Discussion on the Agroforestry on the Loess Plateau

该文在阐述农林复合经营含义的基础上，介绍了黄土高原地区的几种农林复合经营模式及其生态经济效益，并对黄土高原实行农林复合经营存在的问题进行了讨论。同时，针对目前的治理状况，认为农林复合经营是治理黄土高原、发展经济的主要途径和技术措施。因而开展农林复合经营研究，有着重要的理论和实践意义

Summary on Researches of Plant oils for Fuel

本文介绍了植物油作燃料的研究历史以及试验研究状况，表明植物油作为柴油的替代品是最易实现的方案。但植物油燃料还需进一步试验研究才能使其实用化，其技术储备具有深远的现实意义。本文还通过对燃料油植物栽培问题的探讨，认为“农林复合经营”是生产植物燃料油的重要途径

Study on the Shrubbery Growth and Productivity

采用Logistic方程模拟，揭示了沙棘（Hippophae rhamnoides）、刺槐（Robinia Pseudoacecia）、山杏（Prumus armeniaca）等10个树种的生长发育特性．以试验数据分析了造林密度、施肥、平茬与灌木林产量的密切关系

Oscilatory Instability of Rayleigh-Marangoni-Benard Convection in Two-Layer System

The convective instabilities in two or more superposed layers heated from below were studied extensively by many scientists due to several interfacial phenomena in nature and crystal growth application. Most works of them were performed mainly on the instability behaviors induced only by buoyancy force, especially on the oscillatory behavior at onset of convection (see Gershuni et. Al.(1982), Renardy et. Al. (1985,2000), Rasenat et. Al. (1989), and Colinet et. Al.(1994)) . But the unstable situations of multi-layer liquid convection will become more complicated and interesting while considering at the same time the buoyancy effect combined with thermocapillary effect. This is the case in the gravity reduced field or thin liquid layer where the thermocapillary effect is as important as buoyancy effect. The objective of this study was to investigate theoretically the interaction between Rayleigh-Bénard instability and pure Marangoni instability in a two-layer system, and more attention focus on the oscillatory instability both at the onset of convection and with increasing supercriticality. Oscillatory behavious of Rayleigh-Marangoni-Bénard convective instability (R-M-B instability) and flow patterns are presented in the two-layer system of Silicon Oil (10cSt) over Fluorinert (FC70) for a larger various range of two-layer depth ratios (Hr=Hupper/Hdown) from 0.2 to 5.0. Both linear instability analysis and 2D numerical simulation (A=L/H=10) show that the instability of the system depends strongly on the depth ratio of two-layer liquids. The oscillatory instability regime at the onset of R-M-B convection are found theoretically in different regions of layer thickness ratio for different two-layer depth H=12,6,4,3mm. The neutral stability curve of the system displaces to right while we consider the Marangoni effect at the interface in comparison with the Rayleigh-Bénard instability of the system without the Marangoni effect (Ma=0). The numerical results show different regimes of the developing of convection in the two-layer system for different thickness ratios and some differences at the onset of pure Marangoni convection and the onset of Rayleigh-Bénard convections in two-layer liquids. Both traveling wave and standing wave were detected in the oscillatory instability regime due to the competition between Rayleigh-Bénard instability and Marangoni effect. The mechanism of the standing wave formation in the system is presented numerically in this paper. The oscillating standing wave results in the competition of the intermediate Marangoni cell and the Rayleigh convective rolls. In the two-layer system of 47v2 silicone oil over water, a transition form the steady instability to the oscillatory instability of the Rayleigh-Marangoni-Bénard Convection was found numerically above the onset of convection for ε=0.9 and Hr=0.5. We propose that this oscillatory mechanism is possible to explain the experimental observation of Degen et. Al.(1998). Experimental work in comparison with our theoretical findings on the two-layer Rayleigh-Marangoni-Bénard convection with thinner depth for H<6mm will be carried out in the near future, and more attention will be paid to new oscillatory instability regimes possible in the influence of thermocapillary effects on the competition of two-layer liquid

宁南山区红豆草引种试验研究

该项研究成果采用比较生态学的方法，在不同立地条件下对红豆草的植物学特性、生长发育特性、栽培技术、经济性状、利用等进行了比较系统的观测试验。试验表明: 1、红豆草在宁南山区，无论荒山退耕地或川平地、水地种植，均生长健壮，发育良好，其产量和饲用价值高。自然落种，繁衍后代。2.在栽培技术上，通过适宜播种量试验，改变了国内外长期采用的亩播量6～14斤和20～25斤，使亩播量降低到2～4斤。3.通过形态解剖特征的研究，进一步证明了红豆草具有旱生结构的特征，有较强的抗旱能力。4.当根茎受到不良环境因子危害不能萌发时，其主根和测根上的不定芽能萌发出土形成新的植株，正常开花结实；甚至当子叶出土后长出1～2片真叶的幼苗地上部受害后，可从被害的胚轴处形成幼苗。5.通过试验、示范和推广，已在固原及银南地区种植3万亩，总经济效益达400万元，这对于加快发展牧业和增加群众收入，作用显著。本研究成果不仅对加速牧业基地建设，调整农村经济结构，治穷致富，有现实的科学意义，同时对我国黄土高原和西北广大地区，增加和改善植被、控制水土流失，改善生态环境，具有较高的实用价值

Thermal resistance analytical model for thermoelectric component with series-parallel connection

