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Site type classification for the shelter-forest ecological project along the Tarim Desert Highway 被引量:9
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作者 LI BingWen XU XinWen +6 位作者 LEI JiaQiang QIU YongZhi XU Bo ZHOU HongWei WANG Qiang WANG BO SU Wei 《Chinese Science Bulletin》 SCIE EI CAS 2008年第S2期31-40,共10页
Site types of the afforestation region of the shelter-forest ecological project along the Tarim Desert Highway were classified based on the natural conditions and windblown sand damages. The extremely severe environme... Site types of the afforestation region of the shelter-forest ecological project along the Tarim Desert Highway were classified based on the natural conditions and windblown sand damages. The extremely severe environment, the irrigation with saline water, and large-scale linear project makes this classification of site types most unique and significant. It adopted a three-level classification system integrating the dominant factors and restrictive factors in regard to their impacts on plant survival and growth as well as on the protective property. Six site type districts were classified based on the medium-scale geomorphic unit, the windblown sand damages, and the major production facilities; 21 site type groups were obtained according to the small-scale geomorphic type, terrain, and wind regime; 36 site types were further classified based on the salt contents of the underground water and soil types. Especially, in this study, spatial distribution of the six site type districts along the desert highway is continuous, which is unique and different from that of most other classifications. In addition, the salt-stress tolerance threshold of the main afforestation plant species to underground water have been set to 8 g/L and 15 g/L according to selective breeding tests and the salinity spatial distribution of the underground water. Thus, the underground water with salinity lower than 8 g/L is defined as light saline water in this area. 展开更多
关键词 TARIM DESERT Highway shelter-forest site type classification SALINE water Xinjiang AFFORESTATION
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掺杂反式聚乙炔中Site-type杂质势的唯象模型
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作者 贾荣谊 阎立根 王德民 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 1996年第1期55-60,共6页
利用SSH模型讨论了Site-type杂质势对反式聚乙炔(trans-PA)电子态的影响。具体计算表明:对各向同性情况,Site-fype杂质势破坏了电子能谱的对称性,并使孤子能级发生移动,随着杂质离子与反式聚乙炔链间距的变化,它将引起孤子能级的变动。... 利用SSH模型讨论了Site-type杂质势对反式聚乙炔(trans-PA)电子态的影响。具体计算表明:对各向同性情况,Site-fype杂质势破坏了电子能谱的对称性,并使孤子能级发生移动,随着杂质离子与反式聚乙炔链间距的变化,它将引起孤子能级的变动。但不影响孤子局域化程度;而各向异性Site-type杂质势的不均匀性对trans-PA的电子能谱及孤子局域化程度影响较大。 展开更多
关键词 反式聚乙炔链 SSH模型 杂质势 聚乙炔 唯象模型
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Safety Observation Study on Haemophilus Influenza Type B Conjugate Vaccines Injected at Different Sites in Chinese Infants
