[Objectives]To explore the growth characteristics,nitrogen metabolism and curing characteristics of the new variety NC71 in strongly aromatic tobacco leaves production area.[Methods]With Yunyan 87 as the control and N...[Objectives]To explore the growth characteristics,nitrogen metabolism and curing characteristics of the new variety NC71 in strongly aromatic tobacco leaves production area.[Methods]With Yunyan 87 as the control and NC71 as the experimental material,the experiment was carried out in Nanyang tobacco area for two consecutive years to study the growth characteristics of tobacco plants,the activity of key enzymes in nitrogen metabolism,the content of secondary metabolites,and the differences of tobacco-related water content,PPO enzyme activity and total phenol content.[Results]NC71 plants had lower height,better appearance quality and lower nicotine,total sugar and chlorine content.NC71 high nitrogen treatment and Yunyan 87 medium nitrogen treatment had similar key enzyme activity of nitrogen metabolism,content of secondary metabolites;Yunyan 87 and NC71 were easy to cure and resistant to curing.[Conclusions]This study provides a reference for measuring the appropriate nitrogen application rate and optimizing the curing process from the activities of the key enzymes NR and GS in nitrogen metabolism at the mature stage of the variety.展开更多
Attacks such as APT usually hide communication data in massive legitimate network traffic, and mining structurally complex and latent relationships among flow-based network traffic to detect attacks has become the foc...Attacks such as APT usually hide communication data in massive legitimate network traffic, and mining structurally complex and latent relationships among flow-based network traffic to detect attacks has become the focus of many initiatives. Effectively analyzing massive network security data with high dimensions for suspicious flow diagnosis is a huge challenge. In addition, the uneven distribution of network traffic does not fully reflect the differences of class sample features, resulting in the low accuracy of attack detection. To solve these problems, a novel approach called the fuzzy entropy weighted natural nearest neighbor(FEW-NNN) method is proposed to enhance the accuracy and efficiency of flowbased network traffic attack detection. First, the FEW-NNN method uses the Fisher score and deep graph feature learning algorithm to remove unimportant features and reduce the data dimension. Then, according to the proposed natural nearest neighbor searching algorithm(NNN_Searching), the density of data points, each class center and the smallest enclosing sphere radius are determined correspondingly. Finally, a fuzzy entropy weighted KNN classification method based on affinity is proposed, which mainly includes the following three steps: 1、 the feature weights of samples are calculated based on fuzzy entropy values, 2、 the fuzzy memberships of samples are determined based on affinity among samples, and 3、 K-neighbors are selected according to the class-conditional weighted Euclidean distance, the fuzzy membership value of the testing sample is calculated based on the membership of k-neighbors, and then all testing samples are classified according to the fuzzy membership value of the samples belonging to each class;that is, the attack type is determined. The method has been applied to the problem of attack detection and validated based on the famous KDD99 and CICIDS-2017 datasets. From the experimental results shown in this paper, it is observed that the FEW-NNN method improves the accuracy and efficiency of flow-based network traffic attack detection.展开更多
Long-term survival of 116 leukemia/MDS patients received allo-SCT conditioned by a regimen with ATG-F or without ATG-F was analysed, together with the impact of ATG-F on the long-term survival, GVHD and disease relaps...Long-term survival of 116 leukemia/MDS patients received allo-SCT conditioned by a regimen with ATG-F or without ATG-F was analysed, together with the impact of ATG-F on the long-term survival, GVHD and disease relapse. Seventy patients received an ATG-F containing conditioning regimen FBCA, and 46 patients received a non-ATG-F FBC regimen. The FBCA regimen was associated with a 5-year survival of 65.4% in the complete HLA-matched group and 39.3% in the HLA-mismatched group. The difference between the two groups was significant (P = 0.012). For the FBC conditioning regimen, the 5-year overall survival of HLA-matched patients and the HLA-mismatched patients was 34.2% and 24.2% respectively (P = 0.216). The incidence of cGVHD was 32.9% and 83.6% in the FBCA and FBC condition regimen group respectively. Only 2.9% of the cases showed extensive cGVHD in the FBCA group while it was 69.4% in the FBC group (P = 0.00). Multivariate analysis indicated that relapse was related to the disease status and HLA typing, but unrelated to the conditioning regimens whether or not ATG-F was used (HR 0.54, P = 0.109). We conclude that the addition of ATG-F to conditioning regimen favours the longterm survival of allo-SCT.展开更多
