检索结果-南通市图书馆

Identification of high oxygen-consuming substances in stormwater drainage systems illicitly connected with sewage system

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第4期138卷 132-140页

作者： Chen xu Zuxin xu Wenhai Chu Shanshan Wu Rong Xiao Lei Su State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Ministry of Education Key Laboratory of Yangtze River Water Environment Tongji UniversityShanghai 200092China Guangzhou Resource Environmental Protection Technology Co. Ltd.Guangzhou 510030China

The dissolved oxygen content in water is an important indicator for assessing the quality of the water environment,and maintaining a certain amount of dissolved oxygen is essential for the healthy development of the ecological environment.When a water body is anoxic,the activity of anaerobic microorganisms increases and organic matter is decomposed to produce a large number of blackening and odorizing substances,resulting in black and odorous water bodies,which is a very common and typical phenomenon in China.Presently,there is still a relatively universal occurrence of illicitly connected stormwater and sewage pipes in the urban drainage pipe network in China,which makes oxygen-consuming substances be directly discharged into rivers through stormwater pipes and consume the dissolved oxygen in the water bodies,resulting in an oxygen deficiency of the water.This induces seasonal or year-round black and stink phenomena in urban rivers.Hence,identifying high oxygen-consuming substances,which lays the foundation for the subsequent removal of oxygen-consuming substances,is essential.Through a series of comparisons of water quality indicators and analysis of organic characteristics,it was found that the oxygen consumption capacity of domestic sewage was higher than that of industrial wastewater in the selected area of this study,and the oxygen-consuming substances of domestic sewage were small molecular amino acids.By comparing 20 conventional free amino acids,it was found that seven of them consumed oxygen easily,and compared with chemical oxygen consumption,biological oxygen consumption was in a leading position.

关键词： Urban drainage system Oxygen-consuming substances Domestic sewage Amino acid

Massive data clustering by multi-scale psychological observations

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第2期9卷 43-51页

作者： Shusen Yang Liwen Zhang Chen xu Hanqiao Yu Jianqing Fan Zongben xu National Engineering Laboratory of Big Data Analytics Xi'an Jiaotong University Department of Mathematics and Statistics University of Ottawa Center for Statistics and Machine Learning Princeton University Industrial Artificial Intelligent Center Pazhou Laboratory

Clustering is the discovery of latent group structure in data and is a fundamental problem in artificial intelligence,and a vital procedure in data-driven scientific research over all disciplines.Yet,existing methods have various limitations,especially we ak cognitive interpretability and poor computational scalability,when it comes to clustering massive datasets that are increasingly available in all domains.Here,by simulating the multi-scale cognitive observation process of humans,we design a scalable algorithm to detect clusters hierarchically hidden in massive datasets.The observation scale changes,following the Weber-Fechner law to capture the gradually emerging meaningful grouping structure.We validated our approach in real datasets with up to a billion records and 2000 dimensions,including taxi trajectories,single-cell gene expressions,face images,computer logs and audios.Our approach outperformed popular methods in usability,efficiency,effectiveness and robustness across different domains.

关键词： massive data clustering psychological observation Weber–Fechner law cognitive interpretability computational scalability

Impact of subtropical climate on frequency of ambulance use for trauma patients in a coastal area of China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Traumatology 2015年第3期18卷 141-146页

作者： Yuqiang chen Yucheng Lai Jiajie Ke Yuefeng chen Yuling xu Yuqin Ma Jiayin Yuan Tian Liang Pengzhan Mai Changmin Lin Yang Xie Keng Huang Emergency Department the Second Affiliated Hospital of Shantou University Medical College Guangdong 515041 China Emergency Department Shantou University Medical College Guangdong 515041 China

Purpose: To explore the impact of subtropical maritime monsoon climate on the frequency of ambulance use for trauma patients in a coastal region in China. Method: Statistical analysis of data on ambulance use from the 120 Emergency Command Center in Shantou City, Guangdong Province, from January to December 2012 as well as daily meteorological data from a Shantou observatory was performed to determine how climatic factors (seasons, time, and weather) affect the frequency of ambulance use for trauma patients. Results: The daily ambulance use for trauma patients differed between spring and summer or autumn ( p < 0.05), between sunny and rainy days ( p < 0.05), and between cloudy and lightly or moderately rainy days ( p < 0.05). We found a linear correlation between daily maximum temperature and daily ambulance use for trauma patients ( R 2 = 0.103, p < 0.05). In addition, there was significant difference in ambulance use between good and bad weather ( p < 0.05). Conclusion: Frequency of ambulance use for trauma patients is affected by the subtropical maritime monsoon climate in the coastal region. Better weather contributes to increased daily frequency of ambulance use, which is the highest in autumn and lowest in spring.