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作者 LUO Feng Ji SHI Nian Min +6 位作者 LI Li ZHANG Zheng AI Xing YANG Li Qing BAI Yun Hua WANG Zhao Yun LU Qiang 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2013年第8期693-696,共4页
In the present study, the safety of Hoemophilus influenza type b conjugate vaccines inoculated in the upper arm deltoid and vastus lateralis muscle was evaluated. 680 infants aged 2-5 months and 6-12 months were selec... In the present study, the safety of Hoemophilus influenza type b conjugate vaccines inoculated in the upper arm deltoid and vastus lateralis muscle was evaluated. 680 infants aged 2-5 months and 6-12 months were selected to be the research subjects in whom the Hib conjugate vaccines were inoculated by injection in the upper arm deltoid and vastus lateralis muscle, respectively. The safety analysis indicated that there were no statistic differences in the incidence rates of adverse reactions when the Hib conjugate vaccines were inoculated at different sites. So we concluded that the safety of inoculation injection of Hib conjugate vaccines in vastus lateralis muscle was the same as that inoculated in the upper arm deltoid. 展开更多
关键词 In Safety Observation Study on Haemophilus Influenza type B Conjugate Vaccines Injected at Different sites in Chinese Infants
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面向生态安全屏障构建的尾矿库适宜生态修复物种筛选
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作者 王楠 李海东 +4 位作者 邵雅梅 胡焘 杨润 郑永昌 闫庆武 《生态与农村环境学报》 北大核心 2026年第1期133-142,共10页
尾矿库植被绿化与周边防护林体系建设是“点—线—面”构建区域生态安全屏障的重要内容。然而,由于工矿用地性质特殊及立地条件恶劣,尾矿库区适宜植物种筛选研究相对滞后,制约了防污滞尘林的高效营建与生态修复进程。多年来,富集植物被... 尾矿库植被绿化与周边防护林体系建设是“点—线—面”构建区域生态安全屏障的重要内容。然而,由于工矿用地性质特殊及立地条件恶劣,尾矿库区适宜植物种筛选研究相对滞后,制约了防污滞尘林的高效营建与生态修复进程。多年来,富集植物被认为可移除尾矿废弃地、受污染耕地等污染土壤的重金属,但如何面向尾矿库和周边区域两个尺度进行生态修复,亦亟待基于“目标定位—技术高效—功能提升”的矿区生态修复与污染治理协同控制理论进行进一步探究。为此,本文以长三角地区某铁矿尾矿库为例,通过库面、上坡、中坡、下坡4个立地类型恢复植被的群落调查与地形因子测定,分析了植被绿化区植物种组成和植物多样性变化及微地形的影响。结果表明:(1)尾矿库植被绿化区共发现植物69种,隶属于20科53属,以豆科、禾本科、菊科、蔷薇科和蓼科为主,植物种数占比达71%。(2)草本和灌木是主要植物种,乔木可能是种子在风媒作用下由外部传播而自然定居,狗尾草、芒、阿拉伯黄背草、加拿大一枝黄花是具有代表性的优势植物。(3)尾矿库植被盖度与高程呈负相关(P<0.01),中下坡的植被盖度较高。坡度与物种丰富度、Shannon-Wiener指数、Simpson多样性指数、Pielou均匀度指数均呈正相关(P<0.01)。(4)综合运用“点—线—面”相结合的思路构建多尺度尾矿库生态屏障,在尾矿库“点”上进行植被配置时,库面应优先考虑生命力强且生长迅速的禾本科、菊科等超富集植物和重金属耐性植物,边坡上应种植较高大的禾本科植物并搭配刺槐等豆科多年生灌木用以提升边坡的物种丰富度。研究结果为尾矿库生态修复提供了种质资源参考,为矿区生态屏障建设的植物种优化配置提供了科学依据。 展开更多
关键词 工矿区 生态修复 植物多样性 立地类型 生态安全屏障
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不同土壤类型及施肥处理对三种五加生长影响的研究
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作者 李琳琳 李强峰 严之银 《林业科技》 2026年第1期8-14,33,共8页
[目的]研究不同土壤类型、施肥及追肥处理下对3种五加生长指标的影响。[方法]以1年生刺五加、短梗五加和红毛五加苗为试材,在大通县东峡林区的3种土壤上(栗钙土、黑钙土、灰褐色森林土)进行栽培试验。观察3种五加在黑钙土上5种不同施肥... [目的]研究不同土壤类型、施肥及追肥处理下对3种五加生长指标的影响。[方法]以1年生刺五加、短梗五加和红毛五加苗为试材,在大通县东峡林区的3种土壤上(栗钙土、黑钙土、灰褐色森林土)进行栽培试验。观察3种五加在黑钙土上5种不同施肥水平下的生长状况。于次年在统一施用有机肥的黑钙土基础上,进一步探究了不同化肥追肥量对单株五加生长的促进效果。[结果] 3种五加对土壤要求不严,在不同土壤下均能够正常生长,刺五加、红毛五加以肥力较高的灰褐色森林土上生长较好,短梗五加在黑钙土和灰褐色森林土上生长指标相近。在有机肥施用量(1.5-2.5)×10^(3)/667 m^(2)下对3种五加的生长指标有显著影响;高追肥量(750 g/株)对刺五加、红毛五加在冠幅和地径方面有显著促进作用,一年生枝和分蘖数指标差异不大,短梗五加随着追肥量的增加在冠幅、地径和分蘖数方面效果显著。[结论]根据生长指标分析,3种五加均在灰褐色森林土(II)生长优于其它类型土壤类型,有机肥施用量2.0×10^(3)kg/667 m^(2)左右较为适宜。追加化肥施用量以450-600 g/株的氮磷复合肥或复混肥的效果最好。 展开更多
