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12018 Chinese Pediatric Cardiology Society(CPCS) guideline for diagnosis and treatment of syncope in children and adolescents显示文摘Syncope belongs to the transient loss of consciousness(TLOC), characterized by a rapid onset, short duration, and spontaneous complete recovery. It is common in children and adolescents, accounting for 1% to 2% of emergency department visits.Recurrent syncope can seriously affect children's physical and mental health, learning ability and quality of life and sometimes cardiac syncope even poses a risk of sudden death. The present guideline for the diagnosis and treatment of syncope in children and adolescents was developed for guiding a better clinical management of pediatric syncope. Based on the globally recent development and the evidence-based data in China, 2018 Chinese Pediatric Cardiology Society(CPCS) guideline for diagnosis and treatment of syncope in children and adolescents was jointly prepared by the Pediatric Cardiology Society, Chinese Pediatric Society, Chinese Medical Association(CMA)/Committee on Pediatric Syncope, Pediatricians Branch, Chinese Medical Doctor Association(CMDA)/Committee on Pediatric Cardiology, Chinese College of Cardiovascular Physicians, Chinese Medical Doctor Association(CMDA)/Pediatric Cardiology Society, Beijing Pediatric Society, Beijing Medical Association(BMA). The present guideline includes the underlying diseases of syncope in children and adolescents, the diagnostic procedures, methodology and clinical significance of standing test and headup tilt test, the clinical diagnosis vasovagal syncope, postural orthostatic tachycardia syndrome, orthostatic hypotension and orthostatic hypertension, and the treatment of syncope as well as follow-up.Cheng Wang Yaqi Li Ying Liao Hong Tian Min Huang Xiangyu Dong Lin Shi Jinghui Sun Hongfang Jin Junbao Du Jindou An Jie Chen Mingwu Chen Qi Chen Sun Chen Yonghong Chen Zhi Chen Adolphus Kai-tung Chau Junbao Du Zhongdong Du Junkai Duan Hongyu Duan Xiangyu Dong Lin Feng Lijun Fu Fangqi Gong Yonghao Gui Ling Han Zhenhui Han Bing He Zhixu He Xiufen Hu Yimin Hua Guoying Huang Min Huang Ping Huang Yujuan Huang Hongfang Jin Mei Jin Bo Li Fen Li Tao Li Xiaohui Li Xiaoyan Liu Yan Li Haitao Lv Tiewei Lv Zipu Li Luyi Ma Silin Pan Yusheng Pang Hua Peng Yuming Qin Jie Shen Lin Shi Kun Sun Jinghui Sun Hong Tian Jie Tian Cheng Wang Hong Wang Lei Wang Jinju Wang Wendi Wang Yuli Wang Rongzhou Wu Tianhe Xia Yanyan Xiao Chunhong Xie Yanlin Xing Zhenyu Xiong Baoyuan Xu Yi Xu Hui Yan Shiwei Yang Qijian Yi Xia Yu Xianyi Yu Yue Yuan Hongyan Zhang Huili Zhang Li Zhang Qingyou Zhang Xi Zhang Yanmin Zhang Zhiwei Zhang Cuifen Zhao Bin Zhou Hua Zhu 2018Science Bulletin2018,63,23:54
2Dusty cloud radiative forcing derived from satellite data for middle latitude regions of East Asia显示文摘尘封的云在东亚的中间的纬度区域上的放射的强迫被使用估计 2 年(7 月 2002-June 日 2004 ) 并置的云和地球的绚烂的精力系统(谷神星) 的数据从水编辑 1B SSF (单个扫描仪脚印) 的扫描仪和中等分辨率成像分光辐射函数(MODIS ) 。尘封的云在灰尘暴风雨环境被定义为云或灰尘污染了云。为面对灰尘成长的云,在空气(TOA ) 的顶强迫的即时短波(SW ) 关于 -275.7 W/m 2 为阴郁灰尘(货到付款) 区域。在没有灰尘开发云(CLD ) 区域的云产出最否定的短波(SW ) forcint (是大约 12.8% 的 -311.0 W/m 2), 比那些强壮在货到付款区域。为长波浪(LW ) 放射的强迫,没有灰尘云(CLD ) 在是 20% 的 102.8 W/m 2, 附近不到从货到付款区域强迫的 LW。为 CLD 区域的放射的强迫关于是 42.1% 的 -208.2W/m2, 的即时 TOA 网比货到付款区域的价值大。在云下面的灰尘喷雾器的存在显著地减少云的冷却效果。HUANG Jianping WANG Yujie WANG Tianhe YI Yuhong 2006Progress in Natural Science:Materials International2006,16,10:20
3Progresses and Prospects of Marine Geodetic Datum and Marine Navigation in China显示文摘Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has established relatively complete geodetic coordinate frame in land areas over the past decades,including the lastest developed China Geodetic Coordinate System 2000(CGCS 2000)with its reference frame and the national gravity datum 2000.However,the currently used geodetic infrastructures have not well covered the sea areas of China.The marine geodetic datum and marine navigation technologies need to be further developed and extended to satisfy the national demands of marine environment and resources detection,scientific investigation as well as marine economy development in new era of China.This paper mainly reviews the development and the progress of Chinese marine geodetic datum and marine navigation,analyses related key technologies in establishing our national marine geodetic datum.Some current trends and future directions for independently developing our national marine geodetic datum and marine navigation technologies are discussed.Yuanxi YANG Tianhe XU Shuqiang XUE 2018Journal of Geodesy and Geoinformation Science2018,1,1:16
