检索结果-南通市图书馆

A New Method for Deriving High-Vertical-Resolution Wind Vector Data from the L-Band Radar Sounding System in China

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第11期41卷 2192-2202页

作者： Fang yuan Zijiang ZHOU Jie liao National Meteorological Information Center China Meteorological AdministrationBeijing 100081China

High-vertical-resolution radiosonde wind data are highly valuable for describing the dynamics of the meso-and microscale atmosphere. However, the current algorithm used in China's L-band radar sounding system for calculating highvertical-resolution wind vectors excessively smooths the data, resulting in significant underestimation of the calculated kinetic energy of gravity waves compared to similar products from other countries, which greatly limits the effective utilization of the data. To address this issue, this study proposes a novel method to calculate high-vertical-resolution wind vectors that utilizes the elevation angle, azimuth angle, and slant range from L-band radar. In order to obtain wind data with a stable quality, a two-step automatic quality control procedure, including the RMSE-F(root-mean-square error F) test and elemental consistency test are first applied to the slant range data, to eliminate continuous erroneous data caused by unstable signals or radar malfunctions. Then, a wind calculation scheme based on a sliding second-order polynomial fitting is utilized to derive the high-vertical-resolution radiosonde wind vectors. The evaluation results demonstrate that the wind data obtained through the proposed method show a high level of consistency with the high-resolution wind data observed using the Vaisala Global Positioning System and the data observed by the new Beidou Navigation Sounding System. The calculation of the kinetic energy of gravity waves in the recalculated wind data also reaches a level comparable to the Vaisala observations.

关键词： L-band radar sounding system upper air high-vertical-resolution radiosonde wind vectors quality control polynomial fitting

Genetic Analysis of Structural Styles in the Makran Accretionary Wedge–Insight from Physical Simulations

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2024年第1期23卷 157-172页

作者： SHAO Longfei YU Fusheng GONG Jianming liao jing YU Zhifeng TANG Liang CHEN Jiangong WANG Yuefeng NENG yuan School of Earth Sciences China University of PetroleumBeijing 102249China State Key Laboratory of Petroleum Resources and Processing China University of PetroleumBeijing 102249China Qingdao Institute of Marine Geology China Geological SurveyQingdao 266071China China University of Petroleum–Beijing at Karamay Karamay 834000China

The Makran accretionary wedge has the smallest subduction angle among any accretionary prism in the world. The factors controlling the spacing and morphological development of its deep thrust faults, as well as the formation mechanism of shallow normal faults, remain unclear. Meanwhile, the factors affecting the continuity of plane faults must be comprehensively discussed. Clarifying the development characteristics and deformation mechanisms of the Makran accretionary wedge is crucial to effectively guide the exploration of gas hydrate deposits in the area. This study aims to interpret seismic data to identify typical structures in the Makran accretionary wedge, including deep imbricate thrust faults, shallow and small normal faults, wedge-shaped piggyback basins, mud diapirs with fuzzy and disorderly characteristics of reflection, décollements with a northward tilt of 1° – 2°, and large seamounts. Physical simulation-based experiments are performed to comprehensively analyze the results of the plane, section, and slices of the wedge. Results reveal that the distances between and shapes of thrust faults in the deep parts of the Makran accretionary wedge are controlled by the bottom décollement. The uplift of the thrust fault-related folds and the upwelling of the mud diapirs primarily contribute to the formation of small normal faults in the shallow part of the area. The mud diapirs originate from plastic material at the bottom, while those that have developed in the area near the trench are larger. Seamounts and mud diapirs break the continuity of fault plane distribution.

关键词： Makran accretionary wedge structural styles faults distribution physical simulation

Copper(I)Cluster of Aggregation-Induced Emission and X-Ray Scintillator Characteristic

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第5期40卷 887-893页

作者： XIONG Jiayu WU Minjian YAO liao-yuan MOE Key Laboratory of Cluster Sciences Beijing Key Laboratory of Photoelectroic/Electrophotonic Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing102488P.R.China Tangshan Research Institute Beijing Institute of TechnologyTangshan063000P.R.China

Due to their precise atomic structures,photoluminescent copper nanoclusters(Cu NCs)have promising applications in basic research and technical applications,such as bioimaging,cell labeling,phototherapy,and photoactivation *** this work,we report a simple strategy for synthesizing novel CuNCs co-protected by alkynyl and phosphine ligands with the molecular formula[Cu_(7)(PPh_(3))_(10)(PE)_(3)(CH_(3)O)](Cu_(4)@Cu_(3)).Single-crystal X-ray crystallography reveals that the NC core exhibits an open square structure and an overall pyramid *** Cu_(4)@Cu_(3) units are connected through weak interactions to form dimers in crystals,creating a molecular cage that looks like two tightly closed ***_(4)@Cu_(3)exhibits dual emission in the visible *** is also an aggregation-induced emission(AIE)-active luminescent substance,which exhibits strong emission in the visible light region when ***,it has the properties of radioluminescent(RL)and could be a potential scintillator *** study not only enriches the types of atomically accurate AIE clusters,but also holds significant importance for the development of a new generation of high-performance and environmentally friendly X-ray scintillators.