关键词 红毛五加 刺五加 短梗五加 立地类型 有机肥 追肥效果
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弃渣场地震动响应及失稳机制——大型振动台试验与数值模拟
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作者 黄维 崔圣华 +2 位作者 吕建 蒋涛 聂磊 《成都理工大学学报(自然科学版)》 北大核心 2026年第1期34-50,共17页
为研究坡地型弃渣场地震动响应敏感性及失稳模式,本文以坡地型弃渣场为研究对象,通过振动台模型试验对数值模拟进行校正,以证明利用数值模拟研究坡地型弃渣场的地震动响应的可行性。数值模拟考虑原始斜坡第四系覆盖层、渣体层和地震动3... 为研究坡地型弃渣场地震动响应敏感性及失稳模式,本文以坡地型弃渣场为研究对象,通过振动台模型试验对数值模拟进行校正,以证明利用数值模拟研究坡地型弃渣场的地震动响应的可行性。数值模拟考虑原始斜坡第四系覆盖层、渣体层和地震动3大类因素,研究弃渣场地震动响应规律和失稳模式,探讨失稳机制。研究结果表明:(1)弃渣场地震动响应随堆渣高度、坡度、第四系层倾角、地震动幅值、频率的增加而增大,随第四系层厚度增加而减小;(2)初步获得了坡地型弃渣场地震动响应影响因素敏感性大小:第四系层倾角>第四系层厚度>堆渣坡度>堆渣高度(弃渣场几何参数)、地震动幅值>地震动频率>地震动持时(地震参数);(3)结合试验结果,修正了地震作用下坡地型弃渣场3类失稳模式:(1)“渣-覆界面滑移”模式,(2)“渣体振动溃散”模式,(3)“第四系层蠕变滑移”模式。综合上述分析结果,地震作用下弃渣场主要受堆渣高度、坡度、第四系倾角等影响,对弃渣场选址与堆置方案设计具有重要参考意义。本文提出的坡地型弃渣场失稳模式可为弃渣场防治措施提供依据。 展开更多
关键词 坡地型弃渣场 振动台 数值模拟 动力响应敏感性分析 失稳模式
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斜坡场地深基坑支护结构选型与案例分析
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作者 汪利军 石捷 +4 位作者 陈锋 冯波 吴振斌 陈飞 毛麟飞 《浙江工业大学学报》 北大核心 2026年第1期61-67,共7页
两侧标高差异较大的深基坑支护设计是深基坑工程中的关键问题。针对某斜坡场地深基坑工程,采用有限元方法计算分析了3种支护结构的变形特性,并与现场检测结果进行了对比验证。结果表明:采用钻孔灌注桩结合2道水平斜撑的支护结构型式(方... 两侧标高差异较大的深基坑支护设计是深基坑工程中的关键问题。针对某斜坡场地深基坑工程,采用有限元方法计算分析了3种支护结构的变形特性,并与现场检测结果进行了对比验证。结果表明:采用钻孔灌注桩结合2道水平斜撑的支护结构型式(方案1),其结构的最大水平位移是其他两种方案的45.6%和40.0%;第2层土体开挖完成后,3种方案的地表沉降量分别为1.64,4.02,4.51 mm,方案1的效果优于其他两个方案。对于两侧标高相差较大的深基坑支护工程,方案1的围护结构变形和坑外地表沉降计算结果与实测吻合。研究成果可以为类似工程提供一定的借鉴。 展开更多
关键词 斜坡场地 不对称基坑 支护结构型式 支护结构变形 案例分析
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Site classification of the eastern forest region of Daxing'an Mountains 被引量:1
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作者 扬凯 马英 +1 位作者 谷会岩 刘鹏 《Journal of Forestry Research》 SCIE CAS CSCD 1999年第2期129-130,共2页
Based on the plot data from the investigation and the theory of forest ecology and ecological system,the site classification of the eastern forest region of Daxing’an Mountains was made by mean of mathematical method... Based on the plot data from the investigation and the theory of forest ecology and ecological system,the site classification of the eastern forest region of Daxing’an Mountains was made by mean of mathematical method. The main factors were slope, thickness of soil layer, slope position and slope aspect. Grades of slope were used as the division standard for site type group. The slope aspect, slope position and thickness of soil layer were used as the division standards for site type. Altogether 7 site type groups and 15 main site types were determined the region. It provided reliable fundamental basis for the reasonable management and planting design in the area. 展开更多
