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Propagation of crust deformation anomalies related to the Menyuan M_(S) 6.9 earthquake
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作者 Anfu Niu Chong Yue +3 位作者 Zhengyi yuan Jing Zhao Wei Yan yuan li 《Earthquake Research Advances》 CSCD 2023年第4期43-48,共6页
Decoding the variation laws of the deformation field before strong earthquakes has long been recognized as an essential issue in earthquake prediction research. In this paper, the temporal and spatial distribution cha... Decoding the variation laws of the deformation field before strong earthquakes has long been recognized as an essential issue in earthquake prediction research. In this paper, the temporal and spatial distribution characteristics of deformation anomalies in the northeastern margin of the Qinghai-Tibetan Plateau before and after the Menyuan M_(S)6.9 earthquake were studied by using the Fisher statistical test method. By analyzing the characteristics of these anomalies, we found that: 1) The deformation anomalies are mainly distributed in the marginal front area of the Qinghai-Tibetan Plateau, where short-term deformation anomalies are prone to occur due to a high gradient of gravity;2) The deformation anomalies along the northeastern margin of the Qinghai-Tibetan Plateau are characterized by spatial propagation, and the migration rate is about 2.4 km/d. The propagation pattern is counterclockwise, consistent with the migration direction of M_(S)≥ 6.0 earthquakes;3) The time and location of the Menyuan earthquake are related to the group migration of earthquakes with M_(S)≥ 6.0. Finally,based on the results of gravity field variation and the theory of crust stress wave, the law of deformation anomaly distribution was discussed. We suggest that both the deformation propagation along the northeastern margin of the Qinghai-Tibetan Plateau and the earthquake migration are possibly associated with the variation of the stress field caused by subsurface mass flow. 展开更多
关键词 Northeastern margin of Qinghai-Tibetan Plateau Menyuan M_(S)6.9 earthquake Deformation propagation Earthquake migration Gravity field
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Hard-carbon hybrid Li-ion/metal anode enabled by preferred mesoporous uniform lithium growth mechanism
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作者 Fang Yan Yan liu +11 位作者 yuan li Yan Wang Zicen Deng Meng li Zhenwei Zhu Aohan Zhou Ting li Jingyi Qiu Gaoping Cao Shaobo Huang Biyan Wang Hao Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期252-259,I0006,共9页
To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li me... To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li metal has low transport kinetics and is easy to causes the growth of lithium dendrites and accumulation of dead Li,which seriously affects the cycle life of batteries and even causes safety problems.Here,by comparing graphite with two types of hard carbon,it was found that hybrid anode formed by hard carbon and lithium metal,possessing more disordered mesoporous structure and lithophilic groups,presents better performance.Results indicate that the mesoporous structure provides abundant active site and storage space for dead lithium.With the synergistic effect of this structure and lithophilic functional groups(–COOH),the reversibility of hard carbon/lithium metal hybrid anode is maintained,promoting uniform deposition of lithium metal and alleviating formation of lithium dendrites.The hybrid anode maintains a 99.5%Coulombic efficiency(CE)after 260 cycles at a specific capacity of 500 m Ah/g.This work provides new insights into the hybrid anodes formed by carbon-based materials and lithium metal with high specific energy and fast charging ability. 展开更多
关键词 Hard carbon/Li metal hybrid anode Mesoporous structure Surface oxygen functional group Fast charging Lithium batteries
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Rice canopy temperature is affected by nitrogen fertilizer
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作者 Min Jiang Zhang Chen +3 位作者 yuan li Xiaomin Huang lifen Huang Zhongyang Huo 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第3期824-835,共12页