Based on observation data of dust storm for the years 1960-2006 from weather stations across Jiangsu, this essay provides a statistical analysis on the characteristics and trends, including the timeframes and regions ...Based on observation data of dust storm for the years 1960-2006 from weather stations across Jiangsu, this essay provides a statistical analysis on the characteristics and trends, including the timeframes and regions of the incidences of four weather phenomena: sandstorm, blowing sand, floating dust and haze in an effort to better understand the trend of dust storm changes in Jiangsu Province, China. The result indicates that, on average, the incidences of sandstorm, indi- cated with the total number of days in a year in Jiangsu is low and on a declining trend. With the improvement of the environment, no sandstorm has been observed for many years. In general, those of blowing sand and floating dust have been reducing, and showing a significant improvement during the recent years. What should be noted, however, is the accelerated increase in haze incidences, particularly, in Southern Jiangsu.展开更多
A novel compact multiple-input-multiple-output (MIMO) antenna for portable ul-trawideband (UWB) applications is presented. This antenna consists of two modified planar-monopole antenna elements with coplanar waveguide...A novel compact multiple-input-multiple-output (MIMO) antenna for portable ul-trawideband (UWB) applications is presented. This antenna consists of two modified planar-monopole antenna elements with coplanar waveguides-fed printed on one side of the substrate. To enhance isolation and increase impedance bandwidth, a tree like stubs is placed on the ground plane at the 45°axis. The measured results show that the MIMO antenna operates from 2.3 GHz to 13 GHz, covering WLAN, WiMAX, and UWB. The low mutual coupling and low envelope correlation coefficient of less than 0.2 across the whole frequency band proved that this antenna was suitable for MIMO/diversity systems. Also, good performance of radiation patterns and the antenna’s compact size make it a good candidate for portable devices.展开更多
A model is provided to predict the prawn’s harvest in aquaculture through analytical research in agrometeorology, mathematical statistics, synoptic meteorology and et al. It is found out that the Benefit Analysis of ...A model is provided to predict the prawn’s harvest in aquaculture through analytical research in agrometeorology, mathematical statistics, synoptic meteorology and et al. It is found out that the Benefit Analysis of the Best Harvest is one of the most ideal ways. The models for the breeding objects, climate prediction and analysis of market quotation should be set up and perfected continuously. Only when the dynamic numerical simulation of the growth is accurate and the short-term weather forecast and the market quotation are reliable, will the suitable harvest time be predicted precisely. We used to write this paper with the foundation on ideologies.展开更多
Opioid abuse can suppress the lymphatic system function,and produce severe immunosuppression that poses a significant risk of opportunistic infections such as methicillinresistant Staphylococcus aureus(MRSA)pneumonia....Opioid abuse can suppress the lymphatic system function,and produce severe immunosuppression that poses a significant risk of opportunistic infections such as methicillinresistant Staphylococcus aureus(MRSA)pneumonia.^(1,2)Gypenosides(Gps)are the most important immunomodulator components in the Chinese herbal medicine Gynostemma pentaphyllum.展开更多
Alumina ceramics with different sintering temperatures in argon atmosphere were obtained using stereolithography-based 3D printing.The effects of sintering temperature on microstructure and physical and mechanical pro...Alumina ceramics with different sintering temperatures in argon atmosphere were obtained using stereolithography-based 3D printing.The effects of sintering temperature on microstructure and physical and mechanical properties were investigated.The results show that the average particle size,shrinkage,bulk density,crystallite size,flexural strength,Vickers hardness,and nanoindentation hardness increased with the increase in sintering temperature,whereas the open porosity decreased with increasing sintering temperature.No change was observed in phase composition,chemical bond,atomic ratio,and surface roughness.For the sintered samples,the shrinkage in Z direction is much greater than that in X or Y direction.The optimum sintering temperature in argon atmosphere is 1350℃with a shrinkage of 3.0%,3.2%,and 5.5%in X,Y,and Z directions,respectively,flexural strength of 26.7 MPa,Vickers hardness of 198.5 HV,nanoindentation hardness of 33.1 GPa,bulk density of 2.5 g/cm^3,and open porosity of 33.8%.The optimum sintering temperature was 70℃higher than that sintering in air atmosphere when achieved the similar properties.展开更多