关键词 Daxing’an MOUNTAINS FOREST site classification site type GROUP site type
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A site dependent top height growth model for hybrid aspen 被引量:2
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作者 Tord Johansson 《Journal of Forestry Research》 SCIE CAS CSCD 2013年第4期691-698,共8页
In this study height growth models for hybrid aspen were developed using three growth equations. The mean age of the hybrid aspen was 21 years (range 15-51 years) with a mean stand density of 946 stems ha-~ (87-237... In this study height growth models for hybrid aspen were developed using three growth equations. The mean age of the hybrid aspen was 21 years (range 15-51 years) with a mean stand density of 946 stems ha-~ (87-2374) and a mean diameter at breast height (over bark) of 19.6 cm (8.5-40.8 cm). Site index was also examined in relation to soil type. Multiple samples were collected for three types of soil: light clay, medium clay and till. Site index curves were constructed using the col- lected data and compared with published reports. A number of dynamic equations were assessed for modeling top-height growth from total age. 展开更多
关键词 top height FARMLAND hybrid aspen site index soil types STANDS total age soil type
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Estimating the productive potential of five natural forest types in northeastern China 被引量:8
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作者 Zhaofei Wu Zhonghui Zhang Juan Wang 《Forest Ecosystems》 SCIE CSCD 2019年第4期274-284,共11页
Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for ... Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for this most important forest region in China. Accordingly, the objective of this study is to develop a first comprehensive system for estimating the wood production for the five dominant forest types.Methods: Based on a network of 384 field plots and using the state-space approach, we develop a system of dynamic stand models, for each of the five main forest types. Four models were developed and evaluated, including a base model and three extended models which include the effects of dominant height and climate variables. The four models were fitted, and their predictive strengths were tested, using the "seemingly unrelated regression"(SUR) technique.Results: All three of the extended models increased the accuracy of the predictions at varying degrees for the five major natural forest types of northeastern China. The inclusion of dominant height and two climate factors(precipitation and temperature) in the base model resulted in the best performance for all the forest types. On average, the root mean square values were reduced by 13.0% when compared with the base model.Conclusion: Both dominant height and climate factors were important variables in estimating forest production. This study not only presents a new method for estimating forest production for a large region, but also explains regional differences in the effect of site productivity and climate. 展开更多