关键词： Copper nanocluster Aggregation-induced emission X-Ray scintillator

Biomaterials and tissue engineering in traumatic brain injury:novel perspectives on promoting neural regeneration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第10期19卷 2157-2174页

作者： Shihong Zhu Xiaoyin Liu Xiyue Lu Qiang liao Huiyang Luo yuan Tian Xu Cheng Yaxin Jiang Guangdi Liu jing Chen Department of Neurosurgery West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina National Engineering Research Center for Biomaterials College of Biomedical EngineeringSichuan UniversityChengduSichuan ProvinceChina Department of Anesthesiology West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina Department of Pharmacy West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina Out-patient Department West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina Department of Respiratory and Critical Care Medicine West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina

Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. However, limited accessibility to the injury sites, complicated histological and anatomical structure, intricate cellular and extracellular milieu, lack of regenerative capacity in the native cells, vast variety of damage routes, and the insufficient time available for treatment have restricted the widespread application of several therapeutic methods in cases of central nervous system injury. Tissue engineering and regenerative medicine have emerged as innovative approaches in the field of nerve regeneration. By combining biomaterials, stem cells, and growth factors, these approaches have provided a platform for developing effective treatments for neural injuries, which can offer the potential to restore neural function, improve patient outcomes, and reduce the need for drugs and invasive surgical procedures. Biomaterials have shown advantages in promoting neural development, inhibiting glial scar formation, and providing a suitable biomimetic neural microenvironment, which makes their application promising in the field of neural regeneration. For instance, bioactive scaffolds loaded with stem cells can provide a biocompatible and biodegradable milieu. Furthermore, stem cells-derived exosomes combine the advantages of stem cells, avoid the risk of immune rejection, cooperate with biomaterials to enhance their biological functions, and exert stable functions, thereby inducing angiogenesis and neural regeneration in patients with traumatic brain injury and promoting the recovery of brain function. Unfortunately, biomaterials have shown positive effects in the laboratory, but when similar materials are used in clinical studies of human central nervous system regeneration, their efficacy is unsatisfactory. Here, we review the characteristics and properties

关键词： bioactive materials biomaterials exosomes neural regeneration scaffolds stem cells tissue engineering traumatic brain injury

A Stable Copper-based Metal-Azolate Framework for Efficient Electroreduction of CO_(2)to C_(2+)Products

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第4期40卷 664-669页

作者： LIU yuan-yuan ZHU Hao-Lin liao Pei-Qin CHEN Xiao-Ming Key Laboratory of Bioinorganic and Synthetic Chemistry Ministry of EducationGBRCE for Functional Molecular EngineeringSchool of ChemistryIGCMESun Yat-sen UniversityGuangzhou510275P.R.China Chemistry and Chemical Engineering Guangdong Laboratory Shantou515031P.R.China

Driven by renewable or excess electrical energy,electrochemical CO_(2)reduction reaction(eCO_(2)RR)represents a promising carbon-neutral approach to generating valuable low-carbon fuels by consuming CO_(2)and H_(2)O.C_(2+)products are one of the most economically valuable products among the reduction species of eCO_(2)RR,but there are still some challenges,such as low selectivity or low current *** this work,we showed that a copper-based metal-azolate framework(MAF),denoted as MAF-203,exhibits the high performance of eCO_(2)RR to yield C_(2+)products with the Faradaic efficiency(C_(2+))of 52.5%and a current density of 660 mA/cm^(2)at-1.2 V *** in a flow cell device under alkaline *** experiment,in situ infrared spectroscopy and the density functional theory(DFT)calculations showed that the electron donating effect of methyl substituents on organic ligands of the copper-based MAF could enhance the ligand field and activation of key intermediates(*CO and*CHO species),thus promoting the coupling of*CO and*CHO for yielding C_(2+)products.

关键词： Metal-organic framework Carbon dioxide Electroreduction C_(2+)product Metal-azolate framework

A dataset of lake level changes in China between 2002 and 2023 using multi-altimeter data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Big Earth Data 2024年第1期8卷 166-188页

作者： Shanmu Ma jingjuan liao Ruofan jing Jiaming Chen Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijingChina International Research Center of Big Data for Sustainable Development Goals BeijingChina University of Chinese Academy of Sciences BeijingChina

