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27篇 您的检索式:作者名="DI Pengfei"
    题名 作者 年代 出处 被引量
1The levels, sources and reactivity of volatile organic compounds in a typical urban area of Northeast China显示文摘Air concentrations of volatile organic compounds(VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most(36.15%) to the total propene-equivalent concentration of the measured VOCs,followed by combustion emission(16.92%), vegetation emission and secondary formation(14.33%), solvent usage(10.59%), petrochemical industry emission(9.89%), petrol evaporation(6.28%), and liquefied petroleum gas(LPG) usage(5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O_3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics,e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O_3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O_3 pollution in Shenyang.Zhuobiao Ma Chengtang Liu Chenglong Zhang Pengfei Liu Can Ye Chaoyang Xue Di Zhao Jichen Sun Yiming Du Fahe Chai Yujing Mu 2019Journal of Environmental Sciences2019,31,5:12
2cDNA microarray reveals the alterations of cytoskeleton-related genes in osteoblast under high magneto-gravitational environment显示文摘为模仿减少的严肃环境的一个新奇基于地面的模型广泛地在许多地里被使用了的抗磁的悬浮。在这研究,一个专辑设计了超导的磁铁,它能生产三个明显的严肃层次(0, 1,和 2 g ) ,也就是高的磁电机重力的环境(HMGE ) ,被用来模仿空间严肃环境。造骨细胞基因表示侧面上的 HMGE 的效果被 microarray 调查。对抗磁的悬浮环境(0 g ) 敏感的基因,严肃变化,和高磁场变化根据典型房间功能被排序。作为细胞内部的忍受负担的结构,细胞骨架在严肃感觉起一个重要作用。因此, 13 细胞骨架相关的基因根据 microarray 分析的结果被选择,并且这些基因的表情被发现被即时 PCR 在 HMGE 下面改变。基于 PCR 结果, WASF2 的表情(是蛋白质家庭,成员 2 ) , WIPF1 (WAS/WASL 交往蛋白质家庭,成员 1 ) , paxillin,和 talin 1 被西方的污点试金进一步识别。结果显示了那 WASF2, WIPF1 对改变的严肃层次,和 talin 更敏感 1 并且 paxillin 对磁场和严肃变化敏感。我们的调查结果证明 HMGE 能影响造骨细胞基因表示侧面和细胞骨架相关的基因表示。mechanosensitive 基因的鉴定可以提高我们的理解到 microgravity 导致的骨头损失的机制并且可以为阻止并且对待骨头损失或骨质疏松症提供一些潜在的目标。Airong Qian Shengmeng Di Xiang Gao Wei Zhang Zongcheng Tian Jingbao Li Lifang Hu Pengfei Yang Dachuan Yin Peng Shang 2009Acta Biochimica et Biophysica Sinica2009,41,7:8
3New innovations in pavement materials and engineering:A review on pavement engineering research 2021显示文摘Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges.In the past 10 years,the pavement infrastructure strongly supports the rapid development of the global social economy.New theories,new methods,new technologies and new materials related to pavement engineering are emerging.Deterioration of pavement infrastructure is a typical multi-physics problem.Because of actual coupled behaviors of traffic and environmental conditions,predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis.In order to summarize the current and determine the future research of pavement engineering,Journal of Traffic and Transportation Engineering(English Edition)has launched a review paper on the topic of'New innovations in pavement materials and engineering:A review on pavement engineering research 2021'.Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering,this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world.The content includes asphalt binder performance and modeling,mixture performance and modeling of pavement materials,multi-scale mechanics,green and sustainable pavement,and intelligent pavement.Overall,this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering.JTTE Editorial Office Jiaqi Chen Hancheng Dan Yongjie Ding Yangming Gao Meng Guo Shuaicheng Guo Bingye Han Bin Hong Yue Hou Chichun Hu Jing Hu Ju Huyan Jiwang Jiang Wei Jiang Cheng Li Pengfei Liu Yu Liu Zhuangzhuang Liu Guoyang Lu Jian Ouyang Xin Qu Dongya Ren Chao Wang Chaohui Wang Dawei Wang Di Wang Hainian Wang Haopeng Wang Yue Xiao Chao Xing Huining Xu Yu Yan Xu Yang Lingyun You Zhanping You Bin Yu Huayang Yu Huanan Yu Henglong Zhang Jizhe Zhang Changhong Zhou Changjun Zhou Xingyi Zhu 2021Journal of Traffic and Transportation Engineering(English Edition)2021,8,6:7
