期刊文献+
共找到636篇文章
< 1 2 32 >
每页显示 20 50 100
Discovery and inspiration of large-and medium-sized glutenite-rich oil and gas fields in the eastern South China Sea:An example from Paleogene Enping Formation in Huizhou 26 subsag,Pearl River Mouth Basin 被引量:1
1
作者 XU Changgui GAO Yangdong +4 位作者 LIU Jun PENG Guangrong LIU Pei XIONG Wanlin SONG Penglin 《Petroleum Exploration and Development》 SCIE 2024年第1期15-30,共16页
Based on the practice of oil and gas exploration in the Huizhou Sag of the Pearl River Mouth Basin,the geochemical indexes of source rocks were measured,the reservoir development morphology was restored,the rocks and ... Based on the practice of oil and gas exploration in the Huizhou Sag of the Pearl River Mouth Basin,the geochemical indexes of source rocks were measured,the reservoir development morphology was restored,the rocks and minerals were characterized microscopically,the measured trap sealing indexes were compared,the biomarker compounds of crude oil were extracted,the genesis of condensate gas was identified,and the reservoir-forming conditions were examined.On this basis,the Paleogene Enping Formation in the Huizhou 26 subsag was systematically analyzed for the potential of oil and gas resources,the development characteristics of large-scale high-quality conglomerate reservoirs,the trapping effectiveness of faults,the hydrocarbon migration and accumulation model,and the formation conditions and exploration targets of large-and medium-sized glutenite-rich oil and gas fields.The research results were obtained in four aspects.First,the Paleogene Wenchang Formation in the Huizhou 26 subsag develops extensive and thick high-quality source rocks of semi-deep to deep lacustrine subfacies,which have typical hydrocarbon expulsion characteristics of"great oil generation in the early stage and huge gas expulsion in the late stage",providing a sufficient material basis for hydrocarbon accumulation in the Enping Formation.Second,under the joint control of the steep slope zone and transition zone of the fault within the sag,the large-scale near-source glutenite reservoirs are highly heterogeneous,with the development scale dominated hierarchically by three factors(favorable facies zone,particle component,and microfracture).The(subaqueous)distributary channels near the fault system,with equal grains,a low mud content(<5%),and a high content of feldspar composition,are conducive to the development of sweet spot reservoirs.Third,the strike-slip pressurization trap covered by stable lake flooding mudstone is a necessary condition for oil and gas preservation,and the NE and nearly EW faults obliquely to the principal stress have the best control on traps.Fourth,the spatiotemporal configuration of high-quality source rocks,fault transport/sealing,and glutenite reservoirs controls the degree of hydrocarbon enrichment.From top to bottom,three hydrocarbon accumulation units,i.e.low-fill zone,transition zone,and high-fill zone,are recognized.The main area of the channel in the nearly pressurized source-connecting fault zone is favorable for large-scale hydrocarbon enrichment.The research results suggest a new direction for the exploration of large-scale glutenite-rich reservoirs in the Enping Formation of the Pearl River Mouth Basin,and present a major breakthrough in oil and gas exploration. 展开更多
关键词 Pearl River Mouth Basin Huizhou Sag Huizhou 26 subsag PALEOGENE Enping Formation GLUTENITE large-and medium-sized oil and gas field
下载PDF
Formation of large-and medium-sized Cretaceous volcanic reservoirs in the offshore Bohai Bay Basin,East China
2
作者 XU Changgui ZHANG Gongcheng +3 位作者 HUANG Shengbing SHAN Xuanlong LIU Tingyu LI Jiahui 《Petroleum Exploration and Development》 SCIE 2024年第3期535-547,共13页
