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Influence of external circulation on sludge characteristics during start-up of internal circulation reactor 被引量:4
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作者 丁建南 王淀佐 《Journal of Central South University of Technology》 EI 2005年第4期425-429,共5页
The start-up of external circulationadded internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of gr... The start-up of external circulationadded internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of granular sludge, the characteristics of the granular sludge taken from the two tested laboratory-scale reactors during start-up were studied. The results show that the added external circulation can enhance biomass granulation, accelerate granule development and improve sludge characteristics. At the end of start-up, the granular size of sludge in external circulation-added IC reactor greatly increases with a size distribution much better than that of sludge in IC reactor. The granular sludge originated from external circulationadded IC reactor contains more extracellular polymers and has a greater settling velocity than that from IC reactor. Methanogenic activity of the granular sludge from the external circulationadded IC reactor started 26 d ago reaches 358.23mL·g -1 ·d -1 , 1.66 and 1.20 times as great as that of the sludge from the IC reactor started 26 d and 58 d ago respectively. 展开更多
关键词 external circulation internal circulation reactor characteristics of granular sludge
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Fluid structure interaction for circulation valve of hydraulic shock absorber 被引量:6
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作者 陈齐平 舒红宇 +2 位作者 方文强 何联格 杨茂举 《Journal of Central South University》 SCIE EI CAS 2013年第3期648-654,共7页
Based on the working principle and the damping characteristic of hydraulic shock absorber, a fluid structure interaction method was presented, which was used to analyze the microcosmic and high-frequency processing me... Based on the working principle and the damping characteristic of hydraulic shock absorber, a fluid structure interaction method was presented, which was used to analyze the microcosmic and high-frequency processing mechanism of fluid structure interaction between circulation valve and liquid of hydraulic shock absorber. The fluid mesh distortion was controlled by the CEL language, and the fluid struc^tre interaction mathematical model was established. The finite element model was established by ANSYS CFX software and was analyzed by dynamic mesh technique. The local sensitive computational area was meshed by prismatic grid, which could reduce the negative volume problem during the simulation. The circulation valve and liquid of hydraulic shock absorber were simulated and analyzed under the condition of sinusoidal inlet velocity loads. Flow characteristic and dynamics characteristic were obtained. The pressure distribution and the displacement of circulation value were obtained, and the acceleration curve of circulation valve was simulated and analyzed. The conformity of the final simulation results with the experimental datum indicates that this method is accurate and reliable to analyze the dynamics characteristic between circulation valve and liquid of hydraulic shock absorber, which can provide a theoretical foundation for optimizing hydraulic shock absorber in the future. 展开更多
