We used the surface-pretreated graphite paper(Gp)as a carrier and loaded BiOCl with high selectivity to Cl^(-)on its surface by solvothermal method to form BiOCl@Gp electrode.The morphology,structure,and composition o...We used the surface-pretreated graphite paper(Gp)as a carrier and loaded BiOCl with high selectivity to Cl^(-)on its surface by solvothermal method to form BiOCl@Gp electrode.The morphology,structure,and composition of the materials were characterized by scanning electron microscopy and nitrogen adsorption/desorption,and the results showed that the spherical BiOCl particles were uniformly dispersed on the surface of the Gp,forming a mesoporous BiOCl@Gp composite with a specific surface area of 22.82 m^(2)/g and a pore volume of 0.043 cm3/g.Furthermore,cyclic voltammetry and electrochemical impedance spectroscopy were used to test the electrochemical properties of the composites,and the stability of BiOCl and the high conductivity of Gp were synergistic,the BiOCl@Gp exhibited a specific capacitance of 30.2 F·g^(-1) at a current density of 0.5 A·g^(-1),and the selectivity of the BiOCl@Gp materials for Cl^(-)was significantly higher than that of SO_(4)^(2-),NO_(2)^(-),and HCO_(3)^(-).Therefore,BiOCl@Gp composite electrode materials can be used for the selective adsorption of Cl^(-)in wastewater,in order to achieve efficient wastewater recycling.展开更多
AIM:This study was designed to evaluate the anti-cancer actions of tanshinone I and tanshinone IIA,and six derivatives of tanshinone IIA on normal and cancerous colon cells.Structure activity relationship(SAR) analysi...AIM:This study was designed to evaluate the anti-cancer actions of tanshinone I and tanshinone IIA,and six derivatives of tanshinone IIA on normal and cancerous colon cells.Structure activity relationship(SAR) analysis was conducted to delineate the significance of the structural modifications of tanshinones for improved anti-cancer action.METHOD:Tanshinone derivatives were designed and synthesized according to the literature.The cytotoxicity of different compounds on colon cancer cells was determined by the MTT assay.Apoptotic activity of the tanshinones was measured by flow cytometry(FCM).RESULTS:Tanshinone I and tanshinone IIA both exhibited significant cytotoxicity on colon cancer cells.They are more effective in p53+/+ colon cancer cell line.It was also noted that the anti-cancer activity of tanshinone I was more potent and selective.Two of the derivatives of tanshinone IIA(N1 and N2) also exhibited cytotoxicity on colon cancer cells.CONCLUSIONS:The anti-colon cancer activity of tanshinone I was more potent and selective than tanshinone IIA,and is p53 dependent.The derivatives obtained by structural modifications of tanshinone IIA exhibited lower cytotoxicity on both normal and colon cancer cells.From steric and electronic characteristics point of view,it was concluded that structural modifications of ring A and furan or dihydrofuran ring D on the basic structure of tanshinones influences the activity.An increase of the delocalization of the A and B rings could enhance the cytotoxicity of such compounds,while a non-planar and small sized D ring region would provide improved anti-cancer activity.展开更多
Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO sy...Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO system,the capacity of fiber backhaul that links base station and remote radio heads is usually limited,which becomes a bottleneck for realizing the potential performance gain of both downlink and uplink.To solve this problem,we propose a joint antenna selection and user scheduling which is able to achieve a large portion of the potential gain provided by the massive MIMO array with only limited backhaul capacity.Three sub-optimal iterative algorithms with the objective of sumrate maximization are proposed for the joint optimization of antenna selection and user scheduling,either based on greedy fashion or Frobenius-norm criteria.Convergence and complexity analysis are presented for the algorithms.The provided Monte Carlo simulations show that,one of our algorithms achieves a good tradeoff between complexity and performance and thus is especially fit for massive MIMO systems.展开更多
