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Investigation on the surface active sites variation of mineral dusts

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Journal of Central South University 2001年第3期13卷 169-174页

作者： DONG Fa-qin, WAN Pu, FENG Qi-ming, SONG Gong-bao, PENG Tong-jiang (Institute of Mineral Materials and Applications, Southwest University of Science and Technology, Mianyang 621002, China) Institute of Mineral Materials and Applications Southwest University of Science and Technology Mianyang China

The paper analyzed the groups naked and the transformed of fibro us brucite, wollastonite, chrysotile asbestos, sepiolite, palygorskite, clinopti lolite, crocidolite and diatomaceous earth mineral dusts by using IR under acid and alkali etched, strong mechanical and polarized molecular interaction. The re sults show that the active site focuses on ends in stick dusts and on defects or hole edges in pipe dusts. The inside active sites of dusts play the main role i n small molecular substance. The shape of dusts affects their distributions and densities of active sites. The strong mechanical and weak chemical force make th e active site feature of minerals change, the powder process brings about more n aked surface groups and more combined types. The dust activity relates to the ty pe, contribution, and naked level of surface groups. The studied dust surface gr oups are mainly as follows: OH -, Mg(OH) -, Si-O-Si, Ca-O-Si, -Mg-O H 2, -Al(Si)-OH,-Mg(Ca)-OH 2,Ca-O, -Si...OH, Mg(Fe)-OH. Due to the diffe rence of surface composition and structure, the minerals have a large disparity on activity and character of surface groups. The one side surface group of chrys otile layer is the same as fibrous brucite and stripped layer with more naked gr oup. The fibrous sepiolite and palygorskite surface OH - similar to crocidolit e is naked with their surface structural defects and cleavage. The more deve lopm ent of mineral defects, the higher of OH -(H 2O +)content, the main H 2O + of clinoptilolite is partly transformed into H +, NH + 4 or OH -. The acid etched process may change OH - concentration, distribution and increase the de fects and porosity of mineral fiber surface. The alkali etched has no effect on Si-O, Si-OH etc. and destroyed Al-O,Al-OH - acid site of sepiolite, palygo rskite and clinoptilolite. Some surface groups of remnant differ from original d usts. The surface process of small polarized molecular or middle moleular′s bra nch may produce ionation and new coordinate bond, and change the active properti es and

关键词： mineral dusts surface group active site

Thermal dynamics of the permafrost active layer under increased precipitation at the Qinghai-Tibet Plateau

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Journal of Mountain Science 2019年第2期16卷 309-322页

作者： LI De-sheng WEN Zhi CHENG Qian-gong XING Ai-guo ZHANG Ming-li LI An-yuan State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environmental and ResourcesCAS Department of Geological Engineering Southwest Jiaotong University Department of Civil Engineering Lanzhou University of Technology Department of Civil Engineering Shaoxing University

Precipitation has a significant influence on the hydro-thermal state of the active layer in permafrost regions, which disturbs the surface energy balance, carbon flux, ecosystem, hydrological cycles and landscape processes. To better understand the hydro-thermal dynamics of active layer and the interactions between rainfall and permafrost, we applied the coupled heat and mass transfer model for soil-plant-atmosphere system into high-altitude permafrost regions in this study. Meteorological data, soil temperature, heat flux and moisture content from different depths within the active layer were used to calibrate and validate this model. Thereafter, the precipitation was increased to explore the effect of recent climatic wetting on the thermal state of the active layer. The primary results demonstrate that the variation of active layer thickness under the effect of short-term increased precipitation is not obvious, while soil surface heat flux can show the changing trends of thermal state in active layer, which should not be negligible. An increment in year-round precipitation leads to a cooling effect on active layers in the frozen season, i.e. verifying the insulating effect of "snow cover". However, in the thawed season, the increased precipitation created a heating effect on active layers, i.e. facilitating the degradation of permafrost. The soil thermal dynamic in single precipitation event reveals that the precipitation event seems to cool the active layer, while compared with the results under increased precipitation, climatic wetting trend has a different influence on the permafrost evolution.

关键词： active layer Precipitation Qinghai-Tibet plateau Hydro-thermal dynamic

Ultra-low frequency active vertical vibration isolation system

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Science China Mathematics 1997年第11期40卷 1216-1221页

作者：罗俊吴才章 Department of Physics Huazhong University of Science and TechnologyWuhan 430074China

The difficulties of the traditional active isolation methods are analyzed in detail.A new method used to obtain an ultra-low frequency isolation system is proposed based on the introduction of the concept of a quasi-fixed reference system.A large-scale vibration isolation system can be operated by monitoring the relative displacement of the oscillator with respect to the quasi-fixed reference system by proper feedback control forces,and both the resonant frequency and the resonant peak of the vibration isolation system could be decreased effectively.

