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On island landscape pattern of forests in Helan Mountain and its cause of formation

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Science China(Technological Sciences) 2006年第z1期49卷 45-53页

作者： DENG Hongbing WANG Yingming zhang Qiaoxian yan yan State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Based on the spatial information techniques such as RS, GIS, and GPS, the forest landscape patterns in the Helan Mountain, western China, were studied. The Landsat 5 TM data were used to classify the forest landscapes through RS digital cartography, and then, the landscape characteristics and landscape pattern were analyzed quantificationally. Furthermore, through spatial data collection and spatial analysis of the main disturbances in this area, the cause of landscape formation was studied. The results showed that the total 1177 forest landscape patches could be classified into 21 landscape types, and the forest landscape in the Helan Mountain was island pattern, which was encircled by deserta as matrix. The values of landscape diversity index and landscape fragmentation index were 2.61 and 0.43, respectively. In this area, the landscape pattern was clearly formed and continuously changed in response to geological processes, climate, activities of organisms, forest fire, desertification, human activities and so on. This landscape pattern had an obviously negative effect on the stability and ecosystem services of forests. So, scientific landscape planning and protection should be adopted to improve the sustainability of forest management in this area.

关键词： landscape pattern, island landscape of forest, disturbance, Helan Mountain.

A Rapid Trace Analysis of GBS using the Specific Spectral Absorption of Chromogenic Culture Media

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Biomedical and Environmental Sciences 2023年第7期36卷 649-652页

作者： CHEN yang zhang yan yan SHU Yao Gen Engineering Research Center of Clinical Functional Materials and Diagnosis and Treatment Devices of Zhejiang Province Wenzhou InstituteUniversity of Chinese Academy of SciencesWenzhou 325000ZhejiangChina Biomedical Engineering Wenzhou Medical UniversityWenzhou 325035ZhejiangChina College of Chemical Engineering Fuzhou UniversityFuzhou 350108FujianChina Research Center of Quantitative Detection Technology NMPA Key Laboratory for Quality Monitoring and Evaluation of Vaccines and Biological ProductsWenzhou 325000ZhejiangChina Oujiang Laboratory(Zhejiang Lab for Regenerative Medicine Vision and Brain Health)Wenzhou 325024ZhejiangChina

Group B streptococcus(GBS)is a Gram-positive,encapsulated bacterium that belongs to the group of pyogenic streptococci,and it is an asymptomatic colonizer of the digestive and genitourinary tracts of healthy human ***,it can cause severe invasive infections in neonates and immunocompromised *** the 1960s,GBS was identified as a leading cause of life-threatening neonatal infections[1,2].

关键词： urinary GBS neonatal

Joint optimization of time and frequency synchronization based on polynomial sequences for OFDM systems

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The Journal of China Universities of Posts and Telecommunications 2009年第3期16卷 19-23页

作者： zhang yan-yan zhang Jian-hua HUANG Jiang-chun zhang Ping Key Laboratory of Universal Wireless Communication Beijing University of Posts and Telecommunications Ministry of Education Beijing 100876 China Wireless Technology Innovation Institute Beijing University of Posts and Telecommunications Beijing 100876 China

In orthogonal frequency division multiplexing （OFDM） systems, time and frequency synchronization are two critical elements for guaranteeing the orthogonality of OFDM subcarriers. Conventionally, with the employment of pseudo-noise （PN） sequences in preamble design, the preamble information is not fully utilized in both symbol timing offset acquisition and carrier frequency offset estimation. In this article, a new synchronization algorithm is proposed for jointly optimizing the time and frequency synchronization. This algorithm uses polynomial sequences as synchronization preamble instead of PN sequences. Theoretical analysis and simulation results indicate that the proposed algorithm is much more accurate and reliable than other existing methods.

关键词： frequency synchronization joint optimization OFDM polynomial sequences timing synchronization

ANALYTICAL STUDY ON FLOW PROCESS OF FLOATING-OIL RECOVERY DEVICE FROM OIL-CONTAMINATED SEAWATER BY MHD METHOD

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Journal of Hydrodynamics 2007年第2期19卷 195-200页

作者： zhang Guo-yan PENG yan ZHAO Ling-zhi LI Ran SHA Ci-wen Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100080 China

A new method of recovering maritime oil-spill based on electromagnetic force, the so-called MHD oil-spill recovery method was proposed in the IEECAS. The operating process of MHD channel was described in this article. Numerical study was carried out using a two-dimensional water-air two-phase model and the VOF method. The agreement between the numerical and the experimental results was reached.

