Power electronic devices are of great importance in modern society.After decades of development,Si power devices have approached their material limits with only incremental improvements and large conversion losses.As ...Power electronic devices are of great importance in modern society.After decades of development,Si power devices have approached their material limits with only incremental improvements and large conversion losses.As the demand for electronic components with high efficiency dramatically increasing,new materials are needed for power device fabrication.Betaphase gallium oxide,an ultra-wide bandgap semiconductor,has been considered as a promising candidate,and variousβ-Ga_(2)O_(3)power devices with high breakdown voltages have been demonstrated.However,the realization of enhancement-mode(E-mode)β-Ga_(2)O_(3)field-effect transistors(FETs)is still challenging,which is a critical problem for a myriad of power electronic applications.Recently,researchers have made some progress on E-modeβ-Ga_(2)O_(3)FETs via various methods,and several novel structures have been fabricated.This article gives a review of the material growth,devices and properties of these E-modeβ-Ga_(2)O_(3)FETs.The key challenges and future directions in E-modeβ-Ga_(2)O_(3)FETs are also discussed.展开更多
Wheat stripe rust,caused by Puccinia striiformis Westend. f. sp. tritici Erikss.（ Pst）,is one of the most destructive diseases of wheat（ Triticum aestivum L.） worldwide. Sichuan province plays an important role in...Wheat stripe rust,caused by Puccinia striiformis Westend. f. sp. tritici Erikss.（ Pst）,is one of the most destructive diseases of wheat（ Triticum aestivum L.） worldwide. Sichuan province plays an important role in stripe rust epidemic in China. To identify and evaluate wheat stripe rust resistance in Sichuan Province,134 wheat cultivars（ lines） were inoculated with seven Pst races at seedling stage and adult stage. The results indicated that the resistance frequencies of wheat cultivars（ lines） against seven races CYR31,Su11-7,CYR29,Su11-4,CYR32,CYR33 and V26 were 92. 4%,92. 5%,89. 3%,89. 4%,87. 3%,85. 0% and 82. 8%,respectively. Among 134 materials,76（ 56. 0%） performed resistance against all tested races both in seedling and adult stages. The virulence of new pathogenic type V26 of Pst on wheat cultivars（ lines） was stronger than the dominant races CYR32 and CYR33. All wheat cultivars（ lines） were classified into three types according to analysis of resistance spectrum; 66. 4% of cultivars（ lines） showed all-stage resistance,17. 9% were adult-plant resistance,and 15. 7% were susceptible. This indicated that although the overall resistance level of wheat cultivars（ lines） in Sichuan Province was very high,the resistance type was simple. Therefore,it is important to identify new resistance genes and enhance resistance gene diversity. Meanwhile,pyramiding breeding of all-stage resistance gene and adult-plant resistance gene could be gradually developed,to achieve durable resistance of wheat cultivars（lines） against stripe rust in Sichuan Province.展开更多
Dicarboxylic acids,which are appealing structural motifs in organic synthesis and exist widely in bioactive compounds,have been widely used as important monomers in the polymer industry to construct valuable materials...Dicarboxylic acids,which are appealing structural motifs in organic synthesis and exist widely in bioactive compounds,have been widely used as important monomers in the polymer industry to construct valuable materials.The dicarboxylation with CO_(2)provides a convenient and potent way to furnish value-added dicarboxylic acids via the chemical fixation of two CO_(2)molecules.Beyond any doubt,the development of dicarboxylation,especially the dicarboxylation of bulk chemicals,might represent a promising prospect in CO_(2)capture and utilization(CCU).In this review,we critically summarized and comprehensively reviewed the advances made in the past decades in dicarboxylation with CO_(2)under electro-,photo-and transition metal-mediated/catalytic systems.Moreover,the advantages and limitations of such dicarboxylation reactions are pointed out to unravel further development for future scientific and industrial advances in dicarboxylation with CO_(2)to synthesize dicarboxylic acids in high selectivity and efficiency.展开更多