Based on the geological and geophysical data of Mesozoic oil-gas exploration in the sea area of Bohai Bay Basin and the discovered high-yield volcanic oil and gas wells since 2019,this paper methodically summarizes th... Based on the geological and geophysical data of Mesozoic oil-gas exploration in the sea area of Bohai Bay Basin and the discovered high-yield volcanic oil and gas wells since 2019,this paper methodically summarizes the formation conditions of large-and medium-sized Cretaceous volcanic oil and gas reservoirs in the Bohai Sea.Research shows that the Mesozoic large intermediate-felsic lava and intermediate-felsic composite volcanic edifices in the Bohai Sea are the material basis for the formation of large-scale volcanic reservoirs.The upper subfacies of effusive facies and cryptoexplosive breccia subfacies of volcanic conduit facies of volcanic vent-proximal facies belts are favorable for large-scale volcanic reservoir formation.Two types of efficient reservoirs,characterized by high porosity and medium to low permeability,as well as medium porosity and medium to low permeability,are the core of the formation of large-and medium-sized volcanic reservoirs.The reservoir with high porosity and medium to low permeability is formed by intermediate-felsic vesicular lava or the cryptoexplosive breccia superimposed by intensive dissolution.The reservoir with medium porosity and medium to low permeability is formed by intense tectonism superimposed by fluid dissolution.Weathering and tectonic transformation are main formation mechanisms for large and medium-sized volcanic reservoirs in the study area.The low-source“source-reservoir draping type”is the optimum source-reservoir configuration relationship for large-and medium-sized volcanic reservoirs.There exists favorable volcanic facies,efficient reservoirs and source-reservoir draping configuration relationship on the periphery of Bozhong Sag,and the large intermediate-felsic lava and intermediate-felsic composite volcanic edifices close to strike-slip faults and their branch faults are the main directions of future exploration. 展开更多
关键词 Bohai Sea CRETACEOUS large-and medium-sized volcanic reservoirs effective reservoir source-reservoir configuration exploration direction
下载PDF
Small and Medium-Sized Enterprises Digital Management Facing Difficulties and Solutions
3
作者 Jianhui Li 《Proceedings of Business and Economic Studies》 2024年第5期200-205,共6页
The advent of the digital era has provided strong technical support for the high-quality development of the social economy.The integration of the social economy with Internet technology has given rise to new industrie... The advent of the digital era has provided strong technical support for the high-quality development of the social economy.The integration of the social economy with Internet technology has given rise to new industries.However,the traditional development model of small and medium-sized enterprises(SMEs)is increasingly unable to meet the demands of economic growth,and digital management has gradually become a key approach for these enterprises to achieve their development goals.Currently,SMEs face challenges such as talent shortages,insufficient funds,and a lack of awareness regarding transformation.This paper will analyze the difficulties SMEs encounter in implementing digital management and explore potential development paths for their digital transformation. 展开更多
关键词 Small and medium-sized enterprises Digital management Market economy
下载PDF
Research on the Coordinated Development of Inclusive Finance and Financing for Small and Medium-sized Enterprises