4Validation and application of water levels derived from Sentinel-3A for the Brahmaputra River显示文摘For the first time ever, this study aims at applying Sentinel-3 A to the Great Brahmaputra River(GBR) and validating water levels derived from this newly-launched altimetry satellite mission. The GBR is divided into three primary parts:(1) a large section of the Yarlung Zangbo River in China, also termed the Upper Brahmaputra River(UBR) in this study, featured by high elevation,complex terrain, narrow river widths(from less than 100 to 400 m), and limited in situ measurements;(2) the Middle Brahmaputra River(MBR) with widths varying from ~400 m to ~1 km;(3) the Lower Brahmaputra River(LBR), dominated by braided channels with wide river channels(up to several kilometers). For the altimetry data, both waveform retracking and hooking effect correction were applied to mitigate the influence caused by land contamination and to improve the accuracy of water level retrievals. Water levels were derived from 41 virtual stations(VSs) across the GBR and different retracking algorithms were compared with in situ data from two gauging stations in the UBR. Time series of altimetry-based water levels were categorized into three types based on the quality: no data(type 1), degraded(type 2), and good(type 3). Results showed that the VSs(type 1) only existed in the mountainous regions, accounting for ~ a half of the total in the UBR. Validation with the gauged water levels showed that the TIC algorithm performed best among all of the retrackers applied, followed by the Ice-1 algorithm. The standard deviation of the difference between the gauged and TIC-derived water levels ranged from 0.41 to 0.76 m among four different VSs(type 3). In addition, the quality of VSs in the LBR was best, followed by the MBR. Our study has demonstrated the capability of Sentinel-3 A in monitoring water levels in the GBR, thereby paving the way for future applications such as discharge estimation and hydrologic/hydrodynamic applications.HUANG Qi LI XingDong HAN PengFei LONG Di ZHAO FanYu HOU AiZhong 2019Science China(Technological Sciences)2019,62,10:6
5An improved modeling of precipitation phase and snow in the Lancang River Basin in Southwest China显示文摘Precipitation phase(e.g., rainfall and snowfall) and snow(e.g., snowpack and snowmelt runoff) in high-mountain regions may largely affect runoff generation, which is critical to water supply, hydropower generation, agricultural irrigation, and ecosystems downstream. Accurately modeling precipitation phase and snow is therefore fundamental to developing a better understanding of hydrological processes for high-mountain regions and their lower reaches. The Lancang River(LR, or the Upper Mekong River)in China, among the most important transboundary rivers originating from the Tibetan Plateau, features active dam construction and complex water resources allocation of various stakeholders in Southeast Asian countries under climate change. This study aims to improve precipitation phase and snow modeling for the LR basin with a hydrological model and multisource remotely sensed data. Results show that joint use of the Moderate Resolution Imaging Spectroradiometer(MODIS) land surface temperature product with high spatial resolution(1 km×1 km) and an air temperature product can more precisely distinguish precipitation phase than air and wet-bulb temperature products in the LR basin. Snowfall and snowmelt were found to be controlled primarily by rainfall and snowfall temperature thresholds in snow modeling. The rainfall and snowfall temperature thresholds derived from the hydrological model through calibration with remotely sensed snowpack at basin scales were considerably lower than those derived from in situ observations. Rainfall and snowfall temperature thresholds derived from in situ observations could lead to the overestimation of snowmelt runoff due mostly to the lack of representation of point-based measurements at basin scales. This study serves as a basis for better modeling and predicting snow for the LR basin and potentially other similar basins globally.HAN ZhongYing LONG Di HAN PengFei HUANG Qi DU MingDa HOU AiZhong 2021Science China(Technological Sciences)2021,64,7:6
