共查询到20条相似文献，搜索用时 140 毫秒
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我国空调设备具有多样性和复杂性,应在空调冷源、空气处理设备、空调末端产品、控制系统、机房专用机、家用空调、通风设备等方面开发新技术,新产品,在引进和消化国外技术的基础上,大力保护和发展民族产业。供热设备应开发适用性广的散热器,发展低温地板辐射供热方式和远红外辐射供热设备,研制适合中国国情的热计量手段。 相似文献
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首先分析了通风与空调系统主要噪声源的来源,继而论述了针对其噪声来源采取切实可行的消声措施,其控制噪声的方法和措施是值得借鉴的。 相似文献
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根据大学体育馆使用的特殊性,提出大学体育馆空调通风系统自监控的设计思想、原则、监控内容和目标,并选择合适的监控系统,采取适当的节能措施,进行空调通风系统监控设计,这里介绍了建筑设备监控系统、系统的构成、本监控系统采取的节能措施。 相似文献
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介绍了传染性隔离病房二级隔离的概念、建筑平面布局、空调通风系统的形式、气流组织、气流流向、负压控制等问题,此外还介绍了简易负压隔离病房的概念. 相似文献
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The levels of susceptibility of adult female European red mite, Panonychus ulmi (Koch) populations collected from apple orchards in Bursa region of Turkey, to acaricides, dicofol, bromopropylate and fenpyroximate
belong to two different groups and an acaricide–insecticide, amitraz, were determined by a petri leaf disk-Potter spray tower
method. When compared with the susceptible population, resistance ratios, as indicated by LC50 values, ranged from 2.2 to 11.9, 0.8 to 3.6, 1.0 to 22.5 and 0.9 to 7.9, while LC90 values varied from 1.6 to 9.8, 1.0 to 5.4, 1.0 to 47.4, 1.4 to 36.6, respectively, for amitraz, dicofol, bromopropylate and
fenpyroximate. An examination of bioassay responses showed that susceptibility was lower for fenpyroximate and bromopropylate
than for the other two compounds in the order of amitraz < dicofol. In conclusion, P. ulmi susceptibility to tested compounds varied widely from location to location. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 相似文献
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为逐步改善省会的空气质量,研究了火炬树在石家庄市沙地立地条件下的生长适应性,调查了在沙地条件下耐寒、耐旱、耐热、耐阴、抗病虫及极限条件下的生长情况。提出了火炬树与其它防风固沙植物的配置形式,从而形成乔灌草多层次组合的防风固沙生态体系。 相似文献
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采用硫酸催化剂,考察了苯酚与核桃壳质量比等条件对核桃壳液化的影响。结果表明相同液化条件下,随着苯酚与核桃壳质量比从2∶1升至5∶1,残渣率从26.49%降至6.60%;随着浓硫酸加入量从2%增至4%、反应时间从5 min延至120 min、反应温度从100℃增至150℃,残渣率则分别从20.79%降至10.48%、48.84%降至15.62%、28.86%降至9.39%,游离酚含量分别从17.32%降至12.67%、41.71%降至10.25%、21.94%降至14.33%。同时,液化产物重均相对分子质量(MW)可降至706~1 030、分散度可降至1.04~1.25;液化产物中高相对分子质量部分随着苯酚与核桃壳质量比的增加有所降低,但随着浓硫酸加入量、液化反应时间和温度的增加而有所增加;核桃壳液化产物/苯酚/甲醛共缩聚树脂胶黏剂(WPF)与传统酚醛树脂胶黏剂(PF)的对比表明,WPF的胶接强度可达1.33 MPa,可作为胶合板用胶黏剂。 相似文献
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完善我国林权法律制度初探 总被引：9，自引：0，他引：9
林权是森林、林木、林地所有权和使用权的统称,是以森林、林木、林地的占有、使用、收益和处分为内容的物权.当前的林权法律制度收益权实现途径、处分权的限制等方面存在不足,要以保障林权人利益为出发点,建立权属明晰、收益保障、流转自由、限制合理的林权制度. 相似文献
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CHEN Peng ZHAO Guangjie College of Material Science Technology Beijing Forestry University Beijing P.R.China 《中国林业科技(英文版)》2007,(2)
There are many advantages of bended wood,such as good-looking shape,simple process and low cost.The product,however,is easy to get recovery,which is urgent to be dealt with.This paper concludes the features of deformation and recovery of bended wood and wood-based composites and summarizes four treating methods to keep dimensional stability.Compared to bended solid wood,some elementary perspectives on the research of bended wood-based composites are presented.The purpose of this paper is to suggest:1)to investigate the optimum heating time and temperature that bended wood and wood-based composites need from the formation of deformation to the recovery and to the permanent fixation,according to its changes of dimensional stability such as curvature radius;2)to measure the composites comprised of wood and adhesives on the changes of stress relaxation,dynamic viscoelasticity and crystal1ization field;3)to quantitatively analyze changes of the major components in wood cell wall polymers as well as the composites under heat/steam treatment and untreated conditions.It will be helpful for subsequent research to clarify on the mechanisms of permanent fixation of bended wood and also contribute to that of wood-based composites. 相似文献
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集体林权制度改革的对策探讨 总被引：3，自引：0，他引：3
改革集体林权制度是解放林业生产力,增强林业活力的重要措施;是调整林业生产关系,进一步明晰林业产权,落实林业经营权,确保农民处置权的有效途径。通过改革集体林权制度,能充分调动各社会主体投资发展林业积极性,是我国林业发展的必经之路。 相似文献
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林木低磷胁迫适应机制研究进展 总被引：3，自引：0，他引：3
土壤有效磷缺乏在自然环境中是一种非常普遍的现象,近年来世界各国针对植物的觅磷和耐磷机制进行了大量研究,然而目前相关的综述性报道多限于农作物,对林木低磷胁迫适应性的综述性报道尚不多见。在长期进化过程中,林木为利用土壤中现有的含量极低的有效磷,形成了各种适应低磷胁迫的机制。文中从林木根系的形态学变化、根系分泌物对土壤难溶性磷的活化作用、林木对土壤低浓度有效磷的吸收利用以及应对低磷胁迫的遗传调控等方面综述了低磷环境中林木的适应机制,为揭示林木对缺磷环境的适应机理、发掘林木自身对土壤有效磷高效率的吸收利用能力、以及进一步筛选林木的磷高效品种和合理经营管理人工林提供参考。 相似文献