关键词： numerical simulation water-air two phaseflow VOF method MHD

STUDY ON TURBULENCE FEATURES NEAR AN OSCILLATING CURVED WALL

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Journal of Hydrodynamics 2007年第3期19卷 255-263页

作者： WANG Wen-quan zhang Li-xiang yan yan GUO Yakun Department of Engineering Mechanics Kunming University of Science and Technology Kunming 650051China Department of Engineering University of Aberdeen Aberdeen AB24 3UE UK

In pursuit of possibly true turbulent characters and for exploring a change in turbulence structures near an oscillating flexible wall-curved surface, a sinusoidal oscillation mode was forced to a curved wall, whose vibrations disturbed the flow with an interacting effort between the fluid and the structure. The methodology used was the Large Eddy Simulation （LES） with fluid-structure interaction. The oscillating configuration was on a Fourier sinusoidal mode from the measurements of a Francis hydro turbine blade vibration. The effects of the vibration on the skin friction coefficient, vortices, turbulent coherent structures, and other statistical quantities were studied. The results showed that the streamwise velocity gradient along the normal direction and the normal velocity gradient along the spanwise direction were considerably increased within the viscous sublayer because of the oscillating wall, which additionally caused the low speed streaks to stay away from the wall and the high-momentum flows to be toward the wall. As a result, the streamwise vortices were much more elongated along the downstream to get an energy balance, and the wall skin friction coefficient or the wall friction velocity rose up.

关键词： turbulent flow turbulent structure Large-Eddy Simulation (LES) fluid-structure interaction

Global burden of viral infectious diseases of poverty based on Global Burden of Diseases Study 2021

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贫困所致传染病(英文) 2024年第5期13卷 53-67页

作者： Li Xin-Chen zhang yan-yan zhang Qi-Yu Liu Jing-Shu Ran Jin-Jun Han Le-Fei zhang Xiao-Xi School of Global Health Chinese Center for Tropical Diseases Research Shanghai Jiao Tong University School of Medicine Shanghai People’s Republic of China Institute of One Health Shanghai Jiao Tong University Shanghai People’s Republic of China School of Public Health Shanghai Jiao Tong University School of Medicine Shanghai People’s Republic of China

Background Viral infectious diseases of poverty (vIDPs) remain a significant global health challenge. Despite their profound impact, the burden of these diseases is not comprehensively quantified. This study aims to analyze the global burden of six major vIDPs, including coronavirus disease 2019 (COVID-19), HIV/AIDS, acute hepatitis, dengue, rabies, and Ebola virus disease (EVD), using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 (GBD 2021).Methods Following the GBD 2021 framework, we analyzed the incidence, mortality, and disability-adjusted life years (DALYs) of the six vIDPs across 204 countries and territories from 1990 to 2021. We examined the association between the Socio-Demographic Index (SDI) and the burden of vIDPs. All estimates were reported as numbers and rates per 100,000 population, calculated using the Bayesian statistical model employed by GBD 2021, with 95% uncertainty intervals (UI).Results In 2021, vIDPs caused approximately 8.7 million deaths and 259.2 million DALYs, accounting for 12.8% and 9.0% of the global all-cause totals, respectively. Globally, the burden of vIDPs varied significantly: COVID-19 caused around 7.9 million (95% UI: 7.5, 8.4) deaths and 212.0 million (95% UI 197.9, 234.7) DALYs in 2021. Acute hepatitis had the second-highest age-standardized incidence rate, with 3411.5 (95% UI: 3201.8, 3631.3) per 100,000 population, while HIV/AIDS had a high age-standardized prevalence rate, with 483.1 (95% UI: 459.0, 511.4) per 100,000 population. Dengue incidence cases rose from 26.5 million (95% UI: 3.9, 51.9) in 1990 to 59.0 million (95% UI: 15.5, 106.9) in 2021. Rabies, although reduced in prevalence, continued to pose a significant mortality risk. EVD had the lowest overall burden but significant outbreak impacts. Age-standardized DALY rates for vIDPs were significantly negatively correlated with SDI: acute hepatitis (r = -0.8,P < 0.0001), rabies (r = -0.7,P < 0.0001), HIV/AIDS (r = -0.6,P < 0.0001), C

关键词： Viral infectious diseases of poverty Global Burden of Disease 2021 Disability-adjusted life years Socio-Demographic Index

Response of grain-filling rate and grain quality of mid-season indica rice to nitrogen application

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Journal of Integrative Agriculture 2021年第6期20卷 1465-1473页

作者： zhang Jing zhang yan-yan SONG Ning-yuan CHEN Qiu-li SUN Hong-zheng PENG Ting HUANG Song ZHAO Quan-zhi College of Agronomy Henan Agricultural UniversityZhengzhou 450046P.R.China Xinyang Agriculture and Forestry University Xinyang 464001P.R.China

