动脉粥样硬化是心血管疾病重要的病理生理基础,延缓和防治动脉粥样硬化对于减少和降低心血管疾病的发病率及病死率具有重要意义。高密度脂蛋白(high density lipoprotein,HDL)通过参与介导胆固醇逆向转运(reverse cholesterol transport...动脉粥样硬化是心血管疾病重要的病理生理基础,延缓和防治动脉粥样硬化对于减少和降低心血管疾病的发病率及病死率具有重要意义。高密度脂蛋白(high density lipoprotein,HDL)通过参与介导胆固醇逆向转运(reverse cholesterol transport,RCT)在抗动脉粥样硬化的形成和进展中发挥了重要作用。Preβ-1高密度脂蛋白(prebeta-1 high density lipoprotein,Preβ-1HDL)作为HDL的一种亚类,是外周细胞移出胆固醇的最初接受体,直接参与了RCT的起始步骤,并在随后的胆固醇酯化及转运中起着重要作用。本文就Preβ-1HDL的结构、代谢及其与心血管疾病的关系作一简要综述。展开更多
To obtain the pyrolysis characteristics and kinetics of preparation process of sludge-based activated carbon by ZnCl2 activation method (i.e.the pyrolysis process of the sludge with ZnCl2 activation),the characteris...To obtain the pyrolysis characteristics and kinetics of preparation process of sludge-based activated carbon by ZnCl2 activation method (i.e.the pyrolysis process of the sludge with ZnCl2 activation),the characteristic of mass loss and gas products generated during pyrolysis of the sludge with ZnCl2 activation were analyzed by thermogravimetric analysis coupled with Fourier Transform Infrared Spectroscopy (TG-FTIR).The kinetic parameters were calculated by the Coats-Redfem method and the mechanism models were established.The role of ZnCl2 in the pyrolysis process of the sludge with ZnCl2 activation was also illustrated through the comparison of the pyrolysis characteristics and kinetics of the sludge with and without ZnCl2 activation.The results showed that the pyrolysis process of the sludge with ZnCl2 activation can be divided into four stages including the dehydration of sludge and initial depolymerization of a small portion of organics matters,the decomposition of large molecular organic matters into small molecular intermediates,the further degradation of intermediates and volatilization of ZnCl2,and the decomposition of inorganic minerals and undecomposed organic matters.CO2,CO,CH4,H2O,some aldehydes and carboxylic acids are the major pyrolysis gaseous products.The activation energies and pre-exponential factors are in the range of 28.84-206.42 kJ/mol and 9885.16-8.08× 1011 min-1,respectively.During the pyrolysis of sludge,ZnC12 not only can function as a dehydration agent and inhibit the formation of tar,but also can peptize the organic matters in the sludge,making them easier to be decomposed.展开更多
Recently,both the importance and awareness relating to food safety relating to agrochemicals,chemical fertilizers,the pollution of ecosystem and unwholesome foods are growing rapidly.For the same reason,the purchaser&...Recently,both the importance and awareness relating to food safety relating to agrochemicals,chemical fertilizers,the pollution of ecosystem and unwholesome foods are growing rapidly.For the same reason,the purchaser's curiosity increases to know about the production process which can be accomplished by production traceability system.The traceability system can store and superintend the specific attribute information about products regarding the productive centre,producer and production finish data.The products undergo various circulation processes and they are being managed by individually constructed traceability system.Thus,it is difficult for the producer and the consumer to guarantee the safety from transpirable issues about the falsification of production traceability because the traceability information can be re-produced by forging through various ways.So in this paper,we proposed a system for integrated management of agro-fishery products based on quick response code(QR-code)for forgery prevention which may help to solve these issues.The proposed system makes QR-code using production information provided by producer.And then it is provided to the distributor and the consumer through integrated service model using the QR-code.Therefore,this system make sure to provide the same production traceability about the products to the distributor and the consumer and always keeps both updated with the same information.展开更多
In the field of mobile robotics,human tracking has emerged as an important objective for facilitating human-robot interaction.In this paper,we propose a particle-filter-based walking prediction model that will address...In the field of mobile robotics,human tracking has emerged as an important objective for facilitating human-robot interaction.In this paper,we propose a particle-filter-based walking prediction model that will address an occlusion situation.Since the target being tracked is a human leg,a motion model for a leg is required.The validity of the proposed model is verified experimentally.展开更多
