检索结果-南通市图书馆

Non-Point-Source Nitrogen and Phosphorus Loadings from a Small Watershed in the Three Gorges Reservoir Area

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2012年第1期9卷 10-15页

作者： ZHU BO WANG Zhenhua WANG Tao dong zhixin Key Laboratory of Mountain Environment Evolvement and Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A representative small watershed in the central part of the TGR area was selected to monitor the loss of nitrogen(N) and phosphorous(P) continuously along with the runoff from 2007 through 2009 to understand the exact sources and *** show that the non-point-source nitrogen and phosphorus comes mainly from the storm runoff from residential areas,citrus orchards and sloping croplands,which contributes up to 76% of the loadings in this ***,a crucial measure for controlling non-point-source pollution is to intercept storm runoff from the three *** fields provide a sink for non-point-source N and P by intercepting the runoff and sediment along with their different forms of nitrogen and *** N and P removal efficiency by paddy fields from residential areas is within the range of 56% to 98%.Paddy fields are an important land-use option for reducing the non-point-source loading of N and P in the TGR area.

关键词： Non-point-source pollution Source and sink Nitrogen Phosphorus Paddy fields Three Gorges Reservoir area China

Power Matching and Energy Efficiency Improvement of Hydraulic Excavator Driven with Speed and Displacement Variable Power Source

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2019年第6期32卷 142-153页

作者： Lei Ge Long Quan Xiaogang Zhang zhixin dong Jing Yang Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology

Mobile machinery energy efficiency and emission pollution are the national and worldwide issues. This paper contributes in solving these problems by applying a speed variable power source. Unfortunately, almost all of the speed variable systems have the dynamic response problem when the motor starts with full load or heavy load. To address this problem, a hydraulic accumulator is used to balance the load of the power source for assisting starting of the motor and a matching method combined with speed and displacement control of the pump is proposed to improve the energy efficiency and dynamic performance simultaneously under different working conditions. Also, the power source/valve combined control strategy of an independent metering system is designed to realize flow matching of the whole system. Firstly, a test system is established to study the dynamic performance and energy efficiency of the speed variable power source with an auxiliary accumulator. Working performance and energy consumption of the power source under different rotating speeds and different loads are studied. And then, the hydraulic excavator test rig with the proposed system is constructed. Furthermore, the working performance of the excavator with the speed-fixed and speed-variable strategy are studied comparatively. Results show that, compared with fixed-speed strategy, the electric power consumption during the idle period and partial load condition can be reduced about 2.05 kW and 1.37 kW. The energy efficiency of speed variable power source is about 40%-71%, which is higher than that of the fixed-speed power source by 3%–10%.

关键词： Hydraulic excavator Power matching Speed variable Energy efficiency

Effect of Al_(82.8)Cu_(17)Fe_(0.2) alloy doping on structure and magnetic properties of SmCo5-based ribbons

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2022年第1期40卷 93-101页

作者： zhixin dong Shu Wang Siyi Chen Yunfei Cao Zihui Ge Jibing Sun Key Lab.for New Type of Functional Materials in Hebei Province Hebei University of TechnologyTianjin 300401China

This work tries to improve the magnetic properties by multi-element doping in the form of a ternary ***_(5+)χwt%Al-Cu-Fe(x=0-7)ribbons melt-spun at 40 m/s were produced by adding Al_(82.8)Cu_(17)Fe_(0.2)alloy into SmCo_(5) matrix,and their phases,microstructure,and magnetic properties were *** results show that both x=0 and 3 ribbons form a cellular ***-Cu-Fe addition reduces the content of the Sm_(2)(Co,M)_(7) cell wall,narrows its width,and forms the local disordered micro-regions and solute-segregation nanoclusters in the Sm(Co,M)_(5) *** x increasing to5,Al-Cu-Fe addition promotes the phase separation between and within grains of the SmCo_(5)-based *** Al-Cu-Fe addition can simultaneously improve the coercivity and magnetization of the SmCo_(5)-based ribbons,in particular,the magnetization of the x=3 ribbons increases by 35%,while the coercivity of the x=5 ribbons increases by 3.9 ***,the microstructure evolution models are built up,and the relationship between the microstructure and the magnetic properties is discussed.

