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政策协调、不确定性与大型技术系统创新——中国核电技术赶超的案例研究
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作者 陈玲 孙君 付宇航 《公共行政评论》 北大核心 2024年第3期1-23,195,共24页
后发国家技术赶超需要实现“市场规模”和“技术自主”的双重目标,但现实中这一进程普遍面临技术依赖的“追赶者陷阱”的问题。论文采用个案内过程追踪的研究方法和“政策子系统”的分析视角,基于中国核电50年的技术赶超历程,解释了后... 后发国家技术赶超需要实现“市场规模”和“技术自主”的双重目标,但现实中这一进程普遍面临技术依赖的“追赶者陷阱”的问题。论文采用个案内过程追踪的研究方法和“政策子系统”的分析视角,基于中国核电50年的技术赶超历程,解释了后发国家如何通过政策协调实现大型技术系统的技术赶超。研究发现,大型技术系统的创新绩效与其所在政策子系统的特性密切相关,核电政策子系统具有碎片化的结构和行为目标,需要同步进行政府部门间协调和政府对市场协调,协调机制主要包括国家意志、行政指令、共识信号和市场竞争等。政策协调通过降低大型技术系统中产业主体面临的供需不确定性,解决产业主体专用化投资不足的激励困境。跳出“追赶者陷阱”的关键在于建立国产化率目标硬约束与多种协调机制。研究进一步深化了对技术赶超中政府角色的认识,弥补了已有文献对于大型技术系统产业管理体制研究不足的理论缺口,对新型举国体制下提高系统创新能力有一定的启示。 展开更多
关键词 政策协调 大型技术系统赶超 核电技术 政策子系统 新型举国体制
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Sustained release of vascular endothelial growth factor A and basic fibroblast growth factor from nanofiber membranes reduces oxygen/glucose deprivation-induced injury to neurovascular units 被引量:2
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作者 Yifang Wu jun sun +2 位作者 Qi Lin Dapeng Wang Jian Hai 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第4期887-894,共8页
Upregulation of vascular endothelial growth factor A/basic fibroblast growth factor(VEGFA/b FGF)expression in the penumbra of cerebral ischemia can increase vascular volume,reduce lesion volume,and enhance neural cell... Upregulation of vascular endothelial growth factor A/basic fibroblast growth factor(VEGFA/b FGF)expression in the penumbra of cerebral ischemia can increase vascular volume,reduce lesion volume,and enhance neural cell proliferation and differentiation,thereby exerting neuroprotective effects.However,the beneficial effects of endogenous VEGFA/b FGF are limited as their expression is only transiently increased.In this study,we generated multilayered nanofiber membranes loaded with VEGFA/b FGF using layer-by-layer self-assembly and electrospinning techniques.We found that a membrane containing 10 layers had an ideal ultrastructure and could efficiently and stably release growth factors for more than 1 month.This 10-layered nanofiber membrane promoted brain microvascular endothelial cell tube formation and proliferation,inhibited neuronal apoptosis,upregulated the expression of tight junction proteins,and improved the viability of various cellular components of neurovascular units under conditions of oxygen/glucose deprivation.Furthermore,this nanofiber membrane decreased the expression of Janus kinase-2/signal transducer and activator of transcription-3(JAK2/STAT3),Bax/Bcl-2,and cleaved caspase-3.Therefore,this nanofiber membrane exhibits a neuroprotective effect on oxygen/glucose-deprived neurovascular units by inhibiting the JAK2/STAT3 pathway. 展开更多
关键词 brain ischemia brain microvascular endothelial cell nanofiber membrane neurovascular unit
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Bird species composition and conservation challenges in the Gaoligong Mountains, one of the most diverse bird areas in the world 被引量:1
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作者 Fei Wu Jian-Yun Gao +13 位作者 Dao Yan Le Yang Lu-Ming Liu Shun-Yu Yao Chang-Sheng Zuo jun sun Ge Gao Jian-Yong Su Li Luo Ying-Chun Li Ming Liu Yuan-Fang Hu Ming Wei Xiao-jun Yang 《Zoological Research(Diversity and Conservation)》 2024年第1期20-50,共31页
The Gaoligong Mountains(GLGM),located in southwestern China,extend north to south along the western border of the Hengduan Mountains,spanning approximately 600 km.In this study,we consolidated findings from 17 bird su... The Gaoligong Mountains(GLGM),located in southwestern China,extend north to south along the western border of the Hengduan Mountains,spanning approximately 600 km.In this study,we consolidated findings from 17 bird surveys conducted in the GLGM between 2010 and 2022.We found that the GLGM harbors tremendous bird diversity,with a total of 796 documented bird species in the region.Nearly a quarter(23.0%)of these species are listed as state key protected species