关键词： active isolation quasi-fixed reference system feedback-control detection of gravitational wave.

Velocity structure and active fault of Yanyuan-Mabian seismic zone―The result of high-resolution seismic refraction experiment

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Science China Earth Sciences 2008年第9期51卷 1284-1296页

作者： WANG FuYun1↑, DUAN YongHong1, YANG ZhuoXin1, ZHANG ChengKe1, ZHAO JinRen1, ZHANG JianShi1, ZHANG XianKang1, LIU QiYuan2, ZHU AiLan2, XU XiWei2 & LIU BaoFeng1 1 Geophysical Exploration Center, China Earthquake Administration, Zhengzhou 450002, China 2 Institute of Geology, China Earthquake Administration, Beijing 100029, China Geophysical Exploration Center China Earthquake Administration Zhengzhou China Institute of Geology China Earthquake Administration Beijing China

The authors processed the seismic refraction Pg-wave travel time data with finite difference tomography method and revealed velocity structure of the upper crust on active block boundaries and deep features of the active faults in western Sichuan Province. The following are the results of our investigation. The upper crust of Yanyuan basin and the Houlong Mountains consists of the superficial low-velocity layer and the deep uniform high-velocity layer, and between the two layers, there is a distinct, and gently west-dipping structural plane. Between model coordinates 180-240 km, P-wave velocity distribution features steeply inclined strip-like structure with strongly non-uniform high and low velocities alternately. Xichang Mesozoic basin between 240 and 300 km consists of a thick low-velocity upper layer and a high-velocity lower layer, where lateral and vertical velocity variations are very strong and the interface between the two layers fluctuates a lot. The Daliang Mountains to the east of the 300 km coordinate is a non-uniform high-velocity zone, with a superficial velocity of approximately 5 km/s. From 130 to 150 km and from 280 to 310 km, there are extremely distinct deep anomalous high-velocity bodies, which are supposed to be related with Permian magmatic activity. The Yanyuan nappe structure is composed of the superficial low-velocity nappe, the gently west-dipping detachment surface and the deep high-velocity basement, with Jinhe-Qinghe fault zone as the nappe front. Mopanshan fault is a west-dipping low-velocity zone, which extends to the top surface of the basement. Anninghe fault and Zemuhe fault are east-dipping, tabular-like, and low-velocity zones, which extend deep into the base-ment. At a great depth, Daliangshan fault separates into two segments, which are represented by drastic variation of velocity structures in a narrow strip: the west segment dips westward and the east segment dips eastward, both stretching into the basement. The east margin fault of Xichang Mesozoic basin features a strong

关键词： western Sichuan high-resolution seismic refraction active fault velocity structure of the upper crust

Aeroservoelastic model based active control for large civil aircraft

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Science China(Technological Sciences) 2010年第4期53卷 1126-1137页

作者： FAN Yong1,ZHU JiHong1,HU ChunHua2,MENG XianYu1,WANG XiangYang2 & GE AiXue1 1 Department of Computer Science and Technology,Tsinghua University,Beijing 100084,China 2 School of Astronautics and Aeronautics,Tsinghua University,Beijing 100084,China Department of Computer Science and Technology Tsinghua University Beijing China School of Astronautics and Aeronautics Tsinghua University Beijing China

A modeling and control approach for an advanced configured large civil aircraft with aeroservoelasticity via the LQG method and control allocation is presented.Mathematical models and implementation issues for the multi-input/multi-output(MIMO) aeroservoelastic system simulation developed for a flexible wing with multi control surfaces are described.A fuzzy logic based optimization approach is employed to solve the constrained control allocation problem via intelligently adjusting the components of output vector and find a proper vector in the attainable moment set(AMS) autonomously.The basic idea is to minimize the L2 norm of error between the desired moment and achievable moment using the designing freedom provided by redundantly allocated actuators and control surfaces.Considering the constraints of control surfaces,in order to obtain acceptable performance of aircraft such as stability and maneuverability,the fuzzy weights are updated by the learning algorithm,which makes the closed-loop system self-adaptation.Finally,an application example of flight control designing for the advanced civil aircraft is discussed as a demonstration.The studies we have performed showed that the advanced configured large civil aircraft has good performance with the proper designed control law designed via the proposed approach.The gust alleviation and flutter suppression are applied with the synergetic effects of elevator,ailerons,equivalent rudders and flaps.The results show good closed loop performance and meet the requirement of constraint of control surfaces.

