期刊文献+
共找到178,950篇文章
< 1 2 250 >
每页显示 20 50 100
Uncertainties of ENSO-related Regional Hadley Circulation Anomalies within Eight Reanalysis Datasets
1
作者 Yadi LI Xichen LI +3 位作者 Juan FENG Yi ZHOU Wenzhu WANG Yurong HOU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第1期115-140,共26页
El Nino-Southern Oscillation(ENSO),the leading mode of global interannual variability,usually intensifies the Hadley Circulation(HC),and meanwhile constrains its meridional extension,leading to an equatorward movement... El Nino-Southern Oscillation(ENSO),the leading mode of global interannual variability,usually intensifies the Hadley Circulation(HC),and meanwhile constrains its meridional extension,leading to an equatorward movement of the jet system.Previous studies have investigated the response of HC to ENSO events using different reanalysis datasets and evaluated their capability in capturing the main features of ENSO-associated HC anomalies.However,these studies mainly focused on the global HC,represented by a zonal-mean mass stream function(MSF).Comparatively fewer studies have evaluated HC responses from a regional perspective,partly due to the prerequisite of the Stokes MSF,which prevents us from integrating a regional HC.In this study,we adopt a recently developed technique to construct the three-dimensional structure of HC and evaluate the capability of eight state-of-the-art reanalyses in reproducing the regional HC response to ENSO events.Results show that all eight reanalyses reproduce the spatial structure of HC responses well,with an intensified HC around the central-eastern Pacific but weakened circulations around the Indo-Pacific warm pool and tropical Atlantic.The spatial correlation coefficient of the three-dimensional HC anomalies among the different datasets is always larger than 0.93.However,these datasets may not capture the amplitudes of the HC responses well.This uncertainty is especially large for ENSO-associated equatorially asymmetric HC anomalies,with the maximum amplitude in Climate Forecast System Reanalysis(CFSR)being about 2.7 times the minimum value in the Twentieth Century Reanalysis(20CR).One should be careful when using reanalysis data to evaluate the intensity of ENSO-associated HC anomalies. 展开更多
关键词 regional Hadley circulation ENSO atmosphere-ocean interaction reanalysis data
下载PDF
Otorhinolaryngological (ORL) and Cervicofacial Injuries Resulting from Road Accidents within the Otorhinolaryngology (ORL) Department of the Regional Hospital of Mamou
2
作者 Mamadou Mouctar Ramata Diallo Ibrahima Diallo +8 位作者 Alsény Camara Mamadou Aliou Diallo Raphan Madi Kaba Keita Abdoulaye Sow Alsény Cisse Sory Sacko Mamadou Gouraissiou Diallo Abdoulaye Keita Alpha Oumar Diallo 《International Journal of Otolaryngology and Head & Neck Surgery》 2024年第1期16-28,共13页
Introduction: Otorhinolaryngological (ORL) and cervicofacial traumas encompass injuries affecting the neck, face, and ORL region, resulting from external influence. The objective of this study was to conduct an epidem... Introduction: Otorhinolaryngological (ORL) and cervicofacial traumas encompass injuries affecting the neck, face, and ORL region, resulting from external influence. The objective of this study was to conduct an epidemiological and clinical analysis of ORL and cervicofacial injuries observed in victims of road accidents treated at the Otorhinolaryngology (ORL) department of the Regional Hospital of Mamou. Materials and Methods: This prospective and descriptive study was conducted over a period of 12 months, from January 1st to December 31st, 2021, within the Otorhinolaryngology (ORL) department of the Regional Hospital of Mamou. It included patients hospitalized for ORL and/or cervicofacial traumas resulting from road accidents during the study period. Results: A total of 348 cases were included, representing 36.22% of all traumas related to road accidents (AVP) within the Regional Hospital of Mamou. The average age of the patients was 26.44 years, with a sex ratio of 3.83, favoring males. The dominant socio-professional category was students, encompassing 32.47% of cases. Road accidents were mainly associated with motorcycle use (31.32% motorcycle-to-motorcycle, 24.43% motorcycle skidding, 13.51% motorcycle-pedestrian). Facial region injuries were the most common, accounting for 69.03% of cases, followed by rhinological injuries (17.28%) and otological injuries (13.69%). Associated injuries were predominantly closed head traumas (52.55%) and lower limb fractures (20.41%). Imaging was underutilized. Regarding surgical interventions, reconstructive surgery was the most predominant, accounting for 52.51% of cases, with a management timeframe of 30 minutes to 12 hours for 99.72% of patients. Conclusion: Road traffic accidents remain a serious public health issue, primarily affecting young males. Emphasis should be placed on road safety measures to reduce the frequency of these accidents. 展开更多
