混凝土力学的研究现状与发展

从混凝土裂缝的发展机理、混凝土本构关系、力学模型的建立等方面内容入手,基于混凝土连续介质力学的假定,以断裂力学和损伤力学为工具,研究了混凝土力学的研究现状以及发展状况。     

Dirac函数在力学教学中的应用

在力学课程教学中,通过引入Dirac函数,可以方便地对力学中的集中力、集中力偶矩以及瞬时脉冲力等物理量,以连续分布的形式加以统一地表达和解决。在介绍Dirac函数的定义、基本性质以及物理背景的基础上,给出了Dirac函数在力学课程教学中的典型应用。Dirac函数在材料力学、结构力学和弹性力学课程中的教学示例,体现了力学教学过程的多样性。     

高职院校《建筑力学》课程标准制订与实证研究——以行业背景下道桥专业力学课程特色发展为例

高职院校《建筑力学》课程基于行业、产业背景,以后续专业发展、行业产业知识需求和职业素养要求为目标,力学、结构、施工融为一体,结合道桥专业课程建设,对行业背景下道桥专业力学课程特色发展和课程标准制定、实证进行分析。高职院校《建筑力学》课程存在课程体系开发弱化、课时不足、内容选取不合理、学习难度大和考核单一化等问题,需要基于行业背景下进行力学知识目标和职业素养目标定位、力学教学与道桥结构教学、施工教学及职业素养相融合和力学产教和科教融合发展,合作共建以行业、专业特色为支撑的力学特色课程并形成课程标准。     

对岩石力学与工程发展战略的己见

1 岩石力学与工程学科的现状五十年来,岩石力学学科有了巨大的发展。国际岩石力学学会和中国岩石力学与工程学会为发展本学科做了大量艰苦的开拓工作,在学术和实践等方面都取得了丰硕成果。人类生活的环境是地球上层的岩石圈,许多工程如水利、矿业、交通、人防等,都涉及岩石的力学特性。通过     

土木工程类力学、结构系列课程改革尝试

根据新的教育改革形势和土木工程类专业的发展需求,对土木工程类的理论力学、材料力学、结构力学、弹性力学、钢结构、钢筋砼结构学等力学与结构方面的课程进行了优化调整,重新构组了土木工程类力学与结构系列课程,并通过实践取得了良好的效果.     

浅谈力学在建筑工程中的应用

针对力学基础内容与建筑工程的关联性展开分析,结合材料力学、结构力学、理论力学、固体力学、流体力学等在建筑工程中的具体应用,通过研究材料选择、结构选择、环保材料应用等注意事项,其目的在于提升力学在建筑工程中的应用,加快建筑工程项目的作业速度。     

关于中职建筑力学课程教学改革的思考

结合建筑力学对建筑工程专业学生的重要性及目前中职学生在建筑力学学习过程中难度大的现状,分析了建筑学专业建筑力学课程教学中存在的主要问题,探讨了建筑力学课程在教学内容、教学方法和教学手段等方面改革的途径和方法,以提高教学效果。     

近代非线性科学与岩石力学问题

近代非线性科学与岩石力学问题郑颖人，刘兴华（重庆后勤工程学院，重庆，６３００４１）１岩石力学发展面临的问题岩石力学是一门年青的学科，目前使用的理论主要是连续介质力学和地质力学。近年来，不连续介质岩体力学迅速发展，岩石损伤、断裂、固流耦合等力学问题也有...     

美国大学计算机软件辅助力学课程教学模式探讨

笔者通过在美国新泽西州州立大学对多门力学课程跟班听课,感受Matlab、Excel、ANSYS等计算机辅助软件在理论力学、材料力学、结构力学等力学系列课程中的应用。通过辅助软件加深学生对抽象力学知识的理解,培养他们的学习兴趣,提高他们的工程能力、创新能力,值得国内高校借鉴。     

岩体力学课程教学方法探讨

岩体力学课程是土木工程和地质工程等专业的基础理论课程,也是本科阶段重要的专业课程。文章总结出岩体力学课程本科教学的三个重要理念：突出岩体介质的复杂性、强调岩体力学理论的实践性、阐明岩体力学发展的前瞻性。实际证明,将这三大理念在课堂教学融会贯通,能够让学生更加完整地学习岩体力学知识体系的精髓。     