4
作者 Yanfei Li Xue Liang 《Proceedings of Business and Economic Studies》 2024年第4期214-219,共6页
As an important force in promoting economic and social development,small and medium-sized enterprises play a crucial role in enhancing China’s economic strength,creating employment opportunities,and promoting industr... As an important force in promoting economic and social development,small and medium-sized enterprises play a crucial role in enhancing China’s economic strength,creating employment opportunities,and promoting industrial structural transformation.However,due to their inherent weaknesses,small and medium-sized enterprises often face difficulties in financing within the traditional financial service system.This makes it difficult for small and medium-sized enterprises to inject vitality into the development of the market economy by expanding their financing scale.Since 2013,China has vigorously developed inclusive finance and extended the services of traditional financial institutions to small and medium-sized enterprises,providing policy guidance,resource support,and technical support to alleviate the financing difficulties of small and medium-sized enterprises.Based on this,this article focuses on the current financing problems faced by small and medium-sized enterprises and specifically elaborates on how to lower the financing threshold for small and medium-sized enterprises and broaden their financing channels through inclusive finance,in order to promote the development of inclusive finance and a virtuous cycle of financing for small and medium-sized enterprises. 展开更多
关键词 Inclusive finance Financing for small and medium-sized enterprises Financial institution
下载PDF
Research on the Generation of Professional Skill Modules for Talent Cultivation in the Landscape Architecture Profession for Industry-Education Integration of Small and Medium-Sized Enterprises
5
作者 Fengyi Xu Yang Su 《Journal of Contemporary Educational Research》 2024年第6期227-232,共6页
Due to industry characteristics or regional limitations,many students in certain majors tend to seek employment in small and medium-sized enterprises(SMEs).SMEs face certain challenges in implementing industry-educati... Due to industry characteristics or regional limitations,many students in certain majors tend to seek employment in small and medium-sized enterprises(SMEs).SMEs face certain challenges in implementing industry-education integration,and there is a lack of mature methods in specific implementation processes and talent cultivation plan generation.Taking the landscape architecture profession as an example,this paper conducts a correlation analysis and cross-analysis of the industry-required professional skills based on surveys of over 300 industry practitioners employed in SMEs.It provides professional skill cultivation modules based on market feedback.This research process and analysis method have certain reference significance for the rapid production of adaptive talent cultivation professional skill modules in other industries targeting SMEs. 展开更多
关键词 Landscape architecture profession Talent cultivation Industry-education integration Small and medium-sized enterprises
下载PDF
Maintenance,Repair,and Reinforcement Measures for Dilapidated Small and Medium-Sized Bridges
6
作者 Xu Meng Bo Liu +1 位作者 Ji Li Zhi Tu 《Journal of Architectural Research and Development》 2024年第1期62-67,共6页