Canopy temperature strongly influences crop yield formation and is closely related to plant physiological traits.However, the effects of nitrogen treatment on canopy temperature and rice growth have yet to be comprehe... Canopy temperature strongly influences crop yield formation and is closely related to plant physiological traits.However, the effects of nitrogen treatment on canopy temperature and rice growth have yet to be comprehensively examined. We conducted a two-year field experiment with three rice varieties(HD-5, NJ-9108, and YJ-805) and three nitrogen treatments(zero-N control(CK), 200 kg ha~(–1)(MN), and 300 kg ha~(–1)(HN)). We measured canopy temperature using a drone equipped with a high-precision camera at the six stages of the growth period. Generally,canopy temperature was significantly higher for CK than for MN and HN during the tillering, jointing, booting, and heading stages. The temperature was not significantly different among the nitrogen treatments between the milky and waxy stages. The canopy temperature of different rice varieties was found to follow the order: HD-5>NJ-9108>YJ-805, but the difference was not significant. The canopy temperature of rice was mainly related to plant traits, such as shoot fresh weight(correlation coefficient r=–0.895), plant water content(–0.912), net photosynthesis(–0.84), stomatal conductance(–0.91), transpiration rate(–0.90), and leaf stomatal area(–0.83). A structural equation model(SEM) showed that nitrogen fertilizer was an important factor affecting the rice canopy temperature.Our study revealed:(1) A suite of plant traits was associated with the nitrogen effects on canopy temperature,(2) the heading stage was the best time to observe rice canopy temperature, and(3) at that stage, canopy temperature was negatively correlated with rice yield, panicle number, and grain number per panicle. This study suggests that canopy temperature can be a convenient and accurate indicator of rice growth and yield prediction. 展开更多
关键词 canopy temperature RICE physiological and biochemical characteristics YIELD
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ATM Activation is Key in Vasculogenic Mimicry Formation by Glioma Stem-like Cells
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作者 Jing Xie Jiaxin Tang +3 位作者 yuan li Xue Kong Wei Wang Haibo Wu 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第8期834-849,共16页
Objective Vasculogenic mimicry(VM)is a novel vasculogenic process integral to glioma stem cells(GSCs)in glioblastoma(GBM).However,the relationship between VM and ataxia-telangiectasia mutated(ATM)serine/threonine kina... Objective Vasculogenic mimicry(VM)is a novel vasculogenic process integral to glioma stem cells(GSCs)in glioblastoma(GBM).However,the relationship between VM and ataxia-telangiectasia mutated(ATM)serine/threonine kinase activation,which confers chemoradiotherapy resistance,remains unclear.Methods We investigated VM formation and phosphorylated ATM(pATM)levels by CD31/GFAPperiodic acid-Schiff dual staining and immunohistochemical staining in 145 GBM specimens.Glioma stem-like cells(GSLCs)derived from the formatted spheres of U87 and U251 cell lines and their pATM level and VM formation ability were examined using western blot and three-dimensional culture.For the examination of the function of pATM in VM formation by GSLCs,ATM knockdown by shRNAs and deactivated via ATM phosphorylation inhibitor KU55933 were studied.Results VM and high pATM expression occurred in 38.5% and 41.8% of tumors,respectively,and were significantly associated with reduced progression-free and overall survival.Patients with VM-positive GBMs exhibited higher pATM levels(r_(s)=0.425,P=0.01).The multivariate analysis established VM as an independent negative prognostic factor(P=0.002).Furthermore,GSLCs expressed high levels of pATM and formed vascular-like networks in vitro.ATM inactivation or knockdown hindered VM-like network formation concomitant with the downregulation of pVEGFR-2,VE-cadherin,and laminin B2.Conclusion VM may predict a poor GBM prognosis and is associated with pATM expression.We propose that pATM promotes VM through extracellular matrix modulation and VE-Cadherin/pVEGFR-2 activation,thereby highlighting ATM activation as a potential target for enhancing anti-angiogenesis therapies for GBM. 展开更多
