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31.
持续发展是唯一出路   总被引:1,自引:0,他引:1  
讨论了人类、环境与发展的关系,指出不适当的发展模式已使三者之间形成恶性循环,必须及时地改变发展模式。列举了中国面临的严重环境问题,指出只有走可持续发展的道路才是唯一出路。并提出为实施可持续发展应注意的6个主要问题。  相似文献   
32.
半刚性钢-混凝土组合节点受弯承载力的计算   总被引:1,自引:0,他引:1  
在半刚性钢 -混凝土组合框架中 ,混凝土板中的纵向钢筋增加了节点的强度和刚度 ,但是 ,传统的设计方法往往忽略纵向钢筋的作用而采用简化的计算模型。因此 ,出于经济效益考虑 ,应该根据半刚性组合节点的实际受力性能建立更加准确的计算方法。这里详细介绍了考虑混凝土板纵向钢筋作用的半刚性组合节点受弯承载力的计算方法 ,计算结果表明 ,建议的公式与试验结果吻合良好 ,可供规范制定和工程应用参考。  相似文献   
33.
赵怡红  吴晓燕  杜玉宁 《农药》2004,43(7):329-330
枸杞黑果病是枸杞产区的主要病害.发病后造成黑花、黑蕾和黑果,使枸杞产量降低,品质变劣。为探明四种杀菌剂对枸杞黑果病的防治效果及最佳剂量,2003年对下述四种杀菌剂进行了田间药效对比试验,调查防效结果如下:20%三苯基醋酸锡WP450~281g/hm^2(以有效成分计,下同),20%氟硅唑EC21.08g/hm^21.5%噻霉酮EW16、88~21.08g/hm^2、40%氟硅唑EC450g/hm^2和70%甲基托布津WP787.5g/hm^2对枸杞黑果病防效均在88.25%以上。经LSD检验各处理间防效无显著差异。  相似文献   
34.
氟硅唑微乳剂的研制   总被引:2,自引:1,他引:2  
陈福良  王仪  郑斐能  石伶俐  刘西莉  刘铁斌 《农药》2004,43(12):544-546
对国内外文献未见报道的8%氟硅唑微乳剂制剂进行了研制,测定了其冷贮和热贮稳定性等理化性状及生物活性。对黄瓜自粉病室内毒力测定和田间药效试验结果表明,药效与40%乳油相当,对黄瓜安全。  相似文献   
35.
A series of polyimide–silica hybrid films with silica contents up to 30 wt % were successfully prepared by the sol‐gel reaction of tetraethoxysiliane in the presence of poly(amic acid) containing pendent hydroxyl groups. The films were yellow and transparent when the silica content was less than 11 wt %. The chemical structure of the films was characterized by Fourier transform infrared spectroscopy, and the morphology of the films was investigated by scanning electronic microscopy and atomic force microscopy. Thermogravimetric analysis, differential scanning calorimetry, and stress–strain tests were used to measure the performance of the films. The results indicate that the glass‐transition temperatures and decomposition temperatures of the hybrid films increased with increasing silica content, whereas the tensile strength had a maximum with the variety of silica contents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2210–2214, 2003  相似文献   
36.
The leucite crystallization kinetics from a hydrothermally derived precursor seeded with nano-crystalline leucite was investigated by X-ray diffraction and non-isothermal differential thermal analysis. The nano-crystalline leucite was prepared by high-energy milling of high-purity leucite powder and the leucite precursor was prepared by the hydrothermal method of silica sol, aluminum nitrate, and potassium nitrate. After the seeds were introduced, the crystallization temperature of the precursor was lowered by 100°C and the transition phase kalsilite did not appear during the crystallization process. When the seeded precursor was heat treated at 700°C, a small amount of cubic leucite was stabilized to room temperature. The seeded precursor showed an exothermic peak between 800° and 920°C under different heating rates. The activation energy for the growth of leucite from the seeded precursor was 256(SD9) kJ/mol.  相似文献   
37.
The effects of pH, ferrous ion and hydrogen peroxide dosage on the decolorisation and mineralisation of CI Reactive Black 8 by the Fenton process with/without ultrasonic irradiation were investigated. It was verified that the presence of ultrasonic irradiation did not enhance the decolorisation of CI Reactive Black 8 significantly by Fenton's reagents, but it enhanced the chemical oxygen demand removal efficiency. The enhancement was more pronounced for lower (<0.89 mm) or higher (>1.78 mm) ferrous ion dosage. The optimal pH for chemical oxygen demand removal was 3.0. Chemical oxygen demand removal efficiency increased with the increasing H2O2 dosage and reached the highest level at 5.88 mm, but further increase in H2O2 dosage would not increase removal efficiency significantly.  相似文献   
38.
Tall oil, a by-product of the kraft process for pulping softwood, has been shown to have insecticidal properties. In the present study, the active principles in tall oil against the variegated cutworm,Peridroma saucia Hübner, were investigated. GC-MS analysis showed that abietic, dehydroabietic, and isopimaric acids were major resin acid components of crude tall oil and depitched tall oil. When crude tall oil samples of differing resin acid composition were incorporated into artificial diet at a concentration of 2.0% fresh weight, they suppressed larval growth by 45–60% compared to controls. This suppression was significantly (P0.05) correlated with the equivalent contents of abietic, dehydroabietic, isopimaric, and total resin acids. These results were also evident from a diet choice test, showing that the second-instar larvae obviously selected diets with low levels of resin acids when different diets were randomly arranged in a Petri dish. Bioassays with pure resin acids (abietic, dehydroabietic, and isopimaric acids) demonstrated that all individual chemicals have similar bioactivity against this insect. Comparison of the bioactivities of depitched tall oil and an equivalent mixture of pure resin acids in thePeridroma chronic growth bioassay indicated that pure resin acids and depitched tall oil share a common mode of action to this insect. This study confirms that resin acids are major active principles in tall oil against the variegated cutworm, but other chemicals likely also contribute to the bioactivity of tall oil.  相似文献   
39.
陈怡 《贵州化工》2003,28(6):21-22
介绍了合成型机动车制动液的生产和配方,讨论了物料组成对产品的影响。  相似文献   
40.
从提高学生职业能力理念出发,以高素质技能型人才培养为目标,教学改革和课程体系设计为先导,整合信息安全课程体系并进行优化,构建人才培养新方案,对教学内容进行有效探索,以期提高信息安全专业人才培养质量.  相似文献   
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