关键词 hydraulic shock absorber circulation valve finite element method fluid structure interaction simulation analysis
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Circulation Retrieval of Wake Vortices under Rainy Conditions with an X Band Radar 被引量:1
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作者 Jean-Yves Schneider Gilles Beauquet Frederic Barbaresco 《雷达学报(中英文)》 CSCD 2017年第6期673-688,共16页
At airports, runway operation is the limiting factor for the overall throughput; specifically the fixed and overly conservative ICAO wake turbulence separation minima. The wake turbulence hazardous flows can dissipate... At airports, runway operation is the limiting factor for the overall throughput; specifically the fixed and overly conservative ICAO wake turbulence separation minima. The wake turbulence hazardous flows can dissipate quicker because of decay due to air turbulence or be transported out of the way on oncoming traffic by cross-wind, yet wake turbulence separation minima do not take into account wind conditions. Indeed, for safety reasons, most airports assume a worst-case scenario and use conservative separations; the interval between aircraft taking off or landing therefore often amounts to several minutes. However, with the aid of accurate wind data and precise measurements of wake vortex by radar sensors, more efficient intervals can be set, particularly when weather conditions are stable. Depending on traffic volume, these adjustments can generate capacity gains, which have major commercial benefits. This paper presents the use of Electronic scanning radar for detecting wake vortices. In this method, the raindrops Doppler spectrogram is used to retrieve the strength of the wake vortex. Numerical simulation are performed to establish an empirical model used during the retrieval method. This paper presents also the results obtained during the trials of the PARIS-CDG data set recorded from October 2014 to November 2015 with an X-band RADAR developed and deployed by THALES. 展开更多
关键词 Wake-vortex hazard Airport capacity Airport safety X-band radar Wake-vortex circulation Eddy dissipation rate
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Safe utilization of chromium-bearing vanadate residue by recovery of vanadium and chromium based on calcium circulation 被引量:2
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作者 LIU Gui-hua WU Guo-yu +4 位作者 JIANG Hai-lang QI Tian-gui PENG Zhi-hong ZHOU Qiu-sheng LI Xiao-bin 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第10期2349-2359,共11页