关键词 Forest types Forest growth CLIMATE site conditions Seemingly unrelated regression
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新质生产力背景下职业教育培养现场工程师的内涵要义、现实挑战与定向对策 被引量:1
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作者 徐兰 梅阳寒 王军 《成人教育》 北大核心 2025年第8期62-69,共8页
在新质生产力蓬勃发展的时代背景下,推进现场工程师培养不仅是优化职业教育类型定位的必然选择,也是赋能行业新质生产力的关键纽带,更是支撑我国强国战略目标稳步实现的有效保障。然而,当前职业教育面临着人才培养范式缺失、人才培养效... 在新质生产力蓬勃发展的时代背景下,推进现场工程师培养不仅是优化职业教育类型定位的必然选择,也是赋能行业新质生产力的关键纽带,更是支撑我国强国战略目标稳步实现的有效保障。然而,当前职业教育面临着人才培养范式缺失、人才培养效能不足以及人才评价体系阙如等现实挑战。因此通过搭建产科教协同育人平台,以创新型教学团队建设为抓手,以过程性、增值性评价为媒介,以培养标准体系建设为指南,驱动人才培养紧贴行业数智化转型需求,为产业发展提供源源不断的高素质人力资源支持和应用型技术积累。 展开更多
关键词 新质生产力 现场工程师 职业教育类型定位 数智化转型
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Three-Dimensional Modeling of Shallow Shear-Wave Velocities for Las Vegas, Nevada, Using Sediment Type
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作者 Barbara Luke Helena Murvosh +1 位作者 Wanda Taylor Jeff Wagoner 《Journal of China University of Geosciences》 SCIE CSCD 2009年第3期555-562,共8页
A three-dimensional model of near-surface shear-wave velocity in the deep alluvial basin underlying the metropolitan area of Las Vegas, Nevada (USA), is being developed for earthquake site response projections. The ... A three-dimensional model of near-surface shear-wave velocity in the deep alluvial basin underlying the metropolitan area of Las Vegas, Nevada (USA), is being developed for earthquake site response projections. The velocity dataset, which includes 230 measurements, is interpolated across the model using depth-dependent correlations of velocity with sediment type. The sediment-type database contains more than 1 400 well and borehole logs. Sediment sequences reported in logs are assigned to one of four units. A characteristic shear-wave velocity profile is developed for each unit by analyzing closely spaced pairs of velocity profiles and well or borehole logs. The resulting velocity model exhibits reasonable values and patterns, although it does not explicitly honor the measured shear-wave velocity profiles. Site response investigations that applied a preliminary version of the velocity model support a two-zone ground-shaking hazard model for the valley. Areas in which clay predominates in the upper 30 m are predicted to have stronger ground motions than the rest of the basin. 展开更多
关键词 shear-wave velocity earthquake site response site amplification MICROZONATION sediment type.
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Tripartite states Bell-nonlocality sudden death in a spin environment with multisite interaction 被引量:1
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作者 谢利军 张登玉 +3 位作者 汪新文 詹孝贵 唐世清 高峰 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第8期16-22,共7页