4Humoral immune response to circulating SARS-CoV-2 variants elicited by inactivated and RBD-subunit vaccines显示文摘SARS-CoV-2 variants could induce immune escape by mutations on the receptor-binding domain(RBD)and N-terminal domain(NTD).Here we report the humoral immune response to circulating SARS-CoV-2 variants,such as 501Y.V2(B.1.351),of the plasma and neutralizing antibodies(NAbs)elicited by CoronaVac(inactivated vaccine),ZF2001(RBD-subunit vaccine)and natural infection.Among 86 potent NAbs identified by high-throughput single-cell VDJ sequencing of peripheral blood mononuclear cells from vaccinees and convalescents,near half anti-RBD NAbs showed major neutralization reductions against the K417N/E484K/N501Y mutation combination,with E484K being the dominant cause.VH3-53/VH3-66 recurrent antibodies respond differently to RBD variants,and K417N compromises the majority of neutralizing activity through reduced polar contacts with complementarity determining regions.In contrast,the 242–244 deletion(242–244Δ)would abolish most neutralization activity of anti-NTD NAbs by interrupting the conformation of NTD antigenic supersite,indicating a much less diversity of anti-NTD NAbs than anti-RBD NAbs.Plasma of convalescents and CoronaVac vaccinees displayed comparable neutralization reductions against pseudo-and authentic 501Y.V2 variants,mainly caused by E484K/N501Y and 242–244Δ,with the effects being additive.Importantly,RBD-subunit vaccinees exhibit markedly higher tolerance to 501Y.V2 than convalescents,since the elicited anti-RBD NAbs display a high diversity and are unaffected by NTD mutations.Moreover,an extended gap between the third and second doses of ZF2001 leads to better neutralizing activity and tolerance to 501Y.V2 than the standard three-dose administration.Together,these results suggest that the deployment of RBD-vaccines,through a third-dose boost,may be ideal for combating SARS-CoV-2 variants when necessary,especially for those carrying mutations that disrupt the NTD supersite.Yunlong Cao Ayijiang Yisimayi Yali Bai Weijin Huang Xiaofeng Li Zhiying Zhang Tianjiao Yuan Ran An Jing Wang Tianhe Xiao Shuo Du Wenping Ma Liyang Song Yongzheng Li Xiang Li Weiliang Song Jiajing Wu Shuo Liu Xuemei Li Yonghong Zhang Bin Su Xianghua Guo Yangyang Wei Chuanping Gao Nana Zhang Yifei Zhang Yang Dou Xiaoyu Xu Rui Shi Bai Lu Ronghua Jin Yingmin Ma Chengfeng Qin Youchun Wang Yingmei Feng Junyu Xiao Xiaoliang Sunney Xie 2021Cell Research2021,31,7:12
5Seafloor geodetic network establishment and key technologies显示文摘Seafloor geodetic network construction involves the development of geodetic station shelter, network configuration design, location selection and layout, surveying strategy, observation model establishment and optimization, data processing strategy and so on. This paper tries to present main technological problems involved in the seafloor geodetic network construction, and seek the technically feasible solutions. Basic conceptions of developing seafloor geodetic station shelters for shallow sea and deep-sea are described respectively. The overall criteria of seafloor geodetic network construction for submarine navigation and those of network design for crustal motion monitoring are both proposed. In order to enhance application performances of the seafloor geodetic network, the seafloor network configuration should prefer a symmetrical network structure. The sea surface tracking line measurements for determining the seafloor geodetic station position should also adopt an approximately symmetrical configuration, and we recommend circle tracking line observations combined with cross-shaped line(or double cross-shape line) observations for the seafloor positioning mode. As to the offset correction between the Global Navigation Satellite System antenna phase center and the acoustic transducer, it is recommended