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Distinct MLT asymmetry of auroral kilometric radiation observed by the FAST satellite

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Earth and Planetary Physics 2025年第1期9卷 188-193页

作者： JiaWen Tang Sai Zhang FuLiang Xiao HongMing Yang Si Liu YiHua He chang Yang YuYue jin ZhouKun Deng Ping Li Archie James Johnston School of Physics and Electronic Sciences Changsha University of Science and TechnologyChangsha 410114China Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments Changsha University of Science and TechnologyChangsha 410114China School of Electrical and Information Engineering Changsha University of Science and TechnologyChangsha 410114China

Auroral Kilometric Radiation (AKR) is a common radio emission,which can contribute to the magnetosphere-ionosphereatmosphere co u *** emissions have been observed in all magnetic planet magnetospheres of the solar *** this study,using observations from the FAST satellite from 30 August 1996 to 9 September 2001,the distribution of AKR in altitude=500-4500 km and invariant latitude (|ILAT|)=60°-80°has been analyzed.63045 AKR samples have been identified with~48%(52%) samples on the dayside (nightside).Of considerable interest,there is a distinct MLT asymmetry with the high occurrence rate in MLT=05-08 and 18-22(02-05 and 12-17) in the northern (southern) *** distinct MLT asymmetry is associated with the direction of Bxof the interplaneta ry magnetic *** addition,the occurrence rate on the nightside clearly increases as the AE^(*) index *** study further enriches the information and understanding of AKR in the magnetosphere as well as other similar radio emissions.

关键词： asymmetry auroral kilometric radiation interplanetary magnetic field

循环加载与卸围压组合扰动下红砂岩损伤破裂与渗透特性

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岩土工程学报 2025年第1期47卷 48-56页

作者：姚玮俞缙周先齐常方强常旭厦门理工学院土木工程与建筑学院福建厦门361024 华侨大学福建省隧道与城市地下空间工程技术研究中心福建厦门361021

为探究深地工程开挖诱导岩体损伤破裂及渗透性演化规律,开展了同步测定波速与渗透率的循环加载与卸围压组合扰动三轴试验,研究了不同条件下红砂岩的损伤与渗透性演化规律。结果表明:①岩石在不同组合扰动阶段具有不同的应力应变曲线形态... 详细信息

为探究深地工程开挖诱导岩体损伤破裂及渗透性演化规律,开展了同步测定波速与渗透率的循环加载与卸围压组合扰动三轴试验,研究了不同条件下红砂岩的损伤与渗透性演化规律。结果表明:①岩石在不同组合扰动阶段具有不同的应力应变曲线形态,其末端形态取决于在何种扰动阶段破坏,初始应力比为决定组合扰动诱发岩石破坏难易的主要因素;②总峰值轴向应变随初始应力比增大而增大,其中组合扰动轴向应变占比始终较低,总峰值体积应变绝对值随初始应力比增大而先增大后减小,其中组合扰动体积应变占比较高;③在初始加载阶段,波速增大,渗透率降低,在组合扰动阶段,波速下降,渗透率增加,且损伤与体积应变近似呈线性关系,损伤与渗透率随扰动次数增加均呈先慢后快的增长趋势,且拐点分别近似在一条直线上;④岩石在组合扰动卸围压阶段破坏为单剪切破坏模式,在组合扰动循环加载阶段破坏为共轭剪切破坏模式;⑤双高(高初始应力比与高初始围压)条件将显著加剧岩体开挖失稳破坏风险。

关键词：深地工程组合扰动力学特性损伤渗透性

Recent progress on photoactive nonprecious transition-metal complexes

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Science China Chemistry 2025年第1期68卷 46-95页

作者： Zhong-Liang Gong Hong-Jie Zhang Yan Cheng Jianxun Liu Yuhan Ai Yaqin Li Zhihui Feng Qiong Zhang Shaolong Gong Yong Chen chang-Jiang Yao Yuan-Yuan Zhu Liang-jin Xu Yu-Wu Zhong CAS Key Laboratory of Photochemistry Institute of Chemistry Chinese Academy of Sciences State Key Laboratory of Structural Cemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences School of Chemistry and Chemical Engineering Anhui Key Laboratory of Advanced Catalytic Materials and Reaction EngineeringHefei University of Technology State Key Laboratory of Explosion Science and Safety Protection School of Mechatronical Engineering Beijing Institute of Technology College of Chemistry and Molecular Sciences Hubei Key Lab on Organic and Polymeric Optoelectronic Materials Wuhan University School of Chemistry and Chemical Engineering Anhui University Key Laboratory of Photochemical Conversion and Optoelectronic Materials & CAS-HKU Joint Laboratory on New Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences

Photoactive complexes of nonprecious transition metals, mainly including those in the first-row and partially the second-row of the Periodic table of elements, have received increasing attention in view of their low cost and long-term sustainability. They are recognized as promising alternatives to noble transition metal complex congeners that have been extensively studied in optoelectronic devices, artificial photosynthesis, photocatalysis, biodiagnostics, and therapeutics, etc. This review is devoted to a comprehensive summary on the classical and recent advances on photoactive nonprecious transition metal complexes, including photoactive Zr, V, Cr, Mo, and W complexes, Mn complexes and hybrids, Fe, Co, Ni, and Cu complexes, and Zn and Cd complexes and hybrids. A particular focus is given on the molecular design, modulation of photophysical and photochemical properties, and applications of the representative and lately-developed nonprecious metal complexes. In addition, a perspective on the future development in this field is provided at the end of this review.