or as Chinese and global threatened species.Analysis of species richness at the county level showed a decreasing trend with increasing latitude,with the greatest diversity in Yingjiang(661 species).Observations indicated that the GLGM belongs to the Oriental realm,primarily composed of bird species from southern and southwestern China.The GLGM plays an important role in avian conservation by sheltering exceptional bird diversity,providing corridors and flyways for bird migration and dispersal,and mitigating the effects of climate change.In response to the conservation needs of birds and other wildlife,the Chinese government has established numerous protected areas within the GLGM.Despite these efforts,avian conservation still faces considerable challenges in the GLGM due to limitations in the protected area network,transboundary nature of the regions,and existing gaps in monitoring and research. 展开更多
关键词 BIRDS Gaoligong Mountains Zoogeographic region Conservation challenge
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肠上皮细胞Axin1缺失可调节肠道微生态预防结肠炎
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作者 Shari Garrett Yongguo Zhang +1 位作者 Yinglin Xia jun sun 《Engineering》 SCIE EI CAS CSCD 2024年第4期241-256,共16页
Intestinal homeostasis is maintained by specialized host cells and the gut microbiota.Wnt/β-catenin signaling is essential for gastrointestinal development and homeostasis,and its dysregulation has been implicated in... Intestinal homeostasis is maintained by specialized host cells and the gut microbiota.Wnt/β-catenin signaling is essential for gastrointestinal development and homeostasis,and its dysregulation has been implicated in inflammation and colorectal cancer.Axin1 negatively regulates activated Wnt/β-catenin signaling,but little is known regarding its role in regulating host–microbial interactions in health and disease.Here,we aim to demonstrate that intestinal Axin1 determines gut homeostasis and host response to inflammation.Axin1 expression was analyzed in human inflammatory bowel disease datasets.To explore the effects and mechanism of intestinal Axin1 in regulating intestinal homeostasis and colitis,we generated new mouse models with Axin1 conditional knockout in intestinal epithelial cell(IEC;Axin1^(ΔIEC))and Paneth cell(PC;Axin1^(ΔPC))to compare with control(Axin1^(LoxP);LoxP:locus of X-over,P1)mice.We found increased Axin1 expression in the colonic epithelium of human inflammatory bowel disease(IBD).Axin1^(ΔIEC) mice exhibited altered goblet cell spatial distribution,PC morphology,reduced lysozyme expression,and enriched Akkermansia muciniphila(A.muciniphila).The absence of intestinal epithelial and PC Axin1 decreased susceptibility to dextran sulfate sodium(DSS)-induced colitis in vivo.Axin1^(ΔIEC) and Axin1^(ΔPC)mice became more susceptible to DSS-colitis after cohousing with control mice.Treatment with A.muciniphila reduced DSS-colitis severity.Antibiotic treatment did not change the IEC proliferation in the Axin1Loxp mice.However,the intestinal proliferative cells in Axin1^(ΔIEC)mice with antibiotic treatment were reduced compared with those in Axin1^(ΔIEC) mice without treatment.These data suggest non-colitogenic effects driven by the gut microbiome.In conclusion,we found that the loss of intestinal Axin1 protects against colitis,likely driven by epithelial Axin1 and Axin1-associated A.muciniphila.Our study demonstrates a novel role of Axin1 in mediating intestinal homeostasis and the microbiota.Further mechanistic studies using specific Axin1 mutations elucidating how Axin1 modulates the microbiome and host inflammatory response will provide new therapeutic strategies for human IBD. 展开更多
关键词 Axin1 BACTERIA Microbiome inflammation Inflammatory bowel disease IMMUNITY MICROBIOME Paneth cells Akkermansia muciniphila WNT
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Runout prediction of potential landslides based on the multi-source data collaboration analysis on historical cases
