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Elastic three-dimensional phononic topological insulators with Dirac hierarchy

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 54-62页

作者： Shao-Yong Huo Qiu-Shuang Yang Jiu-Jiu Chen Hong-Kang Li Long-Chao Yao fu-Chun He Chun-Ming fu College of Mechanical Engineering University of South ChinaHengyang 421001China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China

Three-dimensional(3D)phononic topological insulators(TIs)featuring two-dimensional(2D)surface states and one-dimensional(1D)hinge states have opened up a new route for multi-dimensional robust wave transport,providing unprecedented methods for integrated acoustic sensors and energy harvesting ***,aiming at the elastic 3D phononic TI with gapless surface states and hinge states,the realization of elastic 3D phononic TIs with gapless surface states and hinge states is a significant challenge due to the complicated multi-mode polarization of elastic waves in 3D *** this study,we demonstrate an elastic 3D phononic TI with a Dirac hierarchy by elaborately operating the corresponding spatial symmetries of the chiral honeycomb ***,a 3D double Dirac cone of elastic wave can be achieved by doubling the lattice along the outof-plane direction to fold two iso-frequency Weyl *** topological phase transitions and 2D gapless two-fold Dirac surface states of elastic wave are realized by breaking the half-lattice spatial translation ***,based on the Brillouin zone folding along the in-plane direction,the 2D gapless two-fold surface Dirac cones are folded into four-fold surface Dirac ***,by inducing the relative radius of adjacent holes to break the in-plane spatial inversion symmetry,the fourfold surface Dirac cones are gapped and associated with a surface state inversion,in which the gapless 1D hinge Dirac dispersion is *** research offers a route for engineering the hierarchies of TIs in 3D elastic wave systems and provides new possibilities for designing 3D ultrasonic devices with unconventional functions.

关键词： Dirac topological hierarchy

Inactivation of TGF-βsignaling in CAR-T cells

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Cellular & Molecular Immunology 2024年第3期21卷 309-310页

作者： Zaopeng Yang Yang-Xin fu Changping Laboratory Beijing102206China Department of Basic Medical Sciences School of MedicineTsinghua UniversityBeijing100084China

Accumulating evidence suggests that the transforming growth factor(TGF)-βpathway might be an ideal target for optimizing chimeric antigen receptor(CAR)-T-cell therapy for solid *** Cellular&Molecular Immunology,Liang et al.(2024)reported that CAR-T cells expressing SMAD7 displayed favorable antitumor efficacy and a reduced risk of systemic toxicity.

关键词： CAR Immunology

Link between childhood obesity and gut microbiota

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World Journal of Gastroenterology 2024年第30期30卷 3560-3563页

作者： Yan Pan fu-Yong Jiao Department of Pediatrics The First Affiliated Hospital of Yangtze UniversityJingzho 434000Hubei ProvinceChina Shaanxi Kawasaki Disease Diagnosis and Treatment Center Children's HospitalShaanxi Provincial People's Hospital of Xi'anJiaotong UniversityXi'an 710000Shaanxi ProvinceChina

Childhood obesity is a critical global health concern with rising prevalence and significant long-term health *** studies have implicated gut microbiota in the development and progression of *** editorial analyzes the research conducted by Li et al,who utilized 16S rRNA gene sequencing to compare the gut microbiome of overweight and healthy-weight *** study found significant differences in microbial diversity and composition between the two groups,with potential implications for understanding and managing childhood *** analyzed the study’s advantages and drawbacks,proposing potential areas for future research to better understand the connection between gut microbiota and obesity.

关键词： 16S rRNA Childhood obesity Gut microbiota future research Global health

Experimental study and correlation development for the two-phase frictional pressure drop of flow boiling in copper foam fin microchannels

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Science China(Technological Sciences) 2024年第9期67卷 2758-2776页

作者： fu Kai XU XiangHua LIANG XinGang School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

Flow boiling in microchannels with porous walls has received extensive attention in recent years. Compared with the emphasis on heat transfer, there is a lack of research on the effect of the porous wall structures on the pressure drop characteristics. In this study, systematic experiments are performed to measure the pressure drop of water-vapor two-phase flow in five microchannels with copper foam fins, which consist of nine or six channels and fins of copper foam. The porosities of the foam fins range from0.78 to 0.82 and ratios of fin width to channel width range from 0.5 to 2. The channels are approximately 0.5 or 1 mm in width and 1 mm in height. Both adiabatic and flow boiling experiments are conducted with water at mass fluxes ranging from 66 to 407 kg/(m^(2)s). In the adiabatic experiments, the average quality in channels is between 0.017 and 0.846. In the flow boiling experiments, the outlet quality of channels is between 0.040 and 0.863. Slug flow, churn flow, annular flow, and wispy-annular flow are observed in adiabatic experiments. A two-phase frictional pressure drop correlation based on the Lockhart-Martinelli model is developed for copper foam fin microchannels by introducing the effects of the mass flux, porosity, ratio of fin width to channel width, and heating condition step by step. The mean absolute percentage errors of the new correlation are 7.53% for 325data points under adiabatic conditions and 5.51% for 268 data points under flow boiling conditions, respectively. This work provides insight into the correlations of frictional pressure drop in microchannels with porous walls.

