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An optimal rigidity theorem for complete submanifolds in a sphere

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Applied Mathematics(A Journal of Chinese Universities) 2008年第2期23卷 219-226页

作者： XU Hong-wei ZHU jiao-feng Center of Math. Sci. Zhejiang Univ. Hangzhou 310027 China

It is proved that if M^n is an n-dimensional complete submanifold with parallel mean curvature vector and flat normal bundle in S^n＋p（1）, and if supM S 〈 α（n, H）, where α（n,H）=n＋n^3/2（n-1）H^2-n（n-2）/n（n-1）√n^2H^4＋4（n-1）H^2,then M^n must be the totally urnbilical sphere S^n（1/√1＋H^2）.An example to show that the pinching constant α（n, H） appears optimal is given.

关键词： submanifold rigidity flat normal bundle mean curvature.

冷速对10CrMo910钢焊缝组织性能影响的试验研究

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佳木斯大学学报（自然科学版） 2013年第2期31卷 318-320页

作者：李海涛韩涛吴明忠朱永长焦玉凤佳木斯大学材料学院黑龙江佳木斯154007 佳木斯大学机械学院黑龙江佳木斯154007

针对10CrMo910钢焊接中常出现的淬硬、冷裂现象,制定合理的焊接工艺,成功制备了三组焊接接头.利用温度测试系统实时测试了焊后三种冷却方式下的温度-时间曲线,通过金相组织观察和显微硬度试验研究了冷速对接头组织和硬度的影响.结果表明... 详细信息

针对10CrMo910钢焊接中常出现的淬硬、冷裂现象,制定合理的焊接工艺,成功制备了三组焊接接头.利用温度测试系统实时测试了焊后三种冷却方式下的温度-时间曲线,通过金相组织观察和显微硬度试验研究了冷速对接头组织和硬度的影响.结果表明:冷速对焊后组织和硬度影响较大,可通过控制冷速获得焊后所需的组织和性能.

关键词：耐热钢冷却速度焊缝显微硬度

Short-term exposure to ozone and nonaccidental mortality in Northeast China

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Biomedical and Environmental Sciences 2023年第1期36卷 99-102页

作者： ZHANG Yi Fan MA yu Xia LI He Ping CHENG Bo Wen feng feng Liu jiao Hao Ran College of Atmospheric Sciences Key Laboratory of Semi-Arid Climate ChangeMinistry of EducationLanzhou UniversityLanzhou 730000GansuChina Liaoning Provincial Meteorological Bureau Shenyang 111100LiaoningChina

Ambient pollutants are a major environmental risk factor for human health[1]. Ozone(O3) is a highly reactive, oxidative gas that is formed through the interaction of volatile organic compound precursors and nitrogen oxides(NOx). Several studies have demonstrated that exposure to ambient O3in the troposphere is associated with increased mortality.

关键词： oxidative ambient oxides

Interfacial engineering of holey platinum nanotubes for formic acid electrooxidation boosted water splitting

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Journal of Energy Chemistry 2023年第2期77卷 209-216,I0006页

作者： Zi-Xin Ge yu Ding Tian-jiao Wang feng Shi Pu-Jun Jin Pei Chen Bin He Shi-Bin Yin yu Chen Key Laboratory of Macromolecular Science of Shaanxi Province Key Laboratory of Applied Surface and Colloid Chemistry(Ministry of Education)Shaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi’an 710062ShaanxiChina College of New Materials and New Energies Shenzhen Technology UniversityShenzhen 518118GuangdongChina MOE Key Laboratory of New Processing Technology for Non-ferrous Metals and Materials Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured MaterialsGuangxi UniversityNanning 530004GuangxiChina