X-Code is one of the most important redundant array of independent disk (RAID)-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and...X-Code is one of the most important redundant array of independent disk (RAID)-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and such code length restriction of X-Code limits its usage in the real storage systems. Moreover, as a vertical RAID-6 code, X-Code can not be extended easily to an arbitrary code length like horizontal RAID-6 codes. In this paper, a novel and efficient code shortening algorithm for X-Code is proposed to extend X-Code to an arbitrary length. It can be further proved that the code shortening algorithm maintains the maximum-distance-separable (MDS) property of X-Code, and namely, the shortened X-Code is still MDS code with the optimal space efficiency. In the context of the shortening algorithm for X-Code, an in-depth performance analysis on X-Code at consecutive code lengths is conducted, and the impacts of the code shortening algorithm on the performance of X-Code in various performance metrics are revealed.展开更多
A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check (LDPC) codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional densit...A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check (LDPC) codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional density evolution and search the optimal degree profiles with fast-convergence differential evolution,so that it has a lower complexity and a faster convergence speed.Simulation resuits show that the irregular LDPC codes optimized by the presented algorithm can also perform better than Turbo codes at moderate block length even with less computation cost.展开更多
Dental enamel-like hydroxyapatite whiskers with high crystallinity and homogeneous morphology were synthesized by a hydrothermal homogeneous precipitation method.The composition,crystallinity and morphology of prepare...Dental enamel-like hydroxyapatite whiskers with high crystallinity and homogeneous morphology were synthesized by a hydrothermal homogeneous precipitation method.The composition,crystallinity and morphology of prepared hydroxyapatite whiskers were characterized by Ⅹ-ray diffraction and scanning electron microscopy.The effects of urea and sorbitol on their morphology and composition were investigated.Homogeneous and well crystallized enamel-like hydroxyapatite whiskers with 1.17±0.08 μm in length and 84± 14 nm in width were obtained at 0.80 mol · L-1 urea and 0.26 mol · L-1 sorbitol.These hydroxyapatite whiskers may be close to nature hydroxyapatite dental enamel in terms of the morphology and composition,suggesting that they could have potential application as dental restorative materials in the field of stomatology.展开更多
TiO2/SiO2/Fe3O4 nanoparticles have bigger specific area which can greatly increase the efficiency of photo-catalysis.The TiO2/SiO2/Fe3O4 particles in nano scale were prepared with reduction method at high temperature ...TiO2/SiO2/Fe3O4 nanoparticles have bigger specific area which can greatly increase the efficiency of photo-catalysis.The TiO2/SiO2/Fe3O4 particles in nano scale were prepared with reduction method at high temperature in this paper,and their morphology,particle size and magnetic property were characterized by transmission electron microscope(TEM),Xray diffraction(XRD) and magnetometer.The results show that the grain sizes of Fe3O4,SiO2-Fe3O4 and TiO2-SiO2-Fe3O4 particles were 50nm,70nm and 120nm,respectively.With the modification of SiO2,Fe3O4 magnetic cores are protected from oxidation.Moreover,by the addition of TiO2 function layer,TiO2-SiO2-Fe3O4 functional nanoparticles,with the saturation magnetization density of 34.1emu/g,is magnetically recoverable.The processes of this method are so simple that the nanoparticles can be produced in large quantity.展开更多
To improve drying uniformity and anthocyanin content of the raspberry puree dried in a continuous microwave dryer,the effects of process parameters(microwave intensity,air velocity,and drying time)on evaluation indexe...To improve drying uniformity and anthocyanin content of the raspberry puree dried in a continuous microwave dryer,the effects of process parameters(microwave intensity,air velocity,and drying time)on evaluation indexes(average temperature,average moisture content,average retention rate of the total anthocyanin content,temperature contrast value,and moisture dispersion value)were investigated via the response surface method(RSM)and the artificial neural network(ANN)with genetic algorithm(GA).The results showed that the microwave intensity and drying time dominated the changes of evaluation indexes.Overall,the ANN model was superior to the RSM model with better estimation ability,and higher drying uniformity and anthocyanin retention rate were achieved for the ANN-GA model compared with RSM.The optimal parameters were microwave intensity of 5.53 W•g^(-1),air velocity of 1.22 m·s^(-1),and drying time of 5.85 min.This study might provide guidance for process optimization of microwave drying berry fruits.展开更多
