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chinese Journal of Mechanical Engineering 2024年第1期37卷 203-214页

作者： Xiaokang Huang Xiaoyong Tian Qi Zhong Shunwen He cunbao Huo Yi cao Zhiqiang Tong Dichen Li State key Laboratory of Manufacturing Systems Engineering Xi’an Jiaotong UniversityXian 710049China

Improvement of fabrication efficiency and part performance was the main challenge for the large-scale powder bed fusion(PBF)*** this study,a dynamic monitoring and feedback system of powder bed temperature field using an infrared thermal imager has been established and integrated into a four-laser PBF equipment with a working area of 2000 mm×2000 *** heat-affected zone(HAZ)temperature field has been controlled by adjusting the scanning speed ***,the relationship among spot size,HAZ temperature,and part performance has been *** fluctuation of the HAZ temperature in four-laser scanning areas was decreased from 30.85℃to 17.41℃.Thus,the consistency of the sintering performance of the produced large component has been *** on the controllable temperature field,a dynamically adjusting strategy for laser spot size was proposed,by which the fabrication efficiency was improved up to 65.38%.The current research results were of great significance to the further industrial applications of large-scale PBF equipment.

关键词： Powder bed fusion Efficiency Large-scale Spot size Heat-affected zone(HAZ)

Migration mechanism and risk assessment of perand polyfluoroalkyl substances in the Ya'Er Lake oxidation pond area,china

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Journal of Environmental Sciences 2024年第2期136卷 301-312页

作者： chang Li Huifang Zhong Jing Wu Lingyi Meng Yingjun Wang chunyang Liao Yawei Wang Yujian He University of chinese Academy of Sciences Beijing 100049China research center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Institute of Biomedical and Health Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China china National Environmental Monitoring centre Beijing 100012China Hubei key Laboratory of Environmental and Health Effects of Persistent Toxic Substances Institute of Environment and HealthJianghan UniversityWuhan 430056China

The migration mechanisms,sources,and environmental risks of 29 legacy and emerging perfluorinated and polyfluoroalkyl species present in an oxidation pond(Ya'Er Lake)were investigated for treating sewage based on the analysis of their occurrence and *** concentration of per-and polyfluoroalkyl substances(PFAS)in pond area was between0.30 and 63.2 ng/g dw(dry weight),with the overall average concentration of 8.00 ng/g ***,the PFAS concentrations in the surface sediments near the sewage outlet in Pond-1(50.2 ng/g dw)and Pond-5(average 15.1 ng/g dw)were 1–2 orders of magnitude higher than those in other *** general,the legacy PFAS,i.e.,perfluorooctane sulfonic acid was considered to be the major pollutant in the polluted area,on average,accounting for 73.0%of the total concentration of PFAS *** evaluating the regional distribution of different PFAS homologs,the short-chain PFAS pollutants with lower k_(ow)were found to migrate farther in both horizontal and vertical *** sewage outlets in Pond-1 and Pond-5are the main pollution sources in polluted area and the emerging PFAS pollutants in Pond-5have replaced the legacy PFAS pollutants as the main *** on positive matrix factorization analysis,three main industrial sources of PFAS pollutants in the study area were identified:protective coating,fire-fighting,and food packaging ***,the environmental risk assessment results showed that most study areas exhibited medium environmental risk(0.01≤Risk quotient(RQ)cating that the ecological environment risks in this area need further attention.

关键词： Perfluoroalkyl substances Distribution Migration mechanism Risk assessment

High-performance formaldehyde prediction for indoor air quality assessment using time series deep learning

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Building Simulation 2024年第3期17卷 415-429页

作者： Liu Lu Xinyu Huang Xiaojun Zhou Junfei Guo Xiaohu Yang Jinyue Yan School of Human Settlements and civil Engineering Xi’an Jiaotong UniversityXi’anChina Department of Building Environment and Energy Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina Future Energy Profile School of BusinessSocietyand EngineeringMälardalen UniversityVästeråsSweden