In this work,aluminum oxide(Al2O3) ceramic samples were fabricated by 3D stereolithography printing.Printing process was followed by debinding and sintering.In addition,the effect of sintering temperature on micro str...In this work,aluminum oxide(Al2O3) ceramic samples were fabricated by 3D stereolithography printing.Printing process was followed by debinding and sintering.In addition,the effect of sintering temperature on micro structure and properties was investigated.Flexure strength was observed to increase with increasing sintering temperature due to fewer pores,fewer defects and stronger grain boundary bonding of samples at higher sintering temperatures.Maximum flexure strength of 138.5 MPa was obtained when sintering temperature was 150℃.Furthermore,the shrinkage along length direction decreased with the decreasing sintering temperature until reaching minimum value of 1.02% after sintering at 1200℃.After sintering at 1280℃,flexure strength was 24.0 MPa and the shrinkage along length direction was 2.1%,which meets demands of ceramic core.展开更多
Constrained clustering,such as k-means with instance-level Must-Link(ML)and Cannot-Link(CL)auxiliary information as the constraints,has been extensively studied recently,due to its broad applications in data science a...Constrained clustering,such as k-means with instance-level Must-Link(ML)and Cannot-Link(CL)auxiliary information as the constraints,has been extensively studied recently,due to its broad applications in data science and AI.Despite some heuristic approaches,there has not been any algorithm providing a non-trivial approximation ratio to the constrained k-means problem.To address this issue,we propose an algorithm with a provable approximation ratio of O(logk)when only ML constraints are considered.We also empirically evaluate the performance of our algorithm on real-world datasets having artificial ML and disjoint CL constraints.The experimental results show that our algorithm outperforms the existing greedy-based heuristic methods in clustering accuracy.展开更多
The challenges of energy shortage and environmen-tal protection motivate people to take various measures to use energy wisely,and integrated energy systems are such a measure to tackle this challenge.In this paper,an ...The challenges of energy shortage and environmen-tal protection motivate people to take various measures to use energy wisely,and integrated energy systems are such a measure to tackle this challenge.In this paper,an optimal expansion planning model for an integrated energy system consisting of power grid,gas network and multiple energy hubs is proposed,where the planning objective is to minimize operational fuel cost and capital investment cost covering carbon capture equipment and energy hubs among others.To demonstrate the advantage of the proposed planning model,six case studies are investigated,and 13.47%annual cost savings can be achieved compared with the baseline planning scenario,which does not consider bidirectional energy exchange and integrated demand response program.Index Terms-Bidirectional energy exchange,energy hubs,integrated energy system,integrated demand response.展开更多
With recent advances in power electronic packaging technologies,liquid-cooled ceramic heat sinks have been considered as a promising solution for further improving the performance of power electronic devices.In this s...With recent advances in power electronic packaging technologies,liquid-cooled ceramic heat sinks have been considered as a promising solution for further improving the performance of power electronic devices.In this study,several aluminum oxide heat sinks were fabricated and tested using the digital light processing-based ad-ditive manufacturing method,to verify their practical performance.The results showed that the complex cooling structures inside the heat sinks can be completely formed and exhibited high surface quality.The experimental thermal and hydraulic performances of the heat sinks were consistent with the numerically modeled predictions.Furthermore,by exploiting the advantages of additive manufacturing,a direct manifold microchannel(MMC)configuration was designed to reduce the vertical flow of the traditional MMC configuration and achieve an im-proved cooling efficiency.At a constant volumetric flow rate of 1 L/min,the direct MMC configuration achieved a 19.8%reduction in pressure drop and an 11.8%reduction in thermal resistance,as well as a more uniform temperature distribution.展开更多