关键词： photoactive metal complexes earth-abundant metals nonprecious metal complexes luminescence photochemistry

Effects of an Urban Park and Residential Area on the Atmospheric CO_2 Concentration and Flux in Seoul,Korea

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Advances in Atmospheric Sciences 2013年第2期30卷 503-514页

作者： Moon-soo PARK Seung jin JOO chang Seok LEE Center for Atmospheric and Environmental Modeling Seoul 151 919Korea Life and Environmental Engineering Seoul Women's UniversitySeoul 139 774Korea

The CO2 concentrations and fluxes over an urban forest site （Namsan） and an urban residential region （Boramae） in Seoul, Korea, during the non-growing season （2 4 March 2011）, the growing season （10-12 June 2011）, and the late-growing season （22-24 September 2011） were analyzed. The CO2 concentrations of two sites showed nearly the same diurnal variation, with a maximum value occurring during the night and a minimum value occurring during daytime, as well as the same seasonal variation, with a maximum value during the non-growing season （early spring） and a minimum value during the growing season （summer）. The CO2 flux over the urban forest did not show any typical diurnal variation during the non-growing season, but did show diurnal variation with a small positive value during the night and a large negative value during daytime in the growing and late-growing seasons due to photosynthesis in the urban forest. The CO2 flux over the urban residential region showed a positive daily mean value for all periods, with large values during the non-growing season and small values during the growing season, and it also showed diurnal variation with two maxima at 0600-1000 LST and 1800-2400 LST, and two minima at 0300-0600 LST and 1100-1500 LST, and was strongly correlated with the use of liquefied natural gas for cooking and heating by surrounding houses.

关键词： C02 concentration C02 flux Seoul urban forest urban residential region

Ni, Co-double hydroxide wire structures with controllable voids for electrodes of energy-storage devices

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Journal of Materials Science & Technology 2020年第20期52卷 126-135页

作者： jin Kyu Kim chang soo Lee Jae Hun Lee Jung Tae Park Jong Hak Kim Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Republic of Korea Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul 05029Republic of Korea

We re port the facile synthesis of Ni,Co-double hydroxide wire(NCHW)-based electrodes directly grown on a conductive substrate via a hydrothermal *** NCHW nanostructures were grown on Ni foam,and the growth was controlled using different compositions of solvents(ethanol and water).With increasing volume ratio of ethanol to water,the density of the wires decreased,and the spatial voids between the wires *** formation of large empty spaces improved the electrochemical performance because the exposure of a large surface area of the structure to the electrolyte resulted in a large number of active sites and facile electrolyte penetration into the *** different NCHW structures were ascribed to the pivotal role of the solvent in the urea hydrolysis;the solvent triggered the formation of hydroxides during the hydrothermal *** electrochemical performance of the NCHW electrodes was investigated via galvanostatic charge/discha rge tests,cyclic voltammetry,and electrochemical impedance *** highest specific capacitance was 1694.7 m F/cm^2 at 2 mA/cm^2,with excellent capacitance retention of 81.5% after 5000 *** superior electrochemical performance of the NCHW electrodes is attributed to the large number of active sites and facile electrolyte diffusion into the structure,due to the well-organized structure with an optimized density of nanowires and large voids between the wires.

关键词： Ni,Co-double hydroxide Nanowire Electrode Energy-storage device Supercapacitor

Highly efficient reduction of aqueous Cr(VI) with novel ZnO/SnS nanocomposites through the piezoelectric effect

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Journal of Environmental Sciences 2022年第8期34卷 57-66页

作者： Hao Sun soo-jin Park Department of Chemistry and Chemical Engineering Inha UniversityIncheon 22212South Korea

In this work, novel ZnO/SnS nanocomposites were successfully synthesized via a hydrothermal approach, which is developed for piezoelectric catalytic reduction of hexavalent chromium(Cr(VI)) in an aqueous solution. The constructed ZnO/SnS nanocomposites exhibited higher catalytic efficiency for Cr(VI) reduction under a mechanical force(e.g., ultrasonic vibration) compared to pristine ZnO and SnS. In particular, the ZnO/SnS(with 30 wt.% of SnS) heterojunctions revealed an optimal degradation activity among all the prepared samples, which completely removed the Cr(VI)(20 mg/L) solution within 35 min. Moreover, the piezoelectric catalytic activity of ZnO/SnS remained stable after four consecutive cycling experiments. The results of the morphology observations indicated that the SnS nanoparticles adhere to the surface of the ZnO nanorods. The improved piezoelectric catalytic performance of the ZnO/SnS heterojunctions can be attributed to the formation of an intimate interfacial between ZnO and SnS, which effectively inhibits the electron-hole recombination and speeds up the rate of charge transfer. The study reveals a new design of ZnO/SnS heterojunctions as a high-performance and eco-friendly piezoelectric catalyst and provides a promising strategy for addressing environmental problems and energy crises.

