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81.
浅谈复合图书馆的起源与发展 总被引:3,自引:0,他引:3
张戬慧 《农业图书情报学刊》2004,15(1):105-107
随着数字化图书馆的产生 ,出现了数字化图书馆与传统图书馆并存发展的现象 ,我们把它们称为复合图书馆。本文从复合图书馆的起源、含义及地位、发展趋势几方面进行初步的探讨 ,进而阐明复合图书馆在一段时期内将是图书馆存在的基本形态。 相似文献
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研究以不同年限(0 a、1 a和2 a)毛竹—灵芝复合系统为对象,对比分析灵芝不同种植年限的毛竹林土壤理化性质、酶活性等17个土壤质量指标的差异,并基于主成分分析对其土壤质量进行评价,旨在为毛竹林下种植灵芝提供参考。结果表明:随着灵芝种植年限的延长,毛竹林土壤含水率、孔隙度和通气度呈先升高后降低的变化趋势,而土壤容重呈先降低后升高的变化趋势;土壤pH值随种植年限的延长逐渐升高,有利于缓解土壤酸化;土壤有机质、全氮、全磷、全钾、速效养分含量和土壤酶活性均随种植年限的延长呈逐渐升高的变化趋势,且种植2 a显著高于0 a(P<0.05)。综合分析土壤理化性质以及酶活性等指标,毛竹林下种植灵芝后,其土壤质量指数均显著高于未种植的毛竹林地,且随种植年限的延长逐渐升高,说明灵芝种植有利于提高毛竹林地土壤质量。 相似文献
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Neurolytic compounds are widely used by equine practitioners for the management of lameness, mostly related to the foot. The present study aimed to evaluate the neurotoxicity of 2% ammonium chloride (2% AC) applied adjacent to the palmar digital nerves in six miniature horses. The 2% AC and 0.9% saline solution were randomly injected into three and one palmar digital nerve of each horse, respectively. Nerve samples were collected by neurectomy performed under general anesthesia at 5, 12, 19, 35, 47, and 62 days after treatment, with one horse per day of surgery. The inflammatory reaction to perineural injection was evaluated by an increase of pastern superficial skin temperature through thermography 24 hours after treatments. Histological lesions were classified as absent, mild, moderate, and severe Wallerian degeneration. An increase of 2.43 ± 0.79°C and 1.69 ± 0.55°C was observed in the 2% AC and control groups, respectively (P > .05). Moreover, histologic lesions were observed after perineural injection of 2% AC (severe, n = 5/18; moderate, n = 4/18; mild, n = 5/18; and absent, n = 4/18) and saline solution (moderate, n = 3/6; mild, n = 1/6; and absent, n = 2/6) (P = .46). The 2% AC demonstrated to be as safe as 0.9% saline solution, producing mild to severe Wallerian degeneration for up to 62 days after injection with no interference in further neurectomy. 相似文献
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Reaction behavior of lignin in supercritical methanol as studied with lignin model compounds 总被引:2,自引:0,他引:2
The reaction behavior and kinetics of lignin model compounds were studied in supercritical methanol with a batch-type supercritical
biomass conversion system. Guaiacol, veratrole, 2,6-dimethoxyphenol, and 1,2,3-trimethoxybenzene were used as model compounds
for aromatic rings in lignin. In addition, 5-5, β-1, β-O-4, and α-O-4 types of dimeric lignin model compounds were used as representatives of linkages in lignin. As a result, aromatic rings
and 5-5 (biphenyl)-type structures were stable in supercritical methanol, and the β-1 linkage was not cleaved in the β-1-type structure but converted rapidly to stilbene. On the other hand, β-ether and α-ether linkages of β-O-4 and α-O-4 lignin model compounds were cleaved rapidly, and these compounds decomposed to some monomeric compounds. Phenolic compounds
were found to be more reactive than nonphenolic compounds. These results indicate that cleavages of ether linkages mainly
contribute to the depolymerization of lignin, whereas condensed linkages such as the 5-5 and β-1 types are not cleaved in supercritical methanol. Therefore, it is suggested that the supercritical methanol treatment effectively
depolymerizes lignin into the lower-molecular-weight products as a methanol-soluble portion mainly by cleavage of the β-ether structure, which is the dominant linkage in lignin.
Received: December 19, 2001 / Accepted: April 30, 2002
Acknowledgments This research has been done under the research program for the development of technologies for establishing an ecosystem
based on recycling in rural villages for the twenty-first century from the Ministry of Agriculture, Forestry and Fisheries,
Japan; by a Grant-in-Aid for Scientific Research (B)(2) (no.12460144, 2001.4–2003.3) from the Ministry of Education, Culture,
Sports, Science and Technology, Japan; and under the research program from Kansai Research Foundation for Technology Promotion,
Japan. The authors thank them for their financial support.
This study was presented in part at the 45th Lignin Symposium, Ehime, Japan, October 2000 and the 52nd Annual Meeting of the
Japan Wood Research Society, Gifu, Japan, April 2002
Correspondence to:S. Saka 相似文献
88.
农林复合模式研究与进展 总被引:8,自引:0,他引:8
文章对农林复合经营模式的发展历史、经营类型进行了概述,对其系统结构、生物物种设计原则、生态、经济、社会效益以及今后研究的重点进行了探讨,为农林复合经营模式在实践中的推广和理论研究的深入进行提供了理论依据。 相似文献
89.
扬州市邗江低湿江滩地林农复合构建模式早期经济效益研究 总被引:5,自引:0,他引:5
对江苏省扬州市邗江渔业乡低湿江滩地构建的4类16种林农复合模式的经济效益评估结果表明,意大利杨与菊苣、意大利杨与荩草、意大利杨与苏丹草、意大利杨与银杏苗、意大利杨与棕榈、意大利杨与莲、水杉与药用蚂蝗、水杉与精鱼等8种复合模式是低湿江滩地开发经济效益高的优良构建模式;围网养殖尤其是船带网箱移动养殖长江水特产品是江滩水面资源开发利用的高效特色模式。认为滩地开发应在巩固“八五”绿化滩地,营建抑螺防病林成果的基础上,引进新树种,新种植、养殖优良生物品种,用新技术进行优化配置,以优化现有湿地森林结构,创立体现沿江湿地林渔特色的“多物种、多功能、多效益”人工林系统,建设观光林网,观光渔业,滨江湿地森林生态旅游村,进一步促进江滩湿地资源深度开发及沿江农村经济与社会可持续发展。 相似文献
90.