There are two approaches to metaphysics that concern language,the logical and the linguistic. Zeno Vendler,who took the linguistic one,distinguished with transformational techniques between two semantic categories,nam...There are two approaches to metaphysics that concern language,the logical and the linguistic. Zeno Vendler,who took the linguistic one,distinguished with transformational techniques between two semantic categories,namely fact and event,and regarded them as corresponding respectively to a metaphysical category of beings. In doing this he presupposed that independent semantic categories could be sorted out,and corresponding categories of beings that are independent of language can be derived. But our analysis of Vendler's case shows that it is not semantic categories but grammar that functions in differentiating event and fact. At least some semantic categories could not be separated from grammar,and this casts doubt on the linguistic approach to metaphysics. If semantic categories are not independent of grammar,we could not derive metaphysics from linguistic study.展开更多
The cardiovascular diseases(CVD)continue to be the major threat to global public health over the years,while one of the effective methods to treat CVD is stent intervention.Biomedical magnesium(Mg)alloys have great po...The cardiovascular diseases(CVD)continue to be the major threat to global public health over the years,while one of the effective methods to treat CVD is stent intervention.Biomedical magnesium(Mg)alloys have great potential applications in cardiovascular stents benefit from their excellent biodegradability and absorbability.However,excessive degradation rate and the delayed surface endothelialization still limit their further application.In this study,we modified a Mg-Zn-Y-Nd alloy(ZE21B)by preparing MgF_(2) as the corrosion resistance layer,the dopamine polymer film(PDA)as the bonding layer,and hyaluronic acid(HA)loaded astaxanthin(ASTA)as an important layer to directing the cardiovascular cells fate.The electrochemical test results showed that the MgF_(2)/PDA/HA-ASTA coating improved the corrosion resistance of ZE21B.The cytocompatibility experiments also demonstrated that this novel composite coating also selectively promoted endothelial cells proliferation,inhibited hyperproliferation of smooth muscle cells and adhesion of macrophages.Compared with the HAloaded rapamycin(RAPA)coating,our MgF_(2)/PDA/HA-ASTA coating showed better blood compatibility and cytocompatibility,indicating stronger multi-functions for the ZE21B alloy on cardiovascular application.展开更多
随着计算机技术、网络技术以及通讯技术的迅速发展,实现地理空间信息共享势在必行。该文实现了一个地理空间信息共享系统(GeospAtial Information System),详细论述了该系统的设计思路与实现机制。利用统一的地理空间信息资源元数据标...随着计算机技术、网络技术以及通讯技术的迅速发展,实现地理空间信息共享势在必行。该文实现了一个地理空间信息共享系统(GeospAtial Information System),详细论述了该系统的设计思路与实现机制。利用统一的地理空间信息资源元数据标准框架,解决了来自多个异构数据源具有多种数据格式的地理空间信息资源产品难以被有效管理和使用的问题;采用推拉技术相结合的方式,实现了分发服务的主动性;提出了一种基于策略的缓存管理技术,大大提高了系统效率;采用的基于集群的查询服务和文件传输服务具有高性价比和良好的可扩充性。展开更多
新型制冷剂R1234ze(E)(trans-1,3,3,3-tetrafluoropropene)因较低的GWP而被广泛关注,有望在热泵中作为R134a的替代品。本文对R1234ze(E)在内径为8 mm水平管内流动沸腾过程中摩擦压降特性进行实验研究,并在相同实验工况下与R134a进行对...新型制冷剂R1234ze(E)(trans-1,3,3,3-tetrafluoropropene)因较低的GWP而被广泛关注,有望在热泵中作为R134a的替代品。本文对R1234ze(E)在内径为8 mm水平管内流动沸腾过程中摩擦压降特性进行实验研究,并在相同实验工况下与R134a进行对比。实验研究的流动沸腾换热的饱和温度为10℃,热流密度为5.0 k W/m^2和10.0 k W/m^2,质流密度范围为300~500 kg/(m^2·s),并分析质流密度、热流密度对R1234ze(E)和R134a饱和流动沸腾过程中摩擦压降的影响。结果表明,在相同工况下R1234ze(E)的流动沸腾过程的摩擦压降略大于R134a,如质流密度为500 kg/(m^2·s)时,R1234ze(E)的平均摩擦压降值比R134a大8.4%左右。最后,将实验结果同四种摩擦压降经验关联式进行比较分析。展开更多
Using Harrison's model and anisotropic parabolic approximation,the band structure of In1- x- y Gay Alx As compressively strained quantum wells is calculated.To design lasers with1.55μm wavelength,it is necessary...Using Harrison's model and anisotropic parabolic approximation,the band structure of In1- x- y Gay Alx As compressively strained quantum wells is calculated.To design lasers with1.55μm wavelength,it is necessary to an- alyze the well width,differential gain,transparency carrier density and the characteristic gain for an arbitrary com- position.Some useful empirical formulas are also presented.展开更多
文摘There are two approaches to metaphysics that concern language,the logical and the linguistic. Zeno Vendler,who took the linguistic one,distinguished with transformational techniques between two semantic categories,namely fact and event,and regarded them as corresponding respectively to a metaphysical category of beings. In doing this he presupposed that independent semantic categories could be sorted out,and corresponding categories of beings that are independent of language can be derived. But our analysis of Vendler's case shows that it is not semantic categories but grammar that functions in differentiating event and fact. At least some semantic categories could not be separated from grammar,and this casts doubt on the linguistic approach to metaphysics. If semantic categories are not independent of grammar,we could not derive metaphysics from linguistic study.
