基于计算机相关课程的编程项目实践探讨——以北京林业大学为例

编程实践教育对当代大学生编程能力的培养和综合素质的提升具有重要作用。然而,当前高等院校学生编程实践能力的培养存在着编程实践内容相对单一、各编程实践项目间的内容关联性不强等问题,影响了学生编程实践能力的提升。为此,探讨了基于课程体系的编程实践项目的设计与实施方法,即在相对宽松的时间条件下,根据课程体系安排编程实践项目,以此来锻炼学生的综合编程实践能力,促进课堂教学与编程实践的快速结合。该方法能够有效锻炼学生的编程实践能力,增强学生对专业知识的理解,提升学生的创新意识。     

浅析宏程序在FANUC 0i数控系统中的应用

通过典型零件的宏程序编程实例分析其编程方法，并归纳出手工编程中应．用宏程序解决复杂零件数控加工编程问题的作用和技巧。     

C#与SAS混合编程——以学生成绩评估可视化开发中的应用为例

探讨了Visual C#和SAS基于调用.bat文件的混合编程方法,通过编写.bat文件、Visual C#调用.bat文件和Visual C#调用EXCEL等文件这3个步骤,形成了一种便利的编程方法,可以解决使用跨平台软件混合编程的问题。并且,将该方法在学生成绩评估可视化开发中加以了应用,较好地验证了C#与SAS混合编程的有效性和便利性。     

植物细胞编程性死亡综述

细胞编程性死亡现象普遍存在于植物体的整个生长发育过程中。综述了植物细胞编程性死亡的特征与检测方法及植物正常生长发育中发生的细胞编程性死亡;阐述了植物超敏反应、逆境胁迫与细胞编程性死亡之间的关系;总结了对植物细胞编程性死亡3个层次的调控(基因调控、酶调控和信号调控);并对植物细胞编程性死亡的深入研究进行了展望。     

数控机床坐标系统指令与对刀方法

介绍了数控机床坐标系和工件坐标系(又称编程坐标系),阐述了不同数控系统的具体坐标指令及对刀方法,并分析了各指令之间对刀方法的区别与联系,从而加深理解数控编程及加工的全过程。     

浅析数控机床编程中R参数的几种用法

对FANUC系统中R参数在数控车削编程、加工中心编程、快走丝线切割编程中的应用作了分析归纳。通过在不同场合R参数应用特点阐述,给编程带来方便,对我们的学习、工作有一定的帮助。     

AutoCAD VBA平台下纤维过滤模型的构建

为了构建纤维束三维模型,在ANAYS Fluent平台下进行了纤维过滤器流体模拟,通过AutoCAD的VBA平台下编程的方法,研究了三维规则与随机纤维模型的构建,结果为在AutoCAD2014平台下在VBA语言编程条件下,达到三维规则与随机纤维模型快速、精确构建,并且成功导入ANAYS ICEM的效果,表明了AutoCAD的VBA平台下编程构建三维纤维模型,进行后期数值模拟是可行的。     

在FANUC0i系统中巧用径向切槽循环G75指令

在FANUC0i系统中，采用径向切槽循环G75指令可提高工件外圆沟槽的切削加工效率，简化编程，提高编程的正确性。介绍了G75指令的内容，并以实际加工为例说明了该指令的应用方法。     

利用程序型计算器进行公路坐标计算探讨

本文介绍了一种原理简单、操作方便的道路平曲线坐标计算方法，以及运用程序型计算器编程进行坐标计算，系统地研究了计算器编程的程序设计，以及在野外测量放样工作中全站仪与计算器的联合应用，使现场放样计算变得准确、快捷。     

数控加工手工编程技巧的应用

数控机床所使用的程序是按一定的格式并以代码的形式编制的，一般称为“加工程序”，目前工件加工程序的编制主要采用手工编程和CAD/CAM两种方法。手工编程是利用一般的计算工具，通过各种数学方法，人工进行刀具轨迹的运算，并编制指令。这种方式比较简单，很容易掌握，适用于中等复杂程度程序或计算量不大的工件编程，适应性较广，     