关键词 ENT Injuries Road Accidents regional Hospital of Mamou
下载PDF
Effects of emitter discharge rates on soil salinity distribution and cotton(Gossypium hirsutum L.) yield under drip irrigation with plastic mulch in an arid region of Northwest China 被引量:16
3
作者 Sulitan DANIERHAN Abudu SHALAMU +1 位作者 Hudan TUMAERBAI DongHai GUAN 《Journal of Arid Land》 SCIE CSCD 2013年第1期51-59,共9页
A field experiment was carried out to investigate the effects of different emitter discharge rates under drip irrigation on soil salinity distribution and cotton yield in an extreme arid region of Tarim River catchmen... A field experiment was carried out to investigate the effects of different emitter discharge rates under drip irrigation on soil salinity distribution and cotton yield in an extreme arid region of Tarim River catchment in Northwest China. Four treatments of emitter discharge rates, i.e. 1.8, 2.2, 2.6 and 3.2 L/h, were designed under drip irrigation with plastic mulch in this paper. The salt distribution in the range of 70-cm horizontal distance and 100-cm vertical distance from the emitter was measured and analyzed during the cotton growing season. The soil salinity is expressed in terms of electrical conductivity (dS/m) of the saturated soil extract (ECe), which was measured using Time Domain Reflector (TDR) 20 times a year, including 5 irrigation events and 4 measured times before/after an irrigation event. All the treatments were repeated 3 times. The groundwater depth was observed by SEBA MDS Dipper 3 automatically at three experimental sites. The results showed that the order of reduction in averaged soil salinity was 2.6 L/h 〉 2.2 L/h 〉 1.8 L/h 〉 3.2 L/h after the completion of irrigation for the 3-year cotton growing season. Therefore, the choice of emitter discharge rate is considerably important in arid silt loam. Usually, the ideal emitter discharge rate is 2.4-3.0 L/h for soil desalinization with plastic mulch, which is advisable mainly because of the favorable salt leaching of silt loam and the climatic conditions in the studied arid area. Maximum cotton yield was achieved at the emitter discharge rate of 2.6 L/h under drip irrigation with plastic mulch in silty soil at the study site. Hence, the emitter discharge rate of 2.6 L/h is recommended for drip irrigation with plastiic mulch applied in silty soil in arid regions. 展开更多
关键词 drip irrigation soil salinity salt balance cotton yield emitter discharge rate
下载PDF
Approach to Delimiting Metropolitan Regions' Boundary and Grading Urban Hierarchy Within a Metropolitan Region——A Case Study of Shanghai Metropolitan Region 被引量:6
4
作者 LUO Shougui Andrew JOHNSTON CHEN Dongchun 《Chinese Geographical Science》 SCIE CSCD 2008年第3期197-205,共9页
In metropolitan regions, the change in the strength of "flows" between a core city and surrounding cities re-flects the range of the core city's influence, while the gravity between core city and other c... In metropolitan regions, the change in the strength of "flows" between a core city and surrounding cities re-flects the range of the core city's influence, while the gravity between core city and other cities reflects the strength of potential relation between them. This article firstly attempts to delimit the boundary of metropolitan regions with the two dimensions measure combining "flows" and gravitation. The former is measured through the flow of people be-tween the core city and surrounding cities, and the latter is measured through both population and gross domestic products (GDP) of the core city and surrounding cities. The hierarchy of the cities within a metropolitan region is classified in order to emphasize the roles of the cities belonging to the metropolitan regions, different from the general way through population scale and administrative level, and is typical in China. This paper uses the Shanghai metropolitan region as a research case, determining boundary of this metropolitan region clearly and classifying hierarchy of the cities within the region. The final results are significantly different to previous work, even overthrowing the traditional system of urban hierarchy partly. It is helpful to highlight the function of cities in organizing the regional economy, the level structure of metropolitan regions, and each city's relative importance in a metropolitan region, which can be taken as scientific basis for planning integrated regions or urban systems. 展开更多
关键词 metropolitan regions boundary delimitation urban hierarchy SHANGHAI
下载PDF