A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium c... A safe,economical treatment of hazardous chromium-bearing vanadate residue(CVR)will significantly benefit the clean production of chromate-bearing salts.This study investigated recovery of sodium vanadate and sodium chromate from CVR in sodium bicarbonate solution.Results indicate that the stability of calcium vanadate and calcium chromate depends on pH and[HCO3?].CaV2O6?4H2O transforms into CaV2O6?4H2O,CaV2O6?2H2O,CaV2O6,Ca2V2O7?2H2O,and Ca5(VO4)3(OH)when pH increases from 7.51 to 12.32.Increasing pH and reducing CVR dosage improve the vanadate extraction rate,and high V2O5 and Na2Cr2O7?2H2O extraction rates are achieved in dilute NaHCO3 solution.Moreover,addition of NaOH positively contributes to the recovery of vanadate and chromate from CVR.Over 95%V2O5 and Na2Cr2O7?2H2O in CVR can be extracted from 60 g/L NaHCO3 and 30 g/L NaOH solutions at 90°C for 2 h.In order to reduce the hazardous residue containing chromate after recovery of CVR,calcium circulation is presented.Results show that more than 60%lime can be saved with fresh residue addition to remove vanadate from sodium chromate solution due to the active CaCO3.Moreover,no lime is required in removal of vanadate when the roasting residue is added.Therefore,a novel process is developed for utilization of CVR. 展开更多
关键词 chromium-bearing vanadate residue NaHCO3 calcium vanadate calcium chromate sodium chromate calcium circulation
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Optimal design of auxiliary-teeth to solve circulation current reduction of permanent magnet linear synchronous motor 被引量:1
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作者 JANG Ki-bong KIM Jee-hyun +1 位作者 AN Ho-jin KIM Gyu-tak 《Journal of Central South University》 SCIE EI CAS 2011年第3期690-696,共7页
A discontinuity of magnetic circuits according to the end effect is generated in the permanent magnet linear synchronous motor (PMLSM). Due to the unbalanced back electro-motive force (EMF) and impedance produced,... A discontinuity of magnetic circuits according to the end effect is generated in the permanent magnet linear synchronous motor (PMLSM). Due to the unbalanced back electro-motive force (EMF) and impedance produced, unbalanced current is generated. The cireulatin8 current, which is caused by a decrease in the thrust, is generated by the unbalanced current. The optimal design of auxiliary-teeth at the end of the mover was carried out to solve the unbalance of phase by using design of experiment (DOE), and compared with the basic model through finite element analysis (FEA). As a result, the auxiliary-teeth model compensates for the decrease of thrust caused by the unbalanced phase. Also, this model is proven to reduce the detent force by the vibration and noise of the PMLSM and copper loss caused by the circulating current. 展开更多
关键词 permanent magnet linear synchronous motor auxiliary-teeth circulation current end effect thrust reduction
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Novel technologies and models for studying pharmacological activities of traditional Chinese medicine for promoting blood circulation and removing blood stasis
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作者 ZHAO Yang WEI Zhong-hong +6 位作者 YU Su-yun WANG Ai-yun CHEN Wen-xing ZHENG Xiang-jian Mathew VADAS Jennifer GAMBLE LU Yin 《中国药理学与毒理学杂志》 CAS 北大核心 2021年第10期740-741,共2页