Repair and strengthening of timber cantilever beams

This research aims to study the feasibility of repair and strengthening of timber cantilever beams used in historic buildings. It is conducted to investigate the feasibility of using different valid materials and techniques to repair and strengthen timber cantilever beams in new and historic timber buildings. The study is performed in terms of structural performance as well as historic and architectural values. An experimental program of several different materials and techniques is executed. The results are driven in terms of initial cracking load, crack propagation for the tested samples at different loading stages, deflection values, and failure load for each repaired or strengthened material and technique. The main variables are timber types (new and historic), repair and strengthening materials (steel plates, Glass Fiber Reinforced Polymer wrap, and Carbon Fiber Reinforced Polymer laminates), repair or strengthening techniques (near surface mounted and externally bonded system), and cantilever length (1000 and 1250?mm). Test results indicated that using steel plates, glass fiber wrap, and carbon fiber laminates increases the value of failure loads and decreases the deflection at both; repaired and strengthened timber cantilever beams compared to control beams.     

竹大片刨花板对竹材生物学特性的适应性

以云南四种典型材用丛生竹（龙竹、甜龙竹、黄竹和油勒竹）宏观构造、组织结构、主要物理力学性质和化学组份等竹材主要生物学特性的研究分析结果为依据,提出了竹大片刨花板的结构、制板工艺和设备与原料竹材生物学特性之间应有的适应性关系。继而,通过实验室系列化试验和工厂试生产,确定了竹大片刨花板的应有性能和最佳工艺条件包括竹大片刨花的最佳质量指标及其最佳制备条件。     

Comparative Study in Chemical Character and Fatty acid Compositions of Masked Civet''''s Fat and Nutria''''s Oil

IntroductionMaskedciVet(Paguma18vata),Mammalia,Viverridae,ismainlydiStributedinShanxi,Sichuan,Tibet,Yunnanprovinces,etc..Itsmeatisdeliciousandhasspecialflavor.Itiseasytoberaisedartificially,withhighproduCtivity.Nutria(MyocasterCOypus),Rodentia,Capromyidae,originatedinArgentina,Chili,etc.insouthAmerica.Itisakindofherbivoresfur-bearer.itsartificialraisinghassuchmeritsasdurablefurandlowcostandhighproduCtivity.MaskedcivetandnutriahavehigheconomicvalueandwideprospeCtofutilization.Atpresen…     

自然保护区合作管理(共管)理论研究综述

自然保护区合作管理自20世纪80年代末期开始逐步兴起,在资源管理中被广泛使用。文章介绍了共管的含义、共管实施原则、分析框架和评价指标。从公共部门和私有部门的互动模式、集体行动类型的不同、政府和资源使用者的参与管理方式三个方面论述了共管的模式。分析了政府和社区在共管实施过程中的作用,指出共管仍面临着分权不够、合作中的文化障碍、组织类型简单和信息交流不充分、社区参与能力和认识能力不足等挑战。     

Chemical composition of wood and its connection with wood anatomy in Betula pubescens

ABSTRACT

The connection between chemical composition and anatomy of wood is poorly studied. Abiotic and biotic growth conditions affect the synthesis of structural compounds and the anatomy of wood at the same time as they affect growth. In this study, the wood chemical composition, and connections between wood chemistry and anatomy were studied in downy birch (Betula pubescens Ehrh.) grown on four growth sites possessing mineral and peat soils. Lignin, holocellulose, extractive and ash contents, and effective heating value were analysed and compared with libriform fibre double wall thickness and lumen diameter, vessel size and number, and ray and axial parenchyma numbers. Measured lignin and extractive contents were exceptionally high and holocellulose content low. Correlations between wood anatomy and effective heating value were partly different on different soils. Correlations between holocellulose and anatomy were the opposite of the correlations between other chemical compounds and anatomy. The significant correlations between chemical composition and anatomy were commonly opposite in trees grown on peat than in trees grown on mineral soil. Particularly, vessel characteristics and fibre wall thickness correlated significantly with wood chemistry in trees grown on mineral soil. The connections between wood anatomy and chemistry proved to be soil-dependent.     