Changes in stress within grassland ecosystems in the three counties of the source regions of the Yangtze and Yellow Rivers 被引量:2
5
作者 Fang, YiPing Qin, DaHe Ding, YongJian 《Journal of Arid Land》 SCIE 2010年第2期116-122,共7页
Based on a database of more than 40 years of second production process and energy flow records for Maduo,Qumalai and Yushu counties,a dynamic model of the stress within grassland ecosys-tems was established using a no... Based on a database of more than 40 years of second production process and energy flow records for Maduo,Qumalai and Yushu counties,a dynamic model of the stress within grassland ecosys-tems was established using a nonlinear regression method for this source regions of the Yangtze and Yel-low Rivers.The results show that dynamic curves of stress within grassland ecosystems in the three coun-ties were in the shape of an inverted 'U' during the period 1965-2007.It also revealed that the variation in actual amount of livestock inventories reflected the general trends of the stress within the grassland eco-systems in the source regions,although there were many other factors for the increase or reduction in grassland ecosystem stress. 展开更多
关键词 the source regions of Yangtze and Yellow Rivers the stress within grassland ecosystems inverted 'U' model DRIVER
下载PDF
Thinking on establishing regional diagnostic center 被引量:4
6
作者 王海东 《卫生软科学》 2018年第5期43-46,54,共5页
分析建立区域性医学诊断中心的必要性、可行性,总结了近年来独立医学诊断机构发展存在的瓶颈和 问题,提出通过合理界定区域性医学检验中心的定位、采用政策制定推广机构的建立、探索建设基于AI辅助 诊断团队、搭建第三方机构人才培养体... 分析建立区域性医学诊断中心的必要性、可行性,总结了近年来独立医学诊断机构发展存在的瓶颈和 问题,提出通过合理界定区域性医学检验中心的定位、采用政策制定推广机构的建立、探索建设基于AI辅助 诊断团队、搭建第三方机构人才培养体系以及多渠道采集样本等举措实现区域诊断中心的建立和运行. 展开更多
关键词 独立医学诊断机构 独立医学检验中心 分级诊疗 结果互认 医疗卫生体制改革
下载PDF
Ultrahigh performance passive radiative cooling by hybrid polar dielectric metasurface thermal emitters 被引量:1
7
作者 Yinan Zhang Yinggang Chen +2 位作者 Tong Wang Qian Zhu Min Gu 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第4期17-25,共9页
Real-world passive radiative cooling requires highly emissive,selective,and omnidirectional thermal emitters to maintain the radiative cooler at a certain temperature below the ambient temperature while maximizing the... Real-world passive radiative cooling requires highly emissive,selective,and omnidirectional thermal emitters to maintain the radiative cooler at a certain temperature below the ambient temperature while maximizing the net cooling power.Despite various selective thermal emitters have been demonstrated,it is still challenging to achieve these conditions sim-ultaneously because of the extreme difficulty in controlling thermal emission of photonic structures in multidimension.Here we demonstrated hybrid polar dielectric metasurface thermal emitters with machine learning inverse design,en-abling a high emissivity of~0.92 within the atmospheric transparency window 8-13μm,a large spectral selectivity of~1.8 and a wide emission angle up to 80 degrees,simultaneously.This selective and omnidirectional thermal emitter has led to a new record of temperature reduction as large as~15.4°C under strong solar irradiation of~800 W/m2,signific-antly surpassing the state-of-the-art results.The designed structures also show great potential in tackling the urban heat island effect,with modelling results suggesting a large energy saving and deployment area reduction.This research will make significant impact on passive radiative cooling,thermal energy photonics and tackling global climate change. 展开更多
关键词 radiative cooling dielectric metasurfaces machine learning thermal emitters
下载PDF
Thin paints for durable and scalable radiative cooling 被引量:1
8
作者 Shanquan Liu Fei Zhang +3 位作者 Xingyu Chen Hongjie Yan Wei Chen Meijie Chen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第3期176-182,I0006,共8页
Passive daytime radiative cooling(PDRC) is environment-friendly without energy input by enhancing the coating's solar reflectance(R_(solar)) and thermal emittance(ε_(LWIR)) in the atmosphere's long-wave infra... Passive daytime radiative cooling(PDRC) is environment-friendly without energy input by enhancing the coating's solar reflectance(R_(solar)) and thermal emittance(ε_(LWIR)) in the atmosphere's long-wave infrared transmission window.However,high R_(solar) is usually achieved by increasing the coating's thickness,which not only increases materials' cost but also impairs heat transfer.Additionally,the desired high R_(solar) is vulnerable to dust pollution in the outdoors.In this work,a thin paint was designed by mixing hBN plates,PFOTS,and IPA. R_(solar)=0.963 and ε_(LWIR)=0.927 was achieved at a thickness of 150 μm due to the high backscattering ability of scatters.A high through-plane thermal conductivity(~1.82 W m^(-1) K^(-1)) also can be obtained.In addition,the porous structure coupled with the binder PFOTS resulted in a contact angle of 154°,demonstrating excellent durability under dust contamination.Outdoor experiments showed that the thin paint can obtain a 2.3℃ lower temperature for sub-ambient cooling than the reference PDRC coating in the daytime.Furtherly,the above-ambient heat dissipation performance can be enhanced by spraying the thin paint on a 3D heat sink,which was 15.7℃ lower than the reference 1D structure,demonstrating excellent performance for durable and scalable PDRC applications. 展开更多