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作者 jun sun Yu Zhuang Ai-guo Xing 《China Geology》 CAS CSCD 2024年第2期264-276,共13页
Long runout landslides involve a massive amount of energy and can be extremely hazardous owing to their long movement distance,high mobility and strong destructive power.Numerical methods have been widely used to pred... Long runout landslides involve a massive amount of energy and can be extremely hazardous owing to their long movement distance,high mobility and strong destructive power.Numerical methods have been widely used to predict the landslide runout but a fundamental problem remained is how to determine the reliable numerical parameters.This study proposes a framework to predict the runout of potential landslides through multi-source data collaboration and numerical analysis of historical landslide events.Specifically,for the historical landslide cases,the landslide-induced seismic signal,geophysical surveys,and possible in-situ drone/phone videos(multi-source data collaboration)can validate the numerical results in terms of landslide dynamics and deposit features and help calibrate the numerical(rheological)parameters.Subsequently,the calibrated numerical parameters can be used to numerically predict the runout of potential landslides in the region with a similar geological setting to the recorded events.Application of the runout prediction approach to the 2020 Jiashanying landslide in Guizhou,China gives reasonable results in comparison to the field observations.The numerical parameters are determined from the multi-source data collaboration analysis of a historical case in the region(2019 Shuicheng landslide).The proposed framework for landslide runout prediction can be of great utility for landslide risk assessment and disaster reduction in mountainous regions worldwide. 展开更多
关键词 Landslide runout prediction Drone survey Multi-source data collaboration DAN3D numerical modeling Jianshanying landslide Guizhou Province Geological hazards survey engineering
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Review of Sc microalloying effects in Al-Cu alloys
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作者 Shenghua Wu Chong Yang +7 位作者 Peng Zhang Hang Xue Yihan Gao Yuqing Wang Ruihong Wang Jinyu Zhang Gang Liu jun sun 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期1098-1114,共17页
Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a p... Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a purpose.In this paper,recent advances in lengthscale-dependent scandium (Sc) microalloying effects in Al-Cu model alloys are reviewed.In coarse-grained Al-Cu alloys,the Sc-aided Cu/Sc/vacancies complexes that act as heterogeneous nuclei and Sc segregation at the θ′-Al_(2)Cu/matrix interface that reduces interfacial energy contribute significantly to θ′precipitation.By grain size refinement to the fine/ultrafine-grained scale,the strongly bonded Cu/Sc/vacancies complexes inhibit Cu and vacancy diffusing toward grain boundaries,promoting the desired intragranular θ′precipitation.At nanocrystalline scale,the applied high strain producing high-density vacancies results in the formation of a large quantity of (Cu Sc,vacancy)-rich atomic complexes with high thermal stability,outstandingly improving the strength/ductility synergy and preventing the intractable low-temperature precipitation.This review recommends the use of microalloying technology to modify the precipitation behaviors toward better combined mechanical properties and thermal stability in Al alloys. 展开更多
关键词 aluminum alloy microalloying effect length-scale dependence PRECIPITATION mechanical properties
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社区老年人衰弱、高血压及跌倒风险的关系研究
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作者 滕丽萍 王丹慧 +3 位作者 周州 孙郡 朱敏 王仁荣 《International Journal of Nursing Sciences》 CSCD 2024年第1期11-17,I0001,共8页
