Developing sustainable and clean electrochemical energy conversion technologies is a crucial step in addressing the challenges of energy shortage and environmental pollution. Exploring and developing new electrocataly...Developing sustainable and clean electrochemical energy conversion technologies is a crucial step in addressing the challenges of energy shortage and environmental pollution. Exploring and developing new electrocatalysts with excellent performance and low cost will facilitate the commercial use of these energy conversion technologies. Recently, dual-atom catalysts(DACs) have attracted considerable research interest since they exhibit higher metal atom loading and more flexible active sites compared to single-atom catalysts(SACs). In this paper, the latest preparation methods and characterization techniques of DACs are systematically reviewed. The advantages of homonuclear and heteronuclear DACs and the catalytic mechanism and identification technologies between the two DACs are highlighted. The current applications of DACs in the field of electrocatalysis are summarized. The development opportunities and challenges of DACs in the future are prospected. The ultimate goal is to provide new ideas for the preparation of new catalysts with excellent properties by customizing diatomic catalysts for electrochemical applications.展开更多
MM： To clarify whether serum chemokine and cytokine levels can become useful biological and functional markers to assess the severity of chronic pancreatitis （CP）. This study aimed at clarifying whether serum chemo...MM： To clarify whether serum chemokine and cytokine levels can become useful biological and functional markers to assess the severity of chronic pancreatitis （CP）. This study aimed at clarifying whether serum chemokine and cytokine levels can become useful biological and functional markers to assess the severity of CR METHODS： Serum monocyte chemoattractant protein-1 （MCP-1）, transforming growth factor beta-1 （TGF-βI）, and soluble type fractalkine （s-fractalkine） concentrations were examined in patients with CP （n = 109） and healthy controls （n = 116）. Severity of disease was classified in patients with CP by a staging system. Relationships between stage-specific various clinical factors and serum MCP-1, TGF-β1, and s-fractalkine levels were investigated. Furthermore, 57 patients with non-alcoholic CP were similarly evaluated in order to exclude influence of alcohol intake. RESULTS： Patients with CP showed significant higher levels of serum TGF-β1 and s-fractalkine, but not MCP-1, compared to the controls. Serum TGF-β1 in the severe stage and s-fractalkine in the mild and thesevere stage of CP significantly increased compared to those of controls. However, it was observed that both TGF-β1 and s-fractalkine levels were affected by alcohol intake. In patients with non-alcoholic CP, serum TGF-β1 showed significant increase in the moderate stage of CP, and serum s-fractalkine revealed significant increase in the early stage of CP. CONCLUSION： It is suggested that the measurement of serum F-fractalkine is useful to diagnose early- stage CP. Moreover, the combined determination of both, s-fractalkine and TGF-β1, in human sera may be helpful in evaluating the severity status of CP.展开更多
HL-2A tokamak, the first tokamak with divertor in China, has been constructed and put into operation in 2002. The main parameters are R=1.65 m, a=0.4 m, BT=2.8 T, Ip = 0. 48 MA. The divertor of HL-2A is unique, becaus...HL-2A tokamak, the first tokamak with divertor in China, has been constructed and put into operation in 2002. The main parameters are R=1.65 m, a=0.4 m, BT=2.8 T, Ip = 0. 48 MA. The divertor of HL-2A is unique, because it is characterized with a large closed divertor chamber. The device has double divertor chamber, but now it is operating with lower single null configuration to study the physics of divertor for the next step design of a divertor. Supersonic molecular beam injection （SMBI） system with LN2 cooling trap was first installed and demonstrated on the HL-2A tokamak in 2004. The first results of SMBI into HL-2A plasma are to demonstrate the function of the HL-2A divertor and to observe the cold pulse propagation during multi-pulse SMBI on HL-2A Tokamak.展开更多
We investigate the thermoelectric energy conversion efficiency of Si and Ge nanowires, and in particular, that of Si/Ge core-shell nanowires. We show how the presence of a thin Ge shell on a Si core nanowire increases...We investigate the thermoelectric energy conversion efficiency of Si and Ge nanowires, and in particular, that of Si/Ge core-shell nanowires. We show how the presence of a thin Ge shell on a Si core nanowire increases the overall figure of merit. We find the optimal thickness of the Ge shell to provide the largest figure of merit for the devices. We also consider Ge core/Si shell nanowires, and show that an optimal thickness of the Si shell does not exist, since the figure of merit is a monotonically decreasing function of the radius of the nanowire. Finally, we verify the empirical law relating the electron energy gap to the optimal working temperature that maximizes the efficiency of the device.展开更多