6Reduced-order Modeling and Dynamic Stability Analysis of MTDC Systems in DC Voltage Control Timescale显示文摘An equivalent source-load MTDC system including DC voltage control units,power control units and interconnected DC lines is considered in this paper,which can be regarded as a generic structure of low-voltage DC microgrids,mediumvoltage DC distribution systems or HVDC transmission systems with a common DC bus.A reduced-order model is proposed with a circuit structure of a resistor,inductor and capacitor in parallel for dynamic stability analysis of the system in DC voltage control timescale.The relationship between control parameters and physical parameters of the equivalent circuit can be found,which provides an intuitive insight into the physical meaning of control parameters.Employing this model,a second-order characteristic equation is further derived to investigate system dynamic stability mechanisms in an analytical approach.As a result,the system oscillation frequency and damping are characterized in a straight forward manner,and the role of electrical and control parameters and different system-level control strategies in system dynamic stability in DC voltage control timescale is defined.The effectiveness of the proposed reduced-order model and the correctness of the theoretical analysis are verified by simulation based on PSCAD/EMTDC and an experiment based on a hardware low-voltage MTDC system platform.Li Guo Pengfei Li Xialin Li Fei Gao Di Huang Chengshan Wang 2020CSEE Journal of Power and Energy Systems2020,6,3:5
7A novel design of 3D carbon host for stable lithium metal anode显示文摘Rational design of porous conductive hosts with high electrical conductivity,large surface area,and adequate interior space is desirable to suppressing dendritic lithium growth and accommodating large volume change of lithium metal anode during the Li plating/stripping process.However,due to the conductive nature of the conductive hosts,Li is easily deposited directly on the top of the hosts,which hinders it from fully functioning.To circumvent the issue,in this study,we designed a novel porous carbon host with a gradient-pore-size structure based on one-dimensional(1D)carbon with different diameters.With this kind of host,stable cycling with high and stable Coulombic efficiency of~98%is achieved at 0.5 mA cm^(−2) with an areal capacity of 1 mAh cm^(−2) over 320 cycles.In contrast,the normal three-dimensional(3D)carbon nanotube host presents a moss-like Li morphology with wildly fluctuating Coulombic efficiency after 100 cycles.The results reveal that the unique gradient-pore-size structure of the 3D conductive host greatly improves the performance of lithium metal batteries.Hang Liu Jie Di Ping Wang Rui Gao Han Tian Pengfei Ren Qingxi Yuan Wanxia Huang Ruiping Liu Qiang Liu Ming Feng 2022Carbon Energy2022,4,4:5
8In situ X-ray diffraction and thermal analysis of LiNi0.8Co0.15Al0.05O2 synthesized via co-precipitation method显示文摘LiNi_(0.8)Co_(0.15)Al_(0.05)O_2(NCA) material is successfully synthesized with a modified co-precipitation method,in which NH_3·H_2O and EDTA are used as two chelating agents. The obtained LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 material has well-defined layered structure and uniform element distribution, which reveals an enhanced electrochemical performance with a capacity retention of 97.9% after 100 cycles at 0.2 C, and reduced thermal runaway from the isothermal calorimetry test. In situ X-ray diffraction(XRD) was employed to capture the structural changes during the charge–discharge process. The reversible evolutions of lattice parameters(a, b, c, and V) further verify the structural stability.Na Zhang Xiaoyu Zhang Erbo Shi Shiyong Zhao Kezhu Jiang Di Wang Pengfei Wang Shaohua Guo Ping He Haoshen Zhou 2018Journal of Energy Chemistry2018,27,6:2