Tis paper demonstrates that multipartite Bell-inequality violations can be fully destroyed in a finite time in three- qubit states coupled to a general XY spin-chain with a three-site interaction environment. The Merm... Tis paper demonstrates that multipartite Bell-inequality violations can be fully destroyed in a finite time in three- qubit states coupled to a general XY spin-chain with a three-site interaction environment. The Mermin Ardehali- Belinksii-Klyshko inequality is used to detect the degree of nonlocality, as measured by the extent of their violations. The effects of system-environment couplings, the size of degrees of freedom of the environment and the strength of the three-site interaction on the Bell-inequality violations are given. The results indicate that the Bell-inequality violations of the tripartite states will be completely destroyed by decoherence under certain conditions for the GHZ state. The decoherence-free subspaces of our model are identified and the entanglement of quantum states is also discussed. 展开更多
关键词 Bell-type inequality Bell-nonlocality sudden death three-site interaction
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PRELIMINARY STUDY OF A NOVEL HUMAN PAPILLOMAVIRUS TYPE 16 L1/E6-E7 CHIMERIC RECOMBINANT DNA VACCINE
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作者 郑瑾 马军 +4 位作者 张福萍 杨筱凤 董小平 司履生 王一理 《Journal of Pharmaceutical Analysis》 SCIE CAS 2004年第1期45-49,共5页
Objective Preparations of HPV16 L1/E6 and L1/E7 prophylactic and therapeutic DNA vaccines. Methods The nucleotides within HPV16 E6 and E7 genes, which are responsible for viral transforming activity, were mutated by... Objective Preparations of HPV16 L1/E6 and L1/E7 prophylactic and therapeutic DNA vaccines. Methods The nucleotides within HPV16 E6 and E7 genes, which are responsible for viral transforming activity, were mutated by mage primer site-directed mutagenesis method. The correctly mutated E6 and E7 fragments were separately cloned into an eukaryotic expression vector pVAX1, together with HPV16 L1 gene, generating chimeric recombinants plasmids 1MpVAX1-L1E6, 2MpVAX1-L1E6, 1MpVAX1-L1E7, 2MpVAX1-L1E7 and 3MpVAX1-L1E7. CHO cells were transiently transfected with the individual DNA vaccines by calcium phosphate method. Target protein expressions in the extracts of the transfected cell lines were measured by ELISA and immunohistochemistry, with HPV16 L1 and E6 specific monoclonal antibodies. Results ELISA assays showed the P/N ratios in the cell extracts transfected with L1E6 and L1E7 plasmids were more than 2.1. Immunohistochemistry revealed brownish precipitant signal in cytoplasm and nuclei of the transfected cells. Conclusion Successful constructions of prophylactic and therapeutic DNA vaccine plasmids lay solid foundation for future animal experiment and clinical trial. 展开更多