用苯芴酮萃取分光法测定微量锗

本文探讨了用苯芴酮萃取分光法测定微量锗的实验条件和步骤．结果表明，用此法测定微量锗灵敏度高、操作简便、准确，是测定微量锗的较好方法．可用于对植物和食品中的微量锗进行检测．     

Spatial patterns of Douglas-fir and aspen forest expansion

Spatial patterns, rates, and density of encroaching forests into adjacent grasslands have important implications for long-term land use management and resource planning. This study examines the effects of Douglas-fir (Pseudotsuga menzeisii) and aspen (Populus tremuloides) regeneration mechanisms on sucker and seedling spatial patterns, distance from adult trees, and density in encroaching forests. A total of 8,924 aspen suckers and 1,244 Douglas-fir seedlings were counted and mapped in 2,920 quadrats (5 m × 5 m) in 106 plots along a lower forest-grassland ecotone in the Centennial Valley, MT, USA. Sucker and seedling spatial patterns were analyzed using Morisita’s I index. Average sucker and seedling density per quadrat and distance from adult trees were estimated for each plot and compared between aspen-dominated plots and Douglas-fir-dominated plots using ANOVA tests. Aspen suckers were established in a clustered spatial pattern at a significantly higher density and a significantly shorter distance from the adult trees. In contrast, Douglas-fir seedlings were established in varying spatial patterns at a significantly lower density and a significantly greater distance from the adult trees. Forest encroachment into the adjacent grassland in the Centennial Valley is occurring in contrasting patterns and at varying rates and densities due to the difference in aspen and Douglas-fir regeneration mechanisms.     

气候因子对竹子生长的影响研究综述

竹子是集经济、生态和社会效益于一体的优良林种,是区域农村经济社会发展的重要资源和生态环境保护的重要屏障.温度、水分、光照、大气组分等的变化直接影响着竹子的生长发育和分布.该文从主要气候因子对竹子生物学特性、生态学特征及其分布和经济产出的影响研究现状进行了综述,提出了今后需要重点开展的相关研究内容.     

Modelling impacts of changes in carbon dioxide concentration,climate and nitrogen deposition on carbon sequestration by European forests and forest soils

Changes in the Earth's atmosphere are expected to influence the growth, and therefore, carbon accumulation of European forests. We identify three major changes: (1) a rise in carbon dioxide concentration, (2) climate change, resulting in higher temperatures and changes in precipitation and (3) a decrease in nitrogen deposition. We adjusted and applied the hydrological model Watbal, the soil model SMART2 and the vegetation model SUMO2 to asses the effect of expected changes in the period 1990 up to 2070 on the carbon accumulation in trees and soils of 166 European forest plots. The models were parameterized using measured soil and vegetation parameters and site-specific changes in temperature, precipitation and nitrogen deposition. The carbon dioxide concentration was assumed to rise uniformly across Europe. The results were compared to a reference scenario consisting of a constant CO₂ concentration and deposition scenario. The temperature and precipitation scenario was a repetition of the period between 1960 and 1990. All scenarios were compared to the reference scenario for biomass growth and carbon sequestration for both the soil and the trees.     

我国湿地保护管理现状与优化对策

我国湿地资源在全球占据重要地位, 在我国生物多样性保护与社会经济可持续发展方面发挥着重要作用。在总结我国湿地保护管理现状的基础上, 文中指出我国湿地保护管理方面存在着责权不清、管理机构不健全且有重叠、将湿地划为未利用地以及制度与机制有待完善等问题, 提出了优化我国湿地保护管理体制的建议, 以期为湿地相关立法提供依据, 并进一步促进我国湿地保护管理水平的整体提升。