Development of Investigation on the V-notched Rock Blasting

A brief review on the origin of V-notched blasting and its application in engineering is given. A study on the fracturing mechanism and stress intensity factor at the tip of V-notch and parameter of the V-notched rock blasting is introduced based on reference given in this paper. It represents an idea of spiral V-notched blasting at last.     

磷在棕壤中淋溶迁移特征研究

采用室内土柱淋溶模拟试验，研究相当于一年降雨条件下磷肥在棕壤土垂直方向上的淋溶迁移特征及鸡粪、秸秆对磷素迁移转化的影响。结果表明：土壤施肥量与速效磷、迟效态磷增加量呈极显著正相关。相关系数分别是0．99141。，0．99774；水溶性磷、Al—P与土壤速效磷相关性最好，相关系数分别达0．972和0．926，2500mg／kg鸡粪与25mg／kg磷肥配施能降低磷淋溶率，并能极显著提高土壤中速效磷的增加量，相当于单施50mg／kg的磷肥；秸秆与磷肥配合施用在短期内对土壤磷素的有效性影响不大，但可以减少磷素向下层迁移。     

甘蔗螺旋扶起机构的理论研究及虚拟样机仿真

根据田间生长的甘蔗实际状况和固有的力学性能，用系统动力学的观点，建立了田间生长的甘蔗力学模型。基于该模型，探讨了扶起搅龙与甘蔗的作用过程以及其对收获过程的影响。对扶起搅龙的工作过程进行了虚拟仿真研究以及高速摄影试验，从理论上解释了仿真和试验结果。该文的研究为扶起搅龙的改进设计提供了理论依据。     

Landsliding related to land-cover change: A diachronic analysis of hillslope instability distribution in the Sierra Norte,Puebla, Mexico

This study examines mass movement associated with land use change, particularly deforestation, from multiple perspectives. The significance of such understanding is related to the degree of impact landsliding may cause on human settlements and economic activities, and on forest ecosystems. In this paper, the distribution of hillslope instability in the Sierra Norte, Puebla, Mexico is addressed by means of a diachronic analysis, which involves the development of vegetation indexes, as well as vegetation fragmentation derived from Landsat-5 (TM) and Landsat-7 (ETM+) satellite images from 1989 and 1999, respectively. The time period was chosen to compare vegetation cover conditions prior and after the extreme October 1999 rainfall event that triggered hundreds of slope failures in the study area. Results suggested there was a significant vegetation reduction from 1989 to 1999, which was strongly expressed by an increase of 809 km² of bare surfaces. Additionally, areas with highest vegetation density (91–100%) decreased considerably, from 1245 to 363 km², resulting in a net vegetation reduction of 70%. Furthermore, it was possible to highlight that landslide concentration was much higher on surfaces that were bare and had low vegetation density (0–50%), representing 85% of hillslope instability, than on surfaces having a greater density of vegetation cover. Land use change and land degradation are precursors to environmental hazards, such as mass movement events, that pose serious threats to regional population distributions and economic vitality.     

Influence of soil properties on the vertical movement of genetically-marked Pseudomonas fluorescens through large soil microcosms

Summary Vertical translocation of the introduced transposon Tn5-tagged Pseudomonas fluorescens cells was studies after irrigation of 50-cm long soil columns of loamy sand. The soil in the columns was slowly brought to saturation using groundwater, and enough water was then slowly added to permit collection of the percolated water. Introduced bacteria were transported to lower soil layers to a significantly higher degree in undisturbed soil cores than in repacked cores; water transport was hampered in both core types due to high soil bulk densities. Soil bulk density affected the degree of transport of the introduced cells; progressively more cells were translocated to deeper soil layers and into the percolation water at decreasing soil bulk densities. Repeated percolation of soil at a bulk density of 1.25 caused an increase in Tn5-tagged cell numbers in the lower soil layers and in the percolated water. Further, cells initially introduced into a dry (5.3% moisture) soil were translocated to a lesser extent than cells introduced into a wetter (13% moisture) soil. Finally, wheat roots enhanced the water-induced transport of introduced cells to the 40- and 50-cm deep soil layers and into the effluent, but not to the remaining soil layers. Large soil columns such as those used in the present study are useful in assessing the transport and survival of introduced bacterial cells in soils under a variety of simulated environmental conditions.     

