents and forces have played a significant role in shaping the built environment of the city--specially represented by main streets of the city. The paper studies how the social agents, with their different visions and goals, have influenced the process of formation and development of the city. This demonstrates the complexity of the existing relationships between the built environment and the social context that is specific to the city. Different urban forces fight for city spaces, construct and modify its territory so that their needs are fulfilled. Their strength, their experiences and efforts, and their ideas of a city are inscribed in urban landscapes; in similar ways, these are revealed by the city paths we follow here.

A Tentative Probe into the Mode of Cultivating Foreign Language Talents

This paper first relates the problem concerning the cultivation of foreign language talents in foreign language education, and then puts forward some suggestions to its resolution. This paper intends to contribute a little to the improvement on the mode of cultivating foreign language talents.

The Construction of the Aged Carers under the Internationa Comparative Perspective

Objective： To explore how to learn from foreign experience to promote the construction of nursing staff in China.Methods：Based on the social background and the problems faced by nursing staffin China, we selected Germany and Japan as the social environment and problems of nursing staffin China. Germany, Japan and Japan to find out how to solve the dilemma of nursing service personnel to meet the pension needs of Germany and Japan to compare whether the strategy adopted by the current development of nursing staff in China, and finally combined with the analysis of China＇s aging care workers How to draw lessons from international experience to promote the construction of nursing staff in China.Conclusion： In drawing on the experience of foreign nursing service personnel, we must first analyze the reasons for such measures, whether our country has the conditions to implement such measures is not able to solve The experience of other countries must be suitable for our country, we must combine the social environment in which our country in contrast, selectivity and targeted research.

The Disastrous Lifeworld： A Phenomenological Consideration of Safety, Resilience, and Vulnerability

The lifeworld is, according to Husserl, the horizon of all our experiences, in the sense that it is the background environment of human being＇s competences, practices, and attitudes. The lifewofld is the intersubjective, pre-given in the ontie sense, and immediately perceived world of everyday life. Although Husserl has distinguished the lifeworld from the objective world that natural science describes with mathematical methods, we cannot divide the world on the practical level into the perceived world of ordinary life and the scientific world. The characteristic of human beings is that they live in the environment which they have enormously changed. Modem science has accelerated this tendency： the contemporary world is constructed so deeply scientifically and technologically. Accordingly, as Ulrich Beck pointed out, the risk of the technologically constructed world is often invisible/unperceivable. The disaster at Fukushima nuclear power plants is a terrible testament of this kind of risk. In order for a land to become the lifeworld of meaningful human interactions, the land should be first of all safe and livable for all of us. The risk calculation made by Tokyo Electric Power Company was shown to be sloppy and deceptive. The contemporary techno-science should be democratically governed and watched by all kinds of stakeholders, and never be left it to the specialists of science. For re-establishing the livable and sustainable lifeworld, safety, resilience, and vulnerability should be the fundamental values. And, the autonomy of the local residents, including the most vulnerable people, through the democratization of the techno-science must be the fundamental value to establish and protect such a safe environment.

A Systematic Way to Plan Culture Teaching and Enhance Intercultural Competence for English Majors

Culture teaching is an inseparable part of an English major program to enhance students＇ intercultural competence. Yet, in practice, culture teaching does not receive due attention. More often than not, culture is taught and intercultural competence is developed randomly by individual teachers. The practice lacks cooperation, unity and coherence at the curriculum level. This paper proposes a systematic approach to plan, organize and coordinate culture teaching and to enhance intercultural competence for English major students. The theoretical assumption is a language is inseparable from its relative culture and the foreign culture should be openly addressed in actual teaching.

An Analysis on Correlativity between Large Earthquakes in the Hindu Kush-Pamir and Tienshan Seismic Zone

In this paper,we introduce the tectonic setting,historical earthquake focal mechanisms and geodynamic environment of Tienshan and its neighboring regions, and draw a conclusion that large earthquakes in the Tienshan seismic zone are governed mainly by the pushing from Hindu Kush-Pamir syntax. Secondly,the relationship of large earthquakes in the Hindu Kush-Pamir region and the Tienshan seismic zone is investigated,and synchronization features are found existing in the grouped large earthquakes between the large earthquakes in two regions. The relationship between intermediate-focus large earthquakes in Hindu Kush-Pamir and shallow large earthquakes in the Tienshan seismic zone is also discussed. The same synchronization characteristics are found,and the intensity and frequency of intermediate-focus earthquakes are fiercer, while large earthquakes in the Tienshan seismic zone are more intense,with a wider distribution range. The above results confirm the geodynamic correlativity between Hindu Kush-Pamir and the Tienshan seismic zone from the viewpoint of seismicity.

