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Characteristics of indoor/outdoor PM_(2.5) and elemental components in generic urban, roadside and industrial plant areas of Guangzhou City, China

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Journal of Environmental Sciences 2007年第1期19卷 35-43页

作者： HUANG Hong LEE Shun-cheng CAO Jun-ji ZOU Chang-wei CHEN Xin-geng FAN Shao-jia School of Chemistry and Environment South China Normal University Guangzhou 510006 China Department of Civil and Structural Engineering Hong Kong Polytechnic University Hang Hum Kowloon Hong Kong Institute of Earth Environment Chinese Academy of Sciences Xi＇an 710075 China School of Environmental Science and Engineering Nanchang University Nanchang 330029 China School of Environmental Science and Engineering SunYatSen University Guangzhou 510275 China

Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor （I/O） ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission （PIXE） method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5μg/m^3 for summer period, and 109.9-123.7 μg/m^3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m^3 for summer period, and 8416.8-8900.6 ng/m^3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources.

关键词： PM2.5 elemental components indoor air

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Skills for future university librarians

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Chinese Journal of Library and Information Science 2008年第1期1卷 74-85页

作者： Steve O’Connor LI Mei Pao Yue-Kong Library The Hong Kong Polytechnic University

The purpose of this paper is to examine present librarian skills in academic libraries and to propose possible directions of future libraries on skill requirements. This study provides a valuable methodology to understand the current demands of employers for library staff. It also begins to highlight trends in how the skill set and outlook for future employees are currently being viewed. There has been a combination of these understandings with the scenario planning technique to draw threads anticipating skill requirements in three to five years. These approaches create a powerful analysis. An examination of recent library position advertisements and job descriptions in five countries and regions showed broad communication and technology skills required in academic libraries. The key terms of skills were ranked according to the frequencies used in the advertisements and descriptions. Original research based on data from the United States, Australia, the United Kingdom, New Zealand and Hong Kong, SAR, China. The results are harmonized with predicted future trends from scenario planning exercises.

关键词： university libraries Librarians Skills Scenario planning Future Staff development Employees

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Boost Chopper Behaviors in Solar Photovoltaic System

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Smart Grid and Renewable Energy 2021年第3期12卷 31-52页

作者： Sameer Khader Abdel-Karim Daud Palestine polytechnic university Department of Electrical Engineering Hebron Palestine

This paper investigates the behaviors of Boost DC Chopper used in Photovoltaic energy systems where the solar irradiation changes during the day time causing current and voltage changes. Varying the solar irradiation causes output chopper voltage changes in order to keep working at maximum extracted solar power. The chopper voltage changes leading to variable duty cycle operation of chopper switch and causes a significant change in switch losses in terms of the dissipated power. In addition to that the chopper behaviors are studied when the chopper voltage is boosting up to a predetermined reference value leading to a significant change in chopper current, voltage, duty cycle and occurred losses. A mathematical model for chopper performances and switch losses is derived, and a simulation model using Matlab/ Simulink platforms is conducted to follow the chopper behaviors. Simulation results for concreteSUNPOWER panel type SPR-315E-WHT-D with 315 Watts peak indicates that during the daylight time transistors are exposed to

关键词： DC-DC Converters Photovoltaic Source PWM Buck-Boost Boost Converters

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A videogrammetric technique for measuring the vibration displacement of stay cables

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Geo-Spatial Information Science 2012年第2期15卷 135-141页

作者： ZHOU Xiaoqing XIA Yong WEI Zelong WU Qingxiong College of Civil Engineering Shenzhen University3688 Nanhai RoadShenzhen 518060China Department of Civil and Structural Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina College of Civil Engineering Fuzhou University2 Xue Yuan RoadUniversity TownFuzhou 350108China

Stay cables in cable-stayed bridges are prone to large amplitude oscillations under external *** vibration of the cables is predominantly measured by using accelerometers to measure the *** dynamic displacement is then usually obtained indirectly from the double integration of the acceleration *** paper reports an experimental method of measuring the displacement of stayed cables using a digital video *** the newly developed videogrammetric technique,the video clips are transferred into image frames,from which the shape and location of the target are *** displacement time history is then *** technique is applied to a cable-stayed bridge to measure the dynamic displacement of stay *** displacement is compared with the acceleration data in the frequency and time *** results show that the displacement measured by the digital video camera is comparable to the counterparts integrated from the acceleration *** vibration frequencies identified from the acceleration are finally used to estimate the tension forces of the *** results show that the tension forces have insignificant changes after one year’s operation.