Herein, we report a novel synthesis of 1,3-oxazin-6-ones from enamides with CO2 through C--H carboxylation and one-pot cyclization. This transition-metal-free and redox-neutral process features broad substrate scope, ...Herein, we report a novel synthesis of 1,3-oxazin-6-ones from enamides with CO2 through C--H carboxylation and one-pot cyclization. This transition-metal-free and redox-neutral process features broad substrate scope, good functional group tolerance and facile product derivatization. The nucleophilic attack to CO2 from the electron-rich alkene is demonstrated for this reaction.展开更多
We present an algorithm for segmenting a mesh into patches whose boundaries are aligned with prominent ridge and valley lines of the shape. Our key insight is that this problem can be formulated as correlation cluster...We present an algorithm for segmenting a mesh into patches whose boundaries are aligned with prominent ridge and valley lines of the shape. Our key insight is that this problem can be formulated as correlation clustering(CC), a graph partitioning problem originating from the data mining community.The formulation lends two unique advantages to our method over existing segmentation methods. First,since CC is non-parametric, our method has few parameters to tune. Second, as CC is governed by edge weights in the graph, our method offers users direct and local control over the segmentation result. Our technical contributions include the construction of the weighted graph on which CC is defined, a strategy for rapidly computing CC on this graph, and an interactive tool for editing the segmentation. Our experiments show that our method produces qualitatively better segmentations than existing methods on a wide range of inputs.展开更多
Modem storage systems incorporate data compressors to improve their performance and capacity. As a result, data content can significantly influence the result of a storage system benchmark. Because real-world propriet...Modem storage systems incorporate data compressors to improve their performance and capacity. As a result, data content can significantly influence the result of a storage system benchmark. Because real-world proprietary datasets are too large to be copied onto a test storage system, and most data cannot be shared due to privacy issues, a benchmark needs to generate data synthetically. To ensure that the result is accurate, it is necessary to generate data content based on the characterization of real-world data properties that influence the storage system performance during the execution of a benchmark. The existing approach, called SDGen, cannot guarantee that the benchmark result is accurate in storage systems that have built-in word-based compressors. The reason is that SDGen characterizes the properties that influence compression performance only at the byte level, and no properties are characterized at the word level. To address this problem, we present TextGen, a realistic text data content generation method for modem storage system benchmarks. TextGen builds the word corpus by segmenting real-world text datasets, and creates a word-frequency distribution by counting each word in the corpus. To improve data generation performance, the word-frequency distribution is fitted to a lognormal distribution by maximum likelihood estimation. The Monte Carlo approach is used to generate synthetic data. The running time of TextGen generation depends only on the expected data size, which means that the time complexity of TextGen is O（n）. To evaluate TextGen, four real-world datasets were used to perform an experiment. The experimental results show that, compared with SDGen, the compression performance and compression ratio of the datasets generated by TextGen deviate less from real-world datasets when end-tagged dense code, a representative of word-based compressors, is evaluated.展开更多
The traditional random forest algorithm works along with unbalanced data,cannot achieve satisfactory prediction results for minority class,and suffers from the parameter selection dilemma.In view of this problem,this ...The traditional random forest algorithm works along with unbalanced data,cannot achieve satisfactory prediction results for minority class,and suffers from the parameter selection dilemma.In view of this problem,this paper proposes an unbalanced accuracy weighted random forest algorithm(UAW_RF)based on the adaptive step size artificial bee colony optimization.It combines the ideas of decision tree optimization,sampling selection,and weighted voting to improve the ability of stochastic forest algorithm when dealing with biased data classification.The adaptive step size and the optimal solution were introduced to improve the position updating formula of the artificial bee colony algorithm,and then the parameter combination of the random forest algorithm was iteratively optimized with the advantages of the algorithm.Experimental results show satisfactory accuracies and prove that the method can effectively improve the classification accuracy of the random forest algorithm.展开更多