OBJECTIVE Our previous studies demonstrated that various ingredients from the traditional Chinese medicine(TCM)for promoting blood circulation and removing blood stasis,as exemplified by cryptotanshinone and salvianol... OBJECTIVE Our previous studies demonstrated that various ingredients from the traditional Chinese medicine(TCM)for promoting blood circulation and removing blood stasis,as exemplified by cryptotanshinone and salvianolic acid B,exerted striking effects on modulating angiogenesis and vascular permeability,which suggests that they may be effective in treating vascular leak-driven diseases(e.g.tumor,cerebral cavernous malformation and diabetic retinopathy).However,the lack of reliable and advanced technologies and models sets up difficult hurdles for better understanding the role of TCM for promoting blood circulation and removing blood stasis.To this end,this study is to outline numerous cutting-edge platforms that can be utilized for exploring the function of TCM for promoting blood circulation and removing blood stasis in vascular leak-driven diseases.METHODS Two-photon laser scanning fluorescence microscopy was used to observe the interactions between neutrophils and blood vessels in a real-time manner.Dynamic flow system was employed to mimic the in vivo behaviors of neutrophils.RIP1-Tag5 spontaneous pancreatic cancer model was used to study the function of tumor blood vessels.CCM2ECKO(deletion of CCM2 in endothelial cells)mice were employed to establish the cerebral cavernous malformation(CCM)animal model.Micro-computed tomography(micro-CT)was utilized to assess the CCM lesion.Müller cell-knockout mouse model was used to study the progression of diabetic retinopathy.Vascular permeability in this model was assessed by fluorescein angiography.RESULTS The interactions between neutrophils and endothelial cells involve a series of complicated processes,including rolling,adhesion,intraluminal crawling and transmigration,which were all monitored in vivo by two-photon laser scanning fluorescence microscopy in a real-time manner.Dynamic flow system was capable of recapitulating the biological behaviors of neutrophils in vitro.Tumor vascular function in particular vascular perfusion could be assessed in the RIP1-Tag5 spontaneous pancreatic cancer model.In terms of CCM studies,specific deletion of CCM2 in endothelial cells resulted in the initiation of CCM lesion.The size and number of CCM lesions could be visualized and quantified by micro-CT.Furthermore,the Müller cell-knockout mouse model was able to precisely reflect the clinical symptoms of diabetic retinopathy.Vascular leak could be monitored at different time points using fluorescein angiography.CONCLUSION An array of high technologies and animal models can be used in investigating the occurrence and progression of multiple vascular leak-driven diseases.The pre-clinical and clinical studies of TCM for promoting blood circulation and removing blood stasis provide fundamental support for the application of the above-mentioned platforms,with the purpose of uncovering the scientific basis of TCM for promoting blood circulation and removing blood stasis. 展开更多
关键词 traditional Chinese medicine blood circulation blood stasis tumor vessels cerebral cavernous malformation diabetic retinopathy
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A 3-dimensional baroclinic circulation model of the South China Sea
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作者 Yi Cai(蔡怡) +1 位作者 Yuxiang Li(李毓湘) 《海洋预报》 北大核心 2001年第z1期35-49,共15页
