15 research outputs found
公共図書館にある閉架書庫の代替機能に関する研究
法政大学大学院デザイン工学研究科建築学専攻修士課程; 主査 安藤直見, 副査 岩佐明彦In this digital age, the theory of the extinction of libraries and the theory that libraries are no longer needed has been propagated, and libraries have been greatly impacted by the characteristics of digital materials, Under these circumstances, how can we make the most of our libraries? The author has focused on the stacks in small and medium-sized libraries and, based on the hypothetical premise that the stacks should be made unnecessary, has decided to consider alternative functions for the stacks
宁夏贺兰山区的珍禽——蓝马鸡
蓝马鸡(Crossoptilon auritum)属鸡形目(Galliformes)、雉科(Phasianidae)、马鸡属(Crossoptilon),又名马鸡、松鸡、羊角鸡,是我国特有的珍禽,为国家二级重点保护野生动物,被定为宁夏回族自治区区鸟。蓝马鸡羽色艳丽,姿态优雅,成年蓝马鸡体长约95厘米、高约55厘
论“十五”期间宁夏自然保护区建设进展及绩效评估
随着西部大开发战略的实施和社会、经济、科技的不断发展,林业建设迎来了历史性的发展机遇,特别是党的十六大及《中共中央、国务院关于加快林业发展的若干决定》,明确了中国林业必须由林业产业为主向生态建设为主的历史性转变,林业发展不能沿袭原始资本积累以消耗自然资源和破坏自然环境为代价的老路,必须要树立科学的发展观,走跨
宁夏贺兰山——石鸡繁殖巢记述
石鸡(Alectoris chukar),在世界上分布于欧洲南部、小亚细亚、喜马拉雅山脉、亚洲中部至蒙古及中国北部,在我国北方地区为地方性常见鸟类。石鸡喜欢成对或成群活动于开阔山区、高原、草原及干旱草地。宁夏贺兰山国家级自然保护区分布着石鸡的贺兰山亚种(Alectoris chukar potanin),当地人又叫它“呱呱鸡”。 2005年6月8日,在宁夏贺兰山国家级自然保护区木头井沟进行森林资源清查时,发现石鸡巢一个。我们是在野外工作时无意间惊动了正在孵卵的召鸡,石鸡从巢内窜出逃走。我们发现该巢后即对其进行了测量,
贺兰山地区冬季鸟类物种多样性调查
2006年和2007年的11~12月,采用固定样线统计法连续2 a对贺兰山地区冬季鸟类组成进行了调查。共记录鸟类7目17科72种,约占全国鸟类种数(1 319种)的5.46%,占宁夏鸟类种数(320种)的22.50%。在地理区划上,古北界鸟类61种,占该地区鸟类种数的84.72%;广布种类11种,占15.28%;未观测到东洋界鸟类。其中,留鸟51种,占70.83%;冬候鸟11种,占15.28:旅鸟10种,占13.89%。具有明显集群生活方式的有41种,占56.94%。山地草原带出现的鸟类种类最多,有40种,其次是山地疏林草原带和山地针叶林带,分别有34种和35种,亚高山灌丛和草甸带最少,仅有5种。贺兰山冬季有国家Ⅰ级重点保护野生鸟类3种,有国家Ⅱ级重点保护野生鸟类14种
贺兰山蓝马鸡春夏季对栖息地的选择
2008年4~8月,在贺兰山利用痕迹检验法和直接观察法对蓝马鸡春夏季的栖息地选择进行研究。通过在选定的15条沟段里进行调查,春夏季分别测定了135个和126个样方的16种生态因子。结果表明,春夏季贺兰山蓝马鸡在优势乔木、灌木密度、灌木高度、灌木距离、坡向、坡位、海拔高度、人为干扰距离和隐蔽级上差异极显著(P0.05),相对于春季生境而言,贺兰山蓝马鸡夏季更偏爱选择灌木密度小、高度低、距离近,海拔较高,人为干扰距离较远,隐蔽程度较高的栖息地。典则系数显示春夏季蓝马鸡的栖息地选择存在一定的重叠和分离,Wilk’sλ值显示春夏季蓝马鸡的生境选择具有较高的差异性(Wilk’sλ=0.692,x2=121.769,df=12,P<0.001)。逐步判别分析表明在区分春夏季蓝马鸡栖息地选择方面有一系列生态因子发挥作用,依照贡献值的大小依次为海拔高度、人为干扰距离、灌木高度、隐蔽级、灌木密度和乔木高度,由这6个变量构成的方程对春夏季蓝马鸡生境的正确区分率达到84.6%,其中对春季的误判率为15.4%,对夏季的误判率为17.2%
Dynamic investigation of a spatial multi-body mechanism considering joint clearance and friction based on coordinate partitioning method
The dynamic response of the model, which is the series connection of a planar four-bar mechanism and a spatial RSSR mechanism, is analyzed considering revolute joint clearance and friction. A non-holonomic constraint equation is proposed to solve the Euler angles. The dynamic equations are established by combining the Lagrange equation with the modified contact model and the LuGre friction model. A dynamic solution program based on the coordinate partitioning method is designed to solve the dynamic equations. The paper verifies the correctness and applicability of the solution program by comparing the numerical calculation results with Adams simulation. Compared with the results of eccentricity, it is found that the maximum penetration is very sensitive to the change of the slider speed rather than the clearance. The equivalent damping coefficient proposed by authors not only represents whether a collision occurs, but reflects the hysteresis caused by damping. The macroscopic manifestation of the up and down oscillation of eccentricity is the swing of the contact point. Besides, the system quickly changes from the collision into the stable state due to considering friction, and the peak value of each collision reduces greatly. Therefore, when the clearance is unavoidable, the clearance joint should be coated with a material with a large friction coefficient and not easy to wear.</p
Dynamic investigation of a spatial multi-body mechanism considering joint clearance and friction based on coordinate partitioning method
The dynamic response of the model, which is the series connection of a planar four-bar mechanism and a spatial RSSR mechanism, is analyzed considering revolute joint clearance and friction. A non-holonomic constraint equation is proposed to solve the Euler angles. The dynamic equations are established by combining the Lagrange equation with the modified contact model and the LuGre friction model. A dynamic solution program based on the coordinate partitioning method is designed to solve the dynamic equations. The paper verifies the correctness and applicability of the solution program by comparing the numerical calculation results with Adams simulation. Compared with the results of eccentricity, it is found that the maximum penetration is very sensitive to the change of the slider speed rather than the clearance. The equivalent damping coefficient proposed by authors not only represents whether a collision occurs, but reflects the hysteresis caused by damping. The macroscopic manifestation of the up and down oscillation of eccentricity is the swing of the contact point. Besides, the system quickly changes from the collision into the stable state due to considering friction, and the peak value of each collision reduces greatly. Therefore, when the clearance is unavoidable, the clearance joint should be coated with a material with a large friction coefficient and not easy to wear.</p