关键词： modeling active control aeroelastic flutter suppression control allocation

Spatial distribution of water-active soil layer along the south-north transect in the Loess Plateau of China

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Journal of Arid Land 2019年第2期11卷 228-240页

作者： ZHAO Chunlei SHAO Ming'an JIA Xiaoxu HUANG Laiming ZHU Yuanjun Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University College of Natural Resources and Environment Northwest A&F University

Soil water is an important composition of water recycle in the soil-plant-atmosphere continuum.However, intense water exchange between soil-plant and soil-atmosphere interfaces only occurs in a certain layer of the soil profile. For deep insight into water active layer(WAL, defined as the soil layer with a coefficient of variation in soil water content >10% in a given time domain) in the Loess Plateau of China,we measured soil water content(SWC) in the 0.0–5.0 m soil profile from 86 sampling sites along an approximately 860-km long south-north transect during the period 2013–2016. Moreover, a dataset contained four climatic factors(mean annual precipitation, mean annual evaporation, annual mean temperature and mean annual dryness index) and five local factors(altitude, slope gradient, land use, clay content and soil organic carbon) of each sampling site was obtained. In this study, three WAL indices(WALT(the thickness of WAL), WAL-CV(the mean coefficient of variation in SWC within WAL) and WALSWC(the mean SWC within WAL)) were used to evaluate the characteristics of WAL. The results showed that with increasing latitude, WAL-T and WAL-CV increased firstly and then decreased. WAL-SWC showed an opposite distribution pattern along the south-north transect compared with WAL-T and WAL-CV.Average WAL-T of the transect was 2.0 m, suggesting intense soil water exchange in the 0.0–2.0 m soil layer in the study area. Soil water exchange was deeper and more intense in the middle region than in the southern and northern regions, with the values of WAL-CV and WAL-T being 27.3% and 4.3 m in the middle region,respectively. Both climatic(10.1%) and local(4.9%) factors influenced the indices of WAL, with climatic factors having a more dominant effect. Compared with multiple linear regressions, pedotransfer functions(PTFs) from arti?cial neural network can better estimate the WAL indices. PTFs developed by artificial neural network respectively explained 86%, 81% and 64% of the total variations in WAL-T, WAL-SWC and WAL-CV. Knowled

关键词： water active layer soil water content redundancy analysis pedotransfer function artificial neural network Loess Plateau

Prevalence of liver injury among patients with acquired immunodeficiency syndrome treated with highly active antiretroviral therapy in China

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Journal of Traditional Chinese Medicine 2019年第2期39卷 275-280页

作者： Yuan Jun Xu Qianlei Chen Xiumin Meng Pengfei Li Qingya Xu Liran Meng Xiangle Jin Yantao Guo Huijun Department of AIDS Treatment and Research Center the First Affiliated Hospital of Henan University of Traditional Chinese Medicine

OBJECTIVE: To estimate the prevalence of liver injury among patients with acquired immunodeficiency syndrome(AIDS) who received highly active antiretroviral therapy(HAART) in rural Henan Province in China, and to explore whether Traditional Chinese Medicine(TCM) treatment based on HAART would increase this risk.METHODS: This was a retrospective cross-sectional study. We collected medical information on patients with AIDS from two treatment databases in2014. Criteria established by the AIDS Clinical Trials Group in 1996 were used for grading liver injury,classified based on the limit of normal(ULN) for alanine transaminase and aspartate aminotransferase:grade 1(1.25-2.5 × ULN); grade 2(2.6-5 × ULN);grade 3(5.1-10 × ULN); and grade 4(> 10 × ULN).Factors associated with liver injury were evaluated using a logistic regression model.RESULTS: A total 6953 patients with AIDS(3324 male and 3629 female patients) were enrolled into this study. The prevalence of liver injury was 22.0%(18.0% grade 1, 3.1% grade 2, 0.9% grade 3). In multivariate analysis, patients aged 34-45 years were more likely to have liver injury than patients in other age groups [adjusted odds ratio(AOR), 1.39; 95%CI, 1.01-1.91)]. Other factors associated with liver injury included male sex(AOR, 1.64; 95% CI,1.46-1.85), HIV infection via blood(AOR, 1.47; 95%CI, 1.19-1.82), hepatitis B virus antibody positive(AOR, 1.07; 95% CI, 0.85-1.36), and hepatitis C virus(HCV) antibody positive(AOR, 2.76; 95% CI,2.28-3.34).CONCLUSION: The prevalence of liver injury was relatively high among HAART-experienced patients. Several factors associated with liver injury included male sex, age 35-45 years old, HIV infection through blood, and concurrent HCV infection. TCM had no relationship with liver injury in patients receiving HAART.