关键词 GLIOBLASTOMA Vasculogenic mimicry Ataxia-telangiectasia mutated(ATM) Glioma stem-like cell
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Projecting the Dynamic Trends of Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome:Modeling the Epidemic in Sichuan Province, China
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作者 yuan li Qinxi liu +3 位作者 Rongsheng Luan Yi Yang Tao Wu Bihui Yang 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第9期1003-1014,共12页
Objective Our study aimed to provide a comprehensive overview of the current status and dynamic trends of the human immunodeficiency virus(HIV)prevalence in Sichuan,the second most heavily affected province in China,a... Objective Our study aimed to provide a comprehensive overview of the current status and dynamic trends of the human immunodeficiency virus(HIV)prevalence in Sichuan,the second most heavily affected province in China,and to explore future interventions.Methods The epidemiological,behavioral,and population census data from multiple sources were analyzed to extract inputs for an acquired immunodeficiency syndrome(AIDS)epidemic model(AEM).Baseline curves,derived from historical trends in HIV prevalence,were used,and the AEM was employed to examine future intervention scenarios.Results In 2015,the modeled data suggested an adult HIV prevalence of 0.191%in Sichuan,with an estimated 128,766 people living with HIV/AIDS and 16,983 individuals with newly diagnosed infections.Considering current high-risk behaviors,the model predicts an increase in the adult prevalence to 0.306%by 2025,projecting an estimated 212,168 people living with HIV/AIDS and 16,555 individuals with newly diagnosed infections.Conclusion Heterosexual transmission will likely emerge as the primary mode of AIDS transmission in Sichuan.Furthermore,we anticipate a stabilization in the incidence of AIDS with a concurrent increase in prevalence.Implementing comprehensive intervention measures aimed at high-risk groups could effectively alleviate the spread of AIDS in Sichuan. 展开更多
关键词 HIV/AIDS AIDS Epidemic Model Heterosexual transmission Sichuan province
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A Novel Anti-Collision Algorithm for Large Scale of UHF RFID Tags Access Systems
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作者 Xu Zhang Yi He +9 位作者 Haiwen Yi Yulu Zhang yuan li Shuai Ma Gui li Zhiyuan Zhao Yue liu Junyang liu Guangjun Wen Jian li 《Computers, Materials & Continua》 SCIE EI 2024年第7期897-912,共16页
When the radio frequency identification(RFID)system inventories multiple tags,the recognition rate will be seriously affected due to collisions.Based on the existing dynamic frame slotted Aloha(DFSA)algorithm,a sub-fr... When the radio frequency identification(RFID)system inventories multiple tags,the recognition rate will be seriously affected due to collisions.Based on the existing dynamic frame slotted Aloha(DFSA)algorithm,a sub-frame observation and cyclic redundancy check(CRC)grouping combined dynamic framed slotted Aloha(SUBF-CGDFSA)algorithm is proposed.The algorithm combines the precise estimation method of the quantity of large-scale tags,the large-scale tags grouping mechanism based on CRC pseudo-randomcharacteristics,and the Aloha anti-collision optimization mechanism based on sub-frame observation.By grouping tags and sequentially identifying themwithin subframes,it accurately estimates the number of remaining tags and optimizes frame length accordingly to improve efficiency in large-scale RFID systems.Simulation outcomes demonstrate that this proposed algorithmcan effectively break through the system throughput bottleneck of 36.8%,which is up to 30%higher than the existing DFSA standard scheme,and has more significant advantages,which is suitable for application in largescale RFID tags scenarios. 展开更多
关键词 Radio frequency identification ANTI-COLLISION tags grouping dynamic framed slotted Aloha
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Passive IoT Localization Technology Based on SD-PDOA in NLOS and Multi-Path Environments
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作者 Junyang liu yuan li +10 位作者 Yulu Zhang Shuai Ma Gui li Yi He Haiwen Yi Yue liu Xiaotao Xu Xu Zhang Jinyao He Guangjun Wen Jian li 《Computers, Materials & Continua》 SCIE EI 2024年第7期913-930,共18页