Network texts have become important carriers of cybersecurity information on the Internet.These texts include the latest security events such as vulnerability exploitations,attack discoveries,advanced persistent threa...Network texts have become important carriers of cybersecurity information on the Internet.These texts include the latest security events such as vulnerability exploitations,attack discoveries,advanced persistent threats,and so on.Extracting cybersecurity entities from these unstructured texts is a critical and fundamental task in many cybersecurity applications.However,most Named Entity Recognition(NER)models are suitable only for general fields,and there has been little research focusing on cybersecurity entity extraction in the security domain.To this end,in this paper,we propose a novel cybersecurity entity identification model based on Bidirectional Long Short-Term Memory with Conditional Random Fields(Bi-LSTM with CRF)to extract security-related concepts and entities from unstructured text.This model,which we have named XBi LSTM-CRF,consists of a word-embedding layer,a bidirectional LSTM layer,and a CRF layer,and concatenates X input with bidirectional LSTM output.Via extensive experiments on an open-source dataset containing an office security bulletin,security blogs,and the Common Vulnerabilities and Exposures list,we demonstrate that XBi LSTM-CRF achieves better cybersecurity entity extraction than state-of-the-art models.展开更多
An interesting inverter topology is proposed in this paper.It is similar to the typical three-phase full bridge inverter from the topology point of view,but smartly designed for the ground current reduction in single-...An interesting inverter topology is proposed in this paper.It is similar to the typical three-phase full bridge inverter from the topology point of view,but smartly designed for the ground current reduction in single-phase photovoltaic(PV)inverter applications.Theoretical analysis is conducted to clarify the operation mechanism of the proposed topology.Performance evaluation is carried out to verify the effectiveness of the proposed topology for the ground current suppression.展开更多
High porosity and high strength are usually mutually exclusive in the preparation of ceramic materials.However,high porosity and flexural strength are required for the preparation of complex ceramic cores for hollow t...High porosity and high strength are usually mutually exclusive in the preparation of ceramic materials.However,high porosity and flexural strength are required for the preparation of complex ceramic cores for hollow turbine blades.In this study,Al_(2)O_(3)cores with high porosity and high flexural strength were successfully prepared using digital light processing(DLP)3 D printing technology.The influence of sintering temperature on the microstructure,pore evolution,and flexural strength of the cores were investigated.With an increase in the sintering temperature,the porosity of the ceramic cores first increased and then decreased,reaching a maximum value of 35%at 1400℃.The flexural strength increased with the increase in sintering temperature,but at 1400℃the incremental enhancement of flexural strength was greatest.Combined with the core service requirements and core performance,this study selected 1400℃(open porosity of 35.1%and flexural strength of 20.3 MPa)as the optimal sintering temperature for the DLP-3 D printed Al_(2)O_(3)core.展开更多
Cytochrome c activates apoptosis specific protease XCPP32 when being added to Xenopus laevis egg extracts, and induces apoptosis in this cell-free system. During apoptosis, cyto-skeleton proteins in egg extracts are d...Cytochrome c activates apoptosis specific protease XCPP32 when being added to Xenopus laevis egg extracts, and induces apoptosis in this cell-free system. During apoptosis, cyto-skeleton proteins in egg extracts are degraded. Western blot assay indicates that 42-ku acidic keratin in egg extracts has been degraded by XCPP32. The degradation of 42-ku keratin may be crucial in apoptosis.展开更多
When added with cytochrome c, Xenopus laevis egg extract XS-150 can induce exogenous nuclei undergoing apoptosis. Apoptosis specific DNase XAD was activated during this process, and cut chromatin between nucleosome, l...When added with cytochrome c, Xenopus laevis egg extract XS-150 can induce exogenous nuclei undergoing apoptosis. Apoptosis specific DNase XAD was activated during this process, and cut chromatin between nucleosome, leading to DNA Ladder in electrophoresis. Our results showed that an inhibitor of XAD, IXAD, exists abundantly in normal egg extract, its molecular weight is about 40 ku. Normally, IXAD exists either in the form of dimmer or in complex with XAD. It was degraded during apoptosis, releasing active XAD. The results of Western assay and cross-inhibition showed that IXAD was likely homologous to DFF45 in structure and function. At the same time, these results also indicated that the pathway in apoptosis was conserved in evolution.展开更多
An NIH3T3 cell line which overexpresses temperature-sensitive p53Val135 was constructed by introduction of p53Val135 gene. It exhibited rapidly characteristic morphological and biochemical alterations related to repli...An NIH3T3 cell line which overexpresses temperature-sensitive p53Val135 was constructed by introduction of p53Val135 gene. It exhibited rapidly characteristic morphological and biochemical alterations related to repli-cative senescence when being cultured in 32℃. We suggested that the overexpression of p53 activated probably the onset of senescence in NIH3T3 cells, which induced a rapid cellular senescence.展开更多
基金Supported by Key Project of Nanping Tobacco Company of Fujian Province(NYK2021-09-03)Key Project of Tongren Tobacco Company of Guizhou Province(202101).