Pb0.97La0.02Zr0.95Ti0.05O3(PLZT)antiferroelectric thick films derived from different precursor solution concentrations are prepared on platinized silicon substrates by sol-gel processing.The films present polycrystall...Pb0.97La0.02Zr0.95Ti0.05O3(PLZT)antiferroelectric thick films derived from different precursor solution concentrations are prepared on platinized silicon substrates by sol-gel processing.The films present polycrystalline perovskite structure with a(100)preferred orientation by X-ray diffraction(XRD)analysis.The antiferroelectricity of the films is confirmed by the double hysteresis behaviors of polarization and double-bufferfly response of dielectric constant under the applied electrical field.Antiferroelectric properties and dielectric constant are improved while the polarization characteristic values are reduced with the increase of precursor solution concentration.The films at higher precursor solution concentration exhibit excellent dielectric properties.展开更多
GB 6675-2003 National Safety Technical Code for Toys, in which the safetylevel of toys has achieved the advanced international level, is the general standard of all kinds oftoys. It will facilitate the improvement of ...GB 6675-2003 National Safety Technical Code for Toys, in which the safetylevel of toys has achieved the advanced international level, is the general standard of all kinds oftoys. It will facilitate the improvement of the whole quality of toys and the development of toysindustry. It also improves the competitive ability of our toys in international market. It is a newlandmark of the development of toys industry in China.展开更多
The pathways leading to synthesis and post-synthetic modification of DNA employed methionine as donor of atoms: the carbon that came from its –CH3 served for DNA replication and repair either in bacteria or humans;it...The pathways leading to synthesis and post-synthetic modification of DNA employed methionine as donor of atoms: the carbon that came from its –CH3 served for DNA replication and repair either in bacteria or humans;its entire –CH3 served instead for building N6-methyladenine and 5-methylcytosine on bacterial DNA and 5-methylcytosine alone on human DNA. In humans, although a slight extra-S asymmetric methylation appeared de novo yielding on parental DNA 5’-m5CpC-3’/ 3’-GpG-5’, 5’-m5CpT-3’/3’-GpA-5’ and 5’-m5CpA-3’/3’-GpT-5’ monomethylated dinucleotide pairs, a heavy symmetric methylation involved in S semiconservatively newly made DNA to guarantee genetic maintenance of –CH3 in 5’-m5CpG-3’/3’-Gpm5C-5’ dimethylated dinucleotide pairs. In this framework, an inverse correlation was found between bulk genomic DNA methylation occurring in S and bulk polyA-containing pre-mRNA transcription taking place in G1 and G2. Thus, probes of 1 × 106 Daltons (constructed using sheared by sonication newly made methylated DNA filaments) revealed a modular organization in genes: after the hypermethylated promoter, they exhibited an alternation of unmethylated coding and methylated uncoding sequences. This encouraged the search for a language that genes regulated by methylation should have in common. An initial deciphering of restriction minimaps with hypomethylatable exons vs. hypermethylatable promoters and introns was improved when the bisulfite technique allowed a direct sequencing of m5C. In lymphocytes, where the transglutaminase gene is inactive, its promoter exhibited two fully methylated CpG-rich domains at 5’ and one fully unmethylated CpG-rich domain at 3’, including the site +1 and a 5’-UTR. At variance, in HUVEC cells, where the transglutaminase gene is active, in the first CpG-rich domain of promoter few doublets lost their –CH3. Such an inverse correlation suggested new hypotheses especially in connection with repair-modification: UV radiation would cause demethylation in given loci of a promoter by chance, whilst even a partial demethylation in this promoter would be able to resume a previously silent pre-mRNA transcription.展开更多