Addressing the challenges of passive Radio Frequency Identification(RFID)indoor localization technology in Non-Line-of-Sight(NLoS)and multipath environments,this paper presents an innovative approach by introducing a ... Addressing the challenges of passive Radio Frequency Identification(RFID)indoor localization technology in Non-Line-of-Sight(NLoS)and multipath environments,this paper presents an innovative approach by introducing a combined technology integrating an improved Kalman Filter with Space Domain Phase Difference of Arrival(SD-PDOA)and Received Signal Strength Indicator(RSSI).This methodology utilizes the distinct channel characteristics in multipath and NLoS contexts to effectively filter out interference and accurately extract localization information,thereby facilitating high precision and stability in passive RFID localization.The efficacy of this approach is demonstrated through detailed simulations and empirical tests conducted on a custom-built experimental platform consisting of passive RFID tags and an R420 reader.The findings are significant:in NLoS conditions,the four-antenna localization system achieved a notable localization accuracy of 0.25 m at a distance of 5 m.In complex multipath environments,this system achieved a localization accuracy of approximately 0.5 m at a distance of 5 m.When compared to conventional passive localization methods,our proposed solution exhibits a substantial improvement in indoor localization accuracy under NLoS and multipath conditions.This research provides a robust and effective technical solution for high-precision passive indoor localization in the Internet of Things(IoT)system,marking a significant advancement in the field. 展开更多
关键词 Indoor localization multipath and NLoS environments combined SD-PDOA and RSSI technology
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Are cities greener because of innovation?Independent innovation policy and green economic efficiency
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作者 Zhuoji Zheng Xueqin li +3 位作者 Mengjie Yu yuan li Xianfeng Han Yuping Yin 《Chinese Journal of Population,Resources and Environment》 2024年第2期118-126,共9页
The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278... The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278 prefecture-level cities in China from 2006 to 2020 and empirically examines the effect and internal mechanism of the NIIDZ on green economic efficiency(GEE)using the difference-in-difference model(DID).The results show that the NIIDZ effectively enhances the growth of GEE,and the results remain valid through several robustness tests,such as year-by-year propensity score matching.The transmission mechanism suggests that the NIIDZ indirectly drives GEE by accelerating scientific and technological investment,promoting talent concentration,and optimizing the industrial structure.Moreover,heterogeneity analysis reveals that the promotion effect of the NIIDZ on GEE is more prominent in the eastern region and high green development level areas.The study’s findings can serve as a reference for China to further utilize the policy effectiveness of the NIIDZ and accelerate the high-quality development of the green economy in the future. 展开更多
关键词 National innovation independent demonstration Zone(NIIDZ) Green economy efficiency(GEE) Difference-in-difference model(DID)
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Development Strategies for Z County E-sports Town in Chongqing:Integration of E-sports,Tourism,and Agriculture under New Policies
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作者 yuan li Dexin li Yang Wang 《Proceedings of Business and Economic Studies》 2024年第5期169-175,共7页