关键词： Rare earth alloys and compounds Rapid solidification Crystal structure Phase transitions Microstructure Magnetic property

在线全文

学校读者我要写书评

暂无评论

促进新能源消纳的虚拟电厂运营优化策略

科技管理研究 2024年第14期44卷 173-182页

作者：胡洋董治新韩雅萱加鹤萍刘敦楠刘江艳新能源电力系统国家重点实验室(华北电力大学) 北京102206 华北电力大学经济与管理学院北京102206 广州电力交易中心有限责任公司广东广州511458

虚拟电厂进入市场的前提是能够通过聚合优化调度发挥分布式资源的调节潜力、促进新能源消纳,而将新能源消纳考核与超额消纳激励纳入虚拟电厂运营优化策略,能够提升虚拟电厂的资源聚合优化水平,促进虚拟电厂进一步参与市场运营。然而,目... 详细信息

虚拟电厂进入市场的前提是能够通过聚合优化调度发挥分布式资源的调节潜力、促进新能源消纳,而将新能源消纳考核与超额消纳激励纳入虚拟电厂运营优化策略,能够提升虚拟电厂的资源聚合优化水平,促进虚拟电厂进一步参与市场运营。然而,目前相关研究缺乏对此方面的关注,同时缺乏精细化的相关定量分析。为此,构建虚拟电厂参与电能量、调峰辅助服务交易联合的市场框架,基于用户需求弹性分析提出考虑负荷调节概率的虚拟电厂新能源消纳考核与激励模型,根据虚拟电厂运营由于内部资源不确定性带来考核的经济风险,采取用户调节概率以削弱消纳的不确定性,进而提出促进虚拟电厂消纳新能源的运营优化策略。此外,将考虑新能源考核激励的运营优化策略与一般运营策略的结果进行对比,以验证所提出模型的可行性,并通过构建高电价场景和高资源场景修正模型参数,进一步分析模型对不同场景的适应性。结果表明:在参与电力市场联合交易条件下,不同场景下采用考虑新能源考核激励运营优化策略的虚拟电厂,不仅在市场运营效益上有更好表现,同时能够明显提高新能源消纳量、发挥峰谷调节作用,更有效地协调其内部负荷、保障电力系统平稳运行。由此,在完善市场交易机制、因地制宜丰富商业模式等方面得出提高虚拟电厂市场竞争力的相关启示。

关键词：虚拟电厂新能源消纳新能源考核激励运营策略需求弹性分析不确定性分析电力市场

Peptide tyrosine-tyrosine combined with its receptors exhibits an anti-cancer potential in pancreatic cancer MiaPaCa-2 cell

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2014年第24期127卷 4235-4242页

作者： Li Hongxia Wang zhixin dong Lei Jiang Jiong Xu Xinsen Zhou Lei Wan Yong Department of Gastroenterology Department of Hepatobiliary Surgery the First Affiliated Hospital of Xi'an Jiaotong University College of Medicine Xi'an Shaanxi 710061 China

Background Pancreatic cancer is a common malignant tumor of the digestive system. It is the fourth major cause of tumor-related death and its morbidity is increasing, and hence it is imperative to develop effective forms of therapy for pancreatic cancer. Peptide tyrosine-tyrosine （PYY） is an important gastrointestinal peptide hormone. According to previous literatures, PYY has been shown to inhibit tumor proliferation in cellular and animal models, but there has been limited research on the detailed mechanism of PYY in pancreatic cancer. This study was to observe the effects of PYY on pancreatic cancer cell and investigate the possible mechanism. Methods The expression of Y1, Y2, and Y5 receptors on pancreatic cancer cell lines were detected by reverse transcription quantitative polymerase chain reaction （RT-qPCR）. The cytotoxicity of PYY toward the MiaPaCa-2 cell was evaluated by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay; the cell morphology and structure changes were observed under inverted microscope and transmission electron microscope respectively. Apoptosis and cell cycle were evaluated by flow cytometry. The activity of caspase-3 was determined by activity assay kits and Western blotting. The expression of survivin, vascular endothelial growth factor （VEGF）, and cyclooxygenase-2 （COX-2） were determined by RT-qPCR and Western blotting. Results Expression of Y2 receptor is the most abundant PYY receptor on pancreatic cancer cell. PYY inhibited MiaPaCa-2 cell proliferation, blocked it in G0/G1 phase, increased the proportion of apoptosis cells and caspase-3 activity, and reduced the expression of survivin, VEGF, and COX-2. Conclusions PYY weakened the ability of the pancreatic MiaPaCa-2 cell viability through cell cycle blocking and apoptosis inducing. The inhibition effect of PYY may be mediated by the Y2 receptor. The increased caspase-3 activity and reduced expression of survivin, VEGF, and COX-2 may serve as a novel mechanism i

关键词： peptide tyrosine-tyrosine (PYY) pancreatic cancer MiaPaCa-2 cell anti-cancer