Indoor air pollution resulting from volatile organic compounds(VOcs),especially formaldehyde,is a significant health concern needed to predict indoor formaldehyde concentration(cf)in green intelligent building *** study develops a thermal and wet coupling calculation model of porous fabric to account for the migration of formaldehyde molecules in indoor air and cotton,silk,and polyester fabric with heat flux in Harbin,Beijing,Xi’an,Shanghai,Guangzhou,and kunming,*** time-by-time indoor dry-bulb temperature(T),relative humidity(RH),and cf,obtained from verified simulations,were collated and used as input data for the long short-term memory(LSTM)of the deep learning model that predicts indoor multivariate time series cf from the secondary source effects of indoor fabrics(adsorption and release of formaldehyde).The trained LSTM model can be used to predict multivariate time series cf at other emission times and *** LSTM-based model also predicted cf with mean absolute percentage error(MAPE),symmetric mean absolute percentage error(SMAPE),mean absolute error(MAE),mean square error(MSE),and root mean square error(RMSE)that fell within 10%,10%,0.5,0.5,and 0.8,*** addition,the characteristics of the input dataset,model parameters,the prediction accuracy of different indoor fabrics,and the uncertainty of the data set are *** results show that the prediction accuracy of single data set input is higher than that of temperature and humidity input,and the prediction accuracy of LSTM is better than recurrent neural network(RNN).The method’s feasibility was established,and the study provides theoretical support for guiding indoor air pollution control measures and ensuring human health and safety.

关键词： multivariate time series formaldehyde concentration deep learning heat-humidity coupling mass transfer secondary source effect

Metal complex catalysts broaden bioorthogonal reactions

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Science china chemistry 2024年第2期67卷 428-449页

作者： Hanjie Zhang Xiaoyu Qin Junping Wang Li Ma Tianfeng chen Department of chemistry Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and ApplicationsJinan UniversityGuangzhou510632China

Bioorthogonal reactions involving transition metals have diversified applications in imaging,drug development,chemical catalysis and other *** metals used to catalyze the bioorthogonal reaction mainly include ruthenium,palladium,copper,and ***,the great potential for translational applications of bioorthogonal reaction needs to be further expanded and their reaction efficiency should be ***,it is an urgent need for the development of this field to find more suitable catalysts to efficiently catalyze existing biological orthogonal reactions and expand the types of biological orthogonal ***,this review not only summarizes those transition metal complexes-based catalysts participating in bioorthogonal reaction and some bioorthogonal reactions involving transition metals inside the cells,but also sheds light into the discovery of new transition metal complexes and their future development in applications.

关键词： transition metal complexes bioorthogonal reactions biological applications

Operation optimization of prefabricated light modular radiant heating system:Thermal resistance analysis and numerical study

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Journal of central South University 2024年第6期31卷 1983-1997页

作者： LI Yao HU Ru-kun XIN Li XUE Jie HUANG Fei XIA Jian-wei YANG Xiao-hu china Northwest Architecture Design and research Institute co. Ltd.Xi’an 710061China Institute of Building Environment and Sustainability Technology School of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi’an 710049China Shaanxi Yuanqing New Building Materials co. Ltd.Xi’an 710054China

The utilization of prefabricated light modular radiant heating system has demonstrated significant increases in heat transfer efficiency and energy conservation *** prefabricated building construction,this new heating method presents an opportunity for the development of comprehensive *** parameters for evaluating the effectiveness of such a system are the upper surface layer’s heat flux and *** this paper,thermal resistance analysis calculation based on a simplified model for this unique radiant heating system analysis is presented with the heat transfer mechanism’s *** results obtained from thermal resistance analysis calculation and numerical simulation indicate that the thermal resistance analysis method is highly accurate with temperature discrepancies ranging from 0.44℃ to−0.44℃ and a heat flux discrepancy of less than 7.54%,which can meet the requirements of practical engineering applications,suggesting a foundation for the prefabricated radiant heating system.