关键词： stay cable vibration displacement measurement videogrammetric technique tension force

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A Review on the Development of Vehicle Driving Simulator

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International Journal of Plant Engineering and Management 2018年第2期23卷 108-121页

作者： LIU Xiaoping FAN Xiaobin Henan polytechnic university He'nan Jiaozuo 454000 China

With the development of the economy, cars have become the common means of transportation for people, and the safety issues related to this and the new technologies are being taken seriously. Vehicle driving simulator, as a kind of simulation equipment, is mostly used in the research, experiment and development of new technology enterprises, meanwhile, it also can realize simulation of car running performance, driving training, and make users get real driving experience. In this paper, present development situation at home and abroad of vehicle driving simulator, and the species, composition and working principle of vehicle driving simulator are introduced and teviewed. Based on vehicle driving simulator ＂driver-vehicle-road environment＂ in the simulation environment, the dynamic simulation of virtual driving system, visual simulation system, driving simulation of ABS and ESP control were analyzed.

关键词： vehicle dynamic simulative driving simulator view simulation system ABS ESP

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Influences of gap size and cyclic-thermal-shock treatment on mechanical properties of TLP bonded IN-738LC superalloy

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Transactions of Nonferrous Metals Society of China 2018年第5期28卷 920-930页

作者： Vahid MALEKI Hamid OMIDVAR Mohammad-Reza RAHIMIPOUR Department of Mining and Metallurgical Engineering Amirkabir University of Technology (Tehran Polytechnic) Department of Ceramic Materials and Energy Research Center

Influences of gap size and cyclic-thermal-shock treatment on the mechanical properties of transient liquid phase（TLP） bonded IN-738 LC superalloy were investigated. For this purpose, TLP bonding of IN-738 LC superalloy was carried out in a vacuum furnace using powdered AMS 4777 as the filler metal. The results showed that isothermal solidified zone（ISZ） consisted of Ni solid-solution and the distribution of alloying elements was homogeneous. High hardness of HV 409 and high shear strength of 506 MPa were observed in 40 μm gap sample. Alloying elements formed γ′ precipitates and the solid-solution in the ISZ. Hardness and shear strength of bonds were reduced with increasing the gap size（in range of 40-120 μm）. The fractured surfaces of complete isothermal solidified bonds showed dimpled rupture, but athermal solidified bonds showed cleavage fracture surface. 10, 20, 30 and 40 thermal-shock cycles were applied to 80 μm gap samples, respectively. The shear strength of the bond was measured to be 268 MPa after the 40 th thermal-shock cycle. The sample with gap size of 80 μm was failed due to crack nucleation on faying surface at 45 th thermal-shock cycle. The amount of the produced brittleness due to quenching the samples in water bath was attributed to the number of thermal-shock cycles.

关键词： IN-738 superalloy TLP bonding mechanical properties cyclic-thermal-shock treatment shear strength

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On the construction of cryptographically strong Boolean functions with desirable trade-off

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2005年第5期6卷 358-364页

作者： REN Kui PARK Jaemin KIM Kwangjo ECE Department Worcester Polytechnic Institute Worcester MA 01609 USAInternational Research Center for Information Security Information and Communication University Daejeon 305-714 Republic of KoreaInternational Research Center for Information Security Information and Communication University Daejeon 305-714 Republic of Korea

This paper proposes a practical algorithm for systematically generating strong Boolean functions (f:GF(2) n →GF(2)) with cryptographic meaning. This algorithm takes bent function as input and directly outputs the resulted Boolean function in terms of truth table sequence. This algorithm was used to develop two classes of balanced Boolean functions, one of which has very good cryptographic properties:nl(f)=2 2k?1?2k+2k?2 (n=2k), with the sum-of-squares avalanche characteristic off satisfying σf=24k+23k+2+23k-2 and the absolute avalanche characteristic off satisfying σf=24k+23k+2+23k-2. This is the best result up to now compared to existing ones. Instead of bent sequences, starting from random Boolean functions was also tested in the algorithm. Experimental results showed that starting from bent sequences is highly superior to starting from random Boolean functions. Key words Boolean functions - Bent sequences - Nonlinearity - GAC - PC - Balancedness Document code A CLC number TP301.6

关键词： Boolean functions Bent sequences Nonlinearity GAC PC Balancedness

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Interfacial engineering of heterostructured carbon-supported molybdenum cobalt sulfides for efficient overall water splitting

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Tungsten 2023年第4期5卷 589-597页

作者： Ming-Yue Ma Han-Zhi Yu Li-Ming Deng Lu-Qi Wang Shu-Yi Liu Hui Pan Jian-Wei Ren Maxim Yu.Maximov Feng Hu Sheng-Jie Peng College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing210016China Institute of Applied Physics and Materials Engineering University of MacaoMacao SAR519000China Department of Mechanical Engineering Science University of JohannesburgCnr Kingsway and University RoadsAuckland ParkJohannesburg2092South Africa Peter the Great Saint-Petersburg polytechnic university 195251Saint PetersburgRussia

