It is essential to learn the temporal and spatial concentration distributions and variations of seeding agents in cloud seeding of precipitation enhancement. A three-dimensional puff trajectory model incorporating a m...It is essential to learn the temporal and spatial concentration distributions and variations of seeding agents in cloud seeding of precipitation enhancement. A three-dimensional puff trajectory model incorporating a mesoscale nonhydrostatic model has been formulated, and is applied to simulating the transporting and diffusive characteristics of multiple line sources of seeding agents within super-cooled stratus. Several important factors are taken into consideration that affect the diffusion of seeding materials such as effects of topography and vertical wind shear, temporal and spatial variation of seeding parameters and wet deposition. The particles of seeding agents are assumed to be almost inert, they have no interaction with the particles of the cloud or precipitation except that they are washed out by precipitation. The model validity is demonstrated by the analyses and comparisons of model results, and checked by the sensitivity experiments of diffusive coefficients and atmospheric stratification. The advantage of this model includes not only its exact reflection of heterogeneity and unsteadiness of background fields, but also its good simulation of transport and diffusion of multiple line sources. The horizontal diffusion rate and the horizontal transport distance have been proposed that they usually were difficult to obtain in other models. In this simulation the horizontal diffusion rate is 0.82 m s(-1) for average of one hour, and the horizontal average transport distance reaches 65 km after 1 4 which are closely related to the background Fields.展开更多
The canalicular membrane represents the excretory pole of hepatocytes.Bile is an important route of elimination of potentially toxic endo-and xenobiotics(including drugs and toxins),mediated by the major canalicular t...The canalicular membrane represents the excretory pole of hepatocytes.Bile is an important route of elimination of potentially toxic endo-and xenobiotics(including drugs and toxins),mediated by the major canalicular transporters:multidrug resistance protein 1(MDR1, ABCB1),also known as P-glycoprotein,multidrug resistance-associated protein 2(MRP2,ABCC2),and the breast cancer resistance protein(BCRP,ABCG2).Their activities depend on regulation of expression and proper localization at the canalicular membrane,as regulated by transcriptional and post-transcriptional events,respectively.At transcriptional level,specific nuclear receptors(NR)s modulated by ligands,co-activators and co-repressors,mediate the physiological requirements of these transporters.This complex system is also responsible for alterations occurring in specific liver pathologies.We briefly describe the major ClassⅡNRs, pregnane X receptor(PXR)and constitutive androstane receptor(CAR),and their role in regulating expression of multidrug resistance proteins.Several therapeutic agents regulate the expression of relevant drug transporters through activation/inactivation of these NRs.We provide some representative examples of the action of therapeutic agents modulating liver drug transporters, which in addition,involve CAR or PXR as mediators.展开更多