Chongqing Z County E-sports Town was once included in the“first batch of sports and leisure characteristic town pilot project list”issued by the General Administration of Sports of China.After several years of devel... Chongqing Z County E-sports Town was once included in the“first batch of sports and leisure characteristic town pilot project list”issued by the General Administration of Sports of China.After several years of development,the e-sports industry in Z County e-sports town has struggled with issues such as a limited market,low popularity,poor business performance,and a lack of income generation capabilities.These challenges have severely hindered the town’s development,resulting in its exclusion from the recent“Chongqing characteristic town list.”Under the requirements of new policies,it can no longer promote itself,attract investment,or undertake project construction under the name of a“characteristic town”and must undergo redevelopment.This paper employs case analysis and comparative investigation methods to conduct an in-depth empirical study on the development of Z County E-sports Town.It is proposed that under the new policy environment,the town should foster the deep integration of its existing e-sports industry and culture with tourism and agriculture,transforming Z County E-sports Town into a new characteristic tourist destination.The findings of this paper offer a reference for the development of similar towns facing stagnation and provide case support for the construction of tourist destinations featuring e-sports. 展开更多
关键词 Characteristic town E-SPORTS Deep integration of culture and tourism Tourist destination
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新医科背景下应用型医学院校基础医学课程改革探索 被引量:6
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作者 程红兵 陈云霞 +4 位作者 张毅强 王佳 张雄鹰 原丽 王金胜 《基础医学教育》 2024年第3期207-211,共5页
在新医科背景下,应用型医学院校基础医学课程势必面临变革。文章在分析现阶段基础医学教学改革存在主要问题的基础上,通过优化基础医学课程教学体系、成立虚拟教研室、建立课程思政素材库、加强线上线下混合式课程建设、构建整合实验教... 在新医科背景下,应用型医学院校基础医学课程势必面临变革。文章在分析现阶段基础医学教学改革存在主要问题的基础上,通过优化基础医学课程教学体系、成立虚拟教研室、建立课程思政素材库、加强线上线下混合式课程建设、构建整合实验教学体系、改革考核评价体系等举措,推进了基础医学教育创新建设,并提出新医科背景下基础医学课程建设持续改进的若干思路和对策,为应用型医学人才培养提供有益的探索。 展开更多
关键词 基础医学 教学改革 教学重构 知识图谱 评价体系 新医科
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Atomic-level insight of sulfidation-engineered Aurivillius-related Bi_(2)O_(2)SiO_(3) nanosheets enabling visible light low-concentration CO_(2) conversion 被引量:8
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作者 Kai Wang Yue Du +6 位作者 yuan li Xiaoyong Wu Haiyan Hu Guohong Wang Yao Xiao Shulei Chou Gaoke Zhang 《Carbon Energy》 SCIE CSCD 2023年第2期1-11,共11页
Unraveling atomic-level active sites of layered photocatalyst towards lowconcentration CO_(2) conversion is still challenging.Herein,the yield and selectivity of photocatalytic CO_(2) reduction of the Aurivillius-rela... Unraveling atomic-level active sites of layered photocatalyst towards lowconcentration CO_(2) conversion is still challenging.Herein,the yield and selectivity of photocatalytic CO_(2) reduction of the Aurivillius-related oxide semiconductor Bi_(2)O_(2)SiO_(3) nanosheet(BOSO)were largely improved using a surface sulfidation strategy.The experiment and theoretical calculation confirmed that surface sulfidation of the Bi_(2)O_(2)SiO_(3) nanosheet(S-BOSO,6.28 nm)redistributed the charge-enriched Bi sites,extended the solar spectrum absorption to the whole visible range,and considerably enhanced the charge separation,in addition to creating new reaction active sites,as compared to pristine BOSO.Subsequently,surface sulfidation played a switchable role,wherein S-BOSO showed a very high CH_(3)OH generation rate(12.78μmol g^(-1) for 4 h,78.6%selectivity)from low-concentration CO_(2)(1000 ppm)under visible light irradiation,which outperforms most of the state-of-the-art photocatalysts under similar conditions.This study presents an atomic-level modification protocol for engineering reactive sites and charge behaviors to promote solar-to-energy conversion. 展开更多
关键词 [Bi_(2)O_(2)]^(2)+layer Bi_(2)O_(2)SiO_(3) low-concentration CO_(2)reduction photocatalysis SULFIDATION
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新发展格局下我国民营经济营商环境的优化策略 被引量:5
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作者 袁莉 《改革》 北大核心 2024年第1期111-120,共10页
民营经济已经成为推动我国经济社会发展不可或缺的重要力量,是新发展格局下畅通国内循环、参与国际合作与国际竞争的生力军。为民营经济发展打造良好的营商环境,是激发市场活力、提升区域经济活跃度的有效方式。在构建新发展格局的过程... 民营经济已经成为推动我国经济社会发展不可或缺的重要力量,是新发展格局下畅通国内循环、参与国际合作与国际竞争的生力军。为民营经济发展打造良好的营商环境,是激发市场活力、提升区域经济活跃度的有效方式。在构建新发展格局的过程中,民营经济营商环境仍存在一些亟须解决的问题,主要表现为政务服务效能仍然不高、公平竞争市场环境尚未形成、营商环境法治化水平有待提高、发展要素保障不足、部分惠企政策实施效果不理想等。下一步,我国应从如下方面优化民营经济营商环境:厘清政府与市场边界,提升政务服务效能;营造公平竞争的市场环境,激发企业发展活力;强化资源要素保障,支持民营企业转型升级发展;营造稳定可预期的法治环境,提振企业发展信心;健全营商环境建设工作机制,确保政策落实到位。 展开更多
关键词 民营经济 营商环境 公平竞争