The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and ... The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and air temperature field at the 1000 mb level from the European Centre for Medium-Range Weather Forecasts as inputs. The boundary conditions at Bashi Channel and Taiwan Strait are taken from the simulation results of the Kuroshio using the same numerical model with a grid size of 0.5°×0.5° and the results of Cai and Li (1996) as boundary conditions. The computational domain for the present paper is between 100°E and 123°E and between 4.5°N and 27°N. The horizontal resolution is 0.25°×0.25° and the vertical variations of the velocity components are resolved by 6 layers The computed steady flow, temperature and elevation fields are consistent with the corresponding fields observed. In particular, the temperature and elevation fields of the South China Sea Warm Current (SCSWC) have been successfully simulated. The paths of the branch of the Kuroshio entering the South China Sea (SCSBK) through Bashi Channel in winter and summer are discussed It is found that the SCSBK flows southward to the southern SCS from the coast of the Guangdong Province. A portion of the SCSBK returns to the Bashi Channel and subdivides again in deep waters in winter with a branch flows to the south along the coast of the Philippines instead of flowing back to the Pacific In addition, our results confirm the existence of a eastward current to the northeast of Dongsha in summer with the Kuroshio as its source as suggested by Huang et al. Since the value of the eddy viscosity adopted for the simulation of the Kuroshio is on the high side, resulting in a weaker west boundary current in the western Pacific as the boundary conditions for the present simulations, some deviations from the actual situations are expected although the results are in general consistent with observations. 展开更多
关键词 MODE In SCS A 3-dimensional baroclinic circulation model of the South China Sea
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Selection and Study of High-yield Aerobic Strains of Treating the Closed Circulation Wastewater for Regenerated Fiber
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作者 MA Yong-wen FU Yan-fang WAN Jin-quan 《中国造纸学报》 EI CAS CSCD 2007年第4期40-43,共4页
Efficient and reliable removal of cellulose,hemicellulose and lignin,that are the major organic pollutants in the wastewater from regenerated fiber,is critically important to prevent toxicity discharge.Low-and high-pH... Efficient and reliable removal of cellulose,hemicellulose and lignin,that are the major organic pollutants in the wastewater from regenerated fiber,is critically important to prevent toxicity discharge.Low-and high-pH stresses sometimes occur in the effluent treatment systems due to the use of a large amount of acid and alkaline in the pulping process.Using flat separation method to select high-yield strains from bio-contact oxidation basin,seeing configuration of the strains and doing some physiological experiments,we found that the strains contain two kinds of main bacteria,Zoogloea sp.and Pseudomona sp.We also discovered the best growing time by spectrophotometer.The best growing time is at 0~32h,the logarithmic phase is about at 12~32h,and the stable growth phase is about 32~60h.Furthermore,we concluded that the disposal ability of high-yield strain is better than the ordinary one by doing parallel experiment.Through orthogonal test we also confirmed that the best growing temperature and pH value are 29℃and 7.3 respectively.The COD removal rate is about 93% when the biomembrane is in good condition. 展开更多