关键词： radiant heating system thermal resistance analysis simplified model numerical simulation heat flux temperatur

A four-band index for both liquid and solid water and its applications in the Aral Sea Basin

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Science china Earth Sciences 2024年第3期67卷 769-788页

作者： Bing YUE Xi cHEN Saibo LI Zhengping DU John WILSON Junhui YANG Yimen JIAO Shuangyan HUANG chenghu ZHOU Xinjiang Institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China college of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Institute of Geographical Sciences and Natural Resources research Chinese Academy of SciencesBeijing 100101China Spatial Sciences Institute University of Southern CaliforniaLos AngelesCA 90089-0374USA

Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices had misclassification problem, which made different research groups present different results. Thus we first ascertain the boundaries of the ASB, the Syr and Amu river basins as well as their upper, middle and lower reaches. Then a four-band index for both liquid and solid water(ILSW) is proposed to address the misclassification problems of the classic water indices. ILSW is calculated by using the reflectance values of the green, red, near infrared, and thermal infrared bands, which combines the normalized difference water index(NDWI) and land surface temperature(LST) together. Validation results show that the ILSW water index has the highest accuracy by far in the Aral Sea Basin. Our results indicate that annual average decline of the water-coverage area was 963 km^(2) in the southern Aral Sea, whereas the northern Aral Sea has experienced little change. In the meanwhile, permanent ice and snow in upper reach of ASB has retreated considerably. Annual retreating rates of the permanent ice and snow were respectively 6233and 3841 km^(2) in upper reaches of Amu river basin(UARB) and Syr river basin(USRB). One of major reasons is that climate has become warmer in ASB. The climate change has caused serious water deficit problem. The water deficit had an increasing trend since the 1990s and its increasing rates was 3.778 billion m^(3) yearly on average. The total water deficit was 76.967 billion m^(3) on average in the whole area of ASB in the 2010s. However, up reaches of Syr river basin(USRB), a component area of ASB, had water surplus of 25.461 billion m^(3). These conclusions are useful for setting out a sustainable development strategy in ASB.

关键词： Aral Sea Basin Syr river basin Amu river basin Water indices Water-coverage area Water deficit climate change

continuous-wave operation of 1550 nm low-threshold triple-lattice photonic-crystal surface-emitting lasers

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Light(Science & Applications) 2024年第3期13卷 446-453页

作者： Ziye Wang Xia Liu Pinyao Wang Huanyu Lu Bo Meng Wei Zhang Lijie Wang Yanjing Wang cunzhu Tong State key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China central research Institute Planning Dept 2012 LabsHuawei Technologies Company Ltd.Shenzhen 518129China

Benefitting from narrow beam divergence,photonic crystal surface-emitting lasers are expected to play an essential role in the ever-growing fields of optical communication and light detection and *** operating with 1.55μm wavelengths have attracted particular attention due to their minimum fiber loss and high eye-safe ***,high interband absorption significantly decreases their performance at this 1.55μm ***,stronger optical feedback is needed to reduce their threshold and thus improve the output *** this goal,photonic-crystal resonators with deep holes and high dielectric contrast are often ***,the relevant techniques for high-contrast photonic crystals inevitably complicate fabrication and reduce the final *** this paper,we demonstrate the first continuous-wave operation of 1.55μm photonic-crystal surface-emitting lasers by using a‘triple-lattice photonic-crystal resonator’,which superimposes three lattice point groups to increase the strength of in-plane optical *** this geometry,the in-plane 180°coupling can be enhanced threefold compared to the normal single-lattice *** theoretical and experimental investigations demonstrate the much lower threshold current density of this structure compared to‘single-lattice’and‘double-lattice’photonic-crystal resonators,verifying our design *** findings provide a new strategy for photonic crystal laser miniaturization,which is crucial for realizing their use in future high-speed applications.