The paper initiates by exploring the importance of maintaining,repairing,and reinforcing bridges.Subsequently,it delves into routine and preventative maintenance measures tailored for small to medium-sized bridges.Add... The paper initiates by exploring the importance of maintaining,repairing,and reinforcing bridges.Subsequently,it delves into routine and preventative maintenance measures tailored for small to medium-sized bridges.Additionally,the paper examines repair and reinforcement techniques specifically designed for deteriorated small and medium-sized bridges,encompassing methods for fortifying both the bridge foundation and upper and lower structures.Lastly,the paper proposes suggestions aimed at fostering discussions and exchanges on the development of maintenance and repair processes for deteriorated small and medium-sized bridges. 展开更多
关键词 Dilapidated small and medium-sized bridges Maintenance Repair and reinforcement
下载PDF
The Application of Knowledge Management(KM)by Small and Medium-Sized Enterprises(SME)in Manufacturing Industry
7
作者 Danrui Yin Chin Lye Ooi 《Proceedings of Business and Economic Studies》 2024年第4期293-299,共7页
To accelerate the digital transformation of small and medium-sized manufacturing enterprises(SMEs),this study delves into the primary challenges encountered in adopting knowledge management(KM)within these organizatio... To accelerate the digital transformation of small and medium-sized manufacturing enterprises(SMEs),this study delves into the primary challenges encountered in adopting knowledge management(KM)within these organizations and identifies the essential methods for successful implementation.The objective is to provide practical recommendations for the effective adoption of KM.This research suggests that enterprises should promote knowledge management through three key approaches:enhancing employees’cognitive understanding,standardizing knowledge systems,and tailoring business scenarios to meet diverse needs.These findings offer valuable insights into the digital transformation of SMEs in the manufacturing sector,ultimately helping these businesses to remain competitive and innovative in a rapidly changing market.By addressing the specific needs and challenges faced by SMEs,this study aims to contribute to a more comprehensive understanding of how knowledge management can be leveraged to drive digital transformation and improve overall business performance. 展开更多
关键词 Knowledge management(KM) Small and medium-sized enterprises(SME) Manufacturing industry
下载PDF
基于CMA-ES的USV自动靠泊研究
8
作者 殷键 陈国权 杨神化 《舰船科学技术》 北大核心 2024年第7期81-87,共7页
本文提出基于CMA-ES优化的LQR船舶自主靠泊控制系统,系统化地解决船舶在靠泊过程中涉及的路径规划、最优控制、外界干扰、物理执行结构约束等问题并使用仿真软件实现基于LQR以及基于CMA-ES优化的LQR的自主靠泊控制系统,实验结果表明,基... 本文提出基于CMA-ES优化的LQR船舶自主靠泊控制系统,系统化地解决船舶在靠泊过程中涉及的路径规划、最优控制、外界干扰、物理执行结构约束等问题并使用仿真软件实现基于LQR以及基于CMA-ES优化的LQR的自主靠泊控制系统,实验结果表明,基于CMA-ES的优化控制方法能够很好地实现小型船舶的自主靠泊,系统鲁棒性表现良好。 展开更多
关键词 自主靠泊 CMA-ES LQR usv
下载PDF
具有避碰和连通性保持的多USV分布式事件触发编队控制
9
作者 李建华 胡清伟 刘中常 《中国舰船研究》 CSCD 北大核心 2024年第1期200-210,共11页
[目的]为解决水面无人艇(USV)编队控制中的实际需求,提出一种具有避碰和连通性保持功能的分布式事件触发编队控制方法。[方法]针对海洋环境扰动和系统模型的不确定性等因素设计扰动观测器;针对编队实现过程中USV间可能发生碰撞和丢失通... [目的]为解决水面无人艇(USV)编队控制中的实际需求,提出一种具有避碰和连通性保持功能的分布式事件触发编队控制方法。[方法]针对海洋环境扰动和系统模型的不确定性等因素设计扰动观测器;针对编队实现过程中USV间可能发生碰撞和丢失通信连接的问题,基于人工势场函数法设计具有避碰和连通性保持功能的编队控制器;为减少USV控制器的执行频率,设计分布式的事件触发机制,使每个USV根据局部信息来独立决定其控制器的执行时刻。[结果]理论分析证明了编队误差的一致最终有界性,且事件触发机制不存在Zeno行为。仿真结果验证了所设计的控制方法能够显著减少USV控制器更新次数并可实施避碰操作及保持连通性。[结论]研究成果可保证USV编队控制的顺利安全完成,同时减轻USV在复杂海洋环境下的控制机构损耗。 展开更多
关键词 多无人艇系统 编队控制 事件触发控制 避碰 连通性保持
下载PDF
Comparative Test on Spring Medium-sized Watermelon Varieties in Beijing
10
作者 Shengqi MU Chao MA +4 位作者 Jianbo ZENG Yanli CHEN Ying ZHANG Xuesong YOU Jin XU 《Agricultural Biotechnology》 CAS 2023年第3期20-22,共3页