to combine the calibration through external measurements and model parameter estimation. Besides, it is suggested to correct the sound speed error with a combination of observation value correction and parameterized model correction, and to mainly use the model correction to reduce the influence of acoustic ray error on the seafloor positioning. Following the proposed basic designs, experiments are performed in shallow sea area and deep-sea area respectively. Based on the developed seafloor geodetic shelter and sufficient verification in the shallow sea experiment, a long-term seafloor geodetic station in the deep-sea area of 3000 m depth was established for the first time, and the preliminary positioning result shows that the internal precision of this station is better than 5 cm.Yuanxi YANG Yanxiong LIU Dajun SUN Tianhe XU Shuqiang XUE Yunfeng HAN Anmin ZENG 2020Science China Earth Sciences2020,63,8:11
6An Overview of Mineral Dust Modeling over East Asia显示文摘East Asian dust(EAD) exerts considerable impacts on the energy balance and climate/climate change of the earth system through its influence on solar and terrestrial radiation, cloud properties, and precipitation efficiency. Providing an accurate description of the life cycle and climate effects of EAD is therefore critical to better understanding of climate change and socioeconomic development in East Asia and even worldwide. Dust modeling has undergone substantial development since the late 1990 s, associated with improved understanding of the role of EAD in the earth system. Here, we review the achievements and progress made in recent decades in terms of dust modeling research,including dust emissions, long-range transport, radiative forcing(RF), and climate effects of dust particles over East Asia. Numerous efforts in dust/EAD modeling have been directed towards furnishing more sophisticated physical and chemical processes into the models on higher spatial resolutions. Meanwhile, more systematic observations and more advanced retrieval methods for instruments that address EAD related science issues have made it possible to evaluate model results and quantify the role of EAD in the earth system, and to further reduce the uncertainties in EAD simulations. Though much progress has been made, large discrepancies and knowledge gaps still exist among EAD simulations. The deficiencies and limitations that pertain to the performance of the EAD simulations referred to in the present study are also discussed.Siyu CHEN Jianping HUANG Yun QIAN Chun ZHAO Litai KANG Ben YANG Yong WANG Yuzhi LIU Tiangang YUAN Tianhe WANG Xiaojun MA Guolong ZHANG 2017Journal of Meteorological Research2017,31,4:7
7China Digital Ocean Prototype System显示文摘Digital Ocean is a new research domain of Digital Earth.Because of the spatiotemporal,three-dimensional(3D)and intrinsically dynamic nature of ocean data,it is more difficult to make a breakthrough in this domain.The construction of the China Digital Ocean Prototype System(CDOPS)pushes Digital Ocean a step forward from its operation as a mere concept to its achievement as a realistic system.In this paper,the technical framework of the CDOPS is discussed,including its data,function,and application layers.Then,two key technologies are studied in detail that will enable the construction of the 3D ocean environment and the visualization of the ocean model output data.Practical demonstrations show that the CDOPS provides a technical reference for the development of Digital Ocean.This paper is based on an ongoing research project of the development of CDOPS that aims at the facilitation,integration,sharing,accessing,visualization,and use of the ocean data and model computing data from the Digital Earth perspective.Xin Zhang Wen Dong Sihai Li Jiancheng Luo Tianhe Chi 2011International Journal of Digital Earth2011,4,3:7
8Prediction of earth rotation parameters based on improved weighted least squares and autoregressive model显示文摘In this paper,an improved weighted least squares(WLS),together with autoregressive(AR) model,is proposed to improve prediction accuracy of earth rotation parameters(ERP).Four weighting schemes are developed and the optimal power e for determination of the weight elements is studied.The results show that the improved WLS-AR model can improve the ERP prediction accuracy effectively,and for different prediction intervals of ERP,different weight scheme should be chosen.Sun Zhangzhen Xu Tianhe 2012Geodesy and Geodynamics2012,3,3:7