Nitrogen is one of the important factors for high yield of *** from high yield,high quality has become the current urgent demand for rice ***-filling stage is crucial for rice yield and quality ***,the effect of nitrogen on grain-filling characteristics and the relationship of grain-filling characteristics and rice quality of mid-season indica rice were still unclear.A field experiment was carried out to ascertain the critical grain-filling characteristics that contribute to rice milling quality,appearance quality and cooking and eating quality under nitrogen *** results showed that nitrogen applications prolonged the duration of superior and inferior grain *** mean grainfilling rate(G_(mean))and the maximum grain-filling rate(G_(max))of the inferior grains were positively correlated with chalky kernel rate,chalkiness,and amylose *** time reaching the maximum grain-filling rate(T_(max)G)of the inferior grains was positively correlated with brown rice rate,milled rice rate,and head milled rice *** kernel rate and chalkiness were negatively correlated with peak paste viscosity and breakdown *** amylose content and more crude protein content were detected in nitrogen application of Liangyoupei 9 and Y Liangyou 2 both in 2016 and *** to the correlation analysis,better cooking and eating quality of Y Liangyou 2 which had less amylose content might result from its higher G_(max)and G_(mean)of inferior grain than that of Liangyoupei 9 in the treatments of nitrogen *** results indicated that the prolonging grain-filling duration and increasing grain weight at the maximum grain-filling rate of inferior grains contributed to the improvement of milling quality,appearance quality,and cooking and eating quality of mid-season indica rice under appropriate nitrogen applications.

关键词： mid-season indica rice grain-filling rate rice quality nitrogen

Impacts of atmospheric and oceanic factors on monthly and interannual variations of polynya in the East Siberian Sea and Chukchi Sea

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Advances in Climate Change Research 2021年第4期12卷 527-538页

作者： zhang Yu zhang yan-yan XU Dan-Ya CHEN Chang-Sheng SHEN Xin-Yi HU Song CHANG Liang ZHOU Xiang-Qian FENG Gui-Ping College of Marine Sciences Shanghai Ocean UniversityShanghai201306China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519082China International Center for Marine Studies Shanghai Ocean UniversityShanghai201306China School for Marine Science and Technology University of Massachusetts-DartmouthNew BedfordMA02744USA State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai200241China

As a key region of Northeast Passage,the polynya along the Siberian coast in the East Siberian and Chukchi Seas is important to local dynamic and thermodynamic processes,sea ice production and marine *** detailed variations of polynya and the contributions of atmospheric and oceanic factors to the polynya have not been explored ***-E satellite data from January to April during the period 2003-2011 were used to study the impacts of wind stress and ocean heat transport on variations of polynya in the East Siberian Sea and Chukchi *** study region was divided into six *** sets of AMSR-E data with resolutions of 6.25 km and 12.5 km were compared based on two algorithms of sea ice concentration(referred to as 6.25 km-IC and 12.5 km-IC)and sea ice thickness(referred to as 6.25 km-h and 12.5 km-h).The monthly and yearly polynya areas in the four cases and six domains had remarkable *** two cases of 6.25 km-h and 12.5 km-h had larger areas of polynya than the other two cases of 6.25 km-IC and 12.5 *** difference in polynya area between the 6.25 km-h and 12.5 km-h cases was much smaller than the difference between the 6.25 km-IC and 12.5 km-IC *** study of atmospheric and oceanic mechanisms on polynya is influenced significantly by the sensitivity of polynya *** general,the impact of wind stress and ocean heat transport on the polynyas had noticeable monthly and interannual variations and was dependent on the locations of the *** alongshore and offshore wind had stronger correlations with the polynya area than ocean heat *** the higher resolution(6.25 km)AMSR-E data are best for the study of atmospheric and oceanic impacts on polynya area,the coarse resolution(12.5 km)AMSR-E data based on sea ice thickness can also be *** direction dominated the polynya area in the East Siberian Sea and wind speed dominated the polynya area in the Chukchi *** variation in ocean heat transpor

关键词： Polynya area AMSR-E Wind Ocean heat transport

Study on Aroma Components in Fruit From Three Different Satsuma Mandarin Varieties

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Agricultural Sciences in China 2007年第12期6卷 1487-1493页

作者： QIAO Yu XIE Bi-jun zhang yan ZHOU Hai-yan PAN Si-yi College of Food Science and Technology Huazhong Agricultural University Wuhan 430070 P.R.China

Fruit aroma of Guoqing 1, Miyagawa Wase, and Owari from three different Satsuma mandarin varieties were investigated by headspace solid phase microextraction （HS-SPME） combined with GC-MS. The results showed that there were 73, 71, and 66 aroma components in the three varieties, and the total contents were 584.67,505.29, and 494.63 μg g^-1, respectively. Total 29 constituents were common in the three varieties. It was also found that Guoqing 1, Miyagawa Wase, and Owari had 12, 5, and 2 unique components, respectively. The key aroma components were limonene, linalool, γ-terpinene, β- myrcene, α-pinene, and octanal in the three fruits. Guoqing 1 contained more key aroma compounds than Miyagawa Wase and Owari.

关键词： Satsuma mandarins fruit volatile compounds aroma