关键词： two-phase flow boiling pressure drop correlation microchannel copper foam porous wall

Engineering Fronts 2023 announced engineering fronts in fields of Energy and Electrical Science and Technology

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Frontiers in Energy 2024年第1期18卷 4-7页

作者： Ruiqin LIU Liang YIN Lingxiao fu Editorial Office of Frontiers in Energy Shanghai Jiao Tong UniversityShanghai 200240China

1 Introduction An engineering front refers to important directions that have a significant impact on and lead the future innovation of engineering science and *** is characterized by its forward looking,leading,and exploratory *** 2017,the Chinese Academy of Engineering(CAE)has annually organized a project known as“Global Engineering Fronts,”identifying and releasing engineering research fronts and engineering development fronts,tracking the trends in engineering science and technology,and actively guiding the academic development and promoting innovation in engineering science and technology.

关键词： technology. annually looking

CFD simulation of pumping ventilation in a three-story isolated building with internal partitioning:Effects of partition widths,heights and locations

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Building Simulation 2024年第2期17卷 267-284页

作者： Huai-Yu Zhong Jie Sun Chao Lin Song-Heng Wu Jin Shang Hideki Kikumoto fu-Ping Qian Carlos Jimenez-Bescos fu-Yun Zhao School of Energy and Environment Anhui University of TechnologyMa-An-ShanAnhui Province243002China State Key Laboratory of Green Building in Western China Xi’an University of Architecture&TechnologyXi’anShaanxi ProvinceChina School of Power and Mechanical Engineering Wuhan UniversityWuhanHubei Province430072China Institute of Industrial Science The University of Tokyo4-6-1 KomabaMeguro-kuTokyo153-8505Japan School of Built and Natural Environment University of DerbyDerbyUK

Pumping ventilation(PV),a special single-sided ventilation(SSV),has been certified as an effective strategy to improve the air exchange rate of ***,most studies targeted on the single space,and few studies have been focused on the effect of internal partitioning on *** paper aims to evaluate the ventilation performance of PV influenced by different configurations of internal *** fluid dynamics(CFD)simulation was used to predict the flow fields and ventilation *** width(w/H),height(h/H)and location(d/H)are the three main internal partition parameters considered in this *** simulation results showed that the total,mean and fluctuating ventilation rates all decrease with wider internal *** normalized total ventilation rate decreases by 7.6%when w/H is increased from 50%to 75%.However,the reduction rate is only 0.23%between w/H=0 and 25%,and only 0.61%between w/H=25%and 50%.The ventilation rate is hardly reduced by increasing the partition width when w/H50%.Increasing the partition height will reduce the mean ventilation rate but promote the fluctuating and total ventilation rate in some *** increase of total ventilation rate by 1.4%is observed from h/H=50%to 75%.The ventilation rate is larger when the internal partition is attached to the leeward or windward *** total,mean and fluctuating ventilation rates for d/H=50%are relatively higher than d/H=0 by 1.5%,3.1%and 0.8%,*** the internal partition should be mounted attached to the windward wall so as to obtain the greatest pumping ventilation *** periodicity of pumping flow oscillation and pumping frequency are independent of the partition *** peak power of pumping flow is the lowest for the widest internal partition and is negatively affected by the partition height,but it generally has a positive correlation with the distance between the partition and leeward wa

关键词： pumping ventilation single-sided ventilation internal partitioning periodic oscillation ventilation rate

Automatic Road Tunnel Crack Inspection Based on Crack Area Sensing and Multiscale Semantic Segmentation

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Computers, Materials & Continua 2024年第4期79卷 1679-1703页

作者： Dingping Chen Zhiheng Zhu Jinyang fu Jilin He College of Mechanical and Electrical Engineering Central South UniversityChangsha410083China Department of Geotechnical Guangdong Hualu Transportation Technology Company LimitedGuangzhou510000China National Engineering Research Center of High-Speed Railway Construction Technology Changsha410075China