关键词 Radiative cooling Heat dissipation Solar reflectance Thermal emittance Contact angle
下载PDF
STUDY ON AUSTENITE-FERRITE TRANSFORMATION WITHIN CRITICAL TEMPERATURE REGION
9
作者 YANG Renshan(Shaanxi Institute of Technology,Hanzhong,Shaanxi,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1995年第2期97-101,共5页
his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isother... his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isothermally from austenite is mainly varied with the austenitizing temperature.The higher the austenitizing temperature,the more volume fraction of the ferrite formed isothermally from austenite.Besides,the phase trans formation of austenite to ferrite within the critical temperature region was checked by austenitizing isothermal time.The volume fraction of ferrite formed isothermally from austenite within the critical temperature region for different isothermal time has heen examined experimen tally.The lglg(l-fv)-1 vs lgt relation does not follow the Avrami equation strictly and consists of two straight lines. 展开更多
关键词 critical temperature region AUSTENITE FERRITE phase trans formation KINETICS
下载PDF
Does digitalization mitigate regional inequalities?Evidence from China 被引量:1
10
作者 Haimeng Liu Xinyang Wang +1 位作者 Zheye Wang Yu Cheng 《Geography and Sustainability》 CSCD 2024年第1期52-63,共12页
Regional inequality significantly influences sustainable development and human well-being.In China,there exists pronounced regional disparities in economic and digital advancements;however,scant research delves into t... Regional inequality significantly influences sustainable development and human well-being.In China,there exists pronounced regional disparities in economic and digital advancements;however,scant research delves into the interplay between them.By analyzing the economic development and digitalization gaps at regional and city levels in China,extending the original Cobb-Douglas production function,this study aims to evaluate the impact of digitalization on China's regional inequality using seemingly unrelated regression.The results indicate a greater emphasis on digital inequality compared to economic disparity,with variable coefficients of 0.59 for GDP per capita and 0.92 for the digitalization index over the past four years.However,GDP per capita demonstrates higher spatial concentration than digitalization.Notably,both disparities have shown a gradual reduction in recent years.The southeastern region of the Hu Huanyong Line exhibits superior levels and rates of economic and digital advancement in contrast to the northwestern region.While digitalization propels economic growth,it yields a nuanced impact on achieving balanced regional development,encompassing both positive and negative facets.Our study highlights that the marginal utility of advancing digitalization is more pronounced in less developed regions,but only if the government invests in the digital infrastructure and education in these areas.This study's methodology can be utilized for subsequent research,and our findings hold the potential to the government's regional investment and policy-making. 展开更多
关键词 regional inequality regional disparities Digital divide DIGITALIZATION Sustainable development Economic growth Seemingly unrelated regression
下载PDF
Molecular Detection of Mutations within the Quinolone Resistance-Determining Regions in Non Typhoidal Salmonella Isolates from Malaysia
11
作者 Fadzilah Mohd-Nor Noor Aini Abu-Bakar +2 位作者 Norzilawati Mohd-Isa Zubaidah A. Wahab Zaini Mohd-Zain 《Health》 2017年第4期640-648,共9页
