白皮松地膜覆盖育苗试验

白皮松是我国北方的特有树种，目前已成为城市和庭园绿化的优良树种。根据其生物学特性，在朝阳县林场苗圃地，进行了地膜覆盖育苗试验，取得了较好效果，文章就该树种的地膜覆盖育苗技术进行了报道。经不同时期的苗木生长情况比较看出，不覆膜的对照区，苗木速生期比覆膜的迟到10多天；从苗木质量来看，覆膜的苗木顶芽封顶已达92．3％，而对照区很少形成顶芽；从产量看，覆膜育苗的产苗量达165万株/hm^2，而对照区仅为130．5万株／hm^2。     

Deterioration of a sustainable agro-silvo-pastoral system in the Sudan: the gum gardens of Kordofan

The development and establishment of agroforestry systems is often suggested as a way to stabilize rural economies in developing countries [King, 1979]. At the same time, some traditional systems are being lost, due to an inability to protect the perennial or tree crop components of the system. These traditional systems and the forces that reinforce or destroy them should be carefully studied by those in the process of encouraging adoption of agroforestry systems in the developing world. The gum gardens of Western Sudan are a case in point.Acacia senegal (hashab) andAcacia seyal (talh) are the two major marketable gum-producing trees found in the western region of Sudan. TheAcacias are grown as part of an agro-silvo-pastoral system that has persisted for more than a hundred years in Kordofan Province, where 70% of Sudan's gum Arabic was once produced, as well as most of its grain and livestock products. After a lengthy drought lasting from 1979 to 1985 gum production in Sudan drastically decreased. It was reported that pest attacks and drought were major causal agents in the decline of gum production [Awouda, 1989; Sungar, 1986]. A survey executed in Northern Kordofan Province, starting in August of 1986, did uncover a great number of deadAcacias due to drought and pest attack, but from interviews with gum farmers we conclude that the decline in gum production is largely due to unfavorable socioeconomic relationships exacerbated by the drought, leading to the deterioration of the agroforestry system of production. An inability to get a fair price for gum at the local level and increasing emphasis on a cash economy led to the neglect of the tree components of the system. The gum gardens have long flourished with the intensive husbandry of small-scale farmers. Once these farmers were no longer able to care for them, the gum trees disappeared from the system, indicating that a lack of community stability can be fatal to even a well-developed agroforestry system.     

廊坊市丰盛小区绿化环境设计

通过对廊坊丰盛小区的绿化规划设计介绍，分析说明了当前居住小区的环境设计应体现以人为本，注重艺术品位，创造生态园林。     

导电胶合板的研究

脲醛树脂中分别添加三种导电剂压制导电胶合板，可使胶层面积电阻率降至１００Ω以下。导电胶合板外加低电压时，板面温度分布的不均匀性主要来自电极处的高温区和板子边角处的低温区，小粒度的导电剂可以改善这一不均匀性，研究表明：在添加ＨＦ－２型导电粉和混加ＭＧ型稀释剂的条件下，板面温度分布均匀，中央区域的温度极差小于４℃，变异系数小于６％，并有利于改善板子的胶合强度。     

云南12种豆科灌木饲料中主要钙形态分析

通过对云南12种豆科灌木饲料中的多种钙形态进行了分离提取, 并用原子吸收分光光度法对各形态钙的含量进行了测定, 结果表明: 12个树种中有8个树种的可利用钙比率>29%, 其中木兰的无机钙含量>3 000mg/kg,可以作为动物补充钙的饲料树种。     

不同措施对提高沙地造林成活率的研究

采用固体水、保水剂和覆膜措施，对提高造林成活率进行了比较试验。结果表明，与对照相比，这些措施明显提高了土壤含水量，从而不同程度提高了沙区造林成活率。其中覆膜措施效果最佳，其次为保水剂，最后是固体水措施。     

1995～2002年中国脂松香质量调查研究与统计分析

从各种不同渠道详细调查了1995年至2002年中国脂松香的质量状况，对调查结果进行了统计分析，并将调查结果与脂松香国家标准（GB／T8145－1987）的各项主要技术指标进行了相应的对比研究，结果表明，单就技术指标的统计平均结果而言，各个级别的脂松香质量均优于目前的国家标准要求，而且仍然具有国际领先水平，但是，“混合松香”等质量问题必须引起各方面的足够重视，根据中国采脂树种和客户实际需求的不断变化，按照不同树种或不同用途分别制定分类松香标准或专用松香标准将是未来质量要求的发展趋势。     

覆盖液态地膜对烟田土壤温度及烤烟生长的影响

在湖南省浏阳烤烟栽培中,进行了液态地膜覆盖栽培技术试验应用,结果表明,新型土壤结构调理剂—液态地膜在地面所形成的黑色胶结膜,在地膜覆盖期能有效地起到增温保温作用,0￣20cm耕层土壤温度较露地栽培提高0.7,且对烤烟的生长有一定的促进作用。     

Measurement of Resistivity and Investigation of Electronic Transport for Carbon Nanotube Film

Temperature-depended resistivity of carbon nanotube film is measured and the results show negative temperature effect because the resistivity is decreased as the temperature increased. An electronic transport model for the carbon nanotube film is set up and the resistivity calculation formula is deduced, whose calculating result is compared with experimental datum. It shows that theoretical calculation is well contented with experiment results. Then, the relationship between resistivity and diameter of the carbon nanotube is discussed.