[Objectives]This study was conducted to select suitable medium-sized watermelon varieties for early spring cultivation in Beijing.[Methods]Seven watermelon varieties were collected,including Beinong Tianjiao 2,Beinong... [Objectives]This study was conducted to select suitable medium-sized watermelon varieties for early spring cultivation in Beijing.[Methods]Seven watermelon varieties were collected,including Beinong Tianjiao 2,Beinong Tianjiao,Hongfuji,Yongfeng 1,Beinong Futian,Beinong Shijia,and Beinong Jinxiu,and Jingxin 2 was used as the control check(CK).The growth period,morphological traits,yield traits and fruit quality of the tested varieties were investigated.[Results]Beinong Tianjiao 2 had an earlier maturation stage,a fruit development period of 38 d and a total growth period of 118 d.It showed stable growth,with a single fruit weight of 7.56 kg,a fruit setting rate of 0.99 per plant,and a yield of 83076.9 kg/hm~2,which ranked,respectively,second,first,and second among all tested varieties,and were significantly superior to the CK.Furthermore,this variety had thin and tough peel,a bright red flesh color,high central sugar content,loose and crisp flesh,and a good taste.[Conclusions]It is preliminarily believed that it is suitable for early spring watermelon production in Beijing area. 展开更多
关键词 medium-sized watermelon Variety comparison Beijing area High yield High quality
下载PDF
Optimization of jamming formation of USV offboard active decoy clusters based on an improved PSO algorithm
11
作者 Zhaodong Wu Yasong Luo Shengliang Hu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期529-540,共12页
Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for t... Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and deployment.To improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is proposed.The formation of the cluster determines the effectiveness of jamming.First,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is proposed.Then,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is designed.Finally,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific scenarios.The results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO algorithm.Compared with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources. 展开更多
关键词 Electronic countermeasure Offboard active decoy usv cluster Jamming formation optimization Improved PSO algorithm
下载PDF
一种动态不确定海洋环境下的USV态势自主感知及避障算法
12
作者 王潋 陈霄 完颜娟 《火力与指挥控制》 CSCD 北大核心 2024年第3期73-79,87,共8页
针对无人艇在动态不确定海洋环境下的态势自主感知和实时避障问题,提出了一种遵守COLREGs海事规则,且考虑传感器测量误差和障碍物随机运动不确定信息的无人艇航行态势自主感知及避障算法。阐述了无人艇在海上航行时须遵守的3类海事规则... 针对无人艇在动态不确定海洋环境下的态势自主感知和实时避障问题,提出了一种遵守COLREGs海事规则,且考虑传感器测量误差和障碍物随机运动不确定信息的无人艇航行态势自主感知及避障算法。阐述了无人艇在海上航行时须遵守的3类海事规则,追越、交叉相遇和正面相遇;考虑到传感器存在的测量误差、观测漂移以及障碍物运动的随机不确定性,对相关误差进行建模,并基于融合COLREGs规则的速度障碍法,设计提出了一种融合COLREGs海事规则的USV态势自主感知及避障算法;通过正面相遇、追越、左右交叉相遇4种典型场景下的仿真实验,验证了所提出算法的有效性。 展开更多
关键词 无人艇 海事规则 冲突场景 自主避障 不确定性建模 极大似然法
下载PDF
融合DWA和QPSO算法的USV动态局部路径规划算法
13
作者 仇坤 李稳 《计算机与数字工程》 2024年第4期1082-1086,1136,共6页
针对无人水面艇(USV)在动态环境中的局部路径规划问题,传统的动态窗口法(DWA)把速度集合离散化处理求取最优速度,计算量大且速度分辨率对动态路径规划的影响大。基于此,论文提出了融合DWA和量子粒子群算法(QP-SO)的USV动态局部路径规划... 针对无人水面艇(USV)在动态环境中的局部路径规划问题,传统的动态窗口法(DWA)把速度集合离散化处理求取最优速度,计算量大且速度分辨率对动态路径规划的影响大。基于此,论文提出了融合DWA和量子粒子群算法(QP-SO)的USV动态局部路径规划算法。首先论文在分析初始DWA的基础上,考虑国际海事规则和船舶机动性能等方面要求,建立融合避碰规则的动态窗口模型。然后在速度窗口中融入QPSO方法,将USV动态局部路径规划问题转化为多目标多约束优化问题。最后仿真验证了融合算法能够使USV在约束和规则下,获得最优的速度和航向,安全与目标船完成会遇,且运行效率更高。 展开更多
关键词 无人水面艇 动态环境 动态窗口法 量子粒子群 规则
下载PDF
激光雷达与卫星融合的USV导航系统设计研究
14
作者 冯献霆 张太煜 《华北自然资源》 2024年第3期103-106,共4页
本研究旨在设计并验证一种结合激光雷达和卫星图像技术的无人水面船(USV)导航系统。该系统通过融合激光雷达的高精度距离测量和卫星图像的广阔视野,提高了USV在复杂水域环境中的导航精度和环境适应性。系统架构包括激光雷达扫描模块、... 本研究旨在设计并验证一种结合激光雷达和卫星图像技术的无人水面船(USV)导航系统。该系统通过融合激光雷达的高精度距离测量和卫星图像的广阔视野,提高了USV在复杂水域环境中的导航精度和环境适应性。系统架构包括激光雷达扫描模块、卫星图像处理模块和数据融合处理模块。通过在开阔湖泊、狭窄河道和多变海岸线等不同水域环境下测试,该系统展现了优异的导航性能,特别是在路径规划准确性和避障能力方面。测试结果表明,该导航系统在实际应用中具有广泛的可行性和有效性。 展开更多
关键词 激光雷达 卫星 usv导航系统
下载PDF
基于滑模负载扰动观测器的USV永磁同步推进电机模糊自适应控制
15