Aiming at technical difficulties in feature extraction for the inverse synthetic aperture radar (ISAR) target recognition, this paper imports the concept of visual perception and presents a novel method, which is ba...Aiming at technical difficulties in feature extraction for the inverse synthetic aperture radar (ISAR) target recognition, this paper imports the concept of visual perception and presents a novel method, which is based on the combination of non-negative sparse coding (NNSC) and linear discrimination optimization, to recognize targets in ISAR images. This method implements NNSC on the matrix constituted by the intensities of pixels in ISAR images for training, to obtain non-negative sparse bases which characterize sparse distribution of strong scattering centers. Then this paper chooses sparse bases via optimization criteria and calculates the corresponding non-negative sparse codes of both training and test images as the feature vectors, which are input into k neighbors classifier to realize recognition finally. The feasibility and robustness of the proposed method are proved by comparing with the template matching, principle component analysis (PCA) and non-negative matrix factorization (NMF) via simulations.展开更多
The KHNP (Korea Hydro & Nuclear Power Co.) has developed a multipurpose nuclear safety analysis code called SPACE (the safety and performance analysis code) for nuclear power plants. SPACE code is a best-estimate...The KHNP (Korea Hydro & Nuclear Power Co.) has developed a multipurpose nuclear safety analysis code called SPACE (the safety and performance analysis code) for nuclear power plants. SPACE code is a best-estimated two-phase three-field thermal-hydraulic analysis code used to analyze the safety and performance of pressurized water reactors. In this paper, LOFT (loss of fluid test) L9-3 experiment using the SPACE code was selected to confirm the capability of SPACE code and the results calculated by the SPACE code are compared with those measured through the experiment. The results were compared with the experimental data and those of the other code simulations. Throughout the simulation result, it was concluded that the SPACE code can effectively simulate LOFT L9-3 experiment.展开更多
针对国际疾病分类(ICD)自动编码方法的长文本处理、编码的层次结构以及长尾分布等导致的模型泛化能力弱的问题,提出一种充分利用医学预训练语言模型的基于提示学习和超球原型的小样本ICD自动编码方法(hypersphere prototypical with pro...针对国际疾病分类(ICD)自动编码方法的长文本处理、编码的层次结构以及长尾分布等导致的模型泛化能力弱的问题,提出一种充分利用医学预训练语言模型的基于提示学习和超球原型的小样本ICD自动编码方法(hypersphere prototypical with prompt learning,PromptHP)。首先,将编码描述与临床文本融合进提示学习模型中的提示模板,使得模型能够更加深入地理解临床文本;然后,充分利用预训练语言模型的先验知识进行初始预测;接着,在预训练语言模型输出表示的基础上引入超球原型进行类别建模和度量分类,并在医学数据集上微调网络,充分纳入数据知识,提高模型在小样本ICD编码分配任务上的性能;最后,对以上两部分预测结果集成加权获得最终编码预测结果。在公开医学数据集MIMIC-Ⅲ上的实验结果表明,该模型优于最先进的基线方法,PromptHP将小样本编码的macro-AUC、micro-AUC、macro-F_(1)和micro-F_(1)分别提高了1.77%、1.54%、14.22%、15.01%。实验结果验证了该模型在小样本编码分类任务中的有效性。展开更多
文摘动脉粥样硬化是心血管疾病重要的病理生理基础,延缓和防治动脉粥样硬化对于减少和降低心血管疾病的发病率及病死率具有重要意义。高密度脂蛋白(high density lipoprotein,HDL)通过参与介导胆固醇逆向转运(reverse cholesterol transport,RCT)在抗动脉粥样硬化的形成和进展中发挥了重要作用。Preβ-1高密度脂蛋白(prebeta-1 high density lipoprotein,Preβ-1HDL)作为HDL的一种亚类,是外周细胞移出胆固醇的最初接受体,直接参与了RCT的起始步骤,并在随后的胆固醇酯化及转运中起着重要作用。本文就Preβ-1HDL的结构、代谢及其与心血管疾病的关系作一简要综述。
基金Sponsored by the National Natural Science Foundation of China(Grant No.51008106)
文摘To obtain the pyrolysis characteristics and kinetics of preparation process of sludge-based activated carbon by ZnCl2 activation method (i.e.the pyrolysis process of the sludge with ZnCl2 activation),the characteristic of mass loss and gas products generated during pyrolysis of the sludge with ZnCl2 activation were analyzed by thermogravimetric analysis coupled with Fourier Transform Infrared Spectroscopy (TG-FTIR).The kinetic parameters were calculated by the Coats-Redfem method and the mechanism models were established.The role of ZnCl2 in the pyrolysis process of the sludge with ZnCl2 activation was also illustrated through the comparison of the pyrolysis characteristics and kinetics of the sludge with and without ZnCl2 activation.The results showed that the pyrolysis process of the sludge with ZnCl2 activation can be divided into four stages including the dehydration of sludge and initial depolymerization of a small portion of organics matters,the decomposition of large molecular organic matters into small molecular intermediates,the further degradation of intermediates and volatilization of ZnCl2,and the decomposition of inorganic minerals and undecomposed organic matters.CO2,CO,CH4,H2O,some aldehydes and carboxylic acids are the major pyrolysis gaseous products.The activation energies and pre-exponential factors are in the range of 28.84-206.42 kJ/mol and 9885.16-8.08× 1011 min-1,respectively.During the pyrolysis of sludge,ZnC12 not only can function as a dehydration agent and inhibit the formation of tar,but also can peptize the organic matters in the sludge,making them easier to be decomposed.