文摘[Objectives]To explore the growth characteristics,nitrogen metabolism and curing characteristics of the new variety NC71 in strongly aromatic tobacco leaves production area.[Methods]With Yunyan 87 as the control and NC71 as the experimental material,the experiment was carried out in Nanyang tobacco area for two consecutive years to study the growth characteristics of tobacco plants,the activity of key enzymes in nitrogen metabolism,the content of secondary metabolites,and the differences of tobacco-related water content,PPO enzyme activity and total phenol content.[Results]NC71 plants had lower height,better appearance quality and lower nicotine,total sugar and chlorine content.NC71 high nitrogen treatment and Yunyan 87 medium nitrogen treatment had similar key enzyme activity of nitrogen metabolism,content of secondary metabolites;Yunyan 87 and NC71 were easy to cure and resistant to curing.[Conclusions]This study provides a reference for measuring the appropriate nitrogen application rate and optimizing the curing process from the activities of the key enzymes NR and GS in nitrogen metabolism at the mature stage of the variety.
基金the Natural Science Foundation of China (No. 61802404, 61602470)the Strategic Priority Research Program (C) of the Chinese Academy of Sciences (No. XDC02040100)+3 种基金the Fundamental Research Funds for the Central Universities of the China University of Labor Relations (No. 20ZYJS017, 20XYJS003)the Key Research Program of the Beijing Municipal Science & Technology Commission (No. D181100000618003)partially the Key Laboratory of Network Assessment Technology,the Chinese Academy of Sciencesthe Beijing Key Laboratory of Network Security and Protection Technology
文摘Attacks such as APT usually hide communication data in massive legitimate network traffic, and mining structurally complex and latent relationships among flow-based network traffic to detect attacks has become the focus of many initiatives. Effectively analyzing massive network security data with high dimensions for suspicious flow diagnosis is a huge challenge. In addition, the uneven distribution of network traffic does not fully reflect the differences of class sample features, resulting in the low accuracy of attack detection. To solve these problems, a novel approach called the fuzzy entropy weighted natural nearest neighbor(FEW-NNN) method is proposed to enhance the accuracy and efficiency of flowbased network traffic attack detection. First, the FEW-NNN method uses the Fisher score and deep graph feature learning algorithm to remove unimportant features and reduce the data dimension. Then, according to the proposed natural nearest neighbor searching algorithm(NNN_Searching), the density of data points, each class center and the smallest enclosing sphere radius are determined correspondingly. Finally, a fuzzy entropy weighted KNN classification method based on affinity is proposed, which mainly includes the following three steps: 1、 the feature weights of samples are calculated based on fuzzy entropy values, 2、 the fuzzy memberships of samples are determined based on affinity among samples, and 3、 K-neighbors are selected according to the class-conditional weighted Euclidean distance, the fuzzy membership value of the testing sample is calculated based on the membership of k-neighbors, and then all testing samples are classified according to the fuzzy membership value of the samples belonging to each class;that is, the attack type is determined. The method has been applied to the problem of attack detection and validated based on the famous KDD99 and CICIDS-2017 datasets. From the experimental results shown in this paper, it is observed that the FEW-NNN method improves the accuracy and efficiency of flow-based network traffic attack detection.
基金Supplementary information is linked to the online version of the paper on the Cell Research website.Acknowledgments We thank Prof Jian Wang (Shanghai University, Shanghai) for his valuable revision and discussion. This work was supported by grants from the National Natural Science Foundation of China (30700411), Shenzhen Bureau of Science Technology and Information (SZKJ-2006018, SZKJ-2007012), Shenzhen Nanshan Bureau of Science Technology and Information (2008036) and Shenzhen Key Laboratory Advancement Scheme.
文摘Long-term survival of 116 leukemia/MDS patients received allo-SCT conditioned by a regimen with ATG-F or without ATG-F was analysed, together with the impact of ATG-F on the long-term survival, GVHD and disease relapse. Seventy patients received an ATG-F containing conditioning regimen FBCA, and 46 patients received a non-ATG-F FBC regimen. The FBCA regimen was associated with a 5-year survival of 65.4% in the complete HLA-matched group and 39.3% in the HLA-mismatched group. The difference between the two groups was significant (P = 0.012). For the FBC conditioning regimen, the 5-year overall survival of HLA-matched patients and the HLA-mismatched patients was 34.2% and 24.2% respectively (P = 0.216). The incidence of cGVHD was 32.9% and 83.6% in the FBCA and FBC condition regimen group respectively. Only 2.9% of the cases showed extensive cGVHD in the FBCA group while it was 69.4% in the FBC group (P = 0.00). Multivariate analysis indicated that relapse was related to the disease status and HLA typing, but unrelated to the conditioning regimens whether or not ATG-F was used (HR 0.54, P = 0.109). We conclude that the addition of ATG-F to conditioning regimen favours the longterm survival of allo-SCT.