关键词： Acquired immunodeficiency syndrome Chemical and drug induced liver injury Prevalence Antiretroviral therapy,highly active Medicine,Chinese traditional

The Study on Effect of Exhaust Performance According to active Muffler Valve Spring as Followed Spring Constant

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Journal of Thermal Science 2002年第4期11卷 372-377页

作者： SeukCheunChoi TaeWooKong HanShikChung HyoMinJeong YoungHeungChun Graduate School of Mechanical and Precision Engineering Gyeongsang National UniversityGraduate School of Mechanical and Precision Engineering Gyeongsang National UniversitySchool of Transport Vehicle Engineering Gyeongsang National UniversitySchool of Transport Vehicle Engineering Gyeongsang National UniversitySchool of Transport Vehicle Engineering Gyeongsang National University Inpyeongdong 445 Tongyong Kyongnam 650-160 Korea Inpyeongdong 445 Tongyong Kyongnam 650-160 Korea The Institute of Marine Industry Inpyeongdong 445 Tongyong Kyongnam 650-160 Korea The Institute of Marine Industry Inpyeongdong 445 Tongyong Kyongnam 650-160 Korea The Institute of Marine Industry Inpyeongdong 445 Tongyong Kyongnam 650-160 Korea

This study represents the influence on exhaust performance by active muffler valve spring. The main experimental parameters were engine speeds and torsion coil spring constants in the active muffler. When the muffler valve spring has a low spring constant of k = 0.75, the sound pressure level was low at the region of engine speed 2000 to 2500 r/min, and the velocity of exhaust gas was high at spring constant k = 0.75. When the engine speed was under 1500 r/min, the mean concentration of CO was high in case without muffler valve. When the engine speed in the range of 1600 to 2600 r/min with spring constant k = 0.75, the mean HC concentration showed the lowest value. Without muffler valve, the temperature in the muffler was higher than the case with muffler valve. This research represented that the performance of the active muffler valve spring constant k = 0.75 was higher than that without muffler valve and valve spring constant k = 0.70. Among the three cases of experimental condition, with a spring

关键词： active muffler torsion coil spring spring constant sound pressure level.

Improving the estimation of hydrothermal state variables in the active layer of frozen ground by assimilating in situ observations and SSM/I data

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Science China Earth Sciences 2009年第11期52卷 1732-1745页

作者： JIN Rui LI Xin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of SciencesLanzhou 730000China

The active layer of frozen ground data assimilation system adopts the SHAW (Simulteneous Heat and Water) model as the model operator. It employs an ensemble kalman filter to fuse state variables predicted by the SHAW model with in situ observation and the SSM/I 19 GHz brightness temperature for the purpose of optimizing model hydrothermal state variables. When there is little water movement in the frozen soil during the winter season, the unfrozen water content depends primarily on soil temperature. Thus, soil temperature is the crucial state variable to be improved. In contrast, soil moisture is heavily influenced by precipitation during the summer season. The simulation accuracy of soil moisture has a strong and direct impact on the soil temperature. In this case, the crucial state variable to be improved is soil moisture. One-dimensional assimilation experiments that have been carried out at AMDO station show that land data assimilation method can improve the estimation of hydrothermal state variables in the soil by fusing model information and observation information. The reasonable model error covariance matrix plays a key role in transferring the optimized surface state information to the deep soil, and it provides improved estimations of whole soil state profiles. After assimilating the 4-cm soil temperature by in situ observation, the soil temperature RMSE (Root Mean Square Error) of each soil layer decreased by 0.96℃ on average relative to the SHAW simulation. After assimilating the 4-cm soil moisture in situ observation, the soil moisture RMSE of each soil layer decreased by 0.020 m3·m-3. When assimilating the SSM/I 19 GHz brightness temperature, the soil temperature RMSE of each soil layer during the winter decreased by 0.76℃, while the soil moisture RMSE of each soil layer during the summer decreased by 0.018 m3·m-3.

关键词： land data assimilation active layer of frozen ground soil moisture soil temperature passive remote sensing