基金For financial support,the authors gratefully acknowledge the National Natural Science Foundation of China(U2004164)the National Key Research and Development Program of China(2018YFC1106703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1804251).
文摘The cardiovascular diseases(CVD)continue to be the major threat to global public health over the years,while one of the effective methods to treat CVD is stent intervention.Biomedical magnesium(Mg)alloys have great potential applications in cardiovascular stents benefit from their excellent biodegradability and absorbability.However,excessive degradation rate and the delayed surface endothelialization still limit their further application.In this study,we modified a Mg-Zn-Y-Nd alloy(ZE21B)by preparing MgF_(2) as the corrosion resistance layer,the dopamine polymer film(PDA)as the bonding layer,and hyaluronic acid(HA)loaded astaxanthin(ASTA)as an important layer to directing the cardiovascular cells fate.The electrochemical test results showed that the MgF_(2)/PDA/HA-ASTA coating improved the corrosion resistance of ZE21B.The cytocompatibility experiments also demonstrated that this novel composite coating also selectively promoted endothelial cells proliferation,inhibited hyperproliferation of smooth muscle cells and adhesion of macrophages.Compared with the HAloaded rapamycin(RAPA)coating,our MgF_(2)/PDA/HA-ASTA coating showed better blood compatibility and cytocompatibility,indicating stronger multi-functions for the ZE21B alloy on cardiovascular application.
文摘随着计算机技术、网络技术以及通讯技术的迅速发展,实现地理空间信息共享势在必行。该文实现了一个地理空间信息共享系统(GeospAtial Information System),详细论述了该系统的设计思路与实现机制。利用统一的地理空间信息资源元数据标准框架,解决了来自多个异构数据源具有多种数据格式的地理空间信息资源产品难以被有效管理和使用的问题;采用推拉技术相结合的方式,实现了分发服务的主动性;提出了一种基于策略的缓存管理技术,大大提高了系统效率;采用的基于集群的查询服务和文件传输服务具有高性价比和良好的可扩充性。
文摘新型制冷剂R1234ze(E)(trans-1,3,3,3-tetrafluoropropene)因较低的GWP而被广泛关注,有望在热泵中作为R134a的替代品。本文对R1234ze(E)在内径为8 mm水平管内流动沸腾过程中摩擦压降特性进行实验研究,并在相同实验工况下与R134a进行对比。实验研究的流动沸腾换热的饱和温度为10℃,热流密度为5.0 k W/m^2和10.0 k W/m^2,质流密度范围为300~500 kg/(m^2·s),并分析质流密度、热流密度对R1234ze(E)和R134a饱和流动沸腾过程中摩擦压降的影响。结果表明,在相同工况下R1234ze(E)的流动沸腾过程的摩擦压降略大于R134a,如质流密度为500 kg/(m^2·s)时,R1234ze(E)的平均摩擦压降值比R134a大8.4%左右。最后,将实验结果同四种摩擦压降经验关联式进行比较分析。
文摘Using Harrison's model and anisotropic parabolic approximation,the band structure of In1- x- y Gay Alx As compressively strained quantum wells is calculated.To design lasers with1.55μm wavelength,it is necessary to an- alyze the well width,differential gain,transparency carrier density and the characteristic gain for an arbitrary com- position.Some useful empirical formulas are also presented.