目的老年人往往同时存在衰弱和高血压,这可能会导致跌倒风险。本研究旨在探讨社区老年人衰弱状态、高血压和跌倒风险之间的关系。方法采用便利抽样选取无锡市社区老年人401名,采用STEADI(Stopping Elderly Accidents,Deaths&Injuri... 目的老年人往往同时存在衰弱和高血压,这可能会导致跌倒风险。本研究旨在探讨社区老年人衰弱状态、高血压和跌倒风险之间的关系。方法采用便利抽样选取无锡市社区老年人401名,采用STEADI(Stopping Elderly Accidents,Deaths&Injuries)工具包中的跌倒自评清单评估老年人跌倒风险,采用衰弱筛查量表评估社区老年人衰弱状况,采用自设问卷调查老年人社会人口学资料和慢性病等情况。采用logistic回归分析、广义加性模型和曲线拟合等方法分析社区老年人衰弱、高血压及跌倒风险的相互关系。结果Logistic回归分析发现,衰弱与较高的跌倒风险密切相关(OR 8.52,95%CI 3.21-22.57;P<0.001),高血压显著增加跌倒风险(OR 1.87,95%CI 1.11~3.13;P=0.019)。高血压伴有衰弱的老年人跌倒风险最高(OR 12.24,95%CI 3.51~42.65)。广义加性模型和光滑曲线拟合结果显示,在高血压老年人中,衰弱和跌倒风险之间存在非线性关联;在衰弱前期到衰弱状态的进程中,老年高血压患者具有较高的跌倒倾向。结论衰弱和高血压独立且可共同增加社区老年人跌倒的风险。加强对社区老年人衰弱状况和高血压的管理可能有助于降低这一人群跌倒的风险。 展开更多
关键词 衰弱 高血压 跌倒风险 关系 老年人
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Multilocular thymic cysts can be easily misdiagnosed as malignant tumor on computer tomography:A case report
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作者 jun sun Qing-Ning Yang +5 位作者 Yi Guo Ping Zeng Long-Yan Ma Ling-Wen Kong Bo-Ying Zhao Chuan-Ming Li 《World Journal of Clinical Cases》 SCIE 2024年第8期1474-1480,共7页
BACKGROUND Multilocular thymic cyst(MTC)is a rare mediastinal lesion which is considered to occur in the process of acquired inflammation.It is usually characterized by well-defined cystic density and is filled with t... BACKGROUND Multilocular thymic cyst(MTC)is a rare mediastinal lesion which is considered to occur in the process of acquired inflammation.It is usually characterized by well-defined cystic density and is filled with transparent liquid.CASE SUMMARY We report on a 39-year-old male with a cystic-solid mass in the anterior mediastinum.Computer tomography(CT)imaging showed that the mass was irregular with unclear boundaries.After injection of contrast agent,there was a slight enhancement of stripes and nodules.According to CT findings,it was diagnosed as thymic cancer.CONCLUSION After surgery,MTC accompanied by bleeding and infection was confirmed by pathological examination.The main lesson of this case was that malignant thymic tumor and MTC of the anterior mediastinum sometimes exhibit similar CT findings.Caution is necessary in clinical work to avoid misdiagnosis. 展开更多
关键词 Multilocular thymic cyst Computer tomography MISDIAGNOSIS HEMORRHAGE INFECTION Case report
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On the strengthening and slip activity of Mg-3Al-1Zn alloy with pre-induced{1012¯}twins 被引量:1
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作者 Jie Kuang Yuqing Zhang +3 位作者 Xinpeng Du Jinyu Zhang Gang Liu jun sun 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第4期1292-1307,共16页
{1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension al... {1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension along different directions.Using crystal plasticity modeling,we found that the strengthening effect of the pre-induced{1012¯}twins on the macroscopic flow stress primarily arised from the increased slip resistance caused by the boundaries,rather than the orientation hardening due to the twinning reorientation(although the latter did make its contribution in some specific loading directions).Besides,the pre-existing{1012¯}twins were found,by both experiments and simulation,to promote the activity of prismatic and pyramidal<c+a>in the parent matrix of the material.Further analysis showed that the enhanced non-basal slip activity is related to the{1012¯}twin boundaries’low micro Hall-Petch slope ratios of non-basal slips to basal slip.With the critical resolved shear stress(CRSS)obtained from crystal plasticity modeling and the orientation data from EBSD,a probability-based slip transfer model was proposed.The model predicts higher slip transfer probabilities and thus lower strain concentration tendencies at{1012¯}twin boundaries than that at grain boundaries,which agrees with the experimental observation that the strain localization was primarily associated with the latter.The present findings are helpful scientifically,in deepening our understanding of how the pre-induced{1012¯}twins affect the strength and slip activity of Mg alloys,and technologically,in guiding the design of the pre-strain protocol of Mg alloys. 展开更多