Introduction: The efficacy of chemotherapy in bacteraemia caused by non-typhoidal Salmonella (NTS) is compromised by antibiotic resistance. Objective: This study was undertaken to describe the mechanism of resistance ... Introduction: The efficacy of chemotherapy in bacteraemia caused by non-typhoidal Salmonella (NTS) is compromised by antibiotic resistance. Objective: This study was undertaken to describe the mechanism of resistance among clinical NTS isolates. Materials & Methodology: Thirty of NTS were isolated from blood (n = 19), stool (n = 10) and bronchioalveolar lavage (BAL;n = 1) respectively. These isolates were tested for susceptibility testing by disc diffusion method against ampicillin, gentamicin, tetracycline, co-trimoxazole, nalidixic acid, ciprofloxacin and ceftriaxone. Epsilometer tests (E-test) for nalidixic acid and ciprofloxacin were performed for nalidixic acid resistant isolates by disc diffusion method. DNA sequencing was carried out on six of the nalidixic acid resistant Salmonella Enteritidis isolates to identify mutations within quinolones resistance determining regions (QRDR) of gyrA, gyrB, parC and parE genes. Results: Resistance rates of NTS isolates from blood, stool, and BAL were respectively 37%, 20% and 0% for ampicillin, 79%, 40% and 0% for tetracycline, 32%, 40% and 0% for co-trimoxazole, 37%, 10% and 100% for nalidixic acid. Eight isolates were resistant to nalidixic acid and had exhibited reduced susceptibility towards ciprofloxacin by E-test. Mutation within QRDR was detected in gyrA gene (n = 6;Asp 47 → His [3], Asp 51 → Asn [1], Asp 73 → Gly [1], and Gly 48 → Asp [1]) and double mutation was detected in parE gene (n = 3;Gly 48 → Asp [3], Glu 82 → Ser [3]). Out of six isolates, three isolates were found to have both gyrA and parE gene mutations. Conclusions: There was no mutation observed in gyrB and parC gene. Mutation in gyrA gene was sufficient to induce decreased susceptibility to ciprofloxacin. Variation in amino acid sequences are novel, while detection of other gene mutation was uncommon. 展开更多
关键词 Non-Typhoidal SALMONELLA QUINOLONES Resistance-Determining regions CIPROFLOXACIN
下载PDF
Current Situation and Development Trend of Regional Clothing Color
12
作者 LIANG Hui’e SHEN Tianqi 《Journal of Landscape Research》 2017年第1期83-86,共4页
This paper applied the method of literature survey to study the current situation of regional clothing color in China and foreign countries,and it summarized the relevant theories in this field. The deficiencies and l... This paper applied the method of literature survey to study the current situation of regional clothing color in China and foreign countries,and it summarized the relevant theories in this field. The deficiencies and losses of the research on regional clothing color in the area of current academic circles were pointed and the development trend of regional color culture in the future clothing design was proposed. The study showed that the research on the regional clothing color has a great theoretical and application significance,and it fits for the present idea of traditional heritage and regional culture dissemination. 展开更多
关键词 CLOthinG COLOR regional culture Geographical environment
下载PDF
Construction and Application of a Regional Kilometer-Scale Carbon Source and Sink Assimilation Inversion System(CCMVS-R) 被引量:2
13
作者 Lifeng Guo Xiaoye Zhang +8 位作者 Junting Zhong Deying Wang Changhong Miao Licheng Zhao Zijiang Zhou Jie Liao Bo Hu Lingyun Zhu Yan Chen 《Engineering》 SCIE EI CAS CSCD 2024年第2期263-275,共13页
CO_(2)is one of the most important greenhouse gases(GHGs)in the earth’s atmosphere.Since the industrial era,anthropogenic activities have emitted excessive quantities of GHGs into the atmosphere,resulting in climate ... CO_(2)is one of the most important greenhouse gases(GHGs)in the earth’s atmosphere.Since the industrial era,anthropogenic activities have emitted excessive quantities of GHGs into the atmosphere,resulting in climate warming since the 1950s and leading to an increased frequency of extreme weather and climate events.In 2020,China committed to striving for carbon neutrality by 2060.This commitment and China’s consequent actions will result in significant changes in global and regional anthropogenic carbon emissions and therefore require timely,comprehensive,and objective monitoring and verification support(MVS)systems.The MVS approach relies on the top-down assimilation and inversion of atmospheric CO_(2)concentrations,as recommended by the Intergovernmental Panel on Climate Change(IPCC)Inventory Guidelines in 2019.However,the regional high-resolution assimilation and inversion method is still in its initial stage of development.Here,we have constructed an inverse system for carbon sources and sinks at the kilometer level by coupling proper orthogonal decomposition(POD)with four-dimensional variational(4DVar)data assimilation based on the weather research and forecasting-greenhouse gas(WRF-GHG)model.Our China Carbon Monito ring and Verification Support at the Regional level(CCMVS-R)system can continuously assimilate information on atmospheric CO_(2)and other related information and realize the inversion of regional and local anthropogenic carbon emissions and natural terrestrial ecosystem carbon exchange.Atmospheric CO_(2)data were collected from six ground-based monito ring sites in Shanxi