Cubic boron arsenide(BAs)has attracted great attention due to its high thermal conductivity,however,its controllable,stable,and ideal preparation remains challenging.Herein,we investigated the effect of iodine-contain...Cubic boron arsenide(BAs)has attracted great attention due to its high thermal conductivity,however,its controllable,stable,and ideal preparation remains challenging.Herein,we investigated the effect of iodine-containing transport agents I_(2) and boron triiodide(BI_(3))on BAs synthesized and grown through chemical vapor transport.Results show that similar to the commonly used I_(2),BI_(3) accelerates the synthesis and improves the mass fraction of BAs from ~12% to over 90% at 820℃ and 1.5 MPa,a value beyond the promoting effect of only increasing temperature and pressure.Both agents enhance the quality of BAs crystals by reducing the full width at half maximum by up to 10%-20%.I_(2) agglomerates the grown crystals with twin defects(~50 nm wide),and BI_(3) improves the crystal anisotropy and element uniformity of BAs crystals with narrow twins(~15 nm wide)and increases the stoichiometry ratio(~0.990)to almost 1.Owing to the boron interstitials from the excessive boron supply,the spacing of layers in {111} increases to 0.286 nm in the presence of I_(2).Owing to its coordinated effect,BI_(3) only slightly influences the layer spacing at 0.275 nm,which is close to the theoretical value of 0.276 nm.In the chemical vapor transport,the anisotropic crystals with flat surfaces exhibit single-crystal characteristics under the action of BI_(3).Different from that of I_(2),the coordinated effect of BI_(3) can promote the efficient preparation of high-quality BAs crystal seeds and facilitate the advanced application of BAs.展开更多
随着智能交通系统的不断发展,未来智能交通系统发展的一个趋势是集成化,而交通综合信息平台是实现集成化智能交通系统的基础和支撑.文中提出了利用(eX tens ib le M arkupL anguage)XM L和移动A gen t技术来实现交通综合信息平台的技术...随着智能交通系统的不断发展,未来智能交通系统发展的一个趋势是集成化,而交通综合信息平台是实现集成化智能交通系统的基础和支撑.文中提出了利用(eX tens ib le M arkupL anguage)XM L和移动A gen t技术来实现交通综合信息平台的技术途径及开发实例.阐述了基于移动A gen t的交通综合信息平台的体系框架;研究了各个层次的功能及实现机制,研究了利用XM L技术来实现智能体之间的通信及实际工作中利用XM L进行的平台的开发实现.研究及开发应用表明XM L和移动A gen t为交通综合信息平台的实现提供了一条可行的实现途径.展开更多
为解决固定航路上飞行冲突探测与解脱(conflict detection and resolution,CDR)的问题,本文提出一种基于高度层分配的解脱方法,并利用分布式多agent系统(multi-agent system,MAS)进行算法求解。首先建立固定航路网络图对管制扇区进行建...为解决固定航路上飞行冲突探测与解脱(conflict detection and resolution,CDR)的问题,本文提出一种基于高度层分配的解脱方法,并利用分布式多agent系统(multi-agent system,MAS)进行算法求解。首先建立固定航路网络图对管制扇区进行建模;然后分析影响高度层分配的主要因素,并建立高度层使用优先权的评价模型;最后,设计基于合同网协议的多agent系统,将目前依靠管制员的集中调配模式,转变为路口agent和航空器agent之间自主进行通信、协商和协作的分布式冲突解脱模式。仿真实验表明:高度层分配方法是可行的,与传统调整航向或速度的方法相比,该方法更接近实际情况,同时设计的分布式多agent系统算法能够快速找到高度层分配的最优解,为CDR问题提供了新的解决思路。展开更多
文摘It is essential to learn the temporal and spatial concentration distributions and variations of seeding agents in cloud seeding of precipitation enhancement. A three-dimensional puff trajectory model incorporating a mesoscale nonhydrostatic model has been formulated, and is applied to simulating the transporting and diffusive characteristics of multiple line sources of seeding agents within super-cooled stratus. Several important factors are taken into consideration that affect the diffusion of seeding materials such as effects of topography and vertical wind shear, temporal and spatial variation of seeding parameters and wet deposition. The particles of seeding agents are assumed to be almost inert, they have no interaction with the particles of the cloud or precipitation except that they are washed out by precipitation. The model validity is demonstrated by the analyses and comparisons of model results, and checked by the sensitivity experiments of diffusive coefficients and atmospheric stratification. The advantage of this model includes not only its exact reflection of heterogeneity and unsteadiness of background fields, but also its good simulation of transport and diffusion of multiple line sources. The horizontal diffusion rate and the horizontal transport distance have been proposed that they usually were difficult to obtain in other models. In this simulation the horizontal diffusion rate is 0.82 m s(-1) for average of one hour, and the horizontal average transport distance reaches 65 km after 1 4 which are closely related to the background Fields.