水分淋洗下菜园土壤各形态锌的迁移转化特征

采用室内模拟降雨淋溶土柱的方法，研究了经过1年降雨的淋溶后，菜园土壤垂直方向上各形态锌的迁移转化规律。结果表明：锌的大多数形态很难随水分运动发生迁移，～年的降雨至多能使占总量0．57％的水溶态锌发生淋溶损失。水分淋洗和施磷锌平均能使分别占总量3％和4％的难溶态RES—Zn和OX-Zn向易被植物利用的EX—Zn、CABS—Zn和OM—Zn形态转化。随施锌量的增加，土壤锌的有效性指数增加30％～78％．有效锌总量增加3．12～10．07mg／kg。当施磷50mg／kg时，土壤Zn的有效性指数增加3％～28％，有效锌总量增加0．04～0．28mg／kg，磷锌在土壤中表现为协同作用。     

Rooted in grass: Challenging patterns of knowledge exchange as a means of fostering social change in a southeast Minnesota farm community

By convening a multidisciplinary team(the Monitoring Team) that included farmers,university and agency researchers, andnon-profit staff; a small group of farmers insoutheast Minnesota, U.S.A., bolstered thelegitimacy of the sustainable agriculturemovement. Through the experience of forming ateam and working with individuals who operatedwithin the mainstream knowledge paradigm,farmers gained validation of their knowledgeabout farming, while researchers came to valuealternative knowledge systems. In the contextof a socially embedded movement, farmers wereempowered by sharing their knowledge withresearchers, and ultimately contributed to thesustainable agriculture movement by challengingtraditional patterns of knowledge exchange.     

外源NO和ABA对杨树气孔运动和SOD及POD活性的影响

研究了外源NO和脱落酸(ABA)对杨树气孔运动和SOD、POD活性的影响。结果表明：NO和ABA均可诱导杨树叶片气孔关闭，且NO有加强ABA诱导气孔关闭的作用。NO清除剂(C—PTIO)能显抑制NO和ABA对气孔关闭的诱导效应。不同浓度硝普钠(SNP)和ABA处理杨树离体叶片，SOD活性变化不明显，POD活性受到显抑制。粗酶液的体外实验结果表明，不同浓度SNP对POD活性的抑制呈明显的浓度及时间效应；而ABA对POD活性则几乎没有影响。说明在ABA调控气孔运动的过程中需要NO的参与，由此推测ABA对杨树叶片气孔运动的调节与NO对POD的抑制有关。     

农村社区发展的资金问题──Ⅰ．农村社区资金的新特点

资金是经济发展的一个重要条件．农村社区的社会主义新农村的建设需要大量资金的投入，但是农村社区却最缺乏资金，因此要加强农村资金问题的研究．首先，农村金融组织需改革深化，挖掘农村资金的潜力，着重使农民的资金的“资产”投入转向“生产”投入．其次，农村资金运动已呈现了新特点，这些特点有：分散化及结构复杂化；总量增大，周期时间延长；资金运动的盲目性和不稳定性．再次，农村社区资金的需求与供应呈现的新特点，这些特点有：要求合理地引导资金的流动；不可忽视的社区经济要求；常年性需求；供给和积累的加速．最后，还必须注意到在市场化下产生的与社区发展相矛盾的资金的逆向运动．     

韩国新村运动及对我国新农村建设的启迪

在详细介绍韩国新村运动内容、发展过程的基础上,对其实施效果进行了评析,并结合我国农村发展现状与经济发展实际,提出了其对我国社会主义新农村建设的启示。