基金supported in part by the National Basic Research Program of China(Grant No.2021YFB3600202)Key Laboratory Construction Project of Nanchang(Grant No.2020-NCZDSY-008)the Suzhou Science and Technology Foundation(Grant No.SYG202027)。
文摘Power electronic devices are of great importance in modern society.After decades of development,Si power devices have approached their material limits with only incremental improvements and large conversion losses.As the demand for electronic components with high efficiency dramatically increasing,new materials are needed for power device fabrication.Betaphase gallium oxide,an ultra-wide bandgap semiconductor,has been considered as a promising candidate,and variousβ-Ga_(2)O_(3)power devices with high breakdown voltages have been demonstrated.However,the realization of enhancement-mode(E-mode)β-Ga_(2)O_(3)field-effect transistors(FETs)is still challenging,which is a critical problem for a myriad of power electronic applications.Recently,researchers have made some progress on E-modeβ-Ga_(2)O_(3)FETs via various methods,and several novel structures have been fabricated.This article gives a review of the material growth,devices and properties of these E-modeβ-Ga_(2)O_(3)FETs.The key challenges and future directions in E-modeβ-Ga_(2)O_(3)FETs are also discussed.
基金Supported by China Agriculture Research System(CARS-03)International Joint Research Project of Sichuan Province(2014HH0052)+1 种基金Key Research Project of Wheat Breeding in Sichuan ProvinceInnovation Team Project of Wheat in Sichuan Province
文摘Wheat stripe rust,caused by Puccinia striiformis Westend. f. sp. tritici Erikss.（ Pst）,is one of the most destructive diseases of wheat（ Triticum aestivum L.） worldwide. Sichuan province plays an important role in stripe rust epidemic in China. To identify and evaluate wheat stripe rust resistance in Sichuan Province,134 wheat cultivars（ lines） were inoculated with seven Pst races at seedling stage and adult stage. The results indicated that the resistance frequencies of wheat cultivars（ lines） against seven races CYR31,Su11-7,CYR29,Su11-4,CYR32,CYR33 and V26 were 92. 4%,92. 5%,89. 3%,89. 4%,87. 3%,85. 0% and 82. 8%,respectively. Among 134 materials,76（ 56. 0%） performed resistance against all tested races both in seedling and adult stages. The virulence of new pathogenic type V26 of Pst on wheat cultivars（ lines） was stronger than the dominant races CYR32 and CYR33. All wheat cultivars（ lines） were classified into three types according to analysis of resistance spectrum; 66. 4% of cultivars（ lines） showed all-stage resistance,17. 9% were adult-plant resistance,and 15. 7% were susceptible. This indicated that although the overall resistance level of wheat cultivars（ lines） in Sichuan Province was very high,the resistance type was simple. Therefore,it is important to identify new resistance genes and enhance resistance gene diversity. Meanwhile,pyramiding breeding of all-stage resistance gene and adult-plant resistance gene could be gradually developed,to achieve durable resistance of wheat cultivars（lines） against stripe rust in Sichuan Province.
基金supported by the National Natural Science Foundation of China(21822108)the Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province(2021ZYD0063)+1 种基金the Fundamental Research Funds from Sichuan University(2020SCUNL102)the Fundamental Research Funds for the Central Universities.
文摘Dicarboxylic acids,which are appealing structural motifs in organic synthesis and exist widely in bioactive compounds,have been widely used as important monomers in the polymer industry to construct valuable materials.The dicarboxylation with CO_(2)provides a convenient and potent way to furnish value-added dicarboxylic acids via the chemical fixation of two CO_(2)molecules.Beyond any doubt,the development of dicarboxylation,especially the dicarboxylation of bulk chemicals,might represent a promising prospect in CO_(2)capture and utilization(CCU).In this review,we critically summarized and comprehensively reviewed the advances made in the past decades in dicarboxylation with CO_(2)under electro-,photo-and transition metal-mediated/catalytic systems.Moreover,the advantages and limitations of such dicarboxylation reactions are pointed out to unravel further development for future scientific and industrial advances in dicarboxylation with CO_(2)to synthesize dicarboxylic acids in high selectivity and efficiency.