9Combining GPS carrier phase and Doppler observations for precise velocity determination显示文摘The truncation error and propagation error are analyzed for velocity determination through differential GPS carrier phase observations,and an approach for the choice of the best number of points for the central difference method is developed.In order to overcome the disadvantages of existing GPS velocity determination methods,a new velocity determination algorithm is presented,based on combining carrier phase and Doppler observations.The basic idea is that two types of observation are combined by adding their normal equations,and their weights are evaluated by strict Helmet variance-components estimation.In order to control the influence of outliers,a bifactor equivalent weights strategy is adopted.To validate this method,GPS data of the airborne gravimetry campaign MEXAGE2001 is tested.The results show that the precision and reliability of velocity determination are obviously improved by using the proposed method.WANG QianXin XU TianHe 2011Science China(Physics,Mechanics & Astronomy)2011,54,6:5
10Secure Two-Party Distance Computation Protocol Based on Privacy Homomorphism and Scalar Product in Wireless Sensor Networks显示文摘Numerous privacy-preserving issues have emerged along with the fast development of the Internet of Things. In addressing privacy protection problems in Wireless Sensor Networks(WSN), secure multi-party computation is considered vital, where obtaining the Euclidian distance between two nodes with no disclosure of either side's secrets has become the focus of location-privacy-related applications. This paper proposes a novel Privacy-Preserving Scalar Product Protocol(PPSPP) for wireless sensor networks. Based on PPSPP, we then propose a Homomorphic-Encryption-based Euclidean Distance Protocol(HEEDP) without third parties. This protocol can achieve secure distance computation between two sensor nodes. Correctness proofs of PPSPP and HEEDP are provided, followed by security validation and analysis. Performance evaluations via comparisons among similar protocols demonstrate that HEEDP is superior; it is most efficient in terms of both communication and computation on a wide range of data types, especially in wireless sensor networks.Haiping Huang Tianhe Gong Ping Chen Reza Malekian Tao Chen 2016Tsinghua Science and Technology2016,21,4:5
11An improved adaptive Sage filter with applications in GEO orbit determination and GPS kinematic positioning显示文摘The shortcomings of an adaptive Sage filter are analyzed in this paper.An improved adaptive Sage filter is developed by using a weighted average quadratic form of the historical residuals of observations and predicted states to evaluate the covariance matrices of observations and dynamic model errors at the present epoch.The weight function is constructed based on the variances of observational residuals or predicted state residuals and the space distance between the previous and the present epoch.In order to balance the contributions of the measurements and the dynamic model information,an adaptive factor is applied by using a two-segment function and predicted state discrepancy statistics.Two applications,orbit determination of a maneuvered GEO satellite and GPS kinematic positioning,are conducted to verify the performance of the proposed method.XU TianHe JIANG Nan SUN ZhangZhen 2012Science China(Physics,Mechanics & Astronomy)2012,55,5:3