Constructing hetero-structured catalyst is promising but still challenging to achieve overall water splitting for hydrogen production with high ***,we developed a sulfide-based MoS_(2)/Co_(l-x)S@C hetero-structure for highly efficient electrochemical hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The carbon derived from the filter paper acts as a conducting carrier to ensure adequate exposure of the active sites guaranteed with improved catalytic *** unique hierarchical nano-sheets facilitate the charge and ion transfer by shortening the diffusion path during ***,the robust hetero-interfaces in MoS_(2)/Co_(1-x)S@C can expose rich electrochemical active sites and facilitate the charge transfer,which further cooperates synergistically toward electro-catalytic ***,the optimal MoS_(2)/Co_(1-x)S@C hetero-structures present small over-potentials toward HER(135 mV@10 mA·cm^(-2))and OER(230 mV@10 mA·cm^(-2)).The MoS_(2)/Co_(1-x)S@C electrolyzer requires an ultralow voltage of 1.6 V at the current density of 10 mA·cm^(-2)with excellent durability,outperforming the state-of-the-art *** work sheds light on the design of the hetero-structured catalysts with interfacial engineering toward large-scale water splitting.

关键词： Overall water splitting Composite Pyrolysis Interface regulation Molybdenum cobalt sulfides

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Proteomic analysis of seed germination under salt stress in soybeans

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Journal of Zhejiang university-Science B(Biomedicine & Biotechnology) 2011年第7期12卷 507-517页

作者： Xiao-yan XU Rui FAN Rui ZHENG Chun-mei LI De-yue YU National Center for Soybean Improvement National Key Laboratory of Crop Genetics and Germplasm Enhancement Nanjing Agricultural University Nanjing 210095 China) Foundation Department Jiangsu Polytechnic College of Agriculture and Forestry Jurong 212400 China) College of Life Sciences Ningxia University Yinchuan 750021 China)

Soybean (Glycine max (L.) Merrill) is a salt-sensitive crop,and its production is severely affected by saline ***,the response of soybean seeds to salt stress during germination was investigated at both physiological and proteomic *** salt-tolerant cultivar Lee68 and salt-sensitive cultivar N2899 were exposed to 100 mmol/L NaCl until radicle protrusion from the seed *** both cultivars,the final germination percentage was not affected by salt,but the mean germination times of Lee68 and N2899 were delayed by 0.3 and 1.0 d,respectively,compared with *** response to salt stress,the abscisic acid content increased,and gibberellic acid (GA1+3) and isopentenyladenosine ***-3-acetic acid increased in Lee68,but remained unchanged in *** proteins extracted from germinated seeds were separated using two-dimensional gel electrophoresis (2-DE),followed by Coomassie brilliant blue G-250 *** 350 protein spots from 2-DE gels of pH range 3 to 10 and 650 spots from gels of pH range 4 to 7 were reproducibly resolved,of which 18 protein spots showed changes in abundance as a result of salt stress in both *** matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-TOF-MS) analysis of the differentially expressed proteins,the peptide mass fingerprint was searched against the soybean UniGene database and nine proteins were successfully *** and 20S proteasome subunit β-6 were up-regulated in both *** 3-phosphate dehydrogenase,glutathione S-transferase (GST) 9,GST 10,and seed maturation protein PM36 were down-regulated in Lee68 by salt,but still remained at a certain ***,these proteins were present in lower levels in control N2899 and were up-regulated under salt *** results indicate that these proteins might have important roles in defense mechanisms against salt stress during soybean seed germination.

关键词： Proteomics Salt stress Seed germination Soybean

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Decision-making competency, self-determination, and health lifestyle in nursing students

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Open Journal of Nursing 2013年第2期3卷 221-226页

作者： BongSuk Lee Ji-Su Kim Department of Nursing Hallym Polytechnic University Chuncheon Republic of Korea

Introduction: This study identifies and analyzes the levels of relations between decision-making competency, self-determination, and health lifestyle in nursing students. Methods: This study was designed as a descriptive research to identify the relations of nursing students’ decision-making competency, self-determination, and health lifestyle. The subjects were 187 nursing students. Data were collected using a structured questionnaire and were analyzed by the IBM SPSS Statistics 19 program. Results: Decision-making competency of nursing students was 3.38 ± 0.41 points, and self-determination was 3.07 ± 0.38 points. Stress and physical exercise were the general and health-related lifestyle factors that contributed to the differences in decision-making competency. There were no differences in self-determination according to these factors. Conclusion: The results of the study showed that the levels of decision-making competency and self-determination in nursing students were moderate. Further studies are recommended for the development of these core abilities in nursing students.

关键词： Undergraduate Nursing Students Decision Making Self-Determination Lifestyle

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