基金The MSIP(Ministry of Science,ICT&Future Planning),Korea,under the ITRC(Information Technology Research Center)support program(NIPA-2013-H0301-13-2006)supervised by the NIPA(National IT Industry Promotion Agency)
文摘Recently,both the importance and awareness relating to food safety relating to agrochemicals,chemical fertilizers,the pollution of ecosystem and unwholesome foods are growing rapidly.For the same reason,the purchaser's curiosity increases to know about the production process which can be accomplished by production traceability system.The traceability system can store and superintend the specific attribute information about products regarding the productive centre,producer and production finish data.The products undergo various circulation processes and they are being managed by individually constructed traceability system.Thus,it is difficult for the producer and the consumer to guarantee the safety from transpirable issues about the falsification of production traceability because the traceability information can be re-produced by forging through various ways.So in this paper,we proposed a system for integrated management of agro-fishery products based on quick response code(QR-code)for forgery prevention which may help to solve these issues.The proposed system makes QR-code using production information provided by producer.And then it is provided to the distributor and the consumer through integrated service model using the QR-code.Therefore,this system make sure to provide the same production traceability about the products to the distributor and the consumer and always keeps both updated with the same information.
基金The MKE(Ministry of Knowledge Economy),Korea,under the ITRC(Information Technology Research Center)support program(NIPA-2013-H0301-13-2006)supervised by the NIPA(National IT Industry Promotion Agency)The National Research Foundation of Korea(NRF)grant funded by the Korea government(MEST)(2013-029812)The MKE(Ministry of Knowledge Economy),Korea,under the Human Resources Development Program for Convergence Robot Specialists support program supervised by the NIPA(National IT Industry Promotion Agency)(NIPA-2013-H1502-13-1001)
文摘In the field of mobile robotics,human tracking has emerged as an important objective for facilitating human-robot interaction.In this paper,we propose a particle-filter-based walking prediction model that will address an occlusion situation.Since the target being tracked is a human leg,a motion model for a leg is required.The validity of the proposed model is verified experimentally.
基金supported by the National Basic Research Program of China (Grant Nos.2011CB302300, 2011CB302301)the National High-Technology Research and Development Program of China (Grant Nos.2009AA01A401,2009AA01A402)+1 种基金the National Natural Science Foundation of China (Grant Nos.60873028, 60933002, 61025008)the Changjiang Innovation Group of Education of China (Grant No.IRT0725)
文摘X-Code is one of the most important redundant array of independent disk (RAID)-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and such code length restriction of X-Code limits its usage in the real storage systems. Moreover, as a vertical RAID-6 code, X-Code can not be extended easily to an arbitrary code length like horizontal RAID-6 codes. In this paper, a novel and efficient code shortening algorithm for X-Code is proposed to extend X-Code to an arbitrary length. It can be further proved that the code shortening algorithm maintains the maximum-distance-separable (MDS) property of X-Code, and namely, the shortened X-Code is still MDS code with the optimal space efficiency. In the context of the shortening algorithm for X-Code, an in-depth performance analysis on X-Code at consecutive code lengths is conducted, and the impacts of the code shortening algorithm on the performance of X-Code in various performance metrics are revealed.