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Glycyrrhizic Acid Protects Glomerular Podocytes Induced by High Glucose by Modulating SNARK/AMPK Signaling Pathway 被引量:2
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作者 Tian-qi ZHAO yuan li +3 位作者 Miao ZHANG Meng-chao ZHAO Xue CAO Shao-zhang HOU 《Current Medical Science》 SCIE CAS 2023年第4期696-707,共12页
Objective:Diabetic nephropathy is one of the most important microvascular complications of diabetes,which mainly refers to glomerular capillary sclerosis.Podocytes are an important part of glomerular capillaries.Previ... Objective:Diabetic nephropathy is one of the most important microvascular complications of diabetes,which mainly refers to glomerular capillary sclerosis.Podocytes are an important part of glomerular capillaries.Previous clinical and basic studies have shown that fibrosis is the main factor of diabetic nephropathy.This study aimed to assess the protective mechanism of glycyrrhizic acid(GA)on glomerular podocytes induced by high glucose as we hypothesized that GA may have antifibrotic and anti-inflammatory effects on podocytes through regulation of the adenosine 5'-monophosphate-activated protein kinase(AMPK)/sucrose nonfermenting AMPK-related kinase(SNARK)signaling pathway.Methods:SNARK siRNA was used to transfect podocytes.Real-time quantitative polymerase chain reaction and immunofluorescence staining assays were used for molecular and pathological analysis.The expression levels of key pathway proteins(including TGF-β1,α-SMA,SITR1,AMPKα,LKB1,PGC-1α,NF-κB,IL-6,and TNF-α)were verified by Western blotting.The expression of inflammatory factors in podocytes was detected by ELISA.Results:We demonstrated that GA decreased the expression of podocyte fibrosis signaling pathway-related factors by upregulating the AMPK pathway and its related factors.However,after transfection of podocytes with SNARK siRNA,there was an increased expression of fibrosis-related factors and inflammation-related factors.Conclusion:GA can protect podocytes and alleviate fibrosis and inflammation induced by high glucose,which is related to the AMPK signaling pathway.Meanwhile,knockdown of SNARK protein can inhibit the AMPK signaling pathway,aggravate fibrosis,and increase inflammation. 展开更多
关键词 PODOCYTE glomerular fibrosis glycyrrhizic acid diabetic nephropathy AMPK SNARK
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The enhancement of performance and imbibition effect of slickwater-based fracturing fluid by using MoS_(2)nanosheets 被引量:2
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作者 Hang Xu yuan li +6 位作者 Guo-lin Yu Sa-Sa Yang Bo-Jun li Fu-Jian Zhou Er-Dong Yao Hao Bai Zhi-Yu liu 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期2187-2201,共15页
Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing;however,lots of challenges and limitations such as low viscosity,poor salt tolerance,and possi... Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing;however,lots of challenges and limitations such as low viscosity,poor salt tolerance,and possible formation damage hinder the application of the conventional simple slickwater-based fracturing fluid.In addition,nanomaterials have proven to be potential solutions or improvements to a number of challenges associated with the slickwater.In this paper,molybdenum disulfide(MoS_(2))nanosheets were chemically synthesized by hydrothermal method and applied to improve the performance of conventional slickwater-based fracturing fluid.Firstly,the microstructure characteristics and crystal type of the MoS_(2)nanosheets were analyzed by SEM,EDS,TEM,XPS,and Raman spectroscopy techniques.Then,a series of evaluation experiments were carried out to compare the performance of MoS_(2)nanosheet-modified slickwater with the conventional slickwater,including rheology,drag reduction,and sand suspension.Finally,the enhanced imbibition capacity and potential mechanism of the nanosheet-modified slickwater were systematically investigated.The results showed that the self-synthesized MoS_(2)nanosheets displayed a distinct ultrathin flake-like morphology and a lateral size in the range of tens of nanometers.In the nano-composites,each MoS_(2)nanosheet plays the role of cross-linking point,so as to make the spatial structure of the entire system more