经济转轨背景下城市设计的演变历程和规律探讨

我国经济体制的转轨和建设机制的转型引发了城市设计的演变,促使城市设计在认识论层次上从思想理念向社会实践、从产品主导向过程主导演变,在方法论层次上从指令性控制向弹性引导、从“家长式”管理向制度化管理演变,在价值论层次上从粗放生产向有机生长、从技术工具向价值倡导演变。从总体上说,在经济转轨背景下,我国城市设计呈现从静态到动态、从工具理性到价值理性的演变规律。     

从线性到非线性：我国大学管理思维的延伸

随着科技发展与实践的深入,人们从追求简单性转向探索复杂性,科学思维方式由线性思维转向非线性思维。这启示我国大学管理思维要从封闭思维走向开放思维,从简单性思维走向复杂性思维,从确定性思雏走向随机性思雏。从经验性思维走向前瞻性思维。     

现代生态规划对传统城市规划的启迪

传统的城市规划至少可以从思想和方法两个方面,从现代生态规划中得到启迪。规划思想应从线性思维转向网络性整体思维,从人类中心论转向生态文明观,从以“为经济建设服务”转化为可持续发展。规划方法的启迪有:规划手段应由“硬”变“软”,规划依据应由“自上而下”变为“自下而上”,规划任务应由安排到引导,用地布局应由均质到异质。     

Microbiological and chemical properties of litter from different chicken types and production systems

Chicken litter is produced in large quantities from all types of poultry raising activities. It is primarily used for land application, thus it is essential to analyze its properties before it is released to the environment. The objective of this study is to compare the microbiological and chemical properties of litter generated from layer and broiler chickens reared under intensive and free-range production systems. The microbiological analysis consisted of the enumeration of total bacteria, total coliforms, Staphylococcus species, Salmonella species and Clostridium perfringens. Chicken litter from layers reared under intensive and free range systems showed lower mean total bacterial count than the litter collected from chicken broilers reared under either of the two systems (P=0.0291). The litter from intensive layers had the lowest mean total coliform counts (P=0.0222) while the lowest Staphylococcus species count was observed in the litter from free-range layers (P=0.0077). The C. perfringens count was the lowest in chicken litter from intensively raised broilers and layers (P=0.0001). The chemical properties of litter from the different chicken types and production systems were compared based on determination of pH, electrical conductivity, carbon, nitrogen, phosphorus, potassium, cadmium and zinc. Litter from free-range broilers showed the highest pH value (P=0.0005); however, the electrical conductivity was higher in the litter from both intensive and free-range layers compared to the litter from both broiler production systems (P=0.0117). Chicken litter from intensive systems had higher nitrogen content than litter from free-range systems (P=0.0000). The total phosphorus was the lowest in free-range broiler litter (P=0.0001), while the total potassium was the lowest in litter from intensively managed broilers (P=0.0000). Zinc appeared higher in litter from layers compared to that from broilers (P=0.0101). The cadmium content was higher in the litter from free-range broilers and layers compared to that in the litter from intensively managed systems (P=0.0439). Staphylococcus species in the litter as well as cadmium concentrations seem to be the most critical parameters presenting risks on the environment and on human health. Based on the lowest coliform counts (an indication of water pollution), the high nutrient levels and the low cadmium values, litter from intensively managed layers appears as the most suitable for application on agricultural soils.     

