Over the past few decades,one of the most significant advances in dam construction has been the inven-tion of the rock-filled concrete(RFC)dam,which is constructed by pouring high-performance self-compacting concrete(...Over the past few decades,one of the most significant advances in dam construction has been the inven-tion of the rock-filled concrete(RFC)dam,which is constructed by pouring high-performance self-compacting concrete(HSCC)to fill the voids in preplaced large rocks.The innovative use of large rocks in dam construction provides engineers with a material that requires less cement consumption and hydration heat while enhancing construction efficiency and environmental friendliness.However,two fundamental scientific issues related to RFC need to be addressed:namely,the pouring compactness and the effect of large rocks on the mechanical and physical properties of RFC.This article provides a timely review of fundamental research and innovations in the design,construction,and quality control of RFCdams.Prospects for next-generation concrete dams are discussed from the perspectives of envi-ronmental friendliness,intrinsic safety,and labor savings.展开更多
混合储能系统HESS(hybrid energy storage system)在微电网中有着广泛的应用,其研究主要集中在能量管理、功率分配和拓扑设计等方面。对于功率分配的研究,大多只涉及到基本的功率分配,而无功功率、负序功率和谐波功率的分配问题却很少...混合储能系统HESS(hybrid energy storage system)在微电网中有着广泛的应用,其研究主要集中在能量管理、功率分配和拓扑设计等方面。对于功率分配的研究,大多只涉及到基本的功率分配,而无功功率、负序功率和谐波功率的分配问题却很少被提及。为此,提出了适用于不平衡负载和非线性负载环境的混合储能系统及其协调控制策略。在系统内部,电池功率转换系统工作在下垂模式,提供能量,只输出基本的有功功率;超电容器系统工作在补偿模式,分析总输出功率构成,输出无功、负序和谐波功率。该策略可以在不平衡和非线性负载条件下提供更好的系统性能;此外,该混合储能系统采用双逆变结构,有利于现有设备的升级改造;最后,仿真和实验结果验证了该策略的有效性。展开更多
Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface （AMI） method were presented. The governing equations were the unsteady Reyn...Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface （AMI） method were presented. The governing equations were the unsteady Reynolds-averaged Navier-Stokes （RANS） which were solved by the pimpleDyMFoam solver, and the AMI method was employed to handle mesh movements. The National Renewable Energy Laboratory （NREL） phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds （5, 10, 15, and 25 m/s） at a fixed blade pitch and constant rotational speed. Detailed numerical results of vortex structure, time histories of thrust, and pressure distribution on the blade and tower were presented. The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine, while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower. Also, strong interaction of blade tip vortices with separation from the tower was observed.展开更多
Detection of circulating tumor-specific DNA, RNA or proteins can be difficult due to relative scarcity. Exosomes are extracellular vesicles, 30 - 150 nm in diameter derived from fusion of multivesicular bodies with th...Detection of circulating tumor-specific DNA, RNA or proteins can be difficult due to relative scarcity. Exosomes are extracellular vesicles, 30 - 150 nm in diameter derived from fusion of multivesicular bodies with the plasma membrane. They are composed of a lipid bilayer membrane and contain proteins, mRNA and miRNA. Exosomes are secreted by multiple cell types, including cancer cells. However, there is a relative lack of information concerning the contents of exosomes secreted by various tumor cell types. To examine exosomes in cancer, we collected blood plasma samples from patients with breast, ovarian, prostate, hepatic, gastric, colon, and pancreatic cancers. Exosomes were isolated from plasma and confirmed by AchE assay, transmission electron microscopy and expression of the CD63 exosomal marker. Expression of AFP, CA724, CA153, CEA, CA125, CA199 and PSA antigens were determined using an automated electro-chemiluminescence assay. Expression of the tumor-related chaperone protein, mortalin, was determined by Western blot analysis. Levels of exosome secretion were variable among the different tumor types. Both exosome levels and mortalin expression within tumor cell exosomes were higher than in healthy donors, except in pancreatic carcinoma, where exosomes were elevated but mortalin expression was not significantly different from healthy donors. Exosomes provide unique opportunities for the enrichment of tumor-specific materials and may be useful as biomarkers and possibly as tools of cancer therapies. Mortalin, which has been linked to cell proliferation and induction of epithelial-mesenchymal transition of cancer cells, may be useful as a prognostic biomarker and as a possible therapeutic target.展开更多
基金the support from the Key Program Grant from National Natural Science Foundation of China (52039005)Grant from State Key Laboratory of Hydroscience and Engineering (2022-KY-01).