For the main purpose of manipulating the functions of molecules, researchers have made great achievements on photoresponsive molecules using light as a trigger. Light has become a promising scientific tool due to it b...For the main purpose of manipulating the functions of molecules, researchers have made great achievements on photoresponsive molecules using light as a trigger. Light has become a promising scientific tool due to it being a clean and noninvasive external stimulant. By attachment of photoresponsive moieties to molecules, the biological activities of molecules can be attenuated by light activation. With wide applications of laser in life sciences, it will be possible to achieve high spatiotemporal resolution. In this review, we focus on photoresponsive nucleic acids for photomodulating gene expression with light activation. With incorporation of photoswitchable or photocleavable moieties, biological behaviors of nucleic acids are photoregulated reversibly or irreversibly. Recent development and applications of photoresponsive nucleic acid in vitro and in vivo have shown a very promising future for manipulation of specific functional genes or disease genes. We expect that photoresponsive nucleic acids will be powerful scientific tools for studying biological events as well as gene therapy agents for genetic diseases.展开更多
OpenCL is an open heterogeneous programming framework. Although OpenCL programs are func- tionally portable, they do not provide performance portability, so code transformation often plays an irreplaceable role. When ...OpenCL is an open heterogeneous programming framework. Although OpenCL programs are func- tionally portable, they do not provide performance portability, so code transformation often plays an irreplaceable role. When adapting GPU-specific OpenCL kernels to run on multi-core/many-core CPUs, coarsening the thread granularity is necessary and thus has been extensively used. However, locality concerns exposed in GPU-specific OpenCL code are usually inherited without analysis, which may give side-effects on the CPU performance. Typi- cally, the use of OpenCL＇s local memory on multi-core/many-core CPUs may lead to an opposite performance effect, because local-memory arrays no longer match well with the hardware and the associated synchronizations are costly. To solve this dilemma, we actively analyze the memory access patterns using array-access descriptors derived from GPU-specific kernels, which can thus be adapted for CPUs by （1） removing all the unwanted local-memory arrays together with the obsolete barrier statements and （2） optimizing the coalesced kernel code with vectorization and locality re-exploitation. Moreover, we have developed an automated tool chain that makes this transformation of GPU-specific OpenCL kernels into a CPU-friendly form, which is accompanied with a scheduler that forms a new OpenCL runtime. Experiments show that the automated transformation can improve OpenCL kernel performance on a multi-core CPU by an average factor of 3.24. Satisfactory performance improvements axe also achieved on Intel＇s many-integrated-core coprocessor. The resultant performance on both architectures is better than or comparable with the corresponding OpenMP performance.展开更多
文摘Developing sustainable and clean electrochemical energy conversion technologies is a crucial step in addressing the challenges of energy shortage and environmental pollution. Exploring and developing new electrocatalysts with excellent performance and low cost will facilitate the commercial use of these energy conversion technologies. Recently, dual-atom catalysts(DACs) have attracted considerable research interest since they exhibit higher metal atom loading and more flexible active sites compared to single-atom catalysts(SACs). In this paper, the latest preparation methods and characterization techniques of DACs are systematically reviewed. The advantages of homonuclear and heteronuclear DACs and the catalytic mechanism and identification technologies between the two DACs are highlighted. The current applications of DACs in the field of electrocatalysis are summarized. The development opportunities and challenges of DACs in the future are prospected. The ultimate goal is to provide new ideas for the preparation of new catalysts with excellent properties by customizing diatomic catalysts for electrochemical applications.
基金Supported by The Research Committee of Intractable Diseases of the Pancreas, provided by the Ministry of Health, Labour, and Welfare, Japan, No. 50253448Grant from the Ministry of Education, Culture, Sports, Science, and Technology, Japan (20590808, Ito T)
文摘MM： To clarify whether serum chemokine and cytokine levels can become useful biological and functional markers to assess the severity of chronic pancreatitis （CP）. This study aimed at clarifying whether serum chemokine and cytokine levels can become useful biological and functional markers to assess the severity of CR METHODS： Serum monocyte chemoattractant protein-1 （MCP-1）, transforming growth factor beta-1 （TGF-βI）, and soluble type fractalkine （s-fractalkine） concentrations were examined in patients with CP （n = 109） and healthy controls （n = 116）. Severity of disease was classified in patients with CP by a staging system. Relationships between stage-specific various clinical factors and serum MCP-1, TGF-β1, and s-fractalkine levels were investigated. Furthermore, 57 patients with non-alcoholic CP were similarly evaluated in order to exclude influence of alcohol intake. RESULTS： Patients with CP showed significant higher levels of serum TGF-β1 and s-fractalkine, but not MCP-1, compared to the controls. Serum TGF-β1 in the severe stage and s-fractalkine in the mild and thesevere stage of CP significantly increased compared to those of controls. However, it was observed that both TGF-β1 and s-fractalkine levels were affected by alcohol intake. In patients with non-alcoholic CP, serum TGF-β1 showed significant increase in the moderate stage of CP, and serum s-fractalkine revealed significant increase in the early stage of CP. CONCLUSION： It is suggested that the measurement of serum F-fractalkine is useful to diagnose early- stage CP. Moreover, the combined determination of both, s-fractalkine and TGF-β1, in human sera may be helpful in evaluating the severity status of CP.
