通过刺槐的水力结构特征参数探讨管道理论

为了解刺槐Robinia pseudoacacia苗木对体内水分运输过程的调控机制,基于水力结构理论,在充分供水条件下,利用改良的"冲洗法"对2年生刺槐苗木的水力结构参数进行测定,并探讨了管道理论的合理性和适用范围。结果表明:在充分供水条件下,刺槐苗木茎段导水率、比导率、叶比导率和胡伯尔值均随被测茎段直径的增加而增大;苗木不同生长阶段,其导水率、比导率和叶比导率差异显著(P<0.05),且均为生长旺期>生长初期>生长末期,胡伯尔值为生长初期最大,生长旺期和生长末期差异不显著(P>0.05)。由此可推断,①在水分胁迫条件下,苗木更倾向于保护那些较粗茎段;②苗木水力结构特征与提体内生理活动呈正相关关系;③管道模型假说虽然有其存在的合理性,但也有其局限性和适用性,在对于水分在林木体内的运输过程以及调控机制的解释,管道模型假说过于简单化了。     

顺应理论视角下的冗余信息策略研究

冗余信息作为我们所熟悉的一种语言现象,是语言固有的本质特征之一.现有的研究大多数局限在语言传递信息的功能上,相对较少地关注其社会功能,因此,对冗余信息的理解也不免过于简单和片面.维索尔的语用顺应理论是对语言使用的一种纵观.本文就是从语言顺应角度出发,分析冗余信息策略的应用.     

Stewardship as a Path to Cooperation? Exploring the Role of Identity in Intergroup Conflict Among Michigan Wolf Stakeholders

Post-recovery wolf management remains controversial. In Michigan, dialogue centers on hunting wolves but controversy may be more nuanced than simple pro- or anti-hunting positions. Social identity may cause stakeholders to organize in groups and identity differences may be driving controversy. To explore stakeholder disagreement over wolf management, we conducted semi-structured key informant interviews (n = 21) about identity and stewardship in August–September 2012. Four overarching identity themes emerged regarding: (a) management objectives, (b) focal levels, (c) control methods, and (d) justifications for methods. Themes indicated two main researcher-defined identity groups. Interviewees from both groups identified six common stewardship themes: (a) bequest values, (b) ecosystem health, (c) education, (d) existence values, (e) pride in natural resources, and (f) sustainability. Findings suggest stakeholders may be conflicting over opposing identities vis-à-vis organization affiliation, which may be related to what management strategies individuals oppose. Establishing common stewardship objectives through established participation methods may help alleviate controversy.     

湖泊渔业资源开发的系统动力学模型研究

采用灰色系统理论与国际先进的人工神经网络模拟相结合的先进技术，进行了太湖、濑湖和金鸡湖的渔业资源开发的系统动力学模型研究。认为控制捕涝强度是调空太湖针银鱼，梅鲚，白虾３个主要经济种群的关键因素，专家鉴定认为，本研究填补国内空白，居国内领先水平。     

A socio-ecological exploration of fear of crime in urban green spaces – A systematic review

Studies have pointed at the negative side of urban green spaces in terms of evoking fear of crime. However research on fear-provoking attributes suggests that there usually is no single attribute that influences fear but that rather a combination of attributes prevails. The aim of the paper is to systematically review those attributes that evoke fear of crime in urban green spaces and to highlight their complex interaction by adopting a social-ecological framework. Results include an overview of the reviewed literature with regard to authorship, journal, geographical distribution of the studies, types of urban green spaces studies, types of landscape stimulus used, applied methods, types of respondents involved and main study findings. Forty-eight studies met the authors’ inclusion criteria. The majority of the studies highlighted that individual factors (such as gender and past experience) were more influential than social and physical factors in evoking fear of crime. A proposed socio-ecological framework highlights the attributes which evoke fear of crime in urban green spaces and its interactions and can help guide future research.     

时空尺度对灰色系统理论预测秸秆折标煤量的影响研究

能源供给潜力的准确预测对秸秆生物质资源开发具有重要意义,数据的时空尺度对预测精度有重要的影响。在不同的时间尺度（7、10、12和15a）下研究了灰色系统理论Grey Model（1,1）模型及其拓展形式对全国、京津冀、河北三个空间尺度上秸秆折标煤量的预测精度,确定各空间尺度上的最优模型和数据时间尺度,分析影响可收集秸秆折标煤量的主要因素,并得到2021-2030年的预测结果。结果表明,灰色Verhulst模型的预测效果整体最好,10a时间尺度下的预测精度要明显高于7a、12a和15a,全国地区的预测精度为99.69%和99.72%,高于京津冀和河北省地区的预测精度;全国主要农作物和粮食农作物可收集秸秆折标煤量主要受到播种面积和单位面积产量双因素的影响,而京津冀和河北地区的主要农作物和粮食农作物可收集秸秆折标煤量则主要受单位面积产量的影响;2021-2030年的预测结果表明,全国主要农作物和主要粮食作物的可收集秸秆折标煤量基本稳定,而京津冀和河北地区的秸秆可收集折标煤量呈增加趋势,且主要粮食农作物的秸秆折标煤量的增速高于主要农作物秸秆折标煤量的增速。研究结果反映了京津冀协同发展对京津冀地区尤其是河北现代化农业格局发展和秸秆生物质资源量的影响,得到了不同空间尺度上影响秸秆折标煤量的关键因子,对灰色系统理论预测秸秆生物质资源潜力、推动能源格局转变有理论意义。     