Both structure and interface engineering are highly effective strategies for enhancing the catalytic activity and selectivity of precious metal *** this work,we develop a facile pyrolysis strategy to synthesize the high-quality holey platinum nanotubes(Pt-H-NTs)using nanorods-like Pt^(Ⅱ)-phenanthroline(PT)coordination compound as self-template and self-reduction ***,an up-bottom strategy is used to further synthesize polyallylamine(PA)modified Pt-H-NTs(Pt-HNTs@PA).PA modification sharply promotes the catalytic activity of Pt-H-NTs for the formic acid electrooxidation reaction(FAEOR)by the direct reaction ***,PA modification also elevates the catalytic activity of Pt-H-NTs for the hydrogen evolution reaction(HER)by the proton enrichment at electrolyte/electrode *** from the high catalytic activity of Pt-H-NTs@PA for both FAEOR and HER,a two-electrode FAEOR boosted water electrolysis system is fabricated by using Pt-H-NTs@PA as bifunctio nal *** FAEOR boosted water electrolysis system only requires the operational voltage of 0.47 V to achieve the high-purity hydrogen production,showing an energy-saving hydrogen production strategy compared to traditional water electrolysis system.

关键词： Holey platinum nanotubes Chemical functionalization Formic acid oxidation reaction Hydrogen evolution reaction Water splitting

Clinical outcomes and 5-year follow-up results of keratosis pilaris treated by a high concentration of glycolic acid

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World Journal of Clinical Cases 2021年第18期9卷 4681-4689页

作者： Yan Tian Xiao-Xin Li jiao-jiao Zhang Qing yun Si Zhang Jia-Yi yu Xue-jiao feng Ai-Ting Xia Yang Kang feng Huang Fang Wan Department of Dermatology Air Force Characteristic Medical CenterBeijing 100142China Center of Medical and Health Unit 71901 of PLALiaocheng 252000Shandong ProvinceChina

BACKGROUND Keratosis pilaris is a hereditary abnormal keratosis of the hair follicle ***-brown keratotic plugs in the pores and dark red keratotic papules at the openings of hair follicles can be seen,which contain coiled hair and are often accompanied by perifollicular erythema and *** acid can correct the abnormalities of hair follicular duct keratosis and eliminate excessive accumulation of *** also promotes skin metabolism and accelerates the melanin *** therapeutic effect is related to the glycolic acid *** To evaluate the efficacy and safety of a high concentration of glycolic acid in the treatment of keratosis pilaris,and to observe the outcomes at 5-year of *** Twenty-five participants were recruited and areas with typical keratosis pilaris were selected as testing *** concentrations of glycolic acid(50%or 70%)were applied to a circular area(d=8 cm,S=50 cm2)and repeated four times,on days 0,20,40 and *** each treatment and 20 d after the last treatment,on days 0,20,40,60,and 80 and at a 5-year follow-up,The number of follicular keratotic papules were counted and the extent of perifollicular erythema and pigmentation was *** the same time,the participants provided subjective evaluations of treatment efficacy and *** Treatment effectiveness was indicated by the percentage of keratotic papules in the test site,on days 20,40,60 and 80,which were 8%,12%,36%,and 60%,*** with day 0,each difference was significant(P0

关键词： Keratosis pilaris Glycolic acid Keratotic papules Follicular erythema Melanin pigmentation

Preparation and gas-sensing performance of SnO2/NiO composite oxide synthesized by microwave-assisted liquid phase deposition

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Particuology 2018年第6期16卷 118-125页

作者： Jing He Wanli jiao Lei Zhang Rui feng School of Material Science and Engineering Shandong University of TechnologyZibo 255049China

We synthesized SnO2/NiO composite oxides by microwave-assisted liquid phase deposition to improve their surface physico-chemical properties and gas-sensing selectivity,and we investigated how the molar ratio of Ni^2+to Sn^4+and the microwave power affected their gas-sensing *** microstructure,surface physico-chemical states,and morphology of the samples were characterized by X-ray diffraction,X-ray photoelectron spectroscopy,and scanning electron microscopy,*** adsorption-desorption isotherms were used to characterize the specific surface areas of the *** results showed that microwave-assisted liquid phase deposition increased the surface-adsorbed oxygen content and the specific surface area of the SnO2/NiO composite oxide from about 22to 120m2/*** the molar ratio of Ni^2+to Sn^4+was 0.1,the gas response to 1000ppm ethanol gas reached 84.7at a lower working voltage of ***,the optimum working voltages for methanol and acetone gas were 4.5and 4.0V,***,a new method was found to improve the selectivity of the gas ***,at a working voltage of 4.0V,the gas response of a SnO2/NiO gas sensor synthesized by microwave-assisted liquid phase deposition with the optimum radiation power of 450W to 1000ppm acetone gas was 49.7,twice that of a sensor synthesized by traditional liquid phase deposition.