关键词 Mg alloy {1012¯}twins Strengthening Slip activity Micro Hall-Petch effect
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Down-regulation of DNA key protein-FEN1 inhibits OSCC growth by affecting immunosuppressive phenotypes via IFN-γ/JAK/STAT-1 被引量:1
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作者 Shimeng Wang Xiangjian Wang +4 位作者 jun sun Jin Yang Deyang Wu Fanglong Wu Hongmei Zhou 《International Journal of Oral Science》 SCIE CAS CSCD 2023年第2期255-265,共11页
Oral squamous cell carcinoma(OSCC)escape from the immune system is mediated through several immunosuppressive phenotypes that are critical to the initiation and progression of tumors.As a hallmark of cancer,DNA damage... Oral squamous cell carcinoma(OSCC)escape from the immune system is mediated through several immunosuppressive phenotypes that are critical to the initiation and progression of tumors.As a hallmark of cancer,DNA damage repair is closely related to changes in the immunophenotypes of tumor cells.Although flap endonuclease-1(FEN1),a pivotal DNA-related enzyme is involved in DNA base excision repair to maintain the stability of the cell genome. 展开更多
关键词 JAK/STAT damage squamous
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A new peptide,VD11,promotes structural and functional recovery after spinal cord injury
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作者 Shan-Shan Li Bai-Yu Zhang +11 位作者 Sai-Ge Yin Zi-Qi Wei Nai-Xin Liu Yi-Lin Li Si-Yu Wang Yu-Heng Shi Jian Zhao Li-Juan Wang Yue Zhang jun sun Ying Wang Xin-Wang Yang 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第10期2260-2267,共8页
The regenerative capacity of the central nervous system is very limited and few effective treatments are currently available for spinal cord injury.It is therefore a priority to develop new drugs that can promote stru... The regenerative capacity of the central nervous system is very limited and few effective treatments are currently available for spinal cord injury.It is therefore a priority to develop new drugs that can promote structural and functional recovery after spinal cord injury.Previous studies have shown that peptides can promote substantial repair and regeneration of injured tissue.While amphibians have a pronounced ability to regenerate the spinal cord,few studies have investigated the effect of amphibian spinal cord-derived peptides on spinal cord injury.Here we report for the first time the successful identification and isolation of a new polypeptide,VD11(amino acid sequence:VDELWPPWLPC),from the spinal cord of an endemic Chinese amphibian(Odorrana schmackeri).In vitro experiments showed that VD11 promoted the secretion of nerve growth factor and brain-derived neurotrophic factor in BV2 cells stimulated with lipopolysaccharide,as well as the proliferation and synaptic elongation of PC12 cells subjected to hypoxia.In vivo experiments showed that intravertebral injection of VD11 markedly promoted recovery of motor function in rats with spinal cord injury,alleviated pathological damage,and promoted axonal regeneration.Furthermore,RNA sequencing and western blotting showed that VD11 may affect spinal cord injury through activation of the AMPK and AKT signaling pathways.In summary,we discovered a novel amphibian-derived peptide that promotes structural and functional recovery after spinal cord injury. 展开更多
关键词 Akt signaling pathway amphibian-derived bioactive peptide AMPK signaling pathway axonal regeneration brain-derived neurotrophic factor ischemia/reperfusion injury motor function nerve growth factor neuroprotective effect spinal cord injury
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Enhancing corrosion resistance of ZK60 magnesium alloys via Ca microalloying: The impact of nanoscale precipitates
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作者 Wei Fu Hejie Yang +7 位作者 Tianshu Li Jiapeng sun Shengwu Guo Daqing Fang Weichao Qin Xiangdong Ding Yimin Gao jun sun 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第9期3214-3230,共17页