12Analysis of negative DSA findings in patients with acute nonvariceal gastrointestinal bleeding: A retrospective study of 133 patients显示文摘Purpose: To analyze causes of acute nonvariceal gastrointestinal bleeding(GIB) with negative digital subtraction angiography(DSA) results.Materials and methods: The clinical and follow-up data of 133 patients-recruited between February 2008 and November 2016-with acute nonvariceal GIB and negative DSA results were included in this study. DSA results,diagnoses, and clinical outcomes were recorded.Results: The DSA results were negative in all 133 patients. Of the total, 55 patients(41.4%) chose to undergo surgery and 78(58.6%) opted for conservative treatment. Within 30 days, there was no significant difference in the rebleeding or mortality rates between the two groups(P <.05). Of all 133 patients, 76(57.1%) had upper GIB and 57(42.9%) had lower GIB;within 30 days, the rebleeding rate in the upper GIB group(44.7%, 34/76) was significantly higher than that in the lower GIB group(26.3%, 15/57). There was no significant statistical difference(P <.05) within 30 days in the mortality rates between the two groups.Among patients with upper GIB, 26(34.2%, 26/76) opted to undergo surgery and 50(65.8%, 50/76) chose conservative treatment;within 30 days, the rebleeding rate in the group that chose surgery(61.5%, 16/26) was higher than that in the conservative treatment group(36%, 18/50). There was no significant difference(P <.05)within 30 days in the mortality rate between the two groups.Among the patients with lower GIB, 29(50.9%, 29/57) chose to undergo surgery and 28(49.1%, 28/57) opted for conservative treatment. Within 30 days, the rebleeding rate in the surgery group(13.8%, 4/29) was lower than that in conservative treatment group(39.3%, 11/28). There was no significant difference(P <.05) within 30 days in the mortality rate between the two groups.Sixteen patients underwent prophylactic arterial embolization;in 6 of these, bleeding was stopped for 30 days.DSA was then repeated in these 16 patients after a median interval of 1 day, and a positive bleeding site was found in 9 of the 16. Causes of bleeding were found in 111 patients by surgery or endoscopy, whereas the causes remained unknown in 22 patients.Conclusions: Upper GIB with negative DSA results was stopped by conservative treatment, whereas lower GIB required surgery to detect the culprit bleeding site. Rare causes of GIB should be considered and appropriate management selected in a timely manner in order to detect unusual causes.Tianhe Ye Lian Yang Qi Wang Jiacheng Liu Chen Zhou Chuansheng Zheng Bin Xiong 2019Journal of Interventional Medicine2019,2,1:3
13Structures of SARS-CoV-2 B.1.351 neutralizing antibodies provide insights into cocktail design against concerning variants显示文摘Dear Editor,The spread of the SARS-CoV-2 variants,especially the global variants of concern(VOCs),could seriously dampen our efforts to tackle the COVID-19 pandemic.The SARS-CoV-2 spike protein recognizes the host angiotensin-converting enzyme 2(ACE2)via its receptor-binding domain(RBD)to mediate viral entry into the cells.Several notorious mutations have been identified in the spike RBD of the VOCs.For example,B.1.1.7(Alpha),B.1.351(Beta),and P.1(Gamma)all contain the N501Y mutation,which increases the binding affinity for human ACE2 and confers higher infectivity in mice.Shuo Du Pulan Liu Zhiying Zhang Tianhe Xiao Ayijiang Yasimayi Weijin Huang Youchun Wang Yunlong Cao Xiaoliang Sunney Xie Junyu Xiao 2021Cell Research2021,31,10:3
14Molecular dynamics simulations of CH4 diffusion in kaolinite: influence of water content显示文摘Understanding the interaction of CH4 with kaolinite is significant for researchers in the fields of coalbed CH4 and shale gas.The diffusion behaviors of CH4 in kaolinite with water contents ranging from 0 to 5 wt% have been analyzed by molecular dynamics simulations.The results of the simulations indicate that CH4 molecules can jump between adjacent holes in the kaolinite matrix.CH4 diffusion coefficient was very low (3.28 × 10-9 m2/s) and increased linearly with the increasing of water content.As the water content decreased,the value of radial distribution function first peak between CH4 and oxygen was larger,meaning that with lower water content,the interaction energy between CH4 and oxygen in kaolinite is stronger.The interaction between CH4 and water is linearly positively correlated with water content,in contrast,the interaction energy between kaolinite and water as well as between kaolinite and CH4 decreased linearly with increasing water content.On the other hand,the diffusion of CH4 molecules adsorbed on the surfaces also can be accelerated by the fast diffusion of water molecules in the middle micropore of the kaolinite.Bin Zhang Jianting Kang Tianhe Kang Guanxian Kang Guofei Zhao 2019International Journal of Coal Science & Technology2019,6,4:3