关键词 human papillomavirus type 16 DNA vaccine site-direct mutation
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Oviposition Site Preference and Its Effects on Subsequent Development of Variegated Grasshopper (Zonocerus variegatus L.) under Laboratory Conditions
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作者 Saffea Joseph Torto Abu James Sundufu +4 位作者 Alusaine Edward Samura Sahr Ngoba Fomba Dennis Peter Musa Skeku Alfred Kanu Prince Emmanuel Norman 《Advances in Entomology》 2024年第3期143-154,共12页
Female grasshoppers can affect the fitness of their offspring through their selection of oviposition site. Knowledge of soil type on oviposition, and its effects on subsequent development can provide guidelines for ha... Female grasshoppers can affect the fitness of their offspring through their selection of oviposition site. Knowledge of soil type on oviposition, and its effects on subsequent development can provide guidelines for habitat manipulations that reduce the harmful effects of these pests on farmers fields. The influence of soil types on the oviposition site preference of variegated grasshopper (Zonocerus variegatus L.) reared some cassava (Manihot esculenta Crantz) varieties, was investigated in a cage trial carried out at the Bio factory laboratory, School of Agriculture and Food Sciences, Njala University, Sierra Leone during 2022/2023. The treatments comprised three soil types (Sandy, Loamy and Clay), each with three replications laid out in a randomized complete block design (RCBD) in wooden cages. Data were collected on the following development parameters including, Net reproductive growth ratio (R0), Generation time (Tc), Intrinsic rate of increase (rm), Finite rate of increase (), Doubling time (Dt), and overall survivorship. Findings revealed that, Z. variegatus L. preferred sandy soil in which, on average, most eggs were deposited (338, 6.62 4.40), followed by loamy soil, 286 (5.53 3.96), and then, clayey soil, 200 (3.91 3.85);though, the differences were not significant. This study established that Z. variegatus deposited more eggs in sandy soil > loamy soil > clayey soil, respectively;and subsequent survivorship of the immature unto mature adult insect, revealed a similar order. This indicates that the sandy soil is the most preferred substrate for oviposition and subsequent development into adult insects. 展开更多
关键词 DEVELOPMENT OVIPOSITION Oviposition site Preference Soil types Variegated Grasshopper
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石峁遗址皇城台护墙稳定性计算方法研究
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作者 秦立科 韦坤 +2 位作者 王磊 庞磊 王猛 《文物保护与考古科学》 北大核心 2025年第1期122-132,共11页
皇城台护墙是石峁皇城台的重要组成部分,也是保证皇城台安全的关键,目前护墙灰缝材料风化严重且存在一定外倾变形,急需对其稳定性进行评估。通过理论推导得出了适合皇城台护墙稳定性计算公式,通过室内试验验证了公式的准确性,分析了高... 皇城台护墙是石峁皇城台的重要组成部分,也是保证皇城台安全的关键,目前护墙灰缝材料风化严重且存在一定外倾变形,急需对其稳定性进行评估。通过理论推导得出了适合皇城台护墙稳定性计算公式,通过室内试验验证了公式的准确性,分析了高宽比、灰缝强度和竖向外荷载对护墙稳定性的影响。研究结果表明:护墙为内部松散的重力式挡墙,存在沿内部灰缝滑移和倾覆两种破坏类型,倾覆破坏时的倾覆角度和墙体高度、灰缝强度等多种因素相关;护墙灰缝强度相同时,在护墙底部稳定性系数最小,最易发生倾覆破坏;护墙稳定性随着高宽比及竖向外荷载增加、灰缝强度减小而降低。研究结果为石峁皇城台护墙的稳定性评估和加固提供科学依据。 展开更多