Enhancing corrosion resistance of Mg-Zn alloys with high strength and low cost was critical for broadening their large-scale practical applications. Here we prepared solutionized, peak-and over-aged ZK60 alloys with a... Enhancing corrosion resistance of Mg-Zn alloys with high strength and low cost was critical for broadening their large-scale practical applications. Here we prepared solutionized, peak-and over-aged ZK60 alloys with and without microalloying Ca(0.26 wt.%) to explore the effects of nanoscale precipitates on their corrosion behavior in detail via experimental analyses and theoretical calculations. The results suggested the peak-aged ZK60 alloy with Ca addition showed improved corrosion resistance in comparison with the alloys without Ca,owing to the contribution of Ca on the refinement of precipitates and increase in their number density. Although the precipitates and Mg matrix formed micro-galvanic couples leading to dissolution, the fine and dense precipitates could generate “in-situ pinning” effect on the corrosion products, forming a spider-web-like structure and improving the corrosion inhibition ability accordingly. The pinning effect was closely related to the size and number density of precipitates. This study provided important insight into the design and development of advanced corrosion resistant Mg alloys. 展开更多
关键词 MAGNESIUM PRECIPITATES MICROALLOYING Electrochemical test Pinning effect Calculation
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Synergy mechanism of defect engineering in MoS_(2)/FeS_(2)/C heterostructure for high-performance sodium-ion battery
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作者 Linlin Ma Xiaomei Zhou +9 位作者 jun sun Pan Zhang Baoxiu Hou Shuaihua Zhang Ningzhao Shang Jianjun Song Hongjun Ye Hui Shao Yongfu Tang Xiaoxian Zhao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期268-276,I0006,共10页
MoS_(2) is a promising anode material in sodium-ion battery technologies for possessing high theoretical capacity.However,the sluggish Na^(+) diffusion kinetics and low electronic conductivity hinder the promises.Here... MoS_(2) is a promising anode material in sodium-ion battery technologies for possessing high theoretical capacity.However,the sluggish Na^(+) diffusion kinetics and low electronic conductivity hinder the promises.Herein,a unique MoS_(2)/FeS_(2)/C heterojunction with abundant defects and hollow structure(MFCHHS)was constructed.The synergy of defect engineering in MoS_(2),FeS_(2),and the carbon layer of MFCHHS with a larger specific surface area provides multiple storage sites of Na^(+)corresponding to the surface-controlled process.The MoS_(2)/FeS_(2)/C heterostructure and rich defects in MoS_(2) and carbon layer lower the Na^(+) diffusion energy barrier.Additionally,the construction of MoS_(2)/FeS_(2) heterojunction promotes electron transfer at the interface,accompanying with excellent conductivity of the carbon layer to facilitate reversible electrochemical reactions.The abundant defects and mismatches at the interface of MoS_(2)/FeS_(2) and MoS_(2)/C heterojunctions could relieve lattice stress and volume change sequentially.As a result,the MFCHHS anode exhibits the high capacity of 613.1 mA h g^(-1)at 0.5 A g^(-1) and 306.1 mA h g^(-1) at 20 A g^(-1).The capacity retention of 85.0%after 1400 cycles at 5.0 A g^(-1) is achieved.The density functional theory(DFT)calculation and in situ transmission electron microscope(TEM),Raman,ex-situ X-ray photon spectroscopy(XPS)studies confirm the low volume change during intercalation/deintercalation process and the efficient Na^(+)storage in the layered structure of MoS_(2) and carbon layer,as well as the defects and heterostructures in MFCHHS.We believe this work could provide an inspiration for constructing heterojunction with abundant defects to foster fast electron and Na^(+) diffusion kinetics,resulting in excellent rate capability and cycling stability. 展开更多
关键词 Defect engineering HETEROSTRUCTURE Hollow structure Sodium-ion battery MoS_(2)/FeS_(2)