15Thermal evolution effects on the properties of converting Cs-polluted soil into pollucite-base glass-ceramics for radioactive cesium immobilization显示文摘The Fukushima nuclear accident in Japan on March 11,2011,produced large amounts of Cs-polluted soil which must be controlled to prevent the spread of hazardous Cs into the environment.In this paper,the effects of heat treatment on the structure and properties of Cs-containing glass-ceramics,as a simulated nuclear waste form,were systematically investigated.Cesium atoms are chemically bonded in the pollucite structure,and the amorphous phase further encapsulates the pollucite crystals in the glassceramics,thus providing an extra protective layer for the immobilized Cs.XRD analysis,Raman and FT-IR studies on the glass-ceramics synergistically indicated that the optimum crystallization temperature for pollucite is around 1000℃.The pollucite is predominantly the main crystalline phase with a narrow crystal size distribution between 0.5 and 2 mm.Standard leaching test results show that the leaching rate of Cs was very low(3.0×10^(-3) g/(m^(2)·d)).The study offers a practical method for immobilizing Cs in pollucite-base glass-ceramics.Moreover,the experimentally obtained data may provide some important references for converting Cs-polluted soil into pollucite-base glass-ceramics waste form.Yong Yang Xin Cao Lifen Shi Zhengyi Zhang Pingping Wang Jinwei Li Yangshan Sun Shuyong Chen Tianhe Wang Liyun Ma Shou Peng 2021Journal of Materiomics2021,7,6:2
16Orbit determination and thrust force modeling for a maneuvered GEO satellite using two-way adaptive Kalman filtering显示文摘A two-way adaptive Kalman filter is proposed by combining a two-way filter with an adaptive filter for orbit determination of a maneuvered GEO satellite.A method of using Newton's high-resolution differential formula and polynomial fitting for modeling the thrust force of a maneuvered GEO satellite is developed.The adaptive factor,which balances the contributions of the measurements and the dynamic model information,is determined by using a two-segment function and predicted residual statistics.Simulations with a maneuvered GEO satellite tracked by the Chinese ground tracking network were conducted to verify the performance of the proposed orbit determination technique and the method of thrust force modeling.The results show that refining the thrust force model is beneficial for the orbit determination of a maneuvered GEO satellite;the two-way adaptive Kalman filter can efficiently control the influence of the dynamic model errors on the orbit state estimate.XU TianHe HE KaiFei XU GuoChang 2012Science China(Physics,Mechanics & Astronomy)2012,55,4:2
17Rattan Cultivation for Edible Shoot Production in Guangzhou,Southern China显示文摘Field studies were conducted in the Jiuwantan Forest Farm,Huadu District of Guangzhou City from June 2004 to March 2006 to evaluate the effects of planting spacings(0.5 m × 0.5 m,0.5 m × 1.0 m and 1.0 m × 1.0 m) and different fertilizers(bio-fermented manure,NPK compound fertilizer and NPK mixed fertilizer) on the growth of Daemonorops margaritae grown under irrigation and full-light conditions for edible shoots production.The effects of application of different fertilizers on the mean height,length of stems and number of leaves of 30-month old seedlings were not statistically significant,but the planting spacings were(P < 0.05).The two trial plantations became harvestable 18 months after planting when about one-third of seedlings produced new shoots.Results obtained from a sample harvest 20 months after planting showed that the average number of new shoots(suckers) per plant was 1.8,the average lengths of stems and edible shoots(palm hearts) were 45.3 cm and 18.8 cm,respectively.The average fresh weights of defoliated stems and edible shoots were 182.2 g and 14.9 g,respectively.These results suggest that the productivity in the first harvest is rather low.HUANG Shi’neng1 JIANG Zehui2 ZHAO Xia1 XIAN Guangyong1 1.Research Institute of Tropical Forestry,Chinese Academy of Forestry,No.682 Guangshan Yilu,Tianhe District,Guangzhou 510520,P.R.China 2.International Centre for Bamboo and Rattan(ICBR),No.8 Futong Dongdajie,Wangjing,Chaoyang District,Beijing 100102,P.R.China 2010Chinese Forestry Science and Technology2010,9,3:2