9Exome sequencing reveals genetic architecture in patients with isolated or syndromic short stature显示文摘Short stature is among the most common endocrinological disease phenotypes of childhood and may occur as an isolated finding or in conjunction with other clinical manifestations.Although the diagnostic utility of clinical genetic testing in short stature has been implicated,the genetic architecture and the utility of genomic studies such as exome sequencing(ES)in a sizable cohort of patients with short stature have not been investigated systematically.In this study,we recruited 561 individuals with short stature from two centers in China during a 4-year period.We performed ES for all patients and available parents.All patients were retrospectively divided into two groups:an isolated short stature group(group I,n=257)and an apparently syndromic short stature group(group II,n=304).Causal variants were identified in 135 of 561(24.1%)patients.In group I,29 of 257(11.3%)of the patients were solved by variants in 24 genes.In group II,106 of 304(34.9%)patients were solved by variants in 57 genes.Genes involved in fundamental cellularprocess played an important role in the genetic architecture of syndromic short stature.Distinct genetic architectures and pathophysiological processes underlie isolated and syndromic short stature.Xin Fan Sen Zhao Chenxi Yu Di Wu Zihui Yan Lijun Fan Yanning Song Yi Wang Chuan Li Yue Ming Baoheng Gui Yuchen Niu Xiaoxin Li Xinzhuang Yang Shiyu Luo Qiang Zhang Xiuli Zhao Hui Pan Mei Li Weibo Xia Guixing Qiu Pengfei Liu Shuyang Zhang Jianguo Zhang Zhihong Wu James R.Lupski Jennifer E.Posey Shaoke Chen Chunxiu Gong Nan Wu 2021Journal of Genetics and Genomics2021,48,5:2
10重污染郊区环境中二氧化碳垂直分布的观测和模拟显示文摘CO2垂直分布对于大气传输模式和遥感测量的校准和验证非常重要。由于传统仪器质量大,配套系统体积大,边界层内CO2的原位测量比较少见。本研究利用基于低成本非分散红外(NDIR)传感器的微型化CO2监测仪器,搭载在系留气艇上,测量河北省石家庄西南部低对流层(0–1000米)的CO2垂直分布和气象参数。低成本传感器与传统气相色谱分析仪测得的结果一致,CO2浓度的总体趋势随高度增加而下降。研究结果有助于直接分析大气边界层中CO2浓度的垂直结构,为WRF等大气传输模式的校准和验证提供基础数据。BAO Zhongxiu HAN Pengfei ZENG Ning LIU Di CAI Qixiang WANG Yinghong TANG Guiqian ZHENG Ke YAO Bo 2020Atmospheric and Oceanic Science Letters2020,13,4:2
11Low-loss light transmission in a rectangularshaped hybrid metal trench at 1550 nm显示文摘Yang Pengfei Di Zhigang Xu Hongxing 2013Opt Express2013,21,17:1
12Quantification of Methane Fluxes from Hydrocarbon Seeps to the Ocean and Atmosphere:Development of an in situ and Online Gas Flux Measuring System显示文摘Natural hydrocarbon seeps in the marine environment are important contributors to greenhouse gases in the atmosphere. Such gases include methane, which plays a significant role in global carbon cycling and climate change. To accurately quantify the methane flux from hydrocarbon seeps on the seafloor, a specialized in situ and online gas flux measuring(GFM) device was designed to obtain high-resolution time course gas fluxes using the process of equal volume exchange. The device consists of a 1.0-m diameter, 0.9-m tall, inverted conical tent and a GFM instrument that contains a solenoid valve, level transducer, and gas collection chamber. Rising gas bubbles from seeps were measured by laboratory-calibrated GFM instruments attached to the top of the tent. According to the experimental data, the optimal anti-shake time interval was 5 s. The measurement range of the device was 0–15 L min^(-1), and the relative error was ± 1.0%. The device was initially deployed at an active seep site in the Lingtou Promontory seep field in South China Sea. The amount of gas released from a single gas vent was 30.5 m^3 during the measurement period, and the gas flow rate ranged from 22 to 72 Lh^(-1), depending on tidal period, and was strongly negatively correlated with water depth. The measurement results strongly suggest that oceanic tides and swells had a significant forcing effect on gas flux. Low flow rates were associated with high tides and vice versa. The changes in gas volume escaping from the seafloor seeps could be attributed to the hydrostatic pressure induced by water depth. Our findings suggest that in the marine environment, especially in the shallow shelf area, sea level variation may play an important role in controlling methane release into the ocean. Such releases probably also affect atmospheric methane levels.DI Pengfei CHEN Qinghua CHEN Duofu 2017Journal of Ocean University of China2017,16,3:1