compact.Moreover,nanosheet-modified slickwater demonstrates more excellent properties in rheology,drag reduction,and sand suspension.The nanosheet-modified slickwater has a higher apparent viscosity after shearing 120 min under 90℃ and 170 s^(−1).The maximum drag reduction rate achieved 76.3%at 20℃,and the sand settling time of proppants with different mesh in the nano-composites was prolonged.Spontaneous imbibition experiments showed that the gel-breaking fluid of nanosheet-modified slickwater exhibited excellent capability of oil-detaching,and increase the oil recovery to∼35.43%.By observing and analyzing the interfacial behavior of MoS_(2)nanosheets under stimulated reservoir conditions,it was found that the presence of an interfacial tension gradient and the formation of a climbing film may play an essential role in the spontaneous imbibition mechanism.This work innovatively uses two-dimensional MoS_(2)nanosheets to modify regular slickwater and confirms the feasibility of flake-like nanomaterials to improve the performance of slickwater.The study also reveals the underlying mechanism of enhanced imbibition efficiency of the nano-composites. 展开更多
关键词 Slickwater-based fracturing fluid MoS_(2)nanosheet Performance evaluation spontaneous imbibition Climbing film
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Middle Eocene terrestrial paleoweathering and climate evolution in the midlatitude Bohai Bay Basin of eastern China 被引量:1
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作者 Di Chen Fu-jie Jiang +8 位作者 Xiong-Qi Pang ling-Jian Meng Zheng-Jun Wang Zhi Xu Xue Zhang li-Na Huo Jia-Hao Wen Ren-jie zhao yuan li 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1471-1487,共17页
The middle Eocene climatic optimum(MECO,ca.-42 Ma)is a key time period for understanding Cenozoic cooling of the global climate.Still,midlatitude terrestrial records of climate evolution during MEcO epoch are rare.In ... The middle Eocene climatic optimum(MECO,ca.-42 Ma)is a key time period for understanding Cenozoic cooling of the global climate.Still,midlatitude terrestrial records of climate evolution during MEcO epoch are rare.In this study,continuous high-resolution record of shale sediments in mid-Eocene Shahejie Formation(MES shales)in the Bohai Bay Basin were performed with major-element and wavelet analysis.The midlatitude paleoweathering and paleoclimatic evolution during MEcO epoch were analyzed in this study.The MES shales experienced weak-moderate paleoweathering under a subtropical monsoon paleoclimate with mean annual temperature of 8.3-12.9℃ and mean annual precipitation of 685-1100 mm/yr.The MES shales record a mixed provenance involving intermediate igneous rocks,and low compositional maturity.The nutrient-rich environment led to enrichment in organic matter in the MES shales.Wavelet analysis revealed good periodicity about the paleoclimate and weathering during MECO epoch.In the stage I of MES shales depositional process,the paleolake was high in nutrients,and the MES shales experienced high chemical weathering due to a relatively warmer and more humid climate.In contrast,the climate in stage II was relatively cold and dry,and the maturity of the MES shales was relatively high during this stage,suggesting a relatively stable tectonic background.This work provides more terrestrial records of MEco epoch for midlatitude region,and is benefit for better understanding of the palaeoenvironment when MES shales formed.The implication of organic matters enrichment in this study is meaningful for the shale oil/gas exploration in Nanpu Sag. 展开更多
关键词 Middle Eocene PALEOCLIMATE WEATHERING MES shales Bohai Bay Basin
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Airborne sparse flight array SAR 3D imaging based on compressed sensing in frequency domain 被引量:1
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作者 TIAN He DONG Chunzhu +1 位作者 YIN Hongcheng yuan li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第1期56-67,共12页