文摘Based on observation data of dust storm for the years 1960-2006 from weather stations across Jiangsu, this essay provides a statistical analysis on the characteristics and trends, including the timeframes and regions of the incidences of four weather phenomena: sandstorm, blowing sand, floating dust and haze in an effort to better understand the trend of dust storm changes in Jiangsu Province, China. The result indicates that, on average, the incidences of sandstorm, indi- cated with the total number of days in a year in Jiangsu is low and on a declining trend. With the improvement of the environment, no sandstorm has been observed for many years. In general, those of blowing sand and floating dust have been reducing, and showing a significant improvement during the recent years. What should be noted, however, is the accelerated increase in haze incidences, particularly, in Southern Jiangsu.
文摘A novel compact multiple-input-multiple-output (MIMO) antenna for portable ul-trawideband (UWB) applications is presented. This antenna consists of two modified planar-monopole antenna elements with coplanar waveguides-fed printed on one side of the substrate. To enhance isolation and increase impedance bandwidth, a tree like stubs is placed on the ground plane at the 45°axis. The measured results show that the MIMO antenna operates from 2.3 GHz to 13 GHz, covering WLAN, WiMAX, and UWB. The low mutual coupling and low envelope correlation coefficient of less than 0.2 across the whole frequency band proved that this antenna was suitable for MIMO/diversity systems. Also, good performance of radiation patterns and the antenna’s compact size make it a good candidate for portable devices.
文摘A model is provided to predict the prawn’s harvest in aquaculture through analytical research in agrometeorology, mathematical statistics, synoptic meteorology and et al. It is found out that the Benefit Analysis of the Best Harvest is one of the most ideal ways. The models for the breeding objects, climate prediction and analysis of market quotation should be set up and perfected continuously. Only when the dynamic numerical simulation of the growth is accurate and the short-term weather forecast and the market quotation are reliable, will the suitable harvest time be predicted precisely. We used to write this paper with the foundation on ideologies.
基金supported by the National Natural Science Foundation of China(No.82174498,82174141)the National Administration of Traditional Chinese Medicine Youth Qihuang Scholars Support Project,the Open Project of Chinese Materia Medica First-Class Discipline of Nanjing University of Chinese Medicine(China)(No.2020YLXK013)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(No.KYCX21_1796).
文摘Opioid abuse can suppress the lymphatic system function,and produce severe immunosuppression that poses a significant risk of opportunistic infections such as methicillinresistant Staphylococcus aureus(MRSA)pneumonia.^(1,2)Gypenosides(Gps)are the most important immunomodulator components in the Chinese herbal medicine Gynostemma pentaphyllum.
基金This work was supported by National Key R&D Program of China(No.2018YFB1106600)the Chinese National Foundation for Natural Sciences under Contracts(No.51672217).
文摘Alumina ceramics with different sintering temperatures in argon atmosphere were obtained using stereolithography-based 3D printing.The effects of sintering temperature on microstructure and physical and mechanical properties were investigated.The results show that the average particle size,shrinkage,bulk density,crystallite size,flexural strength,Vickers hardness,and nanoindentation hardness increased with the increase in sintering temperature,whereas the open porosity decreased with increasing sintering temperature.No change was observed in phase composition,chemical bond,atomic ratio,and surface roughness.For the sintered samples,the shrinkage in Z direction is much greater than that in X or Y direction.The optimum sintering temperature in argon atmosphere is 1350℃with a shrinkage of 3.0%,3.2%,and 5.5%in X,Y,and Z directions,respectively,flexural strength of 26.7 MPa,Vickers hardness of 198.5 HV,nanoindentation hardness of 33.1 GPa,bulk density of 2.5 g/cm^3,and open porosity of 33.8%.The optimum sintering temperature was 70℃higher than that sintering in air atmosphere when achieved the similar properties.