13Three-dimensional theoretical analysis of seepage field in front of shield tunnel face显示文摘To evaluate hydraulic head distribution in front of a shield tunnel in a saturated soil layer,theoretical analysis and numerical simulations are carried out in this study.Based on the partial differential equilibrium equation of seepage flow,a three-dimensional(3D)theoretical analytical model of the shield tunnel face and the seepage field in front of it is established using the eigenfunction and the Fourier series expansion methods,and the hydraulic head calculation formula is derived.Combined with engineering cases,the theoretical analysis results and the 3D numerical simulation results are compared and analyzed.The effect of the water pressure of the tunnel face on the hydraulic head distribution is also analyzed.The results of the proposed analytical solution are in agreement with those of the numerical simulation solutions;moreover,the proposed analytical solution requires less time to calculate the seepage hydraulic head than the numerical simulation.The ratio of the initial water table to the diameter(D)of tunnel face has a more significant impact on the hydraulic head distribution at a position 0.5D above the tunnel vault.When the water pressure on the tunnel face is not considered,the values of the hydraulic head are significantly underestimated.Qiguang Di Pengfei Li Mingju Zhang Caixia Guo Fan Wang Jie Wu 2022Underground Space2022,7,4:1
14The distribution and variation in the gas composition of macro-seeps on the near-shore Lingtou Promontory in the South China Sea显示文摘Natural hydrocarbon seeps in a marine environment are one of the important contributors to greenhouse gases in the atmosphere,including methane,which is significant to the global carbon cycling and climate change.Four hydrocarbon seep areas,the Lingtou Promontory,the Yinggehai Rivulet mouth,the Yazhou Bay and the Nanshan Promontory,occurring in the Yinggehai Basin delineate a near-shore gas bubble zone.The gas composition and geochemistry of venting bubbles and the spatial distribution of hydrocarbon seeps are surveyed on the near-shore Lingtou Promontory.The gas composition of the venting bubbles is mainly composed of CO_2,CH_4,N_2 and O_2,with minor amounts of non-methane hydrocarbons.The difference in the bubbles' composition is a possible consequence of gas exchange during bubble ascent.The seepage gases from the seafloor are characterized by a high CO_2 content(67.35%) and relatively positive δ^(13)C_(V_PDB) values(-0.49×10^(-3)-0.86×10^(-3)),indicating that the CO_2 is of inorganic origin.The relatively low CH_4 content(23%) and their negative δ^(13)C_(V-PDB) values(-34.43×10^(-3)--37.53×10^(-3)) and high ratios of C_1 content to C_(1-5) one(0.98-0.99)as well point to thermogenic gases.The hydrocarbon seeps on the 3.5 Hz sub-bottom profile display a linear arrangement and are sub-parallel to the No.1 fault,suggesting that the hydrocarbon seeps may be associated with fracture activity or weak zones and that the seepage gases migrate laterally from the central depression of the Yinggehai Basin.DI Pengfei FENG Dong CHEN Duofu 2016Acta Oceanologica Sinica2016,35,11:1
15In-situ and on-line measurement of gas flux at a hydrocarbon seep from the northern South China Sea显示文摘Di Pengfei Feng Dong Chen Duofu 2014Continental shelf research2014,81,:1