关键词 再生纤维 废水处理 封闭式循环 菌株 氧气 造纸工业
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Current-event Play and Circulation of Information in late Ming China
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作者 Nie Lina 《学术界》 CSSCI 北大核心 2018年第4期238-246,共9页
This essay examines current-event plays( shishiju 时事剧) and their social functions in late Ming China. Drawing on awide range or primary sources and built on secondary scholarship on information history,the essay of... This essay examines current-event plays( shishiju 时事剧) and their social functions in late Ming China. Drawing on awide range or primary sources and built on secondary scholarship on information history,the essay offered a complete picture of the booming,features,social functions and the decline of the current-event plays. The essay argues that many current-event plays addressed on credibility,timeliness and easy accessibility,which enabled current-event plays to play an important role in information circulation. This essay further exposes the current-event plays not only opened a forum for public discussion but also influenced public opinions greatly from literate elites to the masses in Ming China. Through analyzing current-event plays in the context of Ming society,this essay expands the realm of studying information history. 展开更多
关键词 学习信息 事件 中国 循环 社会功能 散文 奖学金 接近性
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Research on Power Circulation in of a front Wheel Assist Tractor
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作者 ShunYumei HuangXinghua 《Journal of Northeast Agricultural University(English Edition)》 CAS 1996年第2期150-155,共6页
Base on dynamic analysis for a Front Wheel Assist (FWA) tractor, a method of calculating and analyzing on the critical angle of steering for a FWA tractor is described in this paper. The mathematical model is also est... Base on dynamic analysis for a Front Wheel Assist (FWA) tractor, a method of calculating and analyzing on the critical angle of steering for a FWA tractor is described in this paper. The mathematical model is also established here. The critical steering angle which is a important parameter affecting the steering performance for a FWA tractor is defined in the article. 展开更多
关键词 FWA tractor power circulation steering process
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我国农产品流通效率时空演变、地区差异与收敛性 被引量:4
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作者 高国生 叶林祥 支海兵 《经济问题》 北大核心 2025年第1期100-112,共13页
农产品流通效率事关我国粮食安全和全国统一大市场的建成。运用熵值法测度了2011—2022年我国31个省级行政区的农产品流通效率,并使用Moran’s I、Kernel核密度估计、Markov链、Dagum基尼系数和β收敛模型分别分析了我国农产品流通效率... 农产品流通效率事关我国粮食安全和全国统一大市场的建成。运用熵值法测度了2011—2022年我国31个省级行政区的农产品流通效率,并使用Moran’s I、Kernel核密度估计、Markov链、Dagum基尼系数和β收敛模型分别分析了我国农产品流通效率的时空演变、地区差异与收敛性情况。结果显示:研究期内我国农产品流通效率存在显著正向空间相关性,“高—高”集聚和“低—低”集聚特征明显;核密度曲线宽度变大呈现右拖尾和高度差明显的双峰形态,表明农产品流通效率逐渐提升,地区内部存在极化趋势;相邻省区市空间滞后水平对本省区市农产品流通效率维持原有状态或向更高水平发展均有较大影响;地区间差异是造成农产品流通效率总体差异显著的主要原因;农产品流通效率存在显著绝对β收敛和条件β收敛。据此,对如何提高农产品流通效率和缩小地区间差距提出了相关政策建议。 展开更多