基金Leading Academic Discipline Project of Shanghai Municipal Education Commission,China(No.J51801)Shanghai Second Polytechnic University Foundation,China(No.QD209008)Leading Academic Discipline Project of Shanghai Second Polytechnic University,China(No.XXKZD1302)
文摘A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check (LDPC) codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional density evolution and search the optimal degree profiles with fast-convergence differential evolution,so that it has a lower complexity and a faster convergence speed.Simulation resuits show that the irregular LDPC codes optimized by the presented algorithm can also perform better than Turbo codes at moderate block length even with less computation cost.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.2010066)the Natural Science Foundation of Heilongjiang Province(Grant No.E201006)the Key Scientific and Technological Projects of Heilongjiang Province(Grant No.GC10A107)
文摘Dental enamel-like hydroxyapatite whiskers with high crystallinity and homogeneous morphology were synthesized by a hydrothermal homogeneous precipitation method.The composition,crystallinity and morphology of prepared hydroxyapatite whiskers were characterized by Ⅹ-ray diffraction and scanning electron microscopy.The effects of urea and sorbitol on their morphology and composition were investigated.Homogeneous and well crystallized enamel-like hydroxyapatite whiskers with 1.17±0.08 μm in length and 84± 14 nm in width were obtained at 0.80 mol · L-1 urea and 0.26 mol · L-1 sorbitol.These hydroxyapatite whiskers may be close to nature hydroxyapatite dental enamel in terms of the morphology and composition,suggesting that they could have potential application as dental restorative materials in the field of stomatology.
基金Ministry of Human and Social Security of Shanxi Province,Natural Science Foundation for Young Scientists of Shanxi province(No.2011011020-2)Shanxi Province Foundation for Returness(No.2008062)
文摘TiO2/SiO2/Fe3O4 nanoparticles have bigger specific area which can greatly increase the efficiency of photo-catalysis.The TiO2/SiO2/Fe3O4 particles in nano scale were prepared with reduction method at high temperature in this paper,and their morphology,particle size and magnetic property were characterized by transmission electron microscope(TEM),Xray diffraction(XRD) and magnetometer.The results show that the grain sizes of Fe3O4,SiO2-Fe3O4 and TiO2-SiO2-Fe3O4 particles were 50nm,70nm and 120nm,respectively.With the modification of SiO2,Fe3O4 magnetic cores are protected from oxidation.Moreover,by the addition of TiO2 function layer,TiO2-SiO2-Fe3O4 functional nanoparticles,with the saturation magnetization density of 34.1emu/g,is magnetically recoverable.The processes of this method are so simple that the nanoparticles can be produced in large quantity.
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘To improve drying uniformity and anthocyanin content of the raspberry puree dried in a continuous microwave dryer,the effects of process parameters(microwave intensity,air velocity,and drying time)on evaluation indexes(average temperature,average moisture content,average retention rate of the total anthocyanin content,temperature contrast value,and moisture dispersion value)were investigated via the response surface method(RSM)and the artificial neural network(ANN)with genetic algorithm(GA).The results showed that the microwave intensity and drying time dominated the changes of evaluation indexes.Overall,the ANN model was superior to the RSM model with better estimation ability,and higher drying uniformity and anthocyanin retention rate were achieved for the ANN-GA model compared with RSM.The optimal parameters were microwave intensity of 5.53 W•g^(-1),air velocity of 1.22 m·s^(-1),and drying time of 5.85 min.This study might provide guidance for process optimization of microwave drying berry fruits.
基金National Natural Science Foundation of China(No.60806039,No.51175483)China Postdoctoral Science Foundation Projects(No.20090461275,No.201003658)+1 种基金Shanxi Provincial Natural Science Foundation of China(No.20100210023-6)Shanxi Provincial Young Leaders on Science
文摘Pb0.97La0.02Zr0.95Ti0.05O3(PLZT)antiferroelectric thick films derived from different precursor solution concentrations are prepared on platinized silicon substrates by sol-gel processing.The films present polycrystalline perovskite structure with a(100)preferred orientation by X-ray diffraction(XRD)analysis.The antiferroelectricity of the films is confirmed by the double hysteresis behaviors of polarization and double-bufferfly response of dielectric constant under the applied electrical field.Antiferroelectric properties and dielectric constant are improved while the polarization characteristic values are reduced with the increase of precursor solution concentration.The films at higher precursor solution concentration exhibit excellent dielectric properties.
文摘GB 6675-2003 National Safety Technical Code for Toys, in which the safetylevel of toys has achieved the advanced international level, is the general standard of all kinds oftoys. It will facilitate the improvement of the whole quality of toys and the development of toysindustry. It also improves the competitive ability of our toys in international market. It is a newlandmark of the development of toys industry in China.