The detection of crack defects on the walls of road tunnels is a crucial step in the process of ensuring travel safetyand performing routine tunnel maintenance. The automatic and accurate detection of cracks on the surface of roadtunnels is the key to improving the maintenance efficiency of road tunnels. Machine vision technology combinedwith a deep neural network model is an effective means to realize the localization and identification of crackdefects on the surface of road *** propose a complete set of automatic inspection methods for identifyingcracks on the walls of road tunnels as a solution to the problem of difficulty in identifying cracks during manualmaintenance. First, a set of equipment applied to the real-time acquisition of high-definition images of walls inroad tunnels is designed. Images of walls in road tunnels are acquired based on the designed equipment, whereimages containing crack defects are manually identified and selected. Subsequently, the training and validationsets used to construct the crack inspection model are obtained based on the acquired images, whereas the regionscontaining cracks and the pixels of the cracks are finely labeled. After that, a crack area sensing module is designedbased on the proposed you only look once version 7 model combined with coordinate attention mechanism (CAYOLOV7) network to locate the crack regions in the road tunnel surface images. Only subimages containingcracks are acquired and sent to the multiscale semantic segmentation module for extraction of the pixels to whichthe cracks belong based on the DeepLab V3+ network. The precision and recall of the crack region localizationon the surface of a road tunnel based on our proposed method are 82.4% and 93.8%, respectively. Moreover, themean intersection over union (MIoU) and pixel accuracy (PA) values for achieving pixel-level detection accuracyare 76.84% and 78.29%, respectively. The experimental results on the dataset show that our proposed two-staged

关键词： Road tunnel crack inspection crack area sensing multiscale semantic segmentation CA-YOLO V7 DeepLab V3+

A New Industrial Intrusion Detection Method Based on CNN-BiLSTM

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Computers, Materials & Continua 2024年第6期79卷 4297-4318页

作者： Jun Wang Changfu Si Zhen Wang Qiang fu College of Computer Science and Technology Shenyang University of Chemical TechnologyShenyang110142China

Nowadays,with the rapid development of industrial Internet technology,on the one hand,advanced industrial control systems(ICS)have improved industrial production ***,there are more and more cyber-attacks targeting industrial control *** ensure the security of industrial networks,intrusion detection systems have been widely used in industrial control systems,and deep neural networks have always been an effective method for identifying cyber *** intrusion detection methods still suffer from low accuracy and a high false alarm ***,it is important to build a more efficient intrusion detection *** paper proposes a hybrid deep learning intrusion detection method based on convolutional neural networks and bidirectional long short-term memory neural networks(CNN-BiLSTM).To address the issue of imbalanced data within the dataset and improve the model’s detection capabilities,the Synthetic Minority Over-sampling Technique-Edited Nearest Neighbors(SMOTE-ENN)algorithm is applied in the preprocessing *** algorithm is employed to generate synthetic instances for the minority class,simultaneously mitigating the impact of noise in the majority *** approach aims to create a more equitable distribution of classes,thereby enhancing the model’s ability to effectively identify patterns in both minority and majority *** the experimental phase,the detection performance of the method is verified using two data *** results show that the accuracy rate on the CICIDS-2017 data set reaches 97.7%.On the natural gas pipeline dataset collected by Lan Turnipseed from Mississippi State University in the United States,the accuracy rate also reaches 85.5%.

关键词： Intrusion detection convolutional neural network bidirectional long short-term memory neural network multi-head self-attention mechanism

Off-farm employment,agriculture production activities,and household dietary diversity in environmentally and economically vulnerable areas of Asia

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Journal of Integrative Agriculture 2024年第2期23卷 359-373页

作者： Yunli Bai Xuanye Zeng Chao fu Linxiu Zhang Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China United Nations Environment Programme-International Ecosystem Management Partnership(UNEP-IEMP) Beijing 100101China University of Chinese Academy of Sciences Beijing 100101China

Access to off-farm employment has been expected to be a critical approach to ending hunger and all forms of malnutrition,two important targets of achieving Zero *** study aims to investigate the role of off-farm employment in improving dietary diversity through substitution effect and complementary effect with agricultural production activities and income *** study adopts Poisson/Tobit/Probit/OLS regressions and the instrument variable method based on the primary survey data collected among 1,282 households at 12 sites in environmentally and economically vulnerable areas of China,Nepal,Cambodia,Thailand,and Myanmar in *** results show that off-farm employment is positively associated with household dietary diversity and the consumption of flesh meat,fish and other aquatic animals,fruits,and milk and dairy products,which are rich in protein and *** results of mechanism analysis show that off-farm employment contributes to household dietary diversity by improving crop diversity,especially for poor households,boosting the probability of livestock raising for households with the middle one-third disposal income,and increasing household *** positive association between off-farm employment and household dietary diversity is much higher for households with the bottom one-third disposal income,low illiteracy,and from upper-middle income *** findings imply that off-farm employment does play a vital role in achieving multiple benefits of poverty alleviation,malnutrition reduction,and agrobiodiversity conservation in environmentally and economically vulnerable ***,it may enlarge the gaps in dietary diversity between households with low human capital and from low and lower-middle income countries and those with high human capital and from middle-high countries.

关键词： off-farm employment dietary diversity income effect substitution effect complementary effect