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The impacts of ambiguity in preparation of 80% sulfuric acid solution and shaking time control of calibration solution on the determination of transparent exopolymer particles
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作者 Congcong Guo Guicheng Zhang +2 位作者 Shan Jian Wei Ma jun sun 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第4期50-58,共9页
The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for par... The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for part steps of the original method.It is obscure that the 80% sulfuric acid solution,acted as the extraction solution in the determination of TEP,is prepared based on a volume ratio or mass ratio.Furthermore,the change of solubility of recently available Gum Xanthan(GX) from the market means that the original protocol is no longer applicable,and the grinding of GX stock solution with a tissue grinder is replaced by shaking with a rotating shaker in the study to prevent the excessive dissolution of GX.We found that different preparation techniques could result in the varied concentrations of 80% H_(2)SO_(4).The duration of shaking during the preparation of standard solution significantly affected the slope of the calibration curve,which caused different correction results of TEP.The impacts of different extraction solution concentrations and shaking time of GX solution on the quantification of TEP were investigated based on the field sampling and laboratory analysis.The extraction capacities of H_(2)SO_(4) with different concentrations for Alcian Blue were distinct,but had limited effect on the final measuring result of TEP.The change of the standard curve slope came along with the variation of shaking time,which markedly altered the detection limit and calibration result,and the extended shaking time was in favor of the determination of low-concentration TEP.It was suggested that the extraction solution concentration,shaking time and filtration volume of standard solution are required to be well controlled and selected to obtain more accurate results for TEP with different concentrations. 展开更多
关键词 transparent exopolymer particles determination method method improvement sulfuric acid shaking time
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Prediction of lattice thermal conductivity with two-stage interpretable machine learning
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作者 胡锦龙 左钰婷 +10 位作者 郝昱州 舒国钰 王洋 冯敏轩 李雪洁 王晓莹 孙军 丁向东 高志斌 朱桂妹 李保文 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期11-18,共8页
Thermoelectric and thermal materials are essential in achieving carbon neutrality. However, the high cost of lattice thermal conductivity calculations and the limited applicability of classical physical models have le... Thermoelectric and thermal materials are essential in achieving carbon neutrality. However, the high cost of lattice thermal conductivity calculations and the limited applicability of classical physical models have led to the inefficient development of thermoelectric materials. In this study, we proposed a two-stage machine learning framework with physical interpretability incorporating domain knowledge to calculate high/low thermal conductivity rapidly. Specifically, crystal graph convolutional neural network(CGCNN) is constructed to predict the fundamental physical parameters related to lattice thermal conductivity. Based on the above physical parameters, an interpretable machine learning model–sure independence screening and sparsifying operator(SISSO), is trained to predict the lattice thermal conductivity. We have predicted the lattice thermal conductivity of all available materials in the open quantum materials database(OQMD)(https://www.oqmd.org/). The proposed approach guides the next step of searching for materials with ultra-high or ultralow lattice thermal conductivity and promotes the development of new thermal insulation materials and thermoelectric materials. 展开更多