关键词： Cr(VI)reduction ZnO/SnS Piezoelectric effect

Velocity Profiles between Two Baffles in a Shell and Tube Heat Exchanger

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Journal of Thermal Science 2015年第4期24卷 356-363页

作者： Tae-Hyun chang chang-Hoan Lee Hae-soo Lee Kwon-soo Lee Senior Research Fellow of RESEAT Korea Institute of Science and Technology Information Korea Institute of Science and Technology Information Postdoctoral Research Fellow School of Mechanical Engineering of Kyungnam University International University of Korea

Heat exchangers are extensively utilized for waste heat recovery,oil refining,chemical processing,and steam *** this study,velocity profiles are measured using a 3D particle image velocimetry(PIV)system between two baffles in a shell and tube heat exchanger for parallel and counter *** PIV and computational fluid dynamics results show the occurrence of some strong vectors near the *** vectors are assumed due to the clearance between the inner tubes and the front ***,the major parts of the vectors are moved out through the bottom opening of the rear baffle,and other vectors produce a large circle between the two *** simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent *** k-εturbulence model is employed to calculate the flows along the heat exchanger.

关键词： Baffle P1V Shell and tube heat exchanger Cut off ratio CFD

Structural considerations in friction welding of hybrid Al_2O_3-reinforced aluminum composites

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 42-46页

作者： In-Duck PARK Choon-Tae LEE Hyun-soo KIM Woo-jin CHOI Myung-chang KANG Busan Metropolitan City Hall Fundamental Industries Division 2001 Jungang-ro Yeonje-gu Busan 611-735 Korea Department of Automotive & Mechanical Engineering Silla University Research & Development Center Sam-Ho precision 1256-1 Daejeo2-dong Gangseo-gu Busan 618-807 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

Comparative studies on the relationship between the welding parameters and joining efficiency in the friction welding of hybrid Al203-reinforced aluminum composites were conducted. Metal matrix composites （MMCs） with 37% （volume fraction） aluminum particle were joined by friction welding. The results show that the effects of the rotation speed on the reduction rate of particle size are greater than those of the upset pressure, and the area of the MMC weld zone decreases as the joining efficiency increases, while it is considered that the joining efficiency does not increase as the reduction rate of particle size decreases. During the macro-examination of the bonding interlace, a gray discolored region was observed on the bonding interface, and the center of the region was dark gray. After the micro-examination of the bonding interface, base metal made some second particulate formed by condensed alumina particulate but discoloration part distributed minute alumina particulate without second particulate. Consequently, it was also observed that rotational speed of 3 000 r/min and upset pressure of 63.6 MPa showed a very ***.

关键词： friction welding hybrid aluminum composite bonding interface joining efficiency metal matrix composite

Significance of age and comorbidity as prognostic indicators for patients with bladder cancer

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Asian Journal of Andrology 2010年第5期12卷 766-774页

作者： Moon soo Ha In Ho chang Department of Urology College of Medicine Chung-Ang University Seou1140-75 7 Korea

The aim of this study was to determine the impact that age and comorbidity status have on both overall and bladder cancer-specific survival of bladder cancer patients. We obtained medical information pertaining to a population of 528 patients with newly diagnosed bladder cancer from Chung-Ang University Hospital cancer registry. The Adult Comorbidity Evaluation-27 （ACE-27） test, which has been previously validated in adult cancer patients, was used to assess comorbidity. We evaluated differences in the demographic and clinical characteristics of included patients, as well as differences in the treatments they received after categorizing them by age. The median age at the time of bladder cancer diagnosis of the entire cohort was 63 years, and the median follow-up time was 97 months. Of the 528 patients who were included in our study, 303 had at least one comorbid condition and 249 died during the follow-up period. When patients were stratified by age, we found that older patients had a higher proportion of severe comorbidities （P 〈 0.01） than younger patients, and that a lower proportion of them underwent radical cystec- tomy for invasive bladder cancer （IBC）（P 〈 0.01）. By multivariate analysis, we found that older age was predictive of lower overall survival （OS） and bladder cancer-specific survival （BCSS） rates among patients with superficial bladder cancer （SBC） and of lower OS rates among patients with IBC. We also found that moderate-severe comorbidity status and treatment through a bladder-conserving approach were predictive of lower OS and cancer-specific survival rates among patients with IBC. The disparity between overall deaths and bladder cancer deaths was shown in SBC and increased along with age and higher comorbidity. Age and comorbidity were found to be independent predictive factors of OS and BCSS among bladder cancer patients, and explained the disparity that we observed between overall bladder cancer-specific mortality rates.

关键词： age comorbidity neoplasm prognostic indicator urinary bladder