18Analytical optimization on GNSS buoy array for underwater positioning显示文摘Global navigation satellite system(GNSS)/acoustic positioning precision is determined by the positioning geometry and the ranging precision;thus optimizing GNSS buoys array is meaningful to improve the positioning accuracy and reliability.An analytical method is proposed for optimizing the GNSS buoys array with regard to the cutoff angle constraints for underwater acoustic observations.For the practical limitation of coplanarity of GNSS buoys and the cutoff angle,an algorithm is proposed to analytically minimize the position dilution of precision(PDOP).The proposed method is validated to give complete solutions of PDOP minimization with five GNSS buoys.At last,in order to search a best configuration among the PDOP solution set,we propose a search algorithm to get the solution with the smallest geometric dilution of precision(GDOP).It indicates that within a given region,the GDOP minimization at the center of a region is equivalent to the PDOP mean minimization over the region.The relation between the positioning accuracy and the positioning geometry with five known points is illustrated in an experiment performed in South China Sea.Ke Qi Guoqing Qu Shuqiang Xue Tianhe Xu Xiaoqing Su Yixu Liu Jun Wan 2019Acta Oceanologica Sinica2019,38,7:2
19Investigation of molecular aggregation mechanism of glipizide/cyclodextrin complexation by combined experimental and molecular modeling approaches显示文摘Cyclodextrin complexation is a wise strategy to enhance aqueous solubility of waterinsoluble drugs.However,the aggregation mechanism of drug-cyclodextrin complexes is still unclear.This research aimed to investigate the molecular aggregation mechanism of glipizide/cyclodextrin complexation by the combination of experimental and modeling methods.Binding free energies between glipizide and cyclodextrins from modeling calculations were higher than those by the phase solubility diagram method.Both experimental and modeling results showed that methylated-β-cyclodextrin exhibited the best solubilizing capability to glipizide.Size-measurement results confirmed the aggregation between glipizide and all four cyclodextrins in high concentrations.Glipizide/γ-cyclodextrin and glipizide/β-cyclodextrin complexes showed stronger aggregation trend than HP-β-cyclodextrin and methylated-β-cyclodextrin.The substituted groups in the rim of HP-β-cyclodextrin and methylated-β-cyclodextrin lead to weak aggregation.This research provided us a clear molecular mechanism of glipizide/cyclodextrin complexation and aggregation.This research will also benefit the formulation development of cyclodextrin solubilization.Tianhe Huang Qianqian Zhao Yan Su Defang Ouyang 2019Asian Journal of Pharmaceutical Sciences2019,14,6:2
20Finite-time Control of Discrete-time Systems With Variable Quantization Density in Networked Channels显示文摘This paper is concerned with the problem of finitetime control for a class of discrete-time networked systems.The measurement output and control input signals are quantized before being transmitted in communication network.The quantization density of the network is assumed to be variable depending on the throughputs of network for the sake of congestion avoidance.The variation of the quantization density modes satisfies persistent dwell-time(PDT)switching which is more general than dwell-time switching in networked channels.By using a quantization-error-dependent Lyapunov function approach,sufficient conditions are given to ensure that the quantized systems are finite-time stable and finite-time bounded with a prescribed H∞performance,upon which a set of controllers depending on the mode of quantization density are designed.In order to show the effectiveness of the designed H_∞controller,we apply the developed theoretical results to a numerical example.Yiming Cheng Xu Zhang Tianhe Liu Changhong Wang 2020IEEE/CAA Journal of Automatica Sinica2020,7,5:2
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