关键词 low lattice thermal conductivity interpretable machine learning thermoelectric materials physical domain knowledge
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Jujube witches’ broom phytoplasmas inhibit ZjBRC1-mediated abscisic acid metabolism to induce shoot proliferation
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作者 Fuli Ma Shanqi Zhang +14 位作者 Yu Yao Mengting Chen Ning Zhang Mingsheng Deng Wei Chen Chi Ma Xinyue Zhang Chenglong Guo Xiang Huang Zhenyuan Zhang Yamei Li Tingyi Li junyong Zhou Qibao sun jun sun 《Horticulture Research》 SCIE CSCD 2023年第9期24-38,共15页
Jujube witches’broom(JWB)phytoplasmas parasitize the sieve tubes of diseased phloem and cause an excessive proliferation of axillary shoots from dormant lateral buds to favour their transmission.In previous research,... Jujube witches’broom(JWB)phytoplasmas parasitize the sieve tubes of diseased phloem and cause an excessive proliferation of axillary shoots from dormant lateral buds to favour their transmission.In previous research,two JWB effectors,SJP1 and SJP2,were identified to induce lateral bud outgrowth by disrupting ZjBRC1-mediated auxin flux.However,the pathogenesis of JWB disease remains largely unknown.Here,tissue-specific transcriptional reprogramming was examined to gain insight into the genetic mechanisms acting inside jujube lateral buds under JWB phytoplasma infection.JWB phytoplasmas modulated a series of plant signalling networks involved in lateral bud development and defence,including auxin,abscisic acid(ABA),ethylene,jasmonic acid,and salicylic acid.JWB-induced bud outgrowth was accompanied by downregulation of ABA synthesis within lateral buds.ABA application rescued the bushy appearances of transgenic Arabidopsis overexpressing SJP1 and SJP2 in Col-0 and ZjBRC1 in the brc1-2 mutant.Furthermore,the expression of ZjBRC1 and ABA-related genes ZjHB40 and ZjNCED3 was negatively correlated with lateral main bud outgrowth in decapitated healthy jujube.Molecular evidence showed that ZjBRC1 interacted with ZjBRC2 via its N-terminus to activate ZjHB40 and ZjNCED3 expression and ABA accumulation in transgenic jujube calli.In addition,ZjBRC1 widely regulated differentially expressed genes related to ABA homeostasis and ABA signalling,especially by binding to and suppressing ABA receptors.Therefore,these results suggest that JWB phytoplasmas hijack the ZjBRC1-mediated ABA pathways to stimulate lateral bud outgrowth and expansion,providing a strategy to engineer plants resistant to JWB phytoplasma disease and regulate woody plant architecture to promote crop yield and quality. 展开更多
关键词 BRC METABOLISM programming
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交替张力热处理对聚对苯二甲酸丙二醇酯纤维弹性的提升 被引量:2
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作者 孙君 熊喜科 戴礼兴 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2019年第12期93-98,共6页
采用松弛、张力和交替张力等受力条件在160℃对聚对苯二甲酸丙二醇酯(PTT)纤维进行干热处理并研究纤维弹性的变化。采用红外光谱分析热处理前后PTT纤维构象的变化;采用弹性仪和动态力学热分析仪研究热处理对PTT纤维弹性回复率的影响。... 采用松弛、张力和交替张力等受力条件在160℃对聚对苯二甲酸丙二醇酯(PTT)纤维进行干热处理并研究纤维弹性的变化。采用红外光谱分析热处理前后PTT纤维构象的变化;采用弹性仪和动态力学热分析仪研究热处理对PTT纤维弹性回复率的影响。结果表明,经交替张力热处理,PTT分子链由构象能较高的g-t-t-g构象转变成构象能较低的t-g-g-t构象,有利于PTT纤维的弹性及其稳定性的提高,以30%定伸长经5次循环拉伸测试后弹性回复率仍达到79%,比未经处理PTT纤维提高了约10%。 展开更多
关键词 聚对苯二甲酸丙二醇酯 纤维 热处理 交替张力 弹性
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Rationales for expression and altered expression of apoptotic protease activating factor-1 gene in gastric cancer 被引量:14
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作者 He-Ling Wang Han Bai +2 位作者 Yan Li jun sun Xue-Qing wang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第38期5060-5064,共5页
AIM: To elucidate the relationship between apoptotic protease activating factor-1 (Apaf-1) gene and gastric cancer. METHODS: Thirty-five postoperative cancer and adjacent normal tissue samples were collected in the pr... AIM: To elucidate the relationship between apoptotic protease activating factor-1 (Apaf-1) gene and gastric cancer. METHODS: Thirty-five postoperative cancer and adjacent normal tissue samples were collected