文摘HL-2A tokamak, the first tokamak with divertor in China, has been constructed and put into operation in 2002. The main parameters are R=1.65 m, a=0.4 m, BT=2.8 T, Ip = 0. 48 MA. The divertor of HL-2A is unique, because it is characterized with a large closed divertor chamber. The device has double divertor chamber, but now it is operating with lower single null configuration to study the physics of divertor for the next step design of a divertor. Supersonic molecular beam injection （SMBI） system with LN2 cooling trap was first installed and demonstrated on the HL-2A tokamak in 2004. The first results of SMBI into HL-2A plasma are to demonstrate the function of the HL-2A divertor and to observe the cold pulse propagation during multi-pulse SMBI on HL-2A Tokamak.
文摘We investigate the thermoelectric energy conversion efficiency of Si and Ge nanowires, and in particular, that of Si/Ge core-shell nanowires. We show how the presence of a thin Ge shell on a Si core nanowire increases the overall figure of merit. We find the optimal thickness of the Ge shell to provide the largest figure of merit for the devices. We also consider Ge core/Si shell nanowires, and show that an optimal thickness of the Si shell does not exist, since the figure of merit is a monotonically decreasing function of the radius of the nanowire. Finally, we verify the empirical law relating the electron energy gap to the optimal working temperature that maximizes the efficiency of the device.
基金State Key Laboratory of Natural and Biomimetic Drugs and Peking University(bmu2009137-121)
文摘For the main purpose of manipulating the functions of molecules, researchers have made great achievements on photoresponsive molecules using light as a trigger. Light has become a promising scientific tool due to it being a clean and noninvasive external stimulant. By attachment of photoresponsive moieties to molecules, the biological activities of molecules can be attenuated by light activation. With wide applications of laser in life sciences, it will be possible to achieve high spatiotemporal resolution. In this review, we focus on photoresponsive nucleic acids for photomodulating gene expression with light activation. With incorporation of photoswitchable or photocleavable moieties, biological behaviors of nucleic acids are photoregulated reversibly or irreversibly. Recent development and applications of photoresponsive nucleic acid in vitro and in vivo have shown a very promising future for manipulation of specific functional genes or disease genes. We expect that photoresponsive nucleic acids will be powerful scientific tools for studying biological events as well as gene therapy agents for genetic diseases.
基金Project supported by the National Natural Science Foundation of China(No.61272145)the National High-Tech R&D Program(863)of China(No.2012AA012706)
文摘OpenCL is an open heterogeneous programming framework. Although OpenCL programs are func- tionally portable, they do not provide performance portability, so code transformation often plays an irreplaceable role. When adapting GPU-specific OpenCL kernels to run on multi-core/many-core CPUs, coarsening the thread granularity is necessary and thus has been extensively used. However, locality concerns exposed in GPU-specific OpenCL code are usually inherited without analysis, which may give side-effects on the CPU performance. Typi- cally, the use of OpenCL＇s local memory on multi-core/many-core CPUs may lead to an opposite performance effect, because local-memory arrays no longer match well with the hardware and the associated synchronizations are costly. To solve this dilemma, we actively analyze the memory access patterns using array-access descriptors derived from GPU-specific kernels, which can thus be adapted for CPUs by （1） removing all the unwanted local-memory arrays together with the obsolete barrier statements and （2） optimizing the coalesced kernel code with vectorization and locality re-exploitation. Moreover, we have developed an automated tool chain that makes this transformation of GPU-specific OpenCL kernels into a CPU-friendly form, which is accompanied with a scheduler that forms a new OpenCL runtime. Experiments show that the automated transformation can improve OpenCL kernel performance on a multi-core CPU by an average factor of 3.24. Satisfactory performance improvements axe also achieved on Intel＇s many-integrated-core coprocessor. The resultant performance on both architectures is better than or comparable with the corresponding OpenMP performance.