Province,China to verify the inversion effect of regio nal anthropogenic carbon emissions by setting ideal and real experiments using a two-layer nesting method(at 27 and 9 km).The uncertainty of the simulated atmospheric CO_(2)decreased significantly,with a root-mean-square error of CO_(2)concentration values between the ideal value and the simulated after assimilation was close to 0.The total anthropogenic carbon emissions in Shanxi Province in 2019 from the assimilated inversions were approximately 28.6%(17%-38%)higher than the mean of five emission inventories using the bottomup method,showing that the top-down CCMVS-R system can obtain more comprehensive information on anthropogenic carbon emissions. 展开更多
关键词 CCMVS-R regional carbon assimilation system Anthropogenic carbon emissions CO_(2) POD 4DVar
下载PDF
Determinants of Regional Obesity (Visceral and Subcutaneous Obesity) within Cardiovascular Risk Factors in the Cardiology Department of the University Clinics of Kinshasa
14
作者 Fabien Kintoki Mbala Junior Mabidi Mbangi +6 位作者 Aliocha Natuhoyila Nkodila Jean-Robert Makulo Risassi Pascal Bayauli Eleuther Kintoki Vita Benjamin Longo-Mbenza Raoul Gombet Christian Kisoka Lusunsi 《World Journal of Cardiovascular Diseases》 CAS 2022年第9期444-456,共13页
Objective: This study aimed to determine searching for the determinants of regional obesity (visceral and subcutaneous obesity) within the cardiovascular risk factors (CVRF) in patients followed in cardiology at the U... Objective: This study aimed to determine searching for the determinants of regional obesity (visceral and subcutaneous obesity) within the cardiovascular risk factors (CVRF) in patients followed in cardiology at the University Clinics of Kinshasa (UCK) in the Democratic Republic of Congo (DRC). Material and Methods: Cross-sectional and analytical study had sought the determinants of regional obesity (visceral and subcutaneous obesity) by bio-impedance inside the CVRF during the period from July 1 to September 31, 2014. The multivariate analysis (logistic regression) has established the levels of association between regional obesity and CVRF. The statistical significance threshold was set at p Results: A total of 642 patients participated in the present study. The frequencies of visceral and subcutaneous obesity were respectively 45.5% (without significant distinction between the two sexes: Men 48% n = 92/188 vs. Women 44.1 n = 200/454;p = 0.148) and 60.7% with a predominance in women (36.2 n = 68/188 vs. 70.9% n = 322/454;p that alongside regional obesity was: advanced age, tobacco use, alcohol use, physical inactivity, high blood pressure (HBP), diabetes mellitus (DM) and Chronic renal failure (CRF) in the respective proportions of 50.8%, 13.4%, 44.2%, 86.3%, 10.7%, 13.4% and 0.3%. The determinants of regional obesity were advanced age, smoking and obesity on body mass index (BMI) for visceral obesity;advanced age, female gender, alcohol intake and obesity on BMI and waist circumference (WC) as well as hypertriglyceridemia for subcutaneous obesity. Conclusion: This study showed a significant frequency of regional obesity with the following determinants: advanced age, female gender, smoking, alcohol, BMI/WC obesity and hypertriglyceridemia. 展开更多
关键词 regional VISCERAL Subcutaneous Adipose Tissue BIO-IMPEDANCE Determinant CVRF DRC
下载PDF
Brightening single-photon emitters by combining an ultrathin metallic antenna and a silicon quasi-BIC antenna
15
作者 Shangtong Jia Zhi Li Jianjun Chen 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第1期313-319,共7页
Bright single-photon emitters(SPEs)are fundamental components in many quantum applications.However,it is difficult to simultaneously get large Purcell enhancements and quantum yields in metallic nanostructures because... Bright single-photon emitters(SPEs)are fundamental components in many quantum applications.However,it is difficult to simultaneously get large Purcell enhancements and quantum yields in metallic nanostructures because of the huge losses in the metallic nanostructures.Herein,we propose to combine an ultrathin metallic bowtie antenna with a silicon antenna above a metallic substrate to simultaneously get large Purcell enhancements,quantum yields,and collection efficiencies.As a result,the brightness of SPEs in the hybrid nanostructure is greatly increased.Due to the deep subwavelength field confinement(mode size<10 nm)of surface plasmons in the ultrathin metallic film(thickness<4 nm),the Purcell enhancement of the metallic bowtie antenna improves by more than 25 times when the metal thickness decreases from 20 nm to 2 nm.In the hybrid nanostructures by combining an ultrathin metallic bowtie antenna with a silicon antenna,the Purcell