关键词 农产品流通效率 时空演变 空间分布 地区差异
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数据要素可信流通交易的研究框架与展望 被引量:2
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作者 刘业政 宗兰芳 +2 位作者 杨祖艳 钱洋 孙见山 《南开管理评论》 北大核心 2025年第4期158-170,共13页
研究和刻画数据要素流通交易中的可信保障,是应对数据交易中可信风险挑战、建立数据要素可信生态体系的关键。虽然学术界在该领域已取得较为丰富的研究成果,但尚未形成全面的、系统的数据要素可信流通交易的研究框架。本文采用文献分析... 研究和刻画数据要素流通交易中的可信保障,是应对数据交易中可信风险挑战、建立数据要素可信生态体系的关键。虽然学术界在该领域已取得较为丰富的研究成果,但尚未形成全面的、系统的数据要素可信流通交易的研究框架。本文采用文献分析法,按照“可信风险→可信体系→可信机制”路径,对现有研究进行系统梳理与整合,期望构建一个新颖、概括性的研究框架。首先,从多个视角分析数据交易中的可信风险;其次,基于信任理论,提出数据交易的PD CA可信体系,并从实践视角提供实现主体可信、数据可信、合约可信和算法可信的具体路径和措施;最后,针对数据要素可信流通交易的现实困境,给出未来的研究议题。本文对促进数据要素型企业有效应对可信风险管理的挑战,帮助政府高效构建数据要素可信生态体系具有重要启示。 展开更多
关键词 可信流通交易 可信风险 PDCA可信体系 可信机制
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数据空间工程建设模式及推广应用研究 被引量:1
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作者 郭明军 于施洋 +4 位作者 窦悦 郭巧敏 庾朝富 李子硕 黄依迪 《中国工程科学》 北大核心 2025年第1期63-71,共9页
随着新一轮科技革命和产业变革加速演进,数据作为新型生产要素正在深刻改变着生产、生活和社会治理方式,促进数据安全有序流通和价值高效释放的数据空间建设,备受社会各界关注。本文聚焦数据空间的工程建设模式及推广应用,在梳理分析国... 随着新一轮科技革命和产业变革加速演进,数据作为新型生产要素正在深刻改变着生产、生活和社会治理方式,促进数据安全有序流通和价值高效释放的数据空间建设,备受社会各界关注。本文聚焦数据空间的工程建设模式及推广应用,在梳理分析国内外数据空间相关研究与实践经验的基础上,基于数据空间工程建设的驱动要素视角,提出了战略引领型、技术驱动型、需求拉动型、生态赋能型4类数据空间,总结了“政府主导+数据基础设施”“技术创新+数据开发利用”“场景牵引+产业转型升级”“服务合作+数字城市建设”4种数据空间工程建设模式。研究建议,完善政策保障机制、强化关键技术创新、深化应用体系建设和启动试点示范工程,以期为构建具有中国特色、国际领先的数据空间提供有益参考。 展开更多
关键词 数据空间 数据流通利用 数据基础设施 工程建设模式
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流通业高质量发展的现实基础、理论阐释与动力机制 被引量:2
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作者 杨向阳 徐从才 汪洁 《求是学刊》 北大核心 2025年第1期78-87,共10页
流通业高质量发展是构建现代流通体系的重要支撑点,对于畅通国民经济循环和建设全国统一大市场具有重要意义。现阶段我国流通业发展规模不断壮大,总体竞争力待增强;流通基础设施日趋完善,流通效率待提升;流通模式创新发展,流通组织重构... 流通业高质量发展是构建现代流通体系的重要支撑点,对于畅通国民经济循环和建设全国统一大市场具有重要意义。现阶段我国流通业发展规模不断壮大,总体竞争力待增强;流通基础设施日趋完善,流通效率待提升;流通模式创新发展,流通组织重构待完善;数字金融强化风险识别,“数据孤岛”待突破;数字金融应用较为广泛,法治化建设亟须完善。在基于效率、新发展理念、产业特点视角阐释流通业高质量发展理论逻辑的基础上,文章从创新动力、主体动力、支撑动力、信用动力四个维度探讨流通业高质量发展的动力机制,认为丰富多元的流通业态模式、更具活力的流通市场主体、更强健的流通承载能力、更安全高效的金融服务能力能够为流通业高质量发展提供重要发展动力。 展开更多
关键词 流通业高质量发展 现实基础 理论阐释 动力机制
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循环肿瘤DNA在食管癌患者全程管理中的应用研究进展 被引量:1
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作者 刘涛 金海 《海军军医大学学报》 北大核心 2025年第2期244-252,共9页
食管癌是常见的恶性肿瘤之一,我国是食管癌的高发国家。由于食管癌预防难、发现晚,有效防控是研究的热点和临床难点。以循环肿瘤DNA(ctDNA)为代表的液态活检技术的发展为食管癌早期诊断、治疗评估及预后监控提供了一种新的思路。ctDNA... 食管癌是常见的恶性肿瘤之一,我国是食管癌的高发国家。由于食管癌预防难、发现晚,有效防控是研究的热点和临床难点。以循环肿瘤DNA(ctDNA)为代表的液态活检技术的发展为食管癌早期诊断、治疗评估及预后监控提供了一种新的思路。ctDNA检测方法具有高特异度及高灵敏度,可以应用于肿瘤的筛查及诊断,并且在判断预后、指导治疗方面也具有很高的应用价值。本文就ctDNA检测技术及其在食管癌诊疗中的研究进展进行阐述。 展开更多
关键词 食管肿瘤 循环肿瘤DNA 筛查 诊断 临床决策 预后
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农产品现代流通体系建设的国际经验及对我国的启示
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作者 陈秧分 徐邵文 钱静斐 《中国流通经济》 北大核心 2025年第7期22-36,共15页