植被和梯田措施对坡沟系统细沟侵蚀调控作用

坡沟系统作为黄土丘陵沟壑区基本的地貌单元,也是黄土高原侵蚀泥沙的主要来源区。植被和梯田作为坡面水土流失治理的主要措施,对于土壤侵蚀控制和生态恢复发挥着重要的作用,定量评估林草、梯田对坡面细沟侵蚀的调控作用以及多措施协同配置问题对于黄土高原水土流失治理和生态保护具有重要意义。为了揭示植被和梯田的格局和配置对坡沟系统细沟侵蚀的协同调控作用,该研究采用人工模拟降雨,结合三维激光扫描技术,分析了坡面4种措施：上坡位植被（措施A）、下坡位植被（措施B）、梯田（措施C）、梯田+植被（措施D）对细沟侵蚀发生和演变过程的影响。结果表明：1）相同植被覆盖度下,下坡位的植被布设细沟最大长度较上坡位的植被布设细沟最大长度减小量更大;2） 第1次降雨中,侵蚀率最大值达到3 500 g/min以上,第2次降雨过程中侵蚀率最大值仅为1 100 g/min以上,在各产流时间内第2次降雨侵蚀率均为第1次降雨侵蚀率的1/3～1/2;3）对于各措施下细沟沟长发育率由大到小表现为措施A（6.55 cm/min）、措施C（5.71 cm/min）、措施B（3.60 cm/min）、措施D（2.69 cm/min）;4）梯田与植被同时布设（措施D）对于细沟侵蚀的调控作用优于单一措施（措施B和C）,梯田和植被对细沟侵蚀指数细沟侵蚀量、细沟面积、细沟密度产生了协同作用（分别为7.71%、13.76%、7.52%）。研究可为黄土高原坡沟治理措施配置和细沟侵蚀调控提供一定的科学参考依据。     

阿克苏地区红枣产业比较优势分析

以阿克苏地区红枣产业发展为依托,结合比较优势理论的原理、方法,分析论证了阿克苏地区红枣产业发展的状况,根据比较优势的结果得出阿克苏地区红枣效率优势相对较弱、规模优势明显、综合比较优势呈逐年递增态势等结果,并就优化、推进阿克苏地区红枣产业发展提出了改善品种结构,提升科技含量、加强产业组织经营、实施品牌发展战略等对策和建议。     

Circular Disc Blade Considerations in Soil Force Prediction Modelling

Previous soil-disc force prediction models have considered spherical and concave blades, as used on disc ploughs and harrows, with many simplifying assumptions. This study proposes an approach applying the fundamental equation of earth moving mechanics for calculating the soil passive reaction acting on a rotating fiat disc blade as used on a zero-till single disc seeder. The study considers the effects of disc variable depth of cut, sweep and tilt angles, free rotation and a scrubbing reaction at the beveled edge. This paper outlines the modeling approach and prediction results for a fixed circular blade operating at 90° sweep angle over a range of speeds and at two tilt angles. To account for the varying depth across the circular disc shape width, elemental wide blade force reactions acting on wide blade segments of elemental width were integrated across the disc working width. By including inertia forces due to speed as well as additional bulldozing forces due to the loose soil accumulation in front of the blade the draught and upward vertical forces acting on the vertical disc blade were predicted with a deviation of 6%-19% and 1.5%-14% from measured data, respectively. The model was able to predict the effect of increasing the tilt angle from 0° to 20° on reducing both draught and upward vertical forces. Further development and validation of the model will be described in subsequent papers, reflecting a step by step approach of increasing complexity to model a disc blade as used on a zero-till single disc seeding system.     

浅述《单片机应用技术》课程理实一体化教学的实施

《单片机应用技术》是一门应用性很强的课程,是高等职业院校数控加工类的专业必修课.该课程借助学院重点专业的建设,坚持职业性与实用性原则,把课程内容划分成实际项目,以真实的任务为载体,进行理论与实践一体化模式的教学,改革考核方法,收到了良好的效果.