enhancement(Fp≈2.6×10^(6))in the hybrid nanostructures is 63 times greater than those(≤4.1×10^(4))in the previous metallic and hybrid nanostructures.Because of the reduced ratio of electromagnetic fields in the ultrathin metallic bowtie antenna when the high-index silicon antenna is under the quasi-BIC state,a high quantum yield(QY≈0.70)is obtained.Moreover,the good radiation directivity of the quasi-BIC(bound state in the continuum)mode of the silicon antenna and the reflection of the metallic substrate result in a high collection efficiency(CE≈0.71).Consequently,the overall enhancement factor of brightness of a SPE in the hybrid nanostructure is EF∗≈Fp×QY×CE≈1.3×10^(6),which is 5.6×10^(2) times greater than those(EF∗≤2.2×103)in the previous metallic and hybrid nanostructures. 展开更多
关键词 single-photon emitters brightness hybrid nanostructures ultrathin metallic antenna quasi-bound state in the continuum(BIC)
下载PDF
Thin Emitter Structure Improved Turn-on Characteristics in RSD
16
作者 梁琳 余岳辉 +1 位作者 周郁明 王璐 《Transactions of Tianjin University》 EI CAS 2008年第3期182-185,共4页
The thin emitter structure was introduced into reversely switched dynistor(RSD) to improve its turn-on characteristics. According to the analysis of turn-on condition, thin emitter structure is capable of reducing t... The thin emitter structure was introduced into reversely switched dynistor(RSD) to improve its turn-on characteristics. According to the analysis of turn-on condition, thin emitter structure is capable of reducing the extraction action for the triggering plasma layer P1 during turn-on process, and satisfying the requirement that triggering electric charge cannot be exhausted and therefore enables RSD to turn on uniformly. The on-state thin emitter RSD was equivalent to an asymmetric pin diode model. The simulation result shows that the forward voltage drop of RSD falls with the decrease of doping dose in p^+-emitter in a certain range, and when the doping concentration is extremely tow, the decrease of the width of p^+-emitter can obtain a tow forward voltage drop. Thin emitter RSD chips were made by sintering AI on n-Si. The test result shows that their turn-on process is uniform and the voltage drop is 7.5 V when the peak conversion current is 5 500 A. 展开更多
关键词 reversely switched dynistor(RSD) thin emitter turn-on characteristics SWITCH forward voltage drop
下载PDF
A core-satellite self-assembled SERS aptasensor containing a“biological-silent region”Raman tag for the accurate and ultrasensitive detection of histamine 被引量:1
17
作者 Chen Chen Yingfang Zhang +3 位作者 Ximo Wang Xuguang Qiao Geoffrey I.N.Waterhouse Zhixiang Xu 《Food Science and Human Wellness》 SCIE CSCD 2024年第2期1029-1039,共11页
Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-s... Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe_(3)O_(4)@Au MNPs(as the recognize probe for histamine)and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile(4-MBN)(Ag@4-MBN@Ag-c-DNA)as the SERS signal probe for the indirect detection of histamine.Under an applied magnetic field in the absence of histamine,the assembly gave an intense Raman signal at“Raman biological-silent”region due to 4-MBN.In the presence of histamine,the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe_(3)O_(4)@Au MNPs,thus decreasing the SERS signal.Under optimal conditions,an ultra-low limit of detection of 0.65×10^(-3)ng/mL and a linear range 10^(-2)-10^5 ng/mL on the SERS aptasensor were obtained.The histamine content in four food samples were analyzed using the SERS aptasensor,with the results consistent with those determined by high performance liquid chromatography.The present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices. 展开更多
关键词 Surface-enhanced Raman spectroscopy Raman biological-silent region APTAMER Histamine detection Universal SERS-tag
下载PDF
Organic Matter Accumulation in the Upper Permian Dalong Formation from the Lower Yangtze Region,South China 被引量:1
18
作者 FANG Chaogang ZHANG Chengcheng +5 位作者 MENG Guixi XU Jinlong XU Naicen LI Hualing LIU Mu LIU Bo 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第1期150-167,共18页