16Influence of zinc state on the catalyst properties of Zn/HZSM-5 zeolite in 1-hexene aromatization and cyclohexane dehydrogenation显示文摘Rational design of Zn-containing HZSM-5 zeolite(Zn/HZSM-5)with high reactivity and excellent aromatization performance for olefin aromatization is crucially desired.We develop a new and uncomplicated method to synthesize Zn/HZSM-5(IMX/Z5)with superior aromatization performance in the paper.Compared to incipient wetness impregnation(IMP/Z5)and mechanical mixing(MIX/Z5),the asprepared IMX/Z5 presents a higher amount of surface ZnOH^(+)species(2.87%)while keeping identical bulk zinc content.As a result,more surface ZnOH^(+)favor both the aromatization of 1-hexene and cyclohexane dehydrogenation.For the two olefin aromatization pathways(hydrogen transfer and dehydrogenation),it is the first time found both the hydrogen transfer ability and the dehydrogenation ability increase linearly with the amount of surface ZnOH^(+)species while keeping identical bulk zinc content.We believe that the linear relationships are essential to design next generation olefin aromatization catalysts.Di Gao Yibo Zhi Liyuan Cao Liang Zhao Jinsen Gao Chunming Xu Mingzhi Ma Pengfei Hao 2022Chinese Journal of Chemical Engineering2022,35,3:1
17Risk factors of recurrence in small-sized, node negative breast cancer in young women: a retrospective study in Chinese population显示文摘We aimed to investigate risk factors of local and distant recurrence in small-sized, node negative breast cancer in women <35 years in a Chinese cohort. Between January 1994 and January 2007, 107 patients with pathologically confirmed small-sized (1cm), node negative breast cancer who did not receive neoadjuvant or adjuvant chemotherapy were included. The 5-year recurrence-free survival (RFS) was estimated according to different prognostic variables. With a median time of 60 months (range, 8-60 months) follow-up, local and distant recurrence were observed in 25 cases (23.4%). By univariate analysis, HER-2 positivity, triple negative (TN), and high Ki-67 index ( 14%) were risk factors of a lower RFS (hazard ratio (HR) 6.680, 95% confidence interval (CI) 2.350-18.985, P<0.0001 for HER-2 positive; HR 4.769, 95%CI 1.559-14.591, P=0.006 for TN; HR6.030, 95%CI2.659-13.674, P<0.0001 for high Ki-67index). Patients with grade 3 tumors had a lower RFS (HR 2.922, 95%CI 1.096-7.791, P=0.032) compared with those with grade 1 or grade 2 tumors. By multivariate analysis, HER-2 positivity (HR 10.204, 95%CI 3.391-30.704, P<0.0001), TN (HR 10.521, 95% CI 3.152-35.113, P<0.0001) and high Ki-67 index (HR 10.820, 95%CI 4.338-27.002, P<0.0001) remained risk factors of RFS. In this cohort, HER-2 positivity, triple negative and high Ki-67 index were independent risk factors of RFS in young patients with T1a,bN0 breast cancer. Subsequent pregnancy did not affect RFS.ZHANG XiaoSan LI PengFei MA WenJie DI WenYu ZHAO Shu GAO QingZu ZHAO YuYing YANG MaoPeng ZHANG QingYuan 2013Science China(Life Sciences)2013,56,4:1
18A two-step three dimensional marine magnetotelluric inversion method with considering rugged seafloor topography:Synthetic studies显示文摘Inversion of magnetotelluric(MT) responses has been used to explore the electrical conductivity distribution of the Earth’s interior. In three-dimensional(3-D) inversions, it is significant to use a good initial model, because final model obtained by most 3-D inversion methods is influenced by the initial model. Although uniform initial models are widely used in 3-D inversions, one-dimensional(1-D) initial models are alternatives, which could more appropriately represent the actual conductivity variations in the Earth’s interior. This study presents a two-step 3-D inversion method, especially for marine cases. This inversion method first concentrates on obtaining a 1-D initial model and then inverts for 3-D conductivity structures with it, in both of which the 3-D topography is carefully taken into consideration. This method was tested by synthetic models of different topography variations(depression-shaped, smoothly varying, channel-shaped and square-shaped plateau topography) and of heterogeneous layers with different checkerboard-type anomalies(sharp or smooth lateral conductivity variations) embedded in1-D model of depth-dependent conductivity. The comparisons were done about obtaining an initial model by the proposed method and that inverted from the corrected responses. The results of 3-D inversions by using the method of this study were also compared to that with different uniform initial models. Results of synthetic tests and comparisons were discussed by using directional information of newly introduced model-vector parameters. The performance and validity of this method was verified.It also revealed that some of the newly introduced model-vector parameters could be used to show the convergence of inversions and help to select inverse model.Pengfei LIANG Qingyun DI Changmin FU Ruo WANG Qihui ZHEN Zhe YUN Jiagang ZHANG 2023Science China Earth Sciences2023,66,4:0
