检索结果-南通市图书馆

Wave Attenuation and Turbulence Driven by Submerged Vegetation Under Current-Wave Flow

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第4期38卷 602-611页

作者： HUANG yu-ming ding Lei WANG Yi-fei CHEN Ben YANG Xiao-yu DOU Xi-ping School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan430072China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China

A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave *** vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged *** show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current ***,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave *** the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and *** time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s *** the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the *** vegetation drag coefficients are obtained by a calibration *** empirical relations of drag coefficient with Reynolds and Keulegane-Carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.

关键词： wave attenuation rigid vegetation following and opposing currents turbulent kinetic energy

在线全文

学校读者我要写书评

暂无评论

高余维退化Hopf分岔系统的最简规范形

振动与冲击 2012年第24期31卷 143-147页

作者：丁玉梅张琪昌天津科技大学理学院天津300222 天津大学机械学院天津300072

利用动力系统中的规范形理论和矩阵表示法的思想,研究高余维退化Hopf分岔系统的最简规范形。在传统规范形的基础上,通过非线性变换和矩阵方程的有关理论,选取合适的非线性变换,继续将传统规范形进行化简,指出退化Hopf分岔系统的传统规... 详细信息

利用动力系统中的规范形理论和矩阵表示法的思想,研究高余维退化Hopf分岔系统的最简规范形。在传统规范形的基础上,通过非线性变换和矩阵方程的有关理论,选取合适的非线性变换,继续将传统规范形进行化简,指出退化Hopf分岔系统的传统规范形不唯一,可以继续化简为唯一的最简规范形。提出退化Hopf分岔系统的最简规范形的(2k+1)阶截断式中,其振幅方程中的非线性部分至多含有两项,由于条件的不同,具有两种不同的最简规范形形式,并给出三个计算公式。

关键词：退化Hopf分岔最简规范形近恒同变换

Detecting bulk and edge exceptional points in non-Hermitian systems through generalized Petermann factors

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第2期19卷 169-177页

作者： yue-yu Zou Yao Zhou Li-mei Chen Peng Ye School of Physics State Key Laboratory of Optoelectronic Materials and Technologiesand Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSun Yat-sen UniversityGuangzhou 510275China

Non-orthogonality in non-Hermitian quantum systems gives rise to tremendous exotic quantum phenomena,which can be fundamentally traced back to *** this paper,we introduce an interesting quantity(denoted asη)as a new variant of the Petermann factor to directly and efficiently measure non-unitarity and the associated non-Hermitian *** tuning the model parameters of underlying non-Hermitian systems,we find that the discontinuity of bothηand its first-order derivative(denoted as■η)pronouncedly captures rich physics that is fundamentally caused by *** concretely,in the 1D non-Hermitian topological systems,two mutually orthogonal edge states that are respectively localized on two boundaries become non-orthogonal in the vicinity of discontinuity ofηas a function of the model parameter,which is dubbed"edge state transition".Through theoretical analysis,we identify that the appearance of edge state transition indicates the existence of exceptional points(EPs)in topological edge *** the discontinuity of■η,we investigate a two-level non-Hermitian model and establish a connection between the points of discontinuity of■ηand EPs of bulk *** studying this connection in more general lattice models,we find that some models have discontinuity of■η,implying the existence of EPs in bulk states.

关键词： non-Hermitian Su−Schrieffer−Heeger(SSH)model exceptional point

The new challenges for the development of NH_(3)-SCR catalysts under new situation of energy transition in power generation industry

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

Chinese Chemical Letters 2024年第6期35卷 95-103页

作者： Feibin Wei Yongfang Rao yu Huang Wei Wang Hui mei Science and Technology on Thermostructural Composite Materials Laboratory School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Aerosol Chemistry and Physics State Key Laboratory of Loess and Quaternary Geology(SKLLQG)Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Center of Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China Department of Environmental Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China

NH_(3)-SCR was one of the most promising de NO_x technologies and it has been widely applied in industrial NO_x ***,with the further development of energy transformation in power generation sector,the development of NH_(3)-SCR catalysts is facing some new *** is becoming an urgent problem to solve low catalytic activity and stability of NH_(3)-SCR catalysts at the working condition of ultra-low temperature(≤200℃)and high concentrations of H_(2)O+SO_(2) due to the gradual deployment of new energy power ***,the traditional coal-fired power plants would need flexible operation with the increasing share of renewable energy *** NH_(3)-SCR catalysts which were applied in coal-fired power industry would be requested to work in a wide temperature window from 200℃ to 500℃ in the near ***,in this review,we summarized the progress of NH_(3)-SCR catalysts in solving these different industrial problems in recent *** the research directions which were deserved to be focused on the development of NH_(3)-SCR catalysts for the energy transition of power generation sector are proposed.