The Late Permian was marked by a series of important geological events and widespread organic-rich black shale depositions,acting as important unconventional hydrocarbon source rocks.However,the mechanism of organic m... The Late Permian was marked by a series of important geological events and widespread organic-rich black shale depositions,acting as important unconventional hydrocarbon source rocks.However,the mechanism of organic matter(OM)enrichment throughout this period is still controversial.Based on geochemical data,the marine redox conditions,paleogeographic and hydrographic environment,primary productivity,volcanism,and terrigenous input during the Late Permian in the Lower Yangtze region have been studied from the Putaoling section,Chaohu,to provide new insights into OM accumulation.Five Phases are distinguished based on the TOC and environmental variations.In Phase I,anoxic conditions driven by water restriction enhanced OM preservation.In Phase II,euxinic and cycling hydrological environments were the two most substantial controlling factors for the massive OM deposition.During Phase III,intensified terrestrial input potentially diluted the OM in sediment and the presence of oxygen in bottom water weakened the preservation condition.Phase IV was characterized by a relatively higher abundance of mercury(Hg)and TOC(peak at 16.98 wt%),indicating that enhanced volcanism potentially stimulated higher productivity and a euxinic environment.In Phase V,extremely lean OM was preserved as a result of terrestrial dilutions and decreasing primary productivity.Phases I,II and IV are characterized as the most prominent OM-rich zones due to the effective interactions of the controlling factors,namely paleogeographic,hydrographic environment,volcanism,and redox conditions. 展开更多
关键词 GEOCHEMISTRY redox condition primary productivity OM accumulation Lopingian/Changhsingian Lower Yangtze region
下载PDF
Diagnostic Study of an Extreme Explosive Cyclone over the Kuroshio/Kuroshio Extension Region 被引量:1
19
作者 ZHANG Shuqin LIAO Qinghua +4 位作者 LIU Chunlei GAO Xiaoyu LONG Jingchao LI Pengyuan XU Jianjun 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第3期605-617,共13页
Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension region.The most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-Apr... Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension region.The most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-April)was studied to reveal the variations of the key factors at different explosive-developing stages.This EC had weak low-level baroclinicity,mid-level cyclonic-vorticity advection,and strong low-level water vapor convergence at the initial explosive-developing stage.The low-level baroclinicity and mid-level cyclonic-vorticity advection increased substantially during the maximum-deepening-rate stage.The diagnostic analyses using the Zwack-Okossi equation showed that diabatic heating was the main contributor to the initial rapid intensification of this EC.The cyclonic-vorticity advection and warm-air advection enhanced rapidly in the middle and upper troposphere and contributed to the maximum rapid intensification,whereas the diabatic heating weakened slightly in the mid-low troposphere.The relative contribution of the diabatic heating decreased from the initial explosive-developing stage to the maximum-deepening-rate stage due to the enhancement of other factors(the cyclonic-vorticity advection and warm-air advection).Furthermore,the physical factors contributing to this EC varied with the explosive-developing stage.The non-key factors at the initial explosive-developing stage need attention to forecast the rapid intensification. 展开更多
关键词 explosive cyclone diabatic heating cyclonic-vorticity advection rapid intensification the Kuroshio/Kuroshio Extension region
下载PDF
Interdecadal variability of summer precipitation in the Three River Source Region: Influences of SST and zonal shifts of the East Asian subtropical westerly jet 被引量:1
20
作者 Yumeng Liu Xianhong Meng +5 位作者 Lin Zhao S-Y.Simon Wang Lixia Zhang Zhaoguo Li Chan Wang Yingying An 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第5期47-53,共7页
Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the i... Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the influence of the East Asian westerly jet(EAWJ)on TRSR rainfall.A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index(JZPI)of the EAWJ from 1961 to 2019(R=0.619,p<0.01).During periods when a positive JZPI indicates a westward shift in the EAWJ,enhanced water vapor anomalies,warmer air,and low-level convergence anomalies contribute to increased TRSR summer precipitation.Using empirical orthogonal function and regression analyses,this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection(AEA)from the North Atlantic(NA).The interdecadal variability between the NA and central tropical Pacific(CTP)significantly affects TRSR precipitation.This influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ,and another south of 45°N.Moreover,the NA–CTP Opposite Phase Index(OPI),which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP,is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ. 展开更多
关键词 Summer precipitation East Asian subtropical westerly jet Three River Source region Atlantic-Eurasian teleconnection
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部