文摘Herein, we report a novel synthesis of 1,3-oxazin-6-ones from enamides with CO2 through C--H carboxylation and one-pot cyclization. This transition-metal-free and redox-neutral process features broad substrate scope, good functional group tolerance and facile product derivatization. The nucleophilic attack to CO2 from the electron-rich alkene is demonstrated for this reaction.
基金supported in part by a gift from Adobe System, Inc
文摘We present an algorithm for segmenting a mesh into patches whose boundaries are aligned with prominent ridge and valley lines of the shape. Our key insight is that this problem can be formulated as correlation clustering(CC), a graph partitioning problem originating from the data mining community.The formulation lends two unique advantages to our method over existing segmentation methods. First,since CC is non-parametric, our method has few parameters to tune. Second, as CC is governed by edge weights in the graph, our method offers users direct and local control over the segmentation result. Our technical contributions include the construction of the weighted graph on which CC is defined, a strategy for rapidly computing CC on this graph, and an interactive tool for editing the segmentation. Our experiments show that our method produces qualitatively better segmentations than existing methods on a wide range of inputs.
基金Project supported by the National Natural Science Foundation of China （Nos. 61572394 and 61272098）, the Shenzhen Funda mental Research Plan （Nos. JCYJ20120615101127404 and JSGG20140519141854753）, and thc National Kcy Technologies R＆D Program of China （No. 2011BAH04B03）
文摘Modem storage systems incorporate data compressors to improve their performance and capacity. As a result, data content can significantly influence the result of a storage system benchmark. Because real-world proprietary datasets are too large to be copied onto a test storage system, and most data cannot be shared due to privacy issues, a benchmark needs to generate data synthetically. To ensure that the result is accurate, it is necessary to generate data content based on the characterization of real-world data properties that influence the storage system performance during the execution of a benchmark. The existing approach, called SDGen, cannot guarantee that the benchmark result is accurate in storage systems that have built-in word-based compressors. The reason is that SDGen characterizes the properties that influence compression performance only at the byte level, and no properties are characterized at the word level. To address this problem, we present TextGen, a realistic text data content generation method for modem storage system benchmarks. TextGen builds the word corpus by segmenting real-world text datasets, and creates a word-frequency distribution by counting each word in the corpus. To improve data generation performance, the word-frequency distribution is fitted to a lognormal distribution by maximum likelihood estimation. The Monte Carlo approach is used to generate synthetic data. The running time of TextGen generation depends only on the expected data size, which means that the time complexity of TextGen is O（n）. To evaluate TextGen, four real-world datasets were used to perform an experiment. The experimental results show that, compared with SDGen, the compression performance and compression ratio of the datasets generated by TextGen deviate less from real-world datasets when end-tagged dense code, a representative of word-based compressors, is evaluated.
基金the CERNET Innovation Project(No.NGII20190315)the Foundation of A Hundred Youth Talents Training Program of Lanzhou Jiaotong University.
文摘The traditional random forest algorithm works along with unbalanced data,cannot achieve satisfactory prediction results for minority class,and suffers from the parameter selection dilemma.In view of this problem,this paper proposes an unbalanced accuracy weighted random forest algorithm(UAW_RF)based on the adaptive step size artificial bee colony optimization.It combines the ideas of decision tree optimization,sampling selection,and weighted voting to improve the ability of stochastic forest algorithm when dealing with biased data classification.The adaptive step size and the optimal solution were introduced to improve the position updating formula of the artificial bee colony algorithm,and then the parameter combination of the random forest algorithm was iteratively optimized with the advantages of the algorithm.Experimental results show satisfactory accuracies and prove that the method can effectively improve the classification accuracy of the random forest algorithm.