关键词： NH_(3)-SCR NOx reduction Power generation Ultra-low temperature Wide temperature windows

Bioactive Hydrogels with Pro-coagulation Effect for Hemostasis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第1期42卷 87-103,I0004页

作者： Quanshi Guo Yihang ding Lisha yu Zongrui Tong Zhengwei Mao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhouZhejiang 310058China Department of Hepatobiliary and Pancreatic Surgery The Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouZhejiang 310009China Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province HangzhouZhejiang 310009China

Hemostatic hydrogels are widely applied for wound management of damaged tissues,traumatic wounds,and surgical *** hydrogels composed of bioactive components,including fibrin and thrombin,showed great promise in the clinic due to their good pro-coagulation *** the expanding knowledge of cascade reaction of blood coagulation and emerging bioactive substances,massive bioactive hydrogels consisting of peptides,hemocoagulase,polyphosphate(polyP),etc.,have been developed as effective hemostatic *** on the coagulation process and mechanism,we summarize the role of reported bioactive hydrogels in hemostasis in this *** conclude the key points in the coagulation process,including activation of coagulation factors,fibrinogen polymerization,etc.,then discuss how to design bioactive hydrogels to accelerate coagulation targeted to these ***,we conclude the progress and propose a perspective of bioactive hydrogels with a pro-coagulation effect for hemostasis.

关键词： Hemostasis Biological activity Biomaterials Enzyme catalysis Composites

Effects of shore-normal coastal structure on medium-to long-term embayed shoreline evolution

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

Acta Oceanologica Sinica 2024年第2期43卷 58-66页

作者： Jitao yu yuanting ding Pei Liu Renfu Fan Lin Zhang Hainan Academy of Ocean and Fisheries Sciences Haikou 571126China Yazhou Bay Innovation Institute Hainan Tropical Ocean UniversitySanya 572025China School of Geography and Environmental Sciences Hainan Normal UniversityHaikou 571158China

Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear characteristics and nonlinear behavior of the medium-to long-term shoreline evolution of Jinghai Bay,eastern Guangdong *** particular,shoreline rotation caused by a shore-normal coastal structure is *** results show that the overall shoreline evolution over the past 30 years is characterized by erosion on the southwest beach,with an average erosion rate of 3.1 m/a,and significant accretion on the northeast beach,with an average accretion rate of 5.6 m/*** of the M–K trend test indicate that significant shoreline changes occurred in early 2006,which can be attributed to shore-normal *** to that engineering construction,the shorelines are slightly eroded,where the average erosion rate is 0.7 m/***,after shore-normal engineering is performed,the shoreline is characterized by significant erosion(3.2 m/a)on the southwest beach and significant accretion(8.5 m/a)on the northeast beach,thus indicating that the shore-normal engineering at the updrift headland contributes to clockwise shoreline *** analysis shows that the clockwise shoreline rotation is promoted not only by longshore sediment transport processes from southwest to northeast,but also by cross-shore sediment transport *** findings are crucial for beach erosion risk management,coastal disaster zoning,regional sediment budget assessments,and further observations and predictions of beach morphodynamics.

关键词： shoreline rotation non-linear behavior longshore sediment transport cross-shore sediment transport embayed beach coastal structure

Research on the cuttings discharge in air cushion chamber of slurry shield based on CFD-DEM coupling method Author links open overlay panel

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第8期91卷 88-105页

作者： Han Wang Wantao ding Weimin Yang Chengzhen Wang Wenduan yu Zhicheng Wang School of Qilu Transportation Shandong UniversityJinan250002China China Railway 14th Bureau Group Co. LtdJinan250101China

The rapid discharge of cuttings from the air cushion chamber is crucial for the construction safety and excavation efficiency of the slurry *** studies have mainly focused on the transport characteristics of cuttings in the slurry discharge pipe,while the complete process of cuttings entering the slurry discharge pipe from the air cushion chamber until they are discharged was often *** on the CFD-DEM coupling method and combined with actual engineering,this paper established a numerical model that can more completely reflect the cuttings discharge process during slurry shield tunneling,and the effects of the slurry velocity at slurry gate and scouring pipes,inclination angle of slurry discharge pipe,cuttings diameter and shape coefficient were investigated by analyzing the variation in the mass flow rate,mass of discharged cuttings,and discharged *** results revealed that increasing the slurry velocity can promote the discharge of *** keep the discharged rate at a high level,it is recommended that the slurry velocity at the slurry gate should be greater than 0.15 m/*** the inclination angle of the discharge pipe is conducive to the rapid discharge of *** with large diameter or small shape coefficient are more prone to accumulate in the air cushion chamber and cause clogging *** research results not only help to improve engineers'understanding of cuttings discharge in slurry shield,but also provide practical guidance for formulating relevant construction measures.