关键词： SnO2/NiO composite powders Microwave Liquid phase deposition Gas-sensing performance

Photonics-aided THz-wireless transmission over 400 m at 335 GHz

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Science China(Technological Sciences) 2022年第12期65卷 3082-3084页

作者： LI WeiPing yu JianJun ZHU BoWen WANG feng TAN yuXuan WANG YanYi ZHU Min ZHANG jiao ZHOU Wen ZHAO feng yu JianGuo Key Laboratory for Information Science of Electromagnetic Waves(MoE) Fudan UniversityShanghai 200433China Purple Mountain Laboratories Nanjing 211111China School of Electronic Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

The terahertz(THz)band(0.3–10 THz),with abundant bandwidth,can satisfy the need for large-capacity transmission of fiber-wireless integration communication systems,which has attracted more and more attention[1–3].

关键词： wireless fiber communication

Atom transfer radical polymerization and copolymerization of isoprene catalyzed by copper bromide/2,2＇-bipyridine

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Chinese Chemical Letters 2016年第6期27卷 910-914页

作者： Yi-feng Zhu feng-jiao Jiang Pan-Pan Zhang jiao Luo Hua-Dong Tang Institute of Industrial Catalysis Zhejiang University of Technology Hangzhou Zhejiang 310014 China

ATRP, as one of the most successful controlled/‘‘living＇＇ radical polymerization techniques, has been applied to a large variety of monomers including styrenes,（meth）acrylates,（meth）acrylamides,acrylonitrile, and vinyl acetate. However, ATRP of isoprene still remains a challenge due to poor solubility of copper catalysts in isoprene and low chain propagation rate constant of the monomer. In this work,Cu Br/2,2＇-bipyridine was found to effectively mediate ATRP of isoprene at 100 °C, 130 °C, and 150 °C with ethyl 2-bromopropionate as an initiator. The polymerizations proceeded smoothly and reached 48.1%,53.3%, and 71.0% conversions, respectively, in 72 h, producing polyisoprenes with molecular weights close to theoretical values and relatively narrow distributions. A block copolymer of polystyrene-bpolyisoprene was prepared using Cu Br/2,2＇＇-bipyridine as a catalyst and polystyrene as a ***-1H NMR and-（13）C NMR analysis of polyisoprene indicated that the polymer had 88.8% 1,4-addition structure and 63.9% of the polymer backbone units were in trans-configuration.

关键词： Atom transfer radical polymerization Isoprene Kinetics Block copolymer

Nonfunctional bladder paraganglioma misdiagnosed as hemangioma:A case report

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World Journal of Clinical Cases 2022年第15期10卷 4929-4934页

作者： jiao Chen Han-feng Yang Department of Obstetrics and Gynecology Affiliated Hospital of North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina Department of Radiology Affiliated Hospital of North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina

BACKGROUND Paraganglioma of the urinary bladder(PUB)is a nonepithelial tumor of the bladder that is also known as bladder *** incidence of nonfunctional paraganglioma of the urinary bladder is rare in clinical *** SUMMARY A case of nonfunctional paraganglioma of the urinary bladder diagnosed and treated in our hospital is reported herein.A 2.5 cm×2.1 cm moderate-echo mass protruding into the right anterior wall of the bladder was incidentally found during transvaginal color Doppler ultrasound *** on a contrastenhanced computed tomography scan of the bladder,the right anterior wall of the bladder was considered to present a *** patient underwent laparoscopic partial resection of the bladder wall in our hospital,and pathological results showed paraganglioma of the *** present,we have followed up with the patient for half a year,and there has been no recurrence of the *** The imaging patterns of PUB and bladder hemangioma are *** clinical practice,the possibility of PUB should be considered for a single wide-based isoechoic mass in the bladder,especially functional PUB may cause some adverse effects during surgery.

关键词： Bladder tumor Paraganglioma Diagnosis and treatment methods Case report