作者 罗鹏 赵红 +2 位作者 张忠伍 程世超 刘兴勇 《电工技术》 2024年第15期33-37,40,共6页
为增强无人水面艇(USV)永磁同步推进电机控制系统的抗负载扰动能力,提出了一种基于模糊自适应控制和负载转矩补偿相结合的非线性转速控制策略。该策略以电机转速和q轴电流为观测对象设计滑模负载转矩观测器,将实时辨识的负载转矩观测值... 为增强无人水面艇(USV)永磁同步推进电机控制系统的抗负载扰动能力,提出了一种基于模糊自适应控制和负载转矩补偿相结合的非线性转速控制策略。该策略以电机转速和q轴电流为观测对象设计滑模负载转矩观测器,将实时辨识的负载转矩观测值引入电流环中形成对参考转矩的前馈补偿,抑制未知负载扰动对控制性能的影响;同时利用模糊自适应控制不需对被控对象建立精确数学模型的优点,将其引入速度环中以提高USV推进系统的鲁棒性。通过MATLAB/Simulink仿真分析,验证了基于滑模负载扰动观测器的USV永磁同步推进电机模糊自适应控制系统方案的正确性和有效性。 展开更多
关键词 无人水面艇 滑模负载转矩观测器 永磁同步电机 模糊自适应控制
下载PDF
Clinical outcome of medium-sized hepatocellular carcinoma treated with microwave ablation 被引量:10
16
作者 Ai-Xue Sun Zhi-Li Cheng +5 位作者 Pan-Pan Wu Yue-Hong Sheng Xiu-Juan Qu Wen Lu Cheng-Gong Zhao Guo-Jun Qian 《World Journal of Gastroenterology》 SCIE CAS 2015年第10期2997-3004,共8页
AIM:To evaluate the outcomes of patients withmedium-sized hepatocellular carcinoma(HCC)who underwent percutaneous microwave ablation(MWA).METHODS:We retrospectively reviewed all patients with a single medium-sized HCC... AIM:To evaluate the outcomes of patients withmedium-sized hepatocellular carcinoma(HCC)who underwent percutaneous microwave ablation(MWA).METHODS:We retrospectively reviewed all patients with a single medium-sized HCC who underwent percutaneous MWA from January 2010 to January2013.Technical success,technical effectiveness and complications were subsequently observed.Survival curves were constructed using the Kaplan-Meier method.The Cox proportional hazards model was fitted to each variable.The relative prognostic significance o f t h e va r i a b l e s fo r p re d i c t i n g ove ra l l s u r v i va l rate,recurrence-free survival rate and local tumor recurrence(s)was assessed using univariate analysis.All variables with a P value<0.20 were subjected to multivariate analysis.RESULTS:The study included 182 patients(mean age,58 years;age range:22-86 years)with a single HCC(mean size,3.72±0.54 cm;range:3.02-5.00cm).The estimated technical effectiveness rate was93%in 182 patients.The major complication rate was2.7%(5/182),including liver abscess in 4 cases,and abdominal bleeding at the puncture site in 1 case.Thirty-day mortality rate was 0.5%(1/182).One patient died due to liver abscess-related septicemia.Cumulative recurrence-free survival and overall survival(OS)rates were 51%,36%,27%and 89%,74%,60%at 1,2,and 3 years,respectively.Age(P=0.017)and tumor diameter(P=0.029)were independent factors associated with local tumor recurrence.None of the factors had a statistically significant impact on recurrence-free survival.Serum albumin level(P=0.009)and new lesion(s)(P=0.029)were independently associated with OS.CONCLUSION:Percutaneous MWA is a relatively safe and effective treatment for patients with medium-sized HCC. 展开更多
关键词 HEPATOCELLULAR CARCINOMA medium-sized TUMOR Microw
下载PDF
Fine-scale activity patterns of large-and medium-sized mammals in a deciduous broadleaf forest in the Qinling Mountains,China 被引量:1
17
作者 Yuke Zhang Xiangbo He +3 位作者 Xuehua Liu Melissa Songer Haishan Dang Quanfa Zhang 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第6期2709-2717,共9页
The composition of animal species and interactions among them are widely known to shape ecological communities and fine-scale(e.g.,<1 km)monitoring of animal communities is essential for understanding the relations... The composition of animal species and interactions among them are widely known to shape ecological communities and fine-scale(e.g.,<1 km)monitoring of animal communities is essential for understanding the relationships among animals and plants.Although the co-existence of large-and medium-sized species has been studied across different scales,research on fine-scale interactions of herbivores in deciduous broadleaf