关键词：沿海地区救护车患者创伤频率热带气候季风气候热带海洋

Circularly Polarized Light-Enabled Chiral Nanomaterials:From Fabrication to Application

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2023年第3期15卷 171-189页

作者： Changlong Hao Gaoyang Wang chen chen Jun xu Chuanlai xu Hua Kuang Liguang xu International Joint Research Laboratory for Biointerface and Biodetection State Key Lab of Food Science and TechnologySchool of Food Science and TechnologyJiangnan UniversityWuxiJiangsu 214122People’s Republic of China Department of Neurology China National Clinical Research Center for Neurological DiseasesBeijing Tiantan HospitalCapital Medical UniversityNo.119 South 4Th Ring West RoadBeijing 100070People’s Republic of China

For decades,chiral nanomaterials have been extensively studied because of their extraordinary properties.Chiral nanostructures have attracted a lot of interest because of their potential applications including biosensing,asymmetric catalysis,optical devices,and negative index materials.Circularly polarized light(CPL)is the most attractive source for chirality owing to its high availability,and now it has been used as a chiral source for the preparation of chiral matter.In this review,the recent progress in the field of CPL-enabled chiral nanomaterials is summarized.Firstly,the recent advancements in the fabrication of chiral materials using circularly polarized light are described,focusing on the unique strategies.Secondly,an overview of the potential applications of chiral nanomaterials driven by CPL is provided,with a particular emphasis on biosensing,catalysis,and phototherapy.Finally,a perspective on the challenges in the field of CPL-enabled chiral nanomaterials is given.

关键词： Circularly polarized light Chiral Nanomaterials Fabrication Application

Tunable room-temperature phosphorescence and circularly polarized luminescence encoding helical supramolecular polymer

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2022年第1期65卷 75-81页

作者： Chen xu chenjia Yin Wenjun Wu Xiang Ma Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center Frontiers Science Center for Materiobiology and Dynamic ChemistryInstitute of Fine ChemicalsSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Supramolecular polymers with different functionalities have been continuously developed in the past decade because of their indispensable role in soft materials.However,pure organic supramolecular polymers with stable room temperature phosphorescence(RTP)emission were very rarely reported for the difficulties of synthesis and achieving RTP in solution.Herein,soluble helical supramolecular polymers with circularly polarized room-temperature phosphorescence were developed via a facile hostguest strategy.Through assembly,a transition from pure fluorescence to almost pure RTP emission was achieved.Adjusting the asymmetry of guest could easily control the chiroptical property of supramolecular polymers.This work provides new opportunities for the design and development of intelligent soft functional soft materials.

关键词： room-temperature phosphorescence circularly polarized luminescence supramolecular polymer helical handedness

Controllable chemical redox reactions to couple microbial degradation for organic contaminated sites remediation:A review

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第5期139卷 428-445页

作者： Bin chen Jiang xu Lizhong Zhu College of Environmental and Resource Sciences Zhejiang UniversityHangzhou 310058China Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control Zhejiang UniversityHangzhou 310058China Zhejiang Agriculture&Forest University Lin'an 311300China

Global environmental concern over organic contaminated sites has been progressively conspicuous during the process of urbanization and industrial restructuring.While traditional physical or chemical remediation technologies may significantly destroy the soil structure and function,coupling moderate chemical degradation with microbial remediation becomes a potential way for the green,economic,and efficient remediation of contaminated sites.Hence,this work systematically elucidates why and how to couple chemical technology with microbial remediation,mainly focused on the controllable redox reactions of organic contaminants.The rational design of materials structure,selective generation of reactive oxygen species,and estimation of degradation pathway are described for chemical oxidation.Meanwhile,current progress on efficient and selective reductions of organic contaminants(i.e.,dechlorination,defluorination,-NO_(2) reduction)is introduced.Combined with the microbial remediation of contaminated sites,several consideration factors of how to couple chemical and microbial remediation are proposed based on both fundamental and practical points of view.This review will advance the understanding and development of chemical-microbial coupled remediation for organic contaminated sites.