文摘The pathways leading to synthesis and post-synthetic modification of DNA employed methionine as donor of atoms: the carbon that came from its –CH3 served for DNA replication and repair either in bacteria or humans;its entire –CH3 served instead for building N6-methyladenine and 5-methylcytosine on bacterial DNA and 5-methylcytosine alone on human DNA. In humans, although a slight extra-S asymmetric methylation appeared de novo yielding on parental DNA 5’-m5CpC-3’/ 3’-GpG-5’, 5’-m5CpT-3’/3’-GpA-5’ and 5’-m5CpA-3’/3’-GpT-5’ monomethylated dinucleotide pairs, a heavy symmetric methylation involved in S semiconservatively newly made DNA to guarantee genetic maintenance of –CH3 in 5’-m5CpG-3’/3’-Gpm5C-5’ dimethylated dinucleotide pairs. In this framework, an inverse correlation was found between bulk genomic DNA methylation occurring in S and bulk polyA-containing pre-mRNA transcription taking place in G1 and G2. Thus, probes of 1 × 106 Daltons (constructed using sheared by sonication newly made methylated DNA filaments) revealed a modular organization in genes: after the hypermethylated promoter, they exhibited an alternation of unmethylated coding and methylated uncoding sequences. This encouraged the search for a language that genes regulated by methylation should have in common. An initial deciphering of restriction minimaps with hypomethylatable exons vs. hypermethylatable promoters and introns was improved when the bisulfite technique allowed a direct sequencing of m5C. In lymphocytes, where the transglutaminase gene is inactive, its promoter exhibited two fully methylated CpG-rich domains at 5’ and one fully unmethylated CpG-rich domain at 3’, including the site +1 and a 5’-UTR. At variance, in HUVEC cells, where the transglutaminase gene is active, in the first CpG-rich domain of promoter few doublets lost their –CH3. Such an inverse correlation suggested new hypotheses especially in connection with repair-modification: UV radiation would cause demethylation in given loci of a promoter by chance, whilst even a partial demethylation in this promoter would be able to resume a previously silent pre-mRNA transcription.
基金supported by the Prominent Youth Fund of the National Natural Science Foundation of China (61025006)
文摘Aiming at technical difficulties in feature extraction for the inverse synthetic aperture radar (ISAR) target recognition, this paper imports the concept of visual perception and presents a novel method, which is based on the combination of non-negative sparse coding (NNSC) and linear discrimination optimization, to recognize targets in ISAR images. This method implements NNSC on the matrix constituted by the intensities of pixels in ISAR images for training, to obtain non-negative sparse bases which characterize sparse distribution of strong scattering centers. Then this paper chooses sparse bases via optimization criteria and calculates the corresponding non-negative sparse codes of both training and test images as the feature vectors, which are input into k neighbors classifier to realize recognition finally. The feasibility and robustness of the proposed method are proved by comparing with the template matching, principle component analysis (PCA) and non-negative matrix factorization (NMF) via simulations.
文摘The KHNP (Korea Hydro & Nuclear Power Co.) has developed a multipurpose nuclear safety analysis code called SPACE (the safety and performance analysis code) for nuclear power plants. SPACE code is a best-estimated two-phase three-field thermal-hydraulic analysis code used to analyze the safety and performance of pressurized water reactors. In this paper, LOFT (loss of fluid test) L9-3 experiment using the SPACE code was selected to confirm the capability of SPACE code and the results calculated by the SPACE code are compared with those measured through the experiment. The results were compared with the experimental data and those of the other code simulations. Throughout the simulation result, it was concluded that the SPACE code can effectively simulate LOFT L9-3 experiment.
文摘针对国际疾病分类(ICD)自动编码方法的长文本处理、编码的层次结构以及长尾分布等导致的模型泛化能力弱的问题,提出一种充分利用医学预训练语言模型的基于提示学习和超球原型的小样本ICD自动编码方法(hypersphere prototypical with prompt learning,PromptHP)。首先,将编码描述与临床文本融合进提示学习模型中的提示模板,使得模型能够更加深入地理解临床文本;然后,充分利用预训练语言模型的先验知识进行初始预测;接着,在预训练语言模型输出表示的基础上引入超球原型进行类别建模和度量分类,并在医学数据集上微调网络,充分纳入数据知识,提高模型在小样本ICD编码分配任务上的性能;最后,对以上两部分预测结果集成加权获得最终编码预测结果。在公开医学数据集MIMIC-Ⅲ上的实验结果表明,该模型优于最先进的基线方法,PromptHP将小样本编码的macro-AUC、micro-AUC、macro-F_(1)和micro-F_(1)分别提高了1.77%、1.54%、14.22%、15.01%。实验结果验证了该模型在小样本编码分类任务中的有效性。