Trees on farms in Bangladesh

Seasonal yields of wetland rice and wheat were measured under traditionally-managed field trees of five species in northwestern Bangladesh over four years. There was a variable depression of rice (Oryza sativa) and wheat (Triticum aestivum) yields under all tree species. Yield depression overall ranged from 16% for the light-canopiedAcacia catechu to a little over 40% for the dense-canopiedArtocarpus heterophyllus andMangifera indica. Percentage yield depression was independent if agroecological zones, years, and location of the trees on the margins of centrally in a field. Yield depression in the dry season extended further in area than in the wet season; and for most tree species was to some extent alleviated by availability of irrigation. Farmers were well aware of and accepted crop yield losses under different tree species in return for the tree products. Trees with greatest impact on crops yielded products of highest value, mainly fruits and leaf fodder. Previous articles 1, 2 and 3 in the series appeared in Agroforestry Systems 25: 193–216, 31: 39–57 and 33: 231–247 respectively, with slightly different main titles.     

浙江省竹材加工利用现状和发展对策

概述了浙江省竹质胶合板生产、竹胶地板、竹制日用品与竹制工艺品竹材加工利用现状,揭示了竹材加工利用中存在的一些问题,提出了浙江省竹材加工业发展的方向与对策。     

Direction analysis on Contactless Power Transmission System

After analysis on the direction relationship betueen primary side and secondary side of existing contactless power transmission system, a random rotatable pick-up is proposed. Two connecting modes of three orthogonal wound coils are studied. Based on analysis and mathematical calculation, instantaneous output voltage and its ratio to the maximal and minimal value when the pick-up rotate in three-dimensional space is given. All the calculation is verified by experiment results.     

甜叶菊组织培养研究进展

从无菌繁殖体系、培养基和培养条件的选择、愈伤组织的诱导与分化、芽分化和继代增殖培养、生根培养及组培苗的移栽等方面综述了甜叶菊组织培养方面的研究。并提出了甜叶菊组织培养的研究方向。     

砂带磨削效率的实验研究

以杨木、水曲柳和中密度纤维板为试材,使用磨削效率测试系统和表面粗糙度测量仪进行磨削实验,分析比较了三种试材磨削效率和表面粗糙度的变化规律,以及相关因素对磨削效率和表面粗糙度的影响。结果表明,在其他条件不变的情况下,杨木的磨削效率高于水曲柳的磨削效率,中密度纤维板的磨削效率最低;横向磨削的磨削效率高于纵向磨削的磨削效率;杨木的表面粗糙度数值Ra高于水曲柳的Ra,中密度纤维板的Ra最高;横向磨削的表面粗糙度数值Ra高于纵向磨削的Ra。     

Studies on Measurement of Moisture Content by X-ray Scanning Method

In order to explore the feasibility of using X-ray to measure moisture content in the drying process and have a further study on the effect of precision of moisture content when scanning through different grain directions,X-ray scanning method and weighting method were used to measure average moisture content of Cunninghamia lanceolata during hot air drying.The results show that the moisture content values of two methods were very close to one another,the determination coefficients of both were highly correlated with a value over 0.99,and the absolute deviation was below 2%;when scanning along radial direction and longitudinal direction,the precisions of average moisture content were higher than that of the tangential direction,but the deviation can be negligible in the actual measurement;in the practical application,the effect of grain direction on precision of moisture content measurement could not be taken into account when using X-ray to measure the moisture distribution of wood.     

对我国当代目录学理论研究轨迹、路向的辨析

认识与掌握目录学理论研究的轨迹,科学、公正、客观地评说目录学理论研究中的利弊得失,是事关目录学学科建设和发展的一个重要问题。文中通对过目录学理论研究轨迹、路向的阐述辩析,提出目录学的理论研究必须建立在科学研究的基础上方才符合本学科发展规律的命题。     

陕西省横山县林业产业发展方向前瞻

根据横山县林业产业发展现状,实事求是地分析林业产业优势项目,客观而全面地描绘出未来横山县林业产业发展的必由之路,具有较强的前瞻性和可操作性。     

粮食安全与小麦栽培发展趋势探讨

20世纪80年代以来,受淡水资源匮乏、土壤肥力下降、荒漠化威胁严重、病虫害多发、环境日益恶化等因素影响,世界粮食产量增长速度趋于缓慢,消费量增速大于产量增速,世界粮食库存不足,造成全球粮食价格不断攀升,粮食生产和消费的地区间不平衡性进一步增强。根据保障国家安全需要和粮食科技发展趋势,从合理利用小麦优良品种、高产优质栽培、资源高效利用、抗逆减灾、地力提升、机械化轻简栽培、无公害健康管理和低碳栽培8个方面分析提出了今后小麦栽培发展方向。