The studies on the paleo-fluid in the OrdovicianeSilurian detachment zone in the MiddleeUpper Yangtze area focus on the origin of highdensity methane inclusions and the evolution process of formation pressure,but rare...The studies on the paleo-fluid in the OrdovicianeSilurian detachment zone in the MiddleeUpper Yangtze area focus on the origin of highdensity methane inclusions and the evolution process of formation pressure,but rarely deal with the significance of paleo-fluid to shale gas preservation.In this paper,the relationship between fracture formation and detachment zone was analyzed by observing the OrdovicianeSilurian outcrops in western HunaneHubei area and by investigating the geological characteristics of fracture veins in the drilling cores.Then,the significance of paleo-fluid forming environment and detachment zone to shale gas preservation was studied by using inclusion compositions of fracture veins and homogenization temperature test data.Finally,accumulationedispersion modes of shale gas in the detachment zone were established.The following results were obtained.First,the detachment zone is lithologically composed of silicite with intercalated shale at the OrdovicianeSilurian interface.In the detachment zone,rocks are broken and small crumples are developed.The conjugate-vertical joints are relatively developed in the silicite above and below the detachment zone.Second,multi-stage and multi-type inclusions,especially the aqueous inclusions,are developed in the veins of the detachment zone.Third,the infiltration depth of ancient meteoric water along the detachment zone in the study area is over 4000 m.High-density overpressure methane inclusions were captured in the detachment zone during early stage,while normal-pressure methane and nitrogen inclusions were captured during late stage.Fourth,the ionic constituents of inclusions recording the fluid activity during the late stage was characterized by high sodium-chloride coefficient,high desulfurization coefficient and low metamorphic coefficient,and it is indicated that the sealing capacity of the shale in the detachment zone gets worse.Fifth,the accumulation and dispersion of shale gas in the detachment zone within the study area is divided into three modes,i.e.,syncline,broad anticline and closed anticline.In conclusion,the detachment zone in the study area is permeable.Synclines and closed anticlines developed in detachment structures are unfavorable for the accumulation of shale gas,while broad anticlines are favorable.展开更多
Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for tax- onomy. Morphologically, the structures used to identify prostomates and haptorians are similar ...Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for tax- onomy. Morphologically, the structures used to identify prostomates and haptorians are similar or even identical, which generate heavy taxonomic and phylogenetic confusion. In present work, phylogenetic positions lineage of two rare genera, Plagiopogon and Askenasia, were investigated. Three genes including small subunit ribosomal RNA gene （hereafter SSU rDNA）, internal transcribed spacer region （ITS region）, and large subunit ribosomal RNA gene （LSU rDNA） were analyzed, 10 new sequences five species each. Our findings included 1） class Prostomatea and order Haptorida are multiphyletic; 2） it may not be appropriate to place order Cyclotriehiida in subclass Haptoria, and the systematic lineage of order Cyclotrichiida needs to be verified further; 3） genus Plagio- pogon branches consistently within a clade covering most prostomes and is basal of clade Colepidae, implying its close lineage to Prostomatea; and 4） Askenasia is phylogenetically distant from the subclass Haptoria but close to classes Prostomatea, Plagiopylea and Oligohymenophorea. We supposed that the toxicyst of Askenasia may be close to taxa of prostomes instead of haptorians, and the dorsal brush is a more typical morphological characteristics of haptorians than toxicysts.展开更多
A quadruped robot is more adjustable to a complex terrain than a wheeled or caterpillar robot to realize the continuous adjustable motions characterized by submissiveness and low energy consumption in basic control of...A quadruped robot is more adjustable to a complex terrain than a wheeled or caterpillar robot to realize the continuous adjustable motions characterized by submissiveness and low energy consumption in basic control of the quadruped robot over rough terrain. This paper presents a static walking mode of ＂altitude hold＂, which means to keep absolute altitude by controlling limbs adjustably on the basis of which biokinetics studies have shown that quadrupeds can move with almost the same body altitude over rough terrains characterized by a nearly horizontal relief. The gait design specifies several characteristic states of stance phase and swing phase for a quadruped robot and controls the phase sequence and phase of four legs through change of characteristic states. Furthermore, we design a robot control system to generate adjustable gaits and control the coordinative movement of robot joints. This planning method is tested through ADAMS and MATLAB interactive co-simulation; the quadruped robot which has 8 degrees of freedom （8-DOF） is used to simulate the motion over a terrain character- ized by randomly arranged humps. The results show that this method can make the quadruped robot capable to walk over certain rough terrain.展开更多