为了选择合适的温差电组件和外部换热器,根据非平衡态热力学理论和牛顿冷却定律,对温差电组件采用串并联连接方式的温差发电系统进行了研究,导出了系统输出功率的热阻解析模型,探讨了温差电组件总数量、并联组件数量、热电模块及其热端和冷端的热阻等对系统性能的影响.结果表明,系统电阻与负载电阻、热电模块热阻与其热端和冷端的热阻之间存在匹配关系,能使系统获得最大的输出功率;随着并联组件数量的增加,最大输出功率和回路电流得到了提高,但系统的输出电压却降低了.研究结果为温差发电系统的合理装配及性能优化提供了理论参考.In order to choose the appropriate thermoelectric components and external heat exchangers,the thermoelectric generation system with series-parallel connection of thermoelectric components was investigated according to the non-equilibrium thermodynamics theory and Newton cooling law,and the thermal resistance analytical model for system output power was derived.In addition,the effect of total number of thermoelectric components,number of components with parallel connection,thermoelectric module as well as thermal resistance at both hot and cold ends of the module on the system performance was discussed.The results show that there is a matching relationship between the system resistance and load resistance.Moreover,the thermal resistance of thermoelectric module and the thermal resistance at both hot and cold ends of the module also exhibit a matching relationship.Therefore the maximum output power can be obtained for the system.With increasing the number of components with parallel connection,the maximum output power and loop current get enhanced,while the output voltage of the system decreases.The present results can provide the theoretical reference for the reasonable assembly and performance optimization of thermoelectric generation system.广东省重大科技专项项目(2008A080302002;2010A080405003);粤港关键领域重点突破项目(佛山专项)(2009Z015

黄土高原半干旱地区西吉县农村能源综合建设试点

&ldquo;黄土高原半干旱地区西吉县农村能源综合建设试点&rdquo;是&ldquo;七&middot;五&rdquo;国家重点科技攻关项目。该项研究认真执行&ldquo;因地制宜，多能互补，综合利用，讲究效益&rdquo;和开源节流并重的农村能源建设方针，选择西吉县为单元，以试区的科学试验为基础从全局出发，探讨了黄土高原类型地区解决农村能源严重短缺问题的模式和途径。该项研究突出以生物质能为主，走林、农、草、牧能综合发展的道路，提出了黄土高原水土保持型薪炭林（草）模式和永续多年生混播草地模式等，是建立农村能源农业生态良性循环的最佳模式，反映了地区的特色，有所创新，对黄土高原地区和我国其它类型的农村能源建设具有重要的指导意义

Oscillatory Instability of Rayleigh-Marangoni-Benard Convection in Two-Layer System

The convective instabilities in two or more superposed layers heated from below were studied extensively by many scientists due to several interfacial phenomena in nature and crystal growth application. Most works of them were performed mainly on the instability behaviors induced only by buoyancy force, especially on the oscillatory behavior at onset of convection (see Gershuni et. Al.(1982), Renardy et. Al. (1985,2000), Rasenat et. Al. (1989), and Colinet et. Al.(1994)) . But the unstable situations of multi-layer liquid convection will become more complicated and interesting while considering at the same time the buoyancy effect combined with thermocapillary effect. This is the case in the gravity reduced field or thin liquid layer where the thermocapillary effect is as important as buoyancy effect. The objective of this study was to investigate theoretically the interaction between Rayleigh-Bénard instability and pure Marangoni instability in a two-layer system, and more attention focus on the oscillatory instability both at the onset of convection and with increasing supercriticality. Oscillatory behavious of Rayleigh-Marangoni-Bénard convective instability (R-M-B instability) and flow patterns are presented in the two-layer system of Silicon Oil (10cSt) over Fluorinert (FC70) for a larger various range of two-layer depth ratios (Hr=Hupper/Hdown) from 0.2 to 5.0. Both linear instability analysis and 2D numerical simulation (A=L/H=10) show that the instability of the system depends strongly on the depth ratio of two-layer liquids. The oscillatory instability regime at the onset of R-M-B convection are found theoretically in different regions of layer thickness ratio for different two-layer depth H=12,6,4,3mm. The neutral stability curve of the system displaces to right while we consider the Marangoni effect at the interface in comparison with the Rayleigh-Bénard instability of the system without the Marangoni effect (Ma=0). The numerical results show different regimes of the developing of convection in the two-layer system for different thickness ratios and some differences at the onset of pure Marangoni convection and the onset of Rayleigh-Bénard convections in two-layer liquids. Both traveling wave and standing wave were detected in the oscillatory instability regime due to the competition between Rayleigh-Bénard instability and Marangoni effect. The mechanism of the standing wave formation in the system is presented numerically in this paper. The oscillating standing wave results in the competition of the intermediate Marangoni cell and the Rayleigh convective rolls. In the two-layer system of 47v2 silicone oil over water, a transition form the steady instability to the oscillatory instability of the Rayleigh-Marangoni-Bénard Convection was found numerically above the onset of convection for ε=0.9 and Hr=0.5. We propose that this oscillatory mechanism is possible to explain the experimental observation of Degen et. Al.(1998). Experimental work in comparison with our theoretical findings on the two-layer Rayleigh-Marangoni-Bénard convection with thinner depth for H<6mm will be carried out in the near future, and more attention will be paid to new oscillatory instability regimes possible in the influence of thermocapillary effects on the competition of two-layer liquid

黄土高原飞机播种造林种草试验

该试验跨森林草原、灌丛草原、干草原、荒漠草原四个自然地带。在年降雨量350至250毫米左右的干草原和荒漠草原地区飞播沙打旺取得了成功，在国内是首次，从而开辟了沙打旺飞播新的生态区。吴旗飞播建造沙棘、沙打旺带状混交植被试验，解决了沙打旺衰败后的植被接替问题，通过辐射诱变技术选育出沙打旺早熟品种，解决了年均温不足10℃地区沙打旺结籽困难的问题