关键词： Soil remediation Groundwater remediation Rational design Reactive species Environmental nanotechnology

Initial micro-galvanic corrosion behavior between Mg_(2)Ca and α-Mg via quasi-in situ SEM approach and first-principles calculation

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第3期11卷 958-965页

作者： Chen xu Jianfeng Wang chen chen Chao Wang Yufeng Sun Shijie Zhu Shaokang Guan School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

The initial micro-galvanic corrosion behavior of Mg-30wt%Ca alloy only containing Mg_(2)Ca andα-Mg was studied by immersion testing in a 0.9%Na Cl solution at 37°C.The quasi-in situ SEM and TEM results show that Mg_(2)Ca corroded easier thanα-Mg,indicating that Mg_(2)Ca acted as an anode.The work function(Φ)for Mg_(2)Ca calculated by first-principles is significantly lower compared to that forα-Mg.The Volta potential measured by a scanning Kelvin probe force microscope reveals that the Mg_(2)Ca had a relatively low Volta potential(ψ)value.The lowerΦandψvalues for Mg_(2)Ca indicate a lower electrochemical nobility,which is consistent with the experimental phenomenon.

关键词： Magnesium alloy Quasi-in situ SEM Galvanic corrosion First-principles calculations Work function Volta potential

Improving intrinsic stability for perovskite/silicon tandem solar cells

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2023年第1期66卷 85-105页

作者： Tailai xu Yihua chen Qi chen School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

Monolithic hybrid halide perovskite/crystalline silicon(c-Si)tandem solar cells have demonstrated their great potential to surpass the theoretical efficiency limit of single-junction devices.However,the stability of perovskite sub-cells is inferior to that of the c-Si solar cells that have been commercialized,casting serious doubt about the lifetime of the entire device.During device operation,light and heat are inevitable,which requires special attention.Herein,we review the current understandings of the intrinsic stability of perovskite/c-Si tandems upon light and/or heat aging.First,we summarize the recent understandings regarding light facilitated ion migration,materials decomposition,and phase segregation.In addition,the reverse bias effect on the stability of tandem modules caused by uneven illumination is discussed.Second,this review also summarizes the thermalinduced degradation and mismatch issue,which underlines the system design of perovskite/c-Si tandems.Third,recent strategies to improve the intrinsic stability of perovskite/c-Si tandems under light and/or heat are reviewed,such as composition engineering,crystallinity enhancement,interface modification,material optimization,and device structure modification.At last,we present several potential research directions that have been overlooked,and hope those are helpful for future research on perovskite based tandem solar cells.

关键词： perovskite c-Si tandem solar cell light stability thermal stability photovoltaic module

Pincer Ru with a single stereogenic identity for highly efficient asymmetric transfer hydrogenation of ketones

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2023年第5期66卷 1443-1449页

作者： Xingjun xu Yipeng You Ming Yu Jin Fan-Jie Meng Chen xu Xiangyou Xing Shenzhen Grubbs Institute and Department of Chemistry Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhen 518055China

The asymmetric reduction of carbonyl compounds by means of the Ru-chiral diphosphine-chiral diamine catalysts is widely useful in organic synthesis where high levels of enantioselectivities have been attributed to multiple ligand chiral elements as well as essential stereochemical matching synergies within them.Described here is the design and discovery of new pincer-type Ru-catalysts that feature only single stereogenic element within ligands,yet the such significantly simplified structure is demonstrated to be well competent for effecting asymmetric reductions as well as kinetic resolutions over a broad range of highly functionalized ketones/alcohols,including heteroaryl substituted substrates that were challenging by known catalyst systems.Alcohols were furnished not only in excellent enantioselectivities,but with turnover numbers(up to 100,000 TONs)that reach the highest levels known to date in asymmetric transfer hydrogenation of ketones.This work should help shed light on the intricate origin of enantioselection in these important processes,and further stimulate rational understanding as well as optimization of chiral catalysts towards efficiency and simplicity.

关键词： pincer Ru-catalysts asymmetric transfer hydrogenation turnover numbers heteroaryl ketones kinetic resolution