基金Funded by the National Natural Science Foundation of China(No.52072180)the Graduate Research and Innovation Projects of Jiangsu Province(No.KYCX21_3461)。
文摘We used the surface-pretreated graphite paper(Gp)as a carrier and loaded BiOCl with high selectivity to Cl^(-)on its surface by solvothermal method to form BiOCl@Gp electrode.The morphology,structure,and composition of the materials were characterized by scanning electron microscopy and nitrogen adsorption/desorption,and the results showed that the spherical BiOCl particles were uniformly dispersed on the surface of the Gp,forming a mesoporous BiOCl@Gp composite with a specific surface area of 22.82 m^(2)/g and a pore volume of 0.043 cm3/g.Furthermore,cyclic voltammetry and electrochemical impedance spectroscopy were used to test the electrochemical properties of the composites,and the stability of BiOCl and the high conductivity of Gp were synergistic,the BiOCl@Gp exhibited a specific capacitance of 30.2 F·g^(-1) at a current density of 0.5 A·g^(-1),and the selectivity of the BiOCl@Gp materials for Cl^(-)was significantly higher than that of SO_(4)^(2-),NO_(2)^(-),and HCO_(3)^(-).Therefore,BiOCl@Gp composite electrode materials can be used for the selective adsorption of Cl^(-)in wastewater,in order to achieve efficient wastewater recycling.
基金supported by the National Major Scientific and Technological Special Project for"Significant New Drugs Development"(No.2011ZX09401-028)
文摘AIM:This study was designed to evaluate the anti-cancer actions of tanshinone I and tanshinone IIA,and six derivatives of tanshinone IIA on normal and cancerous colon cells.Structure activity relationship(SAR) analysis was conducted to delineate the significance of the structural modifications of tanshinones for improved anti-cancer action.METHOD:Tanshinone derivatives were designed and synthesized according to the literature.The cytotoxicity of different compounds on colon cancer cells was determined by the MTT assay.Apoptotic activity of the tanshinones was measured by flow cytometry(FCM).RESULTS:Tanshinone I and tanshinone IIA both exhibited significant cytotoxicity on colon cancer cells.They are more effective in p53+/+ colon cancer cell line.It was also noted that the anti-cancer activity of tanshinone I was more potent and selective.Two of the derivatives of tanshinone IIA(N1 and N2) also exhibited cytotoxicity on colon cancer cells.CONCLUSIONS:The anti-colon cancer activity of tanshinone I was more potent and selective than tanshinone IIA,and is p53 dependent.The derivatives obtained by structural modifications of tanshinone IIA exhibited lower cytotoxicity on both normal and colon cancer cells.From steric and electronic characteristics point of view,it was concluded that structural modifications of ring A and furan or dihydrofuran ring D on the basic structure of tanshinones influences the activity.An increase of the delocalization of the A and B rings could enhance the cytotoxicity of such compounds,while a non-planar and small sized D ring region would provide improved anti-cancer activity.
基金supported in part by National Natural Science Foundation of China No.61171080
文摘Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO system,the capacity of fiber backhaul that links base station and remote radio heads is usually limited,which becomes a bottleneck for realizing the potential performance gain of both downlink and uplink.To solve this problem,we propose a joint antenna selection and user scheduling which is able to achieve a large portion of the potential gain provided by the massive MIMO array with only limited backhaul capacity.Three sub-optimal iterative algorithms with the objective of sumrate maximization are proposed for the joint optimization of antenna selection and user scheduling,either based on greedy fashion or Frobenius-norm criteria.Convergence and complexity analysis are presented for the algorithms.The provided Monte Carlo simulations show that,one of our algorithms achieves a good tradeoff between complexity and performance and thus is especially fit for massive MIMO systems.
基金supported by the National Major Science and Technology Project“Study on high-mature shale gas occurrence mechanism and enriching law in Middle Yangtze region”(No.:2016ZX05034-001-002)the Foundation Project of China Geological Survey“Investigation and evaluation of shale gas resources in Wuling and Western Hunan-Hubei area”(No.:12120114049801).