文摘Over the past few decades,one of the most significant advances in dam construction has been the inven-tion of the rock-filled concrete(RFC)dam,which is constructed by pouring high-performance self-compacting concrete(HSCC)to fill the voids in preplaced large rocks.The innovative use of large rocks in dam construction provides engineers with a material that requires less cement consumption and hydration heat while enhancing construction efficiency and environmental friendliness.However,two fundamental scientific issues related to RFC need to be addressed:namely,the pouring compactness and the effect of large rocks on the mechanical and physical properties of RFC.This article provides a timely review of fundamental research and innovations in the design,construction,and quality control of RFCdams.Prospects for next-generation concrete dams are discussed from the perspectives of envi-ronmental friendliness,intrinsic safety,and labor savings.
文摘混合储能系统HESS(hybrid energy storage system)在微电网中有着广泛的应用,其研究主要集中在能量管理、功率分配和拓扑设计等方面。对于功率分配的研究,大多只涉及到基本的功率分配,而无功功率、负序功率和谐波功率的分配问题却很少被提及。为此,提出了适用于不平衡负载和非线性负载环境的混合储能系统及其协调控制策略。在系统内部,电池功率转换系统工作在下垂模式,提供能量,只输出基本的有功功率;超电容器系统工作在补偿模式,分析总输出功率构成,输出无功、负序和谐波功率。该策略可以在不平衡和非线性负载条件下提供更好的系统性能;此外,该混合储能系统采用双逆变结构,有利于现有设备的升级改造;最后,仿真和实验结果验证了该策略的有效性。
基金Supported by the National Natural Science Foundation of China under Grant Nos.50739004 and 11072154.
文摘Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface （AMI） method were presented. The governing equations were the unsteady Reynolds-averaged Navier-Stokes （RANS） which were solved by the pimpleDyMFoam solver, and the AMI method was employed to handle mesh movements. The National Renewable Energy Laboratory （NREL） phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds （5, 10, 15, and 25 m/s） at a fixed blade pitch and constant rotational speed. Detailed numerical results of vortex structure, time histories of thrust, and pressure distribution on the blade and tower were presented. The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine, while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower. Also, strong interaction of blade tip vortices with separation from the tower was observed.
文摘Detection of circulating tumor-specific DNA, RNA or proteins can be difficult due to relative scarcity. Exosomes are extracellular vesicles, 30 - 150 nm in diameter derived from fusion of multivesicular bodies with the plasma membrane. They are composed of a lipid bilayer membrane and contain proteins, mRNA and miRNA. Exosomes are secreted by multiple cell types, including cancer cells. However, there is a relative lack of information concerning the contents of exosomes secreted by various tumor cell types. To examine exosomes in cancer, we collected blood plasma samples from patients with breast, ovarian, prostate, hepatic, gastric, colon, and pancreatic cancers. Exosomes were isolated from plasma and confirmed by AchE assay, transmission electron microscopy and expression of the CD63 exosomal marker. Expression of AFP, CA724, CA153, CEA, CA125, CA199 and PSA antigens were determined using an automated electro-chemiluminescence assay. Expression of the tumor-related chaperone protein, mortalin, was determined by Western blot analysis. Levels of exosome secretion were variable among the different tumor types. Both exosome levels and mortalin expression within tumor cell exosomes were higher than in healthy donors, except in pancreatic carcinoma, where exosomes were elevated but mortalin expression was not significantly different from healthy donors. Exosomes provide unique opportunities for the enrichment of tumor-specific materials and may be useful as biomarkers and possibly as tools of cancer therapies. Mortalin, which has been linked to cell proliferation and induction of epithelial-mesenchymal transition of cancer cells, may be useful as a prognostic biomarker and as a possible therapeutic target.