Lake water levels are an important indicator of water balance and water cycles,and are essential for climate and environmental change studies and water resource ***,lake level measurements are scarce or inconsistent throughout the country,and traditional gauge measurements of many lakes are not feasible,so satellite altimetry is a vital alternative to gauge lake ***,the accuracy and sam-pling frequency of lake level time series are usually low because of time and space coverage limitations;therefore,it is necessary to utilize multialtimeter data to monitor lake levels and obtain lake level changes over long time *** this study,we extracted the water level changes in 988 lakes(>10 km^(2))in China between 2002 and 2023 based on ICESat/-2,Cryosat-2,Jason-1/2/3,and Sentinel-3A/3B altimetry data using waveform retracking,lake level extraction,lake level time series construction,the fusion of multi-altimeter lake level time series,and outlier removal.A total of 55%of the lakes in this dataset have been monitored for more than 10 years,and 34%have more than 12 times the annual average water level *** the same time,in situ data from 21 lakes were used for validation,and the average root mean square error(RMSE)for each of the datasets of ICESat/-2,Cryosat-2,Jason-1/2/3,and Sentinel-3A/3B versus the in situ lake levels are 0.223 m,0.163 m,0.207 m,0.596 m,0.295 m,0.275 m,0.243 m,and 0.317 m,respectively,and the mean RMSE of the fused lake levels reaches 0.332 *** the monitoring period,the water levels in Chinese lakes generally *** overall annual average rate of change at the 20 and 10-year scales was 0.123 m/a and 0.151 m/a,respectively,among which the overall water levels in large lakes increased *** lakes with a faster rate of decline in the water level were primarily *** water storage in each lake region in China shows an upward trend,with the most significant increase in the Tibetan Plateau reg

关键词： Lake level multi-altimeter China spatiotemporal variation

Development of CONTHAC-3D and hydrogen distribution analysis of HPR1000

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 210-221页

作者： Hui Wang jing-jing Li yuan Chang Gong-Lin Li Ming Ding China Nuclear Power Engineering Co.LTD. Beijing 100084China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin 100049China

An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe ***-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the ***-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling *** validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment *** hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by ***,the hydrogen distribution in the HPR1000 containment during a severe accident was *** results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the *** amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is ***,we do not recommend installing all autocatalytic recombiners at high *** study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.

关键词： Hydrogen risk mitigation Pressurized water reactor HPR1000 Thermal hydraulic CONTHAC-3D

An innovative inertial parameters identification method for non-cooperative space targets based on electrostatic interaction

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第9期37卷 417-432页

作者： Heng jing Zixuan ZHENG Deja CHE Jianping yuan National Key Laboratory of Aerospace Flight Dynamics Northwestern Polytechnical UniversityXi'an 710072China School of Astronautics Northwestern Polytechnical UniversityXi'an 710072China

Inertial characteristics of non-cooperative targets are crucial for space capture and sub-sequent on-orbit *** methods for identifying inertial parameters involve proximity operations,which are associated with the risk of collision with non-cooperative *** paper introduces a long-range,contactless method for identifying the inertial parameters of a non-cooperative target during the pre-capture ***,electrostatic interaction is used as an external excitation to alter the target's motion.A force estimation algorithm that uses measure-ments from visual and potential sensors is proposed to estimate the electrostatic interaction and eliminate the need for force ***,a recursive estimation-identification framework is presented to concurrently estimate the coupled motion state,weak electrostatic interaction,and inertial parameters of the *** simulation results show that the proposed method extends the identification distance to 170 times that of the previous method while maintaining high identifica-tion precision forall parameters.

关键词： Non-cooperative target Inertial parameters identification Electrostatic interaction Force estimation Dynamical coupling

A regression approach for seismic first-break picking

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 1584-1596页

作者： Huan yuan San-Yi yuan Jie Wu Wen-jing Sang Yu-He Zhao CNPC Key Laboratory of Geophysical Exploration China University of Petroleum(Beijing)Beijing 102249China Research Institute of Petroleum Exploration&Development—Northwest(NWGI) Key Laboratory of reservoir characterization of CNPCPetroChinaLanzhou 730020GansuChina

The picking efficiency of seismic first breaks(FBs)has been greatly accelerated by deep learning(DL)***,the picking accuracy and efficiency of DL methods still face huge challenges in low signal-to-noise ratio(SNR)*** address this issue,we propose a regression approach to pick FBs based on bidirectional long short-term memory(Bi LSTM)neural network by learning the implicit Eikonal equation of 3D inhomogeneous media with rugged topography in the target *** employ a regressive model that represents the relationships among the elevation of shots,offset and the elevation of receivers with their seismic traveltime to predict the unknown FBs,from common-shot gathers with sparsely distributed *** from image segmentation methods which automatically extract image features and classify FBs from seismic data,the proposed method can learn the inner relationship between field geometry and *** addition,the predicted results by the regressive model are continuous values of FBs rather than the discrete ones of the binary *** picking results of synthetic data shows that the proposed method has low dependence on label data,and can obtain reliable and similar predicted results using two types of label data with large *** picking results of9380 shots for 3D seismic data generated by vibroseis indicate that the proposed method can still accurately predict FBs in low SNR *** subsequent stacked profiles further illustrate the reliability and effectiveness of the proposed *** results of model data and field seismic data demonstrate that the proposed regression method is a robust first-break picker with high potential for field application.

关键词： First-break picking Low signal-to-noiseratio Regression BiLSTM Traveltime Geometry Noisy seismic data