寒温并用代表方乌梅丸治疗恶性肿瘤的研究进展

在线全文

学校读者我要写书评

暂无评论

医学综述 2024年第4期30卷 433-438页

作者：邢烙涛陈思杨甘秦汉甘雪军董芷辛许梅姚菲方芳石玮广西中医药大学研究生院南宁530200 广西中医药大学第一附属医院肿瘤科二病区南宁530023

乌梅丸是《伤寒论》厥阴病寒热错杂证主方,随着中医药理论和临床实践的不断发展,应用范围逐渐扩大,在肺癌、胃癌、肠癌、胰腺癌、乳腺癌等诸多癌种中均有报道。临床研究中运用乌梅丸协同放化疗、靶向免疫治疗等可有效缓解治疗相关不良反... 详细信息

乌梅丸是《伤寒论》厥阴病寒热错杂证主方,随着中医药理论和临床实践的不断发展,应用范围逐渐扩大,在肺癌、胃癌、肠癌、胰腺癌、乳腺癌等诸多癌种中均有报道。临床研究中运用乌梅丸协同放化疗、靶向免疫治疗等可有效缓解治疗相关不良反应,提高患者生存质量。现代实验研究发现,乌梅丸具有调控相关基因、蛋白以抑制肿瘤细胞增殖、迁移和氧化应激等多种通路及机制的作用。探索乌梅丸调节恶性肿瘤寒热错杂微环境的作用,有望为中医药防治恶性肿瘤的研究提供新方向。

关键词：恶性肿瘤乌梅丸寒温并用法

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

毛泽东指导郭化若研究《孙子兵法》

军事历史研究 2007年第1期21卷 24-31页

作者：董志新沈阳军区政治部

在毛泽东的《孙子兵法》解读史上,指导郭化若研究《孙子兵法》是其中一项重要活动;指导郭化若研究《孙子兵法》并取得世人瞩目的实绩,是他倡导批判继承历史遗产最为成功的范例;而郭化若则受毛泽东之命研究《孙子兵法》,倾注了大半生心血... 详细信息

在毛泽东的《孙子兵法》解读史上,指导郭化若研究《孙子兵法》是其中一项重要活动;指导郭化若研究《孙子兵法》并取得世人瞩目的实绩,是他倡导批判继承历史遗产最为成功的范例;而郭化若则受毛泽东之命研究《孙子兵法》,倾注了大半生心血,可谓躹躬尽瘁,死而后已,这也成就了他“运用马克思主义立场和观点研究《孙子兵法》第一人”的学术地位,被誉为“一代儒将”。

关键词：毛泽东郭化若《孙子兵法》研究

在线全文

学校读者我要写书评

暂无评论

符号拜物教的表现形式及精神异化特质探析

世界哲学 2019年第1期 5-13,160页

作者：范宝舟董志芯上海财经大学人文学院

目前,对符号拜物教的研究,更多是在与马克思拜物教思想的对比中进行,并且在其具体表现形式及其异化特质的揭示上显得含混、抽象而不够明晰。本文认为,符号拜物教具体表现为意象拜物教、景观拜物教和能指拜物教。符号拜物教的异化特质深... 详细信息

目前,对符号拜物教的研究,更多是在与马克思拜物教思想的对比中进行,并且在其具体表现形式及其异化特质的揭示上显得含混、抽象而不够明晰。本文认为,符号拜物教具体表现为意象拜物教、景观拜物教和能指拜物教。符号拜物教的异化特质深层次地表现是精神异化。符号拜物教带来的精神异化,根源不在于符号的自我运动本身,而在于催生符号运动的资本扩张逻辑。马克思拜物教思想关于资本逻辑的批判,对于剖析符号拜物教视域中的精神异化依然具有强烈的现实意义。

关键词：意象拜物教景观拜物教能指拜物教精神异化

在线全文

学校读者我要写书评

暂无评论

何其芳与吴组缃《红楼梦》专题课“擂台赛”

红楼梦学刊 2020年第4期 1-27页

作者：董志新不详

何其芳与吴组缃《红楼梦》专题课"擂台赛"是现代红学史上的重要事件。1956年,北京大学贯彻"向科学进军""百花齐放,百家争鸣"精神,在中文系开设了《红楼梦》选修课,由吴组缃与何其芳两位老师采取"打擂台"的方式,分别授课。何、吴这种"擂... 详细信息

何其芳与吴组缃《红楼梦》专题课"擂台赛"是现代红学史上的重要事件。1956年,北京大学贯彻"向科学进军""百花齐放,百家争鸣"精神,在中文系开设了《红楼梦》选修课,由吴组缃与何其芳两位老师采取"打擂台"的方式,分别授课。何、吴这种"擂台赛"式的学术讲演和文学评论,持续了多年。本文梳理了相关历史文献,力求说清何吴"擂台赛"的缘起经历、论辨焦点、延续影响、争鸣风度,以及对现实红学发展的借鉴价值。

关键词：何其芳吴组缃红学专题课“擂台赛”