基金Grants from Agencia Nacional de Promoción Científicay Tecnológica (PICT N° 05-26306)Consejo Nacional de Investigaciones Científicasy Técnicas (PIP N° 6442)Universidad Nacional de Rosario,Argentina
文摘The canalicular membrane represents the excretory pole of hepatocytes.Bile is an important route of elimination of potentially toxic endo-and xenobiotics(including drugs and toxins),mediated by the major canalicular transporters:multidrug resistance protein 1(MDR1, ABCB1),also known as P-glycoprotein,multidrug resistance-associated protein 2(MRP2,ABCC2),and the breast cancer resistance protein(BCRP,ABCG2).Their activities depend on regulation of expression and proper localization at the canalicular membrane,as regulated by transcriptional and post-transcriptional events,respectively.At transcriptional level,specific nuclear receptors(NR)s modulated by ligands,co-activators and co-repressors,mediate the physiological requirements of these transporters.This complex system is also responsible for alterations occurring in specific liver pathologies.We briefly describe the major ClassⅡNRs, pregnane X receptor(PXR)and constitutive androstane receptor(CAR),and their role in regulating expression of multidrug resistance proteins.Several therapeutic agents regulate the expression of relevant drug transporters through activation/inactivation of these NRs.We provide some representative examples of the action of therapeutic agents modulating liver drug transporters, which in addition,involve CAR or PXR as mediators.
基金financially supported by the National Key R&D Program of China(Nos.2018YFC1900302 and 2020YFC1909201)the National Science Fund for Distinguished Young Scholars(No.51825403)。
文摘Cubic boron arsenide(BAs)has attracted great attention due to its high thermal conductivity,however,its controllable,stable,and ideal preparation remains challenging.Herein,we investigated the effect of iodine-containing transport agents I_(2) and boron triiodide(BI_(3))on BAs synthesized and grown through chemical vapor transport.Results show that similar to the commonly used I_(2),BI_(3) accelerates the synthesis and improves the mass fraction of BAs from ~12% to over 90% at 820℃ and 1.5 MPa,a value beyond the promoting effect of only increasing temperature and pressure.Both agents enhance the quality of BAs crystals by reducing the full width at half maximum by up to 10%-20%.I_(2) agglomerates the grown crystals with twin defects(~50 nm wide),and BI_(3) improves the crystal anisotropy and element uniformity of BAs crystals with narrow twins(~15 nm wide)and increases the stoichiometry ratio(~0.990)to almost 1.Owing to the boron interstitials from the excessive boron supply,the spacing of layers in {111} increases to 0.286 nm in the presence of I_(2).Owing to its coordinated effect,BI_(3) only slightly influences the layer spacing at 0.275 nm,which is close to the theoretical value of 0.276 nm.In the chemical vapor transport,the anisotropic crystals with flat surfaces exhibit single-crystal characteristics under the action of BI_(3).Different from that of I_(2),the coordinated effect of BI_(3) can promote the efficient preparation of high-quality BAs crystal seeds and facilitate the advanced application of BAs.
文摘随着智能交通系统的不断发展,未来智能交通系统发展的一个趋势是集成化,而交通综合信息平台是实现集成化智能交通系统的基础和支撑.文中提出了利用(eX tens ib le M arkupL anguage)XM L和移动A gen t技术来实现交通综合信息平台的技术途径及开发实例.阐述了基于移动A gen t的交通综合信息平台的体系框架;研究了各个层次的功能及实现机制,研究了利用XM L技术来实现智能体之间的通信及实际工作中利用XM L进行的平台的开发实现.研究及开发应用表明XM L和移动A gen t为交通综合信息平台的实现提供了一条可行的实现途径.
文摘为解决固定航路上飞行冲突探测与解脱(conflict detection and resolution,CDR)的问题,本文提出一种基于高度层分配的解脱方法,并利用分布式多agent系统(multi-agent system,MAS)进行算法求解。首先建立固定航路网络图对管制扇区进行建模;然后分析影响高度层分配的主要因素,并建立高度层使用优先权的评价模型;最后,设计基于合同网协议的多agent系统,将目前依靠管制员的集中调配模式,转变为路口agent和航空器agent之间自主进行通信、协商和协作的分布式冲突解脱模式。仿真实验表明:高度层分配方法是可行的,与传统调整航向或速度的方法相比,该方法更接近实际情况,同时设计的分布式多agent系统算法能够快速找到高度层分配的最优解,为CDR问题提供了新的解决思路。