On the Cultural Differences between Chinese and English Speaking People in Their Thinking Modes from the Perspective of Second Language Acquisition

The recent years have witnessed increasing opportunities for people from various cultural backgrounds to communicate with each other, which is naturally based on a general grasp of cultural knowledge and communicative techniques in cross-cultural settings. However, there often exist cultural clashes in such cases, especially between Chinese and English speaking people, which are deeply rooted in the wide differences in their languages and thinking modes. Indeed, this also serves to be an important part in the acquisition of the English culture for Chinese students in the current educational climate. The paper is intended to provide a contrastive analysis of the major cultural differences between Chinese and English speaking people in their thinking modes in three aspects of the descriptive versus the formal, the concrete versus the abstract, and the practical versus the logical form the linguistic perspective. And the paper comes to the conclusion that a general understanding of these significant differences may enable Chinese-speaking people and English-speaking people to establish a more efficient communication with each other.

Effects of 6-Month Weight Loss New Program on Anthropometric Measurements and Biological Profile

Obesity has become a leading global health problem owing to its strong association with a high incidence of diseases. Obesity is results from the complex interaction of environmental factors that act on a genetic background and led to excess accumulated of body fat. Treatment of obesity includes determination of the degree of obesity, management weight loss programme and maintenance of body weight. To investigate effect 6 months safe weight loss program on anthropometric measurements and biological and metabolic profiles in obese patients. 35 obese patients were enrolled in the present study： 20 female, 15 male. Participants underwent a comprehensive series of biochemical, anthropometrical, physical, and nutritional prior to treatment- at baseline and after the six-month of the obesity treatment program. 6 months weight loss program. Diet plan intervention in small groups. In-person training and individual diet plan intervention. There is significant reduction in weight and high improvement in laboratory parameters. Our data showed that there an improvement in weight loss. These finding may be important for controlling obesity-related co-morbidities. It would appear that moderate weight loss of 8-10 % observed in our study resulted in significant improvements in laboratory parameters

The Impact of the Environment Management Act （EMA） on the Accountability of Companies in Fiji

This study seeks to explore the impact of the Environment Management Act （EMA） （2005） on the accountability of three companies in Fiji. The study uses a multi-case study approach based on three subsidiaries of a conglomerate. Data collection methods include semi-structured interviews with accountants, internal auditors, and environmental officers, document reviews, and content analysis of annual reports and websites of the respective companies. The findings suggest that the EMA （2005） had some effects in terms of engendering accountability on the companies studied. Further evidence suggests that while this increased accountability has led to disclosures in annual reports and websites, these disclosures are minimal at best; furthermore, they primarily address that the stakeholder group comprised government regulatory authorities. The study provides policy implications on how environmental legislations could be designed to improve the accountability of commercial entities in developing economies. The experience and issues highlighted are also useful to other developing economies who are contemplating in developing their own environmental legislations. This paper is one of the few papers that explore the impact of environmental legislations on accountability in a developing economy context.

The Experience of Model Minority for High- and Low-Income Asian American Students

The author examines the differentiation of self-identity, school treatment, and academic struggle between two Asian American students in U.S. Midwest urban school environments. Using an interview study, the author focuses on understanding the students＇ perspectives in relation to the label of model minority. The purpose of the study is to investigate how social, academic, and economic factors affect these students, including different outcomes in terms of school achievement and self-identity formation. The findings aim to help urban educators approach complex factors regarding minority students＇ educational opportunities. Comprehensive results identified that： （1） The concept of model minority significantly affects Asian American students at all levels of daily life; （2） Urban schools continue reinforcing social reproduction and producing perceptions based on socioeconomic background and intersectional discrimination; （3） The evidence in the study shows that school environments do not aid students in valuing their cultural capital; （4） Students from different social classes present different linguistic and behavioral patterns; and （5） Social stratification significantly influences students＇ perspectives in response to the Asian stereotype, self-identity, and racial hierarchy in school and society.

Diagenesis tectonic setting and U-Pb dating for zircon from Tanjianshan Group in northern margin of Qaidam Basin

The shape,texture,content and REE characteristics of zircons from the O2tnd-1,O3tnd-2,O3tnd-3pyroclastic rock of Tanjianshan Group on the north margin of Qaidam Basin indicate that the O2-3tndis the product of volcanism during the transitional period from ocean-land interim crust to oceanic crust.The U-Pb surface ages obtained from O3tnd-2and O3tnd-3can be divided into 9 groups,every age group coincides with the period when significant tectonic-heat event took place at Oulongbuluke micro-continental base of northern Qaidam,suggesting that the base rocks have provided materials for the formation of sedimentary and volcanic rock in O2-3tnd.The volcanic rocks of O3tnd-3formed at 440 Ma,with time gap 46 Ma to those of O1tna-1and O3tnd-3may represent the minor period that Xitieshan back-arc extension have lasted,the scale of back-arc basin that formed in Xitieshan extension may approach to 1 400 km.Based on the test of ithochemistry data for major elements and analysis of Sr isotope geochemistry for the clastic sedimentary rock in O1tna-2and O3tnd-2,the authors get the conclusion that the O1tna-2and O3tnd-2of Tanjianshan Group may form in back-arc basin environment,while the lithology difference between these two formations may reflect the changes of geodynamic processes as the diagenesis tectonic environment transformed from continental margin depression to adjacent sea basin.