forests is limited.Camera trapping of large-and medium-sized mammals was carried out over a 1 year period within a 25 ha deciduous broadleaf forest dynamics plot in the Qinling Mountains,China.Fourteen species of large-and medium-sized mammals,including six carnivores,six ungulates,one primate and one rodent species were found.Kernel density estimations were used to analyse the diel or 24 h activity patterns of all species with more than 40 independent detections and general linear models were developed to explore the spatial relationships among the species.The combination of overlapping diel activity patterns and spatial associations showed obvious niche separation among six species:giant panda(Ailuropoda melanoleuca David),takin(Budorcas taxicolor Hodgson),Reeves’s muntjac(Muntiacus reevesi Ogilby),tufted deer(Elaphodus cephalophus Milne-Edwards),Chinese serow(Capricornis milneedwardsii David)and wild boar(Sus scrofa Linnaeus).Long-term fine-scale monitoring is useful for providing information about the co-existence of species and their interactions.The results demonstrate the importance for fine-scale monitoring of animals and plants for improving understanding of species interactions and community dynamics. 展开更多
关键词 Large-and medium-sized mammals Fine-scale interaction Camera trapping Spatiotemporal patterns Forest dynamics plots Qinling mountains
下载PDF
Enucleation combined with guided bone regeneration in small and medium-sized odontogenic jaw cysts 被引量:1
18
作者 Yi-Ting Cao Qin-Hua Gu +1 位作者 Yi-Wei Wang Qian Jiang 《World Journal of Clinical Cases》 SCIE 2022年第9期2764-2772,共9页
BACKGROUND The odontogenic jaw cyst is a cavity containing liquid,semifluid or gaseous components,with the development of the disease.In recent years,with the rapid development of oral materials and the transformation... BACKGROUND The odontogenic jaw cyst is a cavity containing liquid,semifluid or gaseous components,with the development of the disease.In recent years,with the rapid development of oral materials and the transformation of treatment of jaw cysts,more options are available for treatment of postoperative bone defect of jaw cysts.Guided bone regeneration(GBR)places biomaterials in the bone defect,and then uses biofilm to separate the proliferative soft tissue and the slow-growing bone tissue to maintain the space for bone regeneration,which is widely used in the field of implantology.AIM To observe the clinical effect of GBR in repairing bone defect after enucleation of small and medium-sized odontogenic jaw cysts.METHODS From June 2018 to September 2020,13 patients(7 male,6 female)with odontogenic jaw cysts were treated in the Department of Oral Surgery,Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine.Adults without hypertension,heart disease,diabetes or other systemic diseases were selected.The diagnosis was based on the final pathological results:11 cases were diagnosed as apical cysts,one as primordial cyst,and one as dentigerous cyst.The lesions were located in the maxilla in seven cases,and in the mandible in six cases.All cases were treated with the same method of enucleation combined with GBR.RESULTS Three to four months after the operation,the boundary between the implant site and the surrounding normal stroma was not obvious in patients with small-sized odontogenic jaw cysts.The patients with tooth defects were treated with implant after 6 mo.For the patients with medium-sized odontogenic jaw cysts,the density of the center of the implant area was close to the normal mass at 6 mo after surgery,and there was a clear boundary between the periphery of the implant area and the normal mass.The boundary between the periphery of the implant area and the normal mass was blurred at 8-9 mo after surgery.Patients with tooth defects were treated with implants at>6 mo after the operation.CONCLUSION Enucleation combined with guided bone regeneration in small and medium-sized odontogenic jaw cysts can shorten the time of osteogenesis,increase the amount of new bone formation,reduce complications,and improve quality of life. 展开更多