关键词： Slurry shield CFD-DEM coupling method Cuttings discharge Aircushion chamber Slurry discharge pipe

Recent progress on Sn_(3)O_(4)nanomaterials for photocatalytic applications

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

International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 231-244页

作者： Xin yu Congcong Li Jian Zhang Lili Zhao Jinbo Pang Longhua ding Institute for Advanced Interdisciplinary Research(iAIR) School of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China School of Sino-German Engineering Shanghai Technical Institute of Electronics and InformationShanghai 201411China Division of Systems and Synthetic Biology Department of Life SciencesChalmers University of Technology41296 GöteborgSweden

Tin(IV)oxide(Sn_(3)O_(4))is layered tin and exhibits mixed valence *** has emerged as a highly promising visible-light pho-tocatalyst,attracting considerable *** comprehensive review is aimed at providing a detailed overview of the latest advance-ments in research,applications,advantages,and challenges associated with Sn_(3)O_(4)photocatalytic *** fundamental con-cepts and principles of Sn_(3)O_(4)are ***_(3)O_(4)possesses a unique crystal structure and optoelectronic properties that allow it to ab-sorb visible light efficiently and generate photoexcited charge carriers that drive photocatalytic ***,strategies for the control and improved performance of Sn_(3)O_(4)photocatalytic nanomaterials are *** control,ion doping,and hetero-structure construction are widely employed in the optimization of the photocatalytic performance of Sn_(3)O_(4)*** effective imple-mentation of these strategies improves the photocatalytic activity and stability of Sn_(3)O_(4)***,the review explores the diverse applications of Sn_(3)O_(4)photocatalytic nanomaterials in various fields,such as photocatalytic degradation,photocatalytic hydro-gen production,photocatalytic reduction of carbon dioxide,solar cells,photocatalytic sterilization,and optoelectronic *** discus-sion focuses on the potential of Sn_(3)O_(4)-based nanomaterials in these applications,highlighting their unique attributes and ***,the review provides an outlook on the future development directions in the field and offers guidance for the exploration and de-velopment of novel and efficient Sn_(3)O_(4)-based *** the identification of emerging research areas and potential avenues for improvement,this review aims to stimulate further advancements in Sn_(3)O_(4)-based photocatalysis and facilitate the translation of this promising technology into practical applications.

关键词： photocatalysis Sn_(3)O_(4)nanomaterials building heterostructures antibacterial therapy water splitting

CO2-facilitated upcycling of polyolefin plastics to aromatics at low temperature

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第5期11卷 236-243页

作者： Yi ding Shuchi Zhang Cheng Liu yu Shao Xiulian Pan Xinhe Bao State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Chemical Physics University of Science and Technology of China

Plastics are one of the most produced synthetic materials and largest commodities, used in numerous sectors of human life. To upcycle waste plastics into value-added chemicals is a global challenge. Despite significant progress in pyrolysis and hydrocracking, which mainly leads to the formation of pyrolysis oil,catalytic upcycling to value-added aromatics, including benzene, toluene and xylene（BTX）, in one step, is still limited by high reaction temperatures（>500°C） and a low yield. We report herein CO2-facilitated upcycling of polyolefins and their plastic products to aromatics below 300°C, enabled by a bifunctional Pt/Mn Ox-ZSM-5 catalyst. ZSM-5 catalyzes cracking of polyolefins and aromatization, generating hydrogen at the same time, while Pt/Mn Ox catalyzes the reaction of hydrogen with CO2, consequently driving the reaction towards aromatization. Isotope experiments reveal that 0.2 kg CO2is consumed per 1.0 kg polyethylene and 90% of the consumed CO2is incorporated into the aromatic products. Furthermore, this new process yields 0.63 kg aromatics（BTX accounting for 60%）, comparing favorably with the conventional pyrolysis or hydrocracking processes, which produce only 0.33 kg aromatics. In this way, both plastic waste and the greenhouse gas CO2are turned into carbon resources, providing a new strategy for combined waste plastics upcycling and carbon dioxide utilization.

关键词： polyolefins carbon dioxide aromatics upcycling bifunctional catalysis