基金financially supported by the National Key Research and Development Program of China (No. 2018YFB1106600)the Chinese National Foundation for Natural Sciences under Contracts (No. 51672217)the Research Fund of the State Key Laboratory of Solidifi cation Processing (Grant No. 120-TZ-2015).
文摘In this work,aluminum oxide(Al2O3) ceramic samples were fabricated by 3D stereolithography printing.Printing process was followed by debinding and sintering.In addition,the effect of sintering temperature on micro structure and properties was investigated.Flexure strength was observed to increase with increasing sintering temperature due to fewer pores,fewer defects and stronger grain boundary bonding of samples at higher sintering temperatures.Maximum flexure strength of 138.5 MPa was obtained when sintering temperature was 150℃.Furthermore,the shrinkage along length direction decreased with the decreasing sintering temperature until reaching minimum value of 1.02% after sintering at 1200℃.After sintering at 1280℃,flexure strength was 24.0 MPa and the shrinkage along length direction was 2.1%,which meets demands of ceramic core.
基金This work was supported by the National Natural Science Foundation of China(Nos.12271098 and 61772005)the Outstanding Youth Innovation Team Project for Universities of Shandong Province(No.2020KJN008)。
文摘Constrained clustering,such as k-means with instance-level Must-Link(ML)and Cannot-Link(CL)auxiliary information as the constraints,has been extensively studied recently,due to its broad applications in data science and AI.Despite some heuristic approaches,there has not been any algorithm providing a non-trivial approximation ratio to the constrained k-means problem.To address this issue,we propose an algorithm with a provable approximation ratio of O(logk)when only ML constraints are considered.We also empirically evaluate the performance of our algorithm on real-world datasets having artificial ML and disjoint CL constraints.The experimental results show that our algorithm outperforms the existing greedy-based heuristic methods in clustering accuracy.
基金supported by the National Natural Science Foundation of China(No.61873225)and(No.52130702).
文摘The challenges of energy shortage and environmen-tal protection motivate people to take various measures to use energy wisely,and integrated energy systems are such a measure to tackle this challenge.In this paper,an optimal expansion planning model for an integrated energy system consisting of power grid,gas network and multiple energy hubs is proposed,where the planning objective is to minimize operational fuel cost and capital investment cost covering carbon capture equipment and energy hubs among others.To demonstrate the advantage of the proposed planning model,six case studies are investigated,and 13.47%annual cost savings can be achieved compared with the baseline planning scenario,which does not consider bidirectional energy exchange and integrated demand response program.Index Terms-Bidirectional energy exchange,energy hubs,integrated energy system,integrated demand response.
基金This study was supported by the National Natural Science Founda-tion of China(Grant.No.52175333)Basic Research Program of China(Grant.No.JCKY∗∗∗∗∗∗∗C102)+1 种基金Tribology Science Fund of the China State Key Laboratory of Tribology,Tsinghua University(Grant.No.SKLT2021B05)This study was also supported by the Ten Dimensions(Guangdong,China)Technology Co.,Ltd.,in the course of the lead-ing project“Additive Manufacturing of Ceramic Heat Sinks”(Grant.No.20232000308).
文摘With recent advances in power electronic packaging technologies,liquid-cooled ceramic heat sinks have been considered as a promising solution for further improving the performance of power electronic devices.In this study,several aluminum oxide heat sinks were fabricated and tested using the digital light processing-based ad-ditive manufacturing method,to verify their practical performance.The results showed that the complex cooling structures inside the heat sinks can be completely formed and exhibited high surface quality.The experimental thermal and hydraulic performances of the heat sinks were consistent with the numerically modeled predictions.Furthermore,by exploiting the advantages of additive manufacturing,a direct manifold microchannel(MMC)configuration was designed to reduce the vertical flow of the traditional MMC configuration and achieve an im-proved cooling efficiency.At a constant volumetric flow rate of 1 L/min,the direct MMC configuration achieved a 19.8%reduction in pressure drop and an 11.8%reduction in thermal resistance,as well as a more uniform temperature distribution.