文摘The studies on the paleo-fluid in the OrdovicianeSilurian detachment zone in the MiddleeUpper Yangtze area focus on the origin of highdensity methane inclusions and the evolution process of formation pressure,but rarely deal with the significance of paleo-fluid to shale gas preservation.In this paper,the relationship between fracture formation and detachment zone was analyzed by observing the OrdovicianeSilurian outcrops in western HunaneHubei area and by investigating the geological characteristics of fracture veins in the drilling cores.Then,the significance of paleo-fluid forming environment and detachment zone to shale gas preservation was studied by using inclusion compositions of fracture veins and homogenization temperature test data.Finally,accumulationedispersion modes of shale gas in the detachment zone were established.The following results were obtained.First,the detachment zone is lithologically composed of silicite with intercalated shale at the OrdovicianeSilurian interface.In the detachment zone,rocks are broken and small crumples are developed.The conjugate-vertical joints are relatively developed in the silicite above and below the detachment zone.Second,multi-stage and multi-type inclusions,especially the aqueous inclusions,are developed in the veins of the detachment zone.Third,the infiltration depth of ancient meteoric water along the detachment zone in the study area is over 4000 m.High-density overpressure methane inclusions were captured in the detachment zone during early stage,while normal-pressure methane and nitrogen inclusions were captured during late stage.Fourth,the ionic constituents of inclusions recording the fluid activity during the late stage was characterized by high sodium-chloride coefficient,high desulfurization coefficient and low metamorphic coefficient,and it is indicated that the sealing capacity of the shale in the detachment zone gets worse.Fifth,the accumulation and dispersion of shale gas in the detachment zone within the study area is divided into three modes,i.e.,syncline,broad anticline and closed anticline.In conclusion,the detachment zone in the study area is permeable.Synclines and closed anticlines developed in detachment structures are unfavorable for the accumulation of shale gas,while broad anticlines are favorable.
基金supported by the National Natural Science Foundation of China(Nos.31222050,41376141,3112041,and 31471973)the international research projects from King Saud University(Nos.RGP-VPP-083,IRG14-22)
文摘Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for tax- onomy. Morphologically, the structures used to identify prostomates and haptorians are similar or even identical, which generate heavy taxonomic and phylogenetic confusion. In present work, phylogenetic positions lineage of two rare genera, Plagiopogon and Askenasia, were investigated. Three genes including small subunit ribosomal RNA gene （hereafter SSU rDNA）, internal transcribed spacer region （ITS region）, and large subunit ribosomal RNA gene （LSU rDNA） were analyzed, 10 new sequences five species each. Our findings included 1） class Prostomatea and order Haptorida are multiphyletic; 2） it may not be appropriate to place order Cyclotriehiida in subclass Haptoria, and the systematic lineage of order Cyclotrichiida needs to be verified further; 3） genus Plagio- pogon branches consistently within a clade covering most prostomes and is basal of clade Colepidae, implying its close lineage to Prostomatea; and 4） Askenasia is phylogenetically distant from the subclass Haptoria but close to classes Prostomatea, Plagiopylea and Oligohymenophorea. We supposed that the toxicyst of Askenasia may be close to taxa of prostomes instead of haptorians, and the dorsal brush is a more typical morphological characteristics of haptorians than toxicysts.
基金supported by the National High Technology Research and Development Program of China (863Program) under Grant No.2011AA041001
文摘A quadruped robot is more adjustable to a complex terrain than a wheeled or caterpillar robot to realize the continuous adjustable motions characterized by submissiveness and low energy consumption in basic control of the quadruped robot over rough terrain. This paper presents a static walking mode of ＂altitude hold＂, which means to keep absolute altitude by controlling limbs adjustably on the basis of which biokinetics studies have shown that quadrupeds can move with almost the same body altitude over rough terrains characterized by a nearly horizontal relief. The gait design specifies several characteristic states of stance phase and swing phase for a quadruped robot and controls the phase sequence and phase of four legs through change of characteristic states. Furthermore, we design a robot control system to generate adjustable gaits and control the coordinative movement of robot joints. This planning method is tested through ADAMS and MATLAB interactive co-simulation; the quadruped robot which has 8 degrees of freedom （8-DOF） is used to simulate the motion over a terrain character- ized by randomly arranged humps. The results show that this method can make the quadruped robot capable to walk over certain rough terrain.