地下建筑湿负荷计算

从地下建筑围护结构散湿、人体散湿、自由水面散湿、人为散湿、外部空气带湿五个方面介绍了地下建筑物内湿负荷的主要来源和计算方法。     

Detection of virulence genes in Escherichia coli of an existing metabolic fingerprint database to predict the sources of pathogenic E. coli in surface waters

A collection of 366 Escherichia coli strains from 10 host groups and surface waters were tested for the presence of 15 virulence genes associated with strains causing intestinal and extra-intestinal infections. The virulence genes included eaeA, VT1, 2 and 2e, LT1, ST1 and 2, Einv gene, EAgg gene, CNF1 and 2, papC, O111 and O157 side chain LPS. Of the 262 strains obtained from nine different hosts, 39 (15%) carried one or more of these virulence genes. These included six strains from humans, two from horses, eight from dogs, two from ducks, five from cattle, seven from chickens, four from pigs, two from sheep and three from deer. Of the remaining 104 strains obtained from water samples, 10 (10%) also carried one or more of the tested virulence genes. Of these, six had identical biochemical phenotypes (BPTs) to strains isolated from humans (two strains), dogs (two strains), chickens (one strain) and sheep (one strain) with 4 BPTs also carrying same virulence genes. Our results indicate that the sources of clinically important E. coli strains found in surface waters due to faecal contamination can be predicted by using a combination of biochemical fingerprinting method and the detection of virulence genes. From the public health point of view this information will be of great importance for evaluating the risk associated with public use of the catchment.     

上海地区城市化过程中的文化复兴

针对上海地区文化复兴这一现象，利用以人为本的理念，着眼于整体的方法，运用系统理论，建立了从认识到方法，从分析到设计，全方位地开敞框架系统。     

Trace element carriers in combined sewer during dry and wet weather: an electron microscope investigation

The nature of trace element carriers contained in sewage and combined sewer overflow (CSO) was investigated by TEM-EDX-Electron diffraction and SEM-EDX. During dry weather, chalcophile elements were found to accumulate in sewer sediments as early diagenetic sulfide phases. The sulfurization of some metal alloys was also evidenced. Other heavy metal carriers detected in sewage include metal alloys, some iron oxihydroxide phases and neoformed phosphate minerals such as anapaite. During rain events, the detailed characterization of individual mineral species allowed to differentiate the contributions from various specific sources. Metal plating particles, barite from automobile brake, or rare earth oxides from catalytic exhaust pipes, originate from road runoff, whereas PbSn alloys and lead carbonates are attributed to zinc-works from roofs and paint from building siding. Soil contribution can be traced by the presence of clay minerals, iron oxihydroxides, zircons and rare earth phosphates. However, the most abundant heavy metal carriers in CSO samples were the sulfide particles eroded from sewer sediments. The evolution of relative abundances of trace element carriers during a single storm event, suggests that the pollution due to the "first flush" effect principally results from the sewer stock of sulfides and previously deposited metal alloys, rather than from urban surface runoff.     

转型重构语境中的中国城市发展战略规划的演进

2000年以来,受发展环境变迁及发展阶段演进的影响,中国城市处于转型重构的发展语境之中.城市发展战略规划针对发展语境的变迁进行了积极调整:规划目标从增量扩展转向品质内涵提升;规划价值从发展战略转向发展战略与空间规划,从规划研究转向实施性规划;在规划内容方面,发展战略由主体取向转为综合取向,空间规划从聚焦空间实体转向关注...     

Sources and properties of non-exhaust particulate matter from road traffic: a review

While emissions control regulation has led to a substantial reduction in exhaust emissions from road traffic, currently non-exhaust emissions from road vehicles are unabated. These include particles from brake wear, tyre wear, road surface abrasion and resuspension in the wake of passing traffic. Quantification of the magnitude of such emissions is problematic both in the laboratory and the field and the latter depends heavily upon a knowledge of the physical and chemical properties of non-exhaust particles. This review looks at each source in turn, reviewing the available information on the source materials and particles derived from them in laboratory studies. In a final section, some of the key publications dealing with measurements in road tunnels and the roadside environment are reviewed. It is concluded that with the exception of brake dust particles which may be identified from their copper (Cu) and antimony (Sb) content, unequivocal identification of particles from other sources is likely to prove extremely difficult, either because of the lack of suitable tracer elements or compounds, or because of the interactions between sources prior to the emission process. Even in the case of brake dust, problems will arise in distinguishing directly emitted particles from those arising from resuspension of deposited brake dust from the road surface, or that derived from entrainment of polluted roadside soils, either directly or as a component of road surface dust.