基金supported by the National Natural Science Foundation of China(Nos.61702508,61802404,and U1836209)the National Key Research and Development Program of China(Nos.2018YFB0803602 and 2016QY06X1204)+2 种基金the National Social Science Foundation of China(No.19BSH022)supported by the Key Laboratory of Network Assessment Technology,Chinese Academy of SciencesBeijing Key Laboratory of Network Security and Protection Technology。
文摘Network texts have become important carriers of cybersecurity information on the Internet.These texts include the latest security events such as vulnerability exploitations,attack discoveries,advanced persistent threats,and so on.Extracting cybersecurity entities from these unstructured texts is a critical and fundamental task in many cybersecurity applications.However,most Named Entity Recognition(NER)models are suitable only for general fields,and there has been little research focusing on cybersecurity entity extraction in the security domain.To this end,in this paper,we propose a novel cybersecurity entity identification model based on Bidirectional Long Short-Term Memory with Conditional Random Fields(Bi-LSTM with CRF)to extract security-related concepts and entities from unstructured text.This model,which we have named XBi LSTM-CRF,consists of a word-embedding layer,a bidirectional LSTM layer,and a CRF layer,and concatenates X input with bidirectional LSTM output.Via extensive experiments on an open-source dataset containing an office security bulletin,security blogs,and the Common Vulnerabilities and Exposures list,we demonstrate that XBi LSTM-CRF achieves better cybersecurity entity extraction than state-of-the-art models.
基金This work was supported by the National Natural Science Foundation of China(51307149)China Postdoctoral Science Foundation(2014M551050)Specialized Research Fund for the Doctoral Program of Higher Education(20131333120016).
文摘An interesting inverter topology is proposed in this paper.It is similar to the typical three-phase full bridge inverter from the topology point of view,but smartly designed for the ground current reduction in single-phase photovoltaic(PV)inverter applications.Theoretical analysis is conducted to clarify the operation mechanism of the proposed topology.Performance evaluation is carried out to verify the effectiveness of the proposed topology for the ground current suppression.
基金financially supported by the Funding from the National Key R&D Program of China(No.2018YFB1106600)the Fundamental Research Funds for Central Universities(WK5290000002)。
文摘High porosity and high strength are usually mutually exclusive in the preparation of ceramic materials.However,high porosity and flexural strength are required for the preparation of complex ceramic cores for hollow turbine blades.In this study,Al_(2)O_(3)cores with high porosity and high flexural strength were successfully prepared using digital light processing(DLP)3 D printing technology.The influence of sintering temperature on the microstructure,pore evolution,and flexural strength of the cores were investigated.With an increase in the sintering temperature,the porosity of the ceramic cores first increased and then decreased,reaching a maximum value of 35%at 1400℃.The flexural strength increased with the increase in sintering temperature,but at 1400℃the incremental enhancement of flexural strength was greatest.Combined with the core service requirements and core performance,this study selected 1400℃(open porosity of 35.1%and flexural strength of 20.3 MPa)as the optimal sintering temperature for the DLP-3 D printed Al_(2)O_(3)core.
文摘Cytochrome c activates apoptosis specific protease XCPP32 when being added to Xenopus laevis egg extracts, and induces apoptosis in this cell-free system. During apoptosis, cyto-skeleton proteins in egg extracts are degraded. Western blot assay indicates that 42-ku acidic keratin in egg extracts has been degraded by XCPP32. The degradation of 42-ku keratin may be crucial in apoptosis.
基金the National Basic Research Project (Grant No. G1999053905).
文摘When added with cytochrome c, Xenopus laevis egg extract XS-150 can induce exogenous nuclei undergoing apoptosis. Apoptosis specific DNase XAD was activated during this process, and cut chromatin between nucleosome, leading to DNA Ladder in electrophoresis. Our results showed that an inhibitor of XAD, IXAD, exists abundantly in normal egg extract, its molecular weight is about 40 ku. Normally, IXAD exists either in the form of dimmer or in complex with XAD. It was degraded during apoptosis, releasing active XAD. The results of Western assay and cross-inhibition showed that IXAD was likely homologous to DFF45 in structure and function. At the same time, these results also indicated that the pathway in apoptosis was conserved in evolution.
基金the National Natural Science Foundation of China (Grant No. 39300075) and the National Basic Sciences Research Program (Grant No. G19990539).
文摘An NIH3T3 cell line which overexpresses temperature-sensitive p53Val135 was constructed by introduction of p53Val135 gene. It exhibited rapidly characteristic morphological and biochemical alterations related to repli-cative senescence when being cultured in 32℃. We suggested that the overexpression of p53 activated probably the onset of senescence in NIH3T3 cells, which induced a rapid cellular senescence.