农产品现代流通体系建设需立足中国特色并借鉴国际经验。面向中国现代农业发展需要,梳理农产品现代流通体系的基本架构,从国内和国际两个角度总结我国农产品流通体系建设现状,通过分析美国和日本在现代化大农业与小规模特色农业方面的... 农产品现代流通体系建设需立足中国特色并借鉴国际经验。面向中国现代农业发展需要,梳理农产品现代流通体系的基本架构,从国内和国际两个角度总结我国农产品流通体系建设现状,通过分析美国和日本在现代化大农业与小规模特色农业方面的流通体系建设经验,为我国农产品现代流通体系建设提供有益借鉴。研究表明,我国农产品现代流通体系建设正处于规模扩张向质量提升的转型期,其发展呈现出显著的“东高西低、圈层分化”特征。东部地区在流通规模、流通主体素质、流通渠道、流通设施等方面形成显著优势,而中西部地区部分农业生产大省和农产品重点消费地区在流通规模、人才基础、流通渠道现代化水平等方面仍存在较大的提升空间。美国和日本在长期发展过程中,已形成适应本国农业发展需要的现代农业生产经营主体,以消费市场为导向推动流通渠道转型升级,在物流网络建设中注重提高现代物流体系信息化标准化水平,政府形成以法律为基础、专项决策平台为指导、问题为导向的制度保障体系,为我国现代农产品流通体系在提高就业贡献、降低社会流通成本、提升基础设施水平等方面提供很好的借鉴。未来,我国应着力壮大现代流通主体,增强流通环节社会化服务能力;发展零售电商等农产品流通新业态,升级改造传统流通渠道;优化物流体系整体布局,提升流通体系信息化标准化水平;强化监督管理,从制度层面规范农产品生产流通协同发展;强化现代农业、数字经济产业和现代金融业对农产品现代流通体系的支撑能力,充分发挥农产品流通体系建设在实现乡村全面振兴和加快建设农业强国目标进程中的关键作用。 展开更多
关键词 农产品流通 流通主体 流通渠道 物流体系 经验借鉴
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循环模式转型、技术比较优势与制造业创新绩效 被引量:1
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作者 宋炜 曹文静 《科技进步与对策》 北大核心 2025年第2期73-81,共9页
新发展格局下制造业创新绩效提升不仅取决于循环模式转型效果,而且显著受到技术比较优势的影响。利用2001—2021年中国制造业面板数据,估计循环模式转型与技术比较优势对制造业创新绩效的影响。研究发现,由国际循环引致的制造业集聚有... 新发展格局下制造业创新绩效提升不仅取决于循环模式转型效果,而且显著受到技术比较优势的影响。利用2001—2021年中国制造业面板数据,估计循环模式转型与技术比较优势对制造业创新绩效的影响。研究发现,由国际循环引致的制造业集聚有助于优化制造业要素配置,强化制造业技术比较优势,进而提升制造业创新绩效。在新发展格局下,循环模式转型有助于推动制造业利用资本密集型技术进步获得技术比较优势,通过缩小技术势差实现制造业高质量发展,从而对提升制造业创新绩效产生显著作用。 展开更多
关键词 循环模式转型 国际循环 国内循环 技术比较优势 制造业全要素生产率 中国制造业
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信息优势的上下分化:数字时代多层级政府治理变革的一个动力机制 被引量:3
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作者 向静林 钟瑞雪 艾云 《华中科技大学学报(社会科学版)》 北大核心 2025年第1期55-68,共14页
数字时代出现了“数实相融”的新型治理情境,推动中国多层级政府治理呈现出“上下共治”的新模式,其中的动力机制之一是“信息优势的上下分化”。研究细致分析了高层级政府的数字信息优势和低层级政府的属地信息优势的具体内容及其关系... 数字时代出现了“数实相融”的新型治理情境,推动中国多层级政府治理呈现出“上下共治”的新模式,其中的动力机制之一是“信息优势的上下分化”。研究细致分析了高层级政府的数字信息优势和低层级政府的属地信息优势的具体内容及其关系模式,发现高层级政府在线上行为信息、跨域关联信息、超大规模信息方面具有比较优势,低层级政府在线下行为信息、在地关联信息、过程事件信息方面具有比较优势;二者的信息优势之间不是替代关系,而是互依关系,通过自上而下的信息计算、研判、推送和自下而上的信息摸排、核验、反馈,多层级政府之间形成了不同于前数字时代的双向信息流转机制。信息优势上下分化引发的信息流转机制变化及其实际运行的复杂性,值得学界高度关注和深入研究。 展开更多
关键词 数字时代 政府治理 信息优势分化 信息流转机制
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“网箱-池塘”耦联内循环水生态养殖研究 被引量:1
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作者 刘艳辉 邹瑞兴 +3 位作者 刘铁钢 杨炳坤 徐宁 李秀颖 《水产养殖》 2025年第4期1-6,共6页
开展了“网箱-池塘”耦联内循环水生态养殖试验。设置试验组和对照组均为3口池塘,每个试验组在池塘内配有5个网箱,对照组不配网箱,为传统养殖模式。试验组和对照组每667 m^(2)分别投放鲫2200尾,鲢40尾,鳙20尾。试验组网箱外安装推水和... 开展了“网箱-池塘”耦联内循环水生态养殖试验。设置试验组和对照组均为3口池塘,每个试验组在池塘内配有5个网箱,对照组不配网箱,为传统养殖模式。试验组和对照组每667 m^(2)分别投放鲫2200尾,鲢40尾,鳙20尾。试验组网箱外安装推水和微孔增氧设备,池塘两窄边侧设生态浮床,按池塘面积的20%种植浮床水稻;对照池设置普通增氧设备。结果表明,试验组总氮、铵态氮、硝酸盐氮、总磷、磷酸盐质量浓度分别比对照组降低50.69%,69.12%,55.23%,62.62%和54.20%;试验组主养鲫出池规格、成活率、单位面积产量分别比对照组提高5.25%,7.58%和13.28%;试验组饵料系数比对照组降低4.72%;试验组比对照组节水量和减少用药量分别为52.05%和81.82%。指出,“网箱-池塘”耦联内循环水生态养殖对净化水体、提高产量、降低饵料系数等效果显著。 展开更多
关键词 池塘 网箱 内循环 生态养殖 传统养殖
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双循环背景下内外需联合推动企业出口产品质量提升效应 被引量:1
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作者 刘会政 徐琪洋 袁莉琳 《暨南学报(哲学社会科学版)》 北大核心 2025年第1期146-164,共19页
推动外贸质升量稳是扩大高水平对外开放的重要发展战略。面对当前外需冲击和统筹扩大内需的新形势,探究需求格局变化对出口产品质量的影响尤为重要。本文将本土需求和外需冲击纳入企业出口产品质量的分析框架,通过构建一个局部均衡模型... 推动外贸质升量稳是扩大高水平对外开放的重要发展战略。面对当前外需冲击和统筹扩大内需的新形势,探究需求格局变化对出口产品质量的影响尤为重要。本文将本土需求和外需冲击纳入企业出口产品质量的分析框架,通过构建一个局部均衡模型来阐释本土需求和外需冲击对企业出口产品质量的影响。利用2000—2013年中国企业出口数据进行实证检验发现,本土需求增加和正向的外需冲击会提升企业出口产品质量,且正向外需冲击的提升作用更大。机制分析表明,本土需求变动和外需冲击通过创新效应和竞争效应两种途径影响企业出口产品质量。此外,国内市场和国外市场联动能够提升企业出口产品质量,需增强国内国际两个市场两种资源联动效应。区分企业规模发现,本土需求扩张和正向外需冲击可以促进大型企业的出口产品质量提升;区分企业贸易方式发现,本土需求增加和正向外需冲击对加工贸易企业的出口产品质量有显著提升作用。因此,要加快推进构建新发展格局,赋能实现贸易强国的战略目标。 展开更多
关键词 双循环 本土需求 外需冲击 出口质量
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