关键词 石峁遗址 皇城台 护墙 破坏类型 稳定性分析
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白洋淀上游山区典型流域水源涵养林不同植被优化配置 被引量:2
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作者 邓雅元 王美琪 +4 位作者 闫烨琛 杨建英 张广英 王洁 杨瑾 《浙江农林大学学报》 北大核心 2025年第3期457-467,共11页
【目的】基于水文过程模拟分析,研究白洋淀上游山区水源涵养林优化配置,提升该区水源涵养林建设质量。【方法】以2016年为例,利用SWAT(Soil and Water Assessment Tool)模型验证了白洋淀上游山区安各庄流域本地化过程的适用性,根据安各... 【目的】基于水文过程模拟分析,研究白洋淀上游山区水源涵养林优化配置,提升该区水源涵养林建设质量。【方法】以2016年为例,利用SWAT(Soil and Water Assessment Tool)模型验证了白洋淀上游山区安各庄流域本地化过程的适用性,根据安各庄流域立地条件共划分63种立地类型并进行立地质量等级评价。根据立地条件进行水源涵养林空间配置,再利用SWAT模型情景分析模拟不同水源涵养林空间配置下的径流量。【结果】在以调整混交林、针叶林为主的情景下,流域丰水期径流量比实测值减少15.79%,枯水期径流量比实测值增加15.83%。在空间配置上,阔叶林主要配置在缓坡和斜坡地,以阳坡为好;混交林主要配置在斜坡地和陡坡地;针叶林主要配置在陡坡地,以阴坡为好;灌木林主要配置在斜坡地和陡坡地,尤其是在土层薄的部位。【结论】在以混交林、针叶林为主的空间配置下,水源涵养林涵养水源功能发挥最好。 展开更多
关键词 水源涵养林 立地类型 SWAT模型 敏感性分析 空间优化配置 水文响应
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陕西西安弓背崖遗址仰韶文化遗存发掘简报
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作者 翟霖林 袁承志 +4 位作者 郭昕(执笔/照相) 张翔宇 张蕊侠(绘图) 张星(绘图) 王学文(绘图) 《文博》 北大核心 2025年第1期10-21,共12页
弓背崖遗址位于陕西省西安市雁塔区山门口街道曹家堡村,面积约20万平方米。2017年6月至2017年9月,西安市文物保护考古研究院等对弓背崖遗址进行了考古发掘,收获了一批仰韶文化、东周、汉代等时期的遗存,其中仰韶文化遗存大体可分为仰韶... 弓背崖遗址位于陕西省西安市雁塔区山门口街道曹家堡村,面积约20万平方米。2017年6月至2017年9月,西安市文物保护考古研究院等对弓背崖遗址进行了考古发掘,收获了一批仰韶文化、东周、汉代等时期的遗存,其中仰韶文化遗存大体可分为仰韶文化庙底沟类型和半坡晚期类型两个时期。弓背崖遗址的发掘为关中地区仰韶文化的研究提供了新材料。 展开更多
关键词 弓背崖遗址 仰韶文化 庙底沟类型 半坡晚期类型
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铁路简支梁桥组合减隔震体系适应性研究
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作者 江辉 李新 +4 位作者 陈良江 周勇政 王岚 卢文良 宋光松 《铁道工程学报》 北大核心 2025年第9期32-37,57,共7页
研究目的:铁路桥梁建设持续向藏东南、川西、滇西北等高烈度地震区延伸,减隔震支座与各类阻尼器组合使用的减隔震桥梁愈加广泛。为探明地震动特性、结构特性对此类减隔震桥梁抗震性能的影响规律,本文以铁路原型桥梁、原型桥墩为工程背景... 研究目的:铁路桥梁建设持续向藏东南、川西、滇西北等高烈度地震区延伸,减隔震支座与各类阻尼器组合使用的减隔震桥梁愈加广泛。为探明地震动特性、结构特性对此类减隔震桥梁抗震性能的影响规律,本文以铁路原型桥梁、原型桥墩为工程背景,建立具有不同墩高、墩高差的22个桥梁模型,探究桥墩刚度、相邻墩刚度比变化,场地类型变化和长周期、近断层特性的作用影响机理,明确组合减隔震体系适应性。研究结论:(1)墩底弯矩(支座变形)随墩高增加而增加(降低);相邻墩高差会放大高墩弯矩响应与矮墩墩上支座变形响应;长周期、近场地震动以及软弱场地会限制组合减隔震体系的适应性;(2)Ⅰ~Ⅱ类场地桥墩纵向刚度限定值≥396 kN/cm;Ⅲ类场地需>634 kN/cm;Ⅳ类场地则需>1056 kN/cm;(3)在Ⅰ、Ⅱ类场地下,邻墩纵向刚度比应大于0.3;Ⅲ类和Ⅳ类场地的邻墩纵向刚度比应分别大于0.39和0.55;(4)对于Ⅱ类及更坚硬场地,以及不同地震动特性下,桥墩纵向刚度限定值≥1207 kN/cm;(5)本文研究思路与结论对于规范铁路桥梁减隔震设计、确定合理的设计参数具有指导意义,可为相关技术标准的制定提供参考与借鉴。 展开更多
关键词 铁路简支梁桥 组合减隔震体系 适应性 场地类型 近断层地震 长周期地震
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论云阳丝栗包夏商遗址及相关问题
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作者 罗二虎 彭波 《四川文物》 北大核心 2025年第4期58-75,共18页
云阳丝栗包夏商遗址可分为三期五段,其年代约为二里头文化二、三期至殷墟文化三期。这类遗存属于三星堆文化,但与分布在成都平原地区的三星堆类型和鄂西地区的朝天嘴类型等三星堆文化面貌存在一定差异。此类遗存在渝东地区广泛分布,可... 云阳丝栗包夏商遗址可分为三期五段,其年代约为二里头文化二、三期至殷墟文化三期。这类遗存属于三星堆文化,但与分布在成都平原地区的三星堆类型和鄂西地区的朝天嘴类型等三星堆文化面貌存在一定差异。此类遗存在渝东地区广泛分布,可命名为“丝栗包类型”。该类型的确认对于进一步认识三星堆文化和渝东地区夏商时期文化都具有重要意义。 展开更多
关键词 丝栗包遗址 夏商时期 三星堆文化丝栗包类型
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