In airborne array synthetic aperture radar(SAR), the three-dimensional(3D) imaging performance and cross-track resolution depends on the length of the equivalent array. In this paper, Barker sequence criterion is used... In airborne array synthetic aperture radar(SAR), the three-dimensional(3D) imaging performance and cross-track resolution depends on the length of the equivalent array. In this paper, Barker sequence criterion is used for sparse flight sampling of airborne array SAR, in order to obtain high cross-track resolution in as few times of flights as possible. Under each flight, the imaging algorithm of back projection(BP) and the data extraction method based on modified uniformly redundant arrays(MURAs) are utilized to obtain complex 3D image pairs. To solve the side-lobe noise in images, the interferometry between each image pair is implemented, and compressed sensing(CS) reconstruction is adopted in the frequency domain. Furthermore, to restore the geometrical relationship between each flight, the phase information corresponding to negative MURA is compensated on each single-pass image reconstructed by CS. Finally,by coherent accumulation of each complex image, the high resolution in cross-track direction is obtained. Simulations and experiments in X-band verify the availability. 展开更多
关键词 three-dimensional(3D)imaging synthetic aperture radar(SAR) sparse flight INTERFEROMETRY compressed sensing(CS)
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32×32 Si盖革模式激光焦平面探测器
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作者 王江 王鸥 +5 位作者 刘向东 袁利 柯尊贵 郝昕 覃文治 杨赟秀 《激光技术》 CAS CSCD 北大核心 2024年第5期665-670,共6页
为了满足350 nm~1100 nm波长范围内远距离及微弱激光3维成像探测的需求,提出了一种规模为32×32的盖革模式硅激光焦平面阵列探测器,它主要由硅雪崩光电二极管阵列、读出电路芯片、微透镜阵列、半导体制冷器、引脚网格阵列壳体等元... 为了满足350 nm~1100 nm波长范围内远距离及微弱激光3维成像探测的需求,提出了一种规模为32×32的盖革模式硅激光焦平面阵列探测器,它主要由硅雪崩光电二极管阵列、读出电路芯片、微透镜阵列、半导体制冷器、引脚网格阵列壳体等元件组成。硅雪崩光电二极管焦平面阵列采用拉通型N^(+)-Π_(1)-P^(-)-Π_(2)-P^(+)结构,工作在盖革模式下,通过Si片背面抛磨减薄及盲孔刻蚀技术,实现了纤薄光敏区的加工;读出电路采用主动模式淬灭设计,使电路单元的死时间控制在50 ns以内,并利用一种带相移技术的时间数字转换电路优化方案,在满足时间分辨率不大于2 ns的同时,降低了读出电路芯片的功耗。结果表明,在反向过偏电压14 V、工作温度-40℃的条件下,该探测器在850 nm的目标波长可实现20.7%的平均光子探测效率与0.59 kHz的平均暗计数率,时间分辨率为1 ns,有效像元率优于97%。该研究为纤薄型背进光Si基激光焦平面探测器的研制提供了参考。 展开更多
关键词 传感器技术 雪崩焦平面探测器 盖革模式 激光3维成像
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冻融与冻藏对乌鳢肌原纤维蛋白与酸菜鱼汤中特征风味物质结合特性的影响
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作者 袁丽 苏凯 +6 位作者 刘璐 冷伟军 张昊 李梦哲 石彤 包玉龙 高瑞昌 《食品科学》 EI CAS CSCD 北大核心 2024年第21期121-129,共9页
为探究冷冻处理对于鱼片与酸菜鱼汤中风味物质的结合特性影响,以乌鳢的肌原纤维蛋白为对象,研究冻融及冻藏处理对其理化特性及与己醛、辛醛、芳樟醇、月桂烯结合能力的变化。结果表明经过7 d贮藏后,冻融组肌原纤维蛋白溶解度降低了约26%... 为探究冷冻处理对于鱼片与酸菜鱼汤中风味物质的结合特性影响,以乌鳢的肌原纤维蛋白为对象,研究冻融及冻藏处理对其理化特性及与己醛、辛醛、芳樟醇、月桂烯结合能力的变化。结果表明经过7 d贮藏后,冻融组肌原纤维蛋白溶解度降低了约26%,相较于冻藏组,蛋白质氧化和三级结构变化程度更高,产生了更多可溶性聚集体;冻藏组溶解度降低了约33%,相较于冻融组,溶解度降低更加显著(P<0.05),产生了更多不溶性聚集体。影响肌原纤维蛋白冷冻聚集的主要作用力是非共价键。分子对接结果表明,芳樟醇、己醛和辛醛通过疏水作用和氢键与蛋白质结合,月桂烯与蛋白结合的主要驱动力为疏水相互作用。冷冻处理通过减少蛋白质与醛类化合物结合的巯基基团和氢键,降低了对己醛和辛醛的结合能力,蛋白质表面疏水性的提高,增加了对月桂烯和芳樟醇的结合能力,冻融处理后蛋白质对于月桂烯的结合能力强于冻藏处理组。研究结果可以为冷冻酸菜鱼预制品的风味控制提供理论依据和参考。 展开更多
关键词 肌原纤维蛋白 风味物质 冷冻处理 蛋白质聚集 结合能力
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南海及其附属岛礁海洋科学考察历史资料系统整编1.资料整编技术及应用
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作者 徐超 龙丽娟 +3 位作者 李莎 何云开 袁丽 徐晓璐 《热带海洋学报》 CAS CSCD 北大核心 2024年第5期143-149,共7页
南海宽广深厚、资源丰富、自然条件复杂、地理位置重要,是我国的核心利益。自20世纪50年代以来,我国先后组织了十数次大规模的南海与诸岛海洋科学综合考察,取得了大批重要原始数据。但是,早期资料无电子化手段,记录标准不一、质控标准... 南海宽广深厚、资源丰富、自然条件复杂、地理位置重要,是我国的核心利益。自20世纪50年代以来,我国先后组织了十数次大规模的南海与诸岛海洋科学综合考察,取得了大批重要原始数据。但是,早期资料无电子化手段,记录标准不一、质控标准不一、归档标准不一、原始资料散落或濒于遗失,抢救与整编需求迫切。南海及其附属岛礁海洋科学考察历史资料系统整编项目规范化整编了1950年至2019年共353个项目664个航次超过200多种要素的历史数据,构建了包含水文气象、海洋化学、生物生态、渔业资源、地质环境、岛礁地质样品等第一手实测的宝贵科学数据的综合数据库,同时对整编数据完成了相关科学分析,新形成一些分析数据产品,出版了《南海科学考察历史资料整编丛书》1套共12部,以及其他专著7部。本系列文章共3篇,文章1针对历史数据的系统整编,简要论述规范化整编的实施步骤,针对技术难点提出相应实践策略;文章2针对整编数据的科学管理,简要论述南海海洋数据治理技术研究与实践;文章3针对整编数据的共享服务,简要论述“数字南海”的建设实践与创新应用。通过本系列文章完整地论述南海科考历史资料整编综合数据库暨“数字南海”的研究过程与实践经验,为其他海洋科学考察资料系统整编提供参考。 展开更多
关键词 南海 科学考察 历史资料 系统整编 技术应用
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南海及其附属岛礁海洋科学考察历史资料系统整编3.数据共享服务及应用
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作者 徐超 龙丽娟 +2 位作者 李莎 袁丽 徐晓璐 《热带海洋学报》 CAS CSCD 北大核心 2024年第5期158-165,共8页
在南海及其附属岛礁海洋科学考察历史资料系统整编项目实施过程中,数据共享是一项重要工作。文章主要介绍南海科考历史资料整编综合数据库暨“数字南海”平台的设计与建设。首先阐述“数字南海”的设计与开发重点,实现数据管理共享的流... 在南海及其附属岛礁海洋科学考察历史资料系统整编项目实施过程中,数据共享是一项重要工作。文章主要介绍南海科考历史资料整编综合数据库暨“数字南海”平台的设计与建设。首先阐述“数字南海”的设计与开发重点,实现数据管理共享的流程集约化和资源利用高效化;其次以“航次一张图”和“岛礁一张图”模块介绍数据的交互分析应用及动态可视化应用。“数字南海”平台建设按照项目目标,统一规划部署、统一标准体系、统一数据平台、统一成果发布,数据服务贯穿项目实施的全生命周期,推动形成共商共建共享共赢的数据工作发展新格局。 展开更多
关键词 南海 历史资料 系统整编 数字南海 数据共享
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