关键词： resonator crystal lattice

Second-harmonic generation in periodic fork-shaped χ^((2)) gratings at oblique incidence

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chinese Optics Letters 2024年第4期22卷 101-105页

作者：盛艳刘山胡效康陈鑫徐天翔赵如薇 Wieslaw kroli kowski Laboratory of Infrared Materials and Devices Research Institute of Advanced TechnologiesNingbo UniversityNingbo 315211China Engineering research center for Advanced Infrared Photoelectric Materials and Devices of Zhejiang Province Ningbo UniversityNingbo 315211China Department of Quantum Science and Technology Research School of PhysicsAustralian National UniversityCanberra ACT 2601Australia School of Physics and Optoelectronics Engineering Xidian UniversityXi’an 710071China

Three-dimensional(3D) nonlinear photonic crystals have received intensive interest as an ideal platform to study nonlinear wave interactions and explore their applications. Periodic fork-shaped gratings are extremely important in this context because they are capable of generating second-harmonic vortex beams from a fundamental Gaussian wave, which has versatile applications in optical trapping and materials engineering. However, previous studies mainly focused on the normal incidence of the fundamental Gaussian beam, resulting in symmetric emissions of the second-harmonic vortices. Here we present an experimental study on second-harmonic vortex generation in periodic fork-shaped gratings at oblique incidence, in comparison with the case of normal incidence. More quasi-phase-matching resonant wavelengths have been observed at oblique incidence, and the second-harmonic emissions become asymmetric against the incident *** results agree well with theoretic explanations. The oblique incidence of the fundamental wave is also used for the generation of second-harmonic Bessel beams with uniform azimuthal intensity distributions. Our study is important for a deeper understanding of nonlinear interactions in a 3D periodic medium. It also paves the way toward achieving highquality structured beams at new frequencies, which is important for manipulation of the orbital angular momentum of light.

关键词： second-harmonic generation nonlinear photonic crystal periodically poled ferroelectric crystal quasi-phase matching nonlinear wavefront shaping

金属氢化物中质子耦合电子转移反应的理论研究

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chinese Journal of chemical Physics 2024年第2期37卷 199-210,I0102页

作者：刘晓云但晓寒史强中国科学院化学研究所分子动态与稳态结构国家重点实验室北京分子科学国家研究中心北京100190 中国科学院大学北京100049

金属-氢配合物在多种催化反应中起着重要作用最近的研究表明,与吡啶基团共价连接的钨氢配合物可以发生协同的质子耦合电子转移反应.本文使用密度泛函理论和非绝热速率理论研究了该类弱氢键体系中的协同质子耦合电子转移反应.首先通过密... 详细信息

金属-氢配合物在多种催化反应中起着重要作用最近的研究表明,与吡啶基团共价连接的钨氢配合物可以发生协同的质子耦合电子转移反应.本文使用密度泛函理论和非绝热速率理论研究了该类弱氢键体系中的协同质子耦合电子转移反应.首先通过密度泛函理论构建了金属-氢配合物质子自由度的二维势能面.然后求解薛定方程得到了波函数和振动能级,并用于分析各对振动态之间的跃迁速率和总的速率常数.结果表明,由于质子给体-受体之间距离的热涨落,即使在质子给体和受体之间仅存在弱氢键的情况下,协同质子耦合电子转移反应和总反应速率常数也可以得到显著增强.

关键词：质子耦合电子转移速率常数密度泛函理论计算非绝热跃迁

Turnip mosaic virus pathogenesis and host resistance mechanisms in Brassica

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Horticultural Plant Journal 2024年第4期10卷 947-960页

作者： Guanwei Wu Xinxin Fang Tianqi Yu Jianping chen Fei Yan State key Laboratory for Managing Biotic and chemical Threats to the Quality and Safety of Agro-products Institute of Plant VirologyNingbo UniversityNingboZhejiang 315211China key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province Institute of Plant VirologyNingbo UniversityNingboZhejiang 315211China

Turnip mosaic virus(TuMV)is a devastating potyvirus pathogen that infects a wide variety of both cultivated and wild Brassicaceae *** urgently need more information and understanding of TuMV pathogenesis and the host responses involved in disease development in cruciferous *** displays great versatility in viral pathogenesis,especially in its replication and intercellular ***,in the coevolutionary arms races between TuMV and its hosts,the virus has evolved to co-opt host factors to facilitate its infection and counter host defense *** review mainly focuses on recent advances in understanding the viral factors that contribute to the TuMV infection cycle and the host resistance mechanism in ***,we propose some future research directions on TuMV pathogenesis and control strategies to design durable TuMV-resistant Brassica crops.

关键词： Turnip mosaic virus Brassica Resistance genes Host factors Infection biology