关键词 ENUCLEATION Bone defect Guided bone regeneration Small and medium-sized Odontogenic jaw cysts
下载PDF
Mechanism of Impact of Entrepreneurial Spirit on the Development of Small and Medium-sized Private Enterprises in China 被引量:1
19
作者 Feihong CHEN Jiayue LI +1 位作者 Yisheng PENG Xi ZHAN 《Asian Agricultural Research》 2017年第6期1-6,共6页
As a necessary factor for a successful business,entrepreneurial spirit is an important means for enterprises to survive in the unstable environment of fierce competition. Under the circumstance of mass entrepreneurshi... As a necessary factor for a successful business,entrepreneurial spirit is an important means for enterprises to survive in the unstable environment of fierce competition. Under the circumstance of mass entrepreneurship and innovation,a large number of small and medium-sized private enterprises have emerged in all walks of life in China. This paper examines the differences in the definition of entrepreneurial spirit by different scholars,the influence of Chinese entrepreneurship on the development of small and medium-sized private enterprises,the origin of the spirit of private entrepreneurs with Chinese characteristics,and the disadvantages of the spirit of small and medium-sized private entrepreneurs in China. It is necessary to further improve entrepreneurial spirit to contribute to the development of small and medium-sized private enterprises and help China to build the national economic system. 展开更多
关键词 Small and medium-sized private enterprises Entrepreneurial spirit Impact mechanism
下载PDF
Gas concentration monitoring system for small and medium-sized coal mines based on gas-sensing detection and single-chip control 被引量:1
20
作者 Bin Guangfu Huang Zhenyu +1 位作者 Zhu Guanghui Li Xuejun 《Engineering Sciences》 EI 2010年第4期47-51,共5页
This paper is aimed at the actual conditions of disaster caused by gas in small and medium-sized coal mines. A new gas concentration monitoring system for coal mines is developed on the basis of gas-sensing detection ... This paper is aimed at the actual conditions of disaster caused by gas in small and medium-sized coal mines. A new gas concentration monitoring system for coal mines is developed on the basis of gas-sensing detection and single-chip control. The monitoring system uses the tin oxide as the main material of N-type semiconductor gas sensors, be- cause it has good sensitive characteristics for the flammable and explosive gas ( such as methane, carbon monoxide). The QM-N5-semiconductor gas sensor is adopted to detect the output values of the resistance under the different gas con- centrations. The system, designedly, takes the AT89C51 digital chip as the core of the circuit processing hardware structure to analyze and judge the input values of the resistance, and then achieve the control and alarm for going beyond the limit of gas concentration. The gas concentration monitoring system has man), advantages including simple in struc- ture, fast response time, stable performance and low cost. Thus, it can be widely used to monitor gas concentration and provide early wamings in small and medium-sized coal mines. 展开更多
关键词 gas concentration monitoring gas-sensing detection single-chip control small and medium-sized coal
下载PDF
上一页 1 2 32 下一页 到第
使用帮助 返回顶部