19A review of geoanalytical databases显示文摘Geoanalytical data provide fundamental information according to which the Earth's resources can be known and exploited to support human life and development.Large amounts of manpower and material and financial resources have been invested to acquire a wealth of geoanalytical data over the past 40 years.However,these data are usually managed by individual researchers and are preserved in an ad hoc manner without metadata that provide the necessary context for interpretation and data integration requirements.In this scenario,fewer data,except for published data,can be reutilized by geological researchers.Many geoanalytical databases have been constructed to collect existing data and to facilitate their use.These databases are useful tools for preserving,managing,and sharing data for geological research,and provide various data repositories to support geological studies.Since these databases are dispersed and diverse,it is difficult for researchers to make full use of them.This contribution provides an introduction on available geoanalytical databases.The database content can be made accessible to researchers,the ways in which this can be done,and the functionalities that can be used are illustrated in detail.Moreover,constraints that have limited the reutilization of geoanalytical data and creation of more advanced geoanalytical databases are discussed.Yutong He Yang Bai Di Tian Li Yao Runlong Fan Pengfei Chen 2019Acta Geochimica2019,38,5:0
20Experimental investigation of face instability for tunnels in sandy cobble strata显示文摘In order to investigate the influence of face instability for tunnels with different burial depths in sandy cobble strata on earth pressure and the instability region,geomechanical model tests and numerical simulations were performed.The continuous excavation method was adopted to reduce the pressure of the soil bin and restore the real engineering situation.Earth pressure in three directions of the obser-vation section in front of the tunnel face was monitored during the tunneling of the shield.Evolutions of the lateral stress ratios at dif-ferent stages were also investigated.The instability area of the shield tunnel face in sandy cobble strata with different burial depth ratios during the instability stage was obtained based on the change ratio of earth pressure and compared with existing researches.The earth pressure began to change when the excavation was one shield diameter away from the observation section,and when the excavation reached the observation section,the earth pressure decreased significantly.The burial depth of shield tunnel in the sandy cobble strata has a significant impact on the evolution of soil arch and the size of the failure area.The numerical simulation of the continuum medium cannot reflect the stress redistribution characteristics of the granular body like sandy cobble strata,and the failure area or stress distur-bance area obtained by the model test is larger than the numerical simulation result.Existing methods have deviations in analyzing the failure area of shield tunnel face in sandy cobble strata.It provides not only guidance for shield tunnel excavation engineering in sandy cobble strata,but also a reference for the theoretical research on failure areas.Qiguang Di Pengfei Li Mingju Zhang Xiaopu Cui 2023Underground Space2023,,3:0
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