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71.
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Bambang Subyakto Toshimitsu Hata Isamu Ide Shuichi Kawai 《Journal of Wood Science》2001,47(3):199-207
Creep under fire of laminated veneer lumber (LVL) joined with metal connectors was studied. The fire-resistant performance of LVL butt joints connected with metal plates protected with graphite phenolic sphere (GPS) sheeting was discussed. The GPS sheeting was overlaid on the joint in different sizes and locations. The joint was exposed to a burner with a top flame temperature of 800°C and loaded with a load of 200 N to test for creep under fire. The results showed that the fire-resistant performance of the joint was markedly improved by the sheeting. The size and location of the GPS sheet significantly affected the time to rupture of the specimen, which was six times longer than that without GPS. Temperature measurements at the joint showed that the GPS sheeting distributed the heat along the surface and delayed failure. Thermographic images and analyses clarified the improvement in fire-resistant properties due to GPS. 相似文献
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Santos MR Carvalho AA Medeiros IA Alves PB Marchioro M Antoniolli AR 《Fitoterapia》2007,78(3):186-191
In non-anesthetized normotensive rats, Hyptis fruticosa essential oil (HFEO, 5, 10, 20 and 40 mg/kg; i.v.) induced hypotension associated with tachycardia. In intact and isolated rings of rat superior mesenteric artery (control), HFEO (1-1000 microg/ml, n=6, cumulatively) induced concentration-dependent relaxations of tonus induced by 10 microM phenylephrine (Phe) (pD(2)=2.6+/-0.27; E(max)=64+/-8.3%). In denuded endothelium pre-contracted rings with Phe or K(+)-depolarizing solution (80 mM), the concentration-response curves to HFEO were not shifted (pD(2)=2.3+/-0.25 and 2.3+/-0.28, respectively), but their maximal responses were significantly (P<0.05 vs control) increased (E(max)=122.3+/-18.2% and 92+/-3.6%, respectively). HFEO was also capable of antagonizing the concentration-response curves to CaCl(2) (3 microM-30 mM) in a dose-dependent manner. 相似文献
76.
K. Premkumar A. Pachiappan Suresh K. Abraham S. T. Santhiya P. M. Gopinath A. Ramesh 《Fitoterapia》2001,72(8):398-911
Spirulina fusiformis was tested for its possible in vivo protective effects against cyclophosphamide (CP) and mitomycin-C (MMC) induced genotoxicity and oxidative stress in mice. Pre-treatment with S. fusiformis (250, 500 and 1000 mg kg(-1), p.o., daily for 5 days) significantly reduced the chromosomal damage and lipid peroxidation with concomitant changes in antioxidants and detoxification systems. All the three tested doses were effective in exerting a protective effect against CP and MMC. 相似文献
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S. Langton 《Agroforestry Systems》1990,12(2):173-185
A number of different types of edge effects on experimental plots are defined, and it is shown that they are frequently important in agroforestry experiments. Methods of eliminating edge effects, either at the design or the analysis stage, are described. Computer simulations, based on uniformity data, are used to investigate the efficacy of neighbour-balanced designs, with and without neighbour terms, for reducing the problem of neighbour effects between different treatments. It is concluded that, while neighbour-balanced designs may be useful in certain situations or in combination with other methods, it is preferable to eliminate edge effects by using adequate guard rows. Recommendations are therefore made concerning the correct use of guard areas in agroforestry experimentation. 相似文献
79.
Economic evaluation of financial and non-financial costs and benefits in agroforestry development and the value of sustainability 总被引:1,自引:0,他引:1
C. Price 《Agroforestry Systems》1995,30(1-2):75-86
Financial appraisal of agroforestry is not different in kind from appraisals applied to pure forestry. Existing techniques for valuing non-market effects may also be applied. Effects on hydrological and carbon fluxes might be less favourable than those of pure forests. In the confusing field of biodiversity valuation too, only limited and specific claims can be made for agroforestry. Amenity valuation techniques developed for trees and woodlands encounter additional problems of interpretation in an agroforestry context. Agroforestry may offer a quantifiable value in short-term sustainability, and might meet recent economic definitions of long-term sustainable development, without encountering the full dangers to future generations embodied in conversion of natural to human capital. 相似文献
80.
对黄淮海平原农区宽带距多行带梨麦间作系统水分效应、产量效应与土地利用效应进行了研究。结果表明:小麦拔节一乳熟期间,间作系统内小麦日蒸腾耗水比单作麦田低21.6%;距梨树0.0~7.0m,为土壤水分的降低区,7.0~25.0m为土壤水分提高区,间作系统总体上使麦田0~200cm土壤贮水量提高11.81%;间作系统内小麦水分利用率比单作麦田约高8.7%;间作系统小麦单产量比单作麦田高6.6%,土地当量值可达1.19。就水分效应和土地利用效应而言,在黄淮海平原农区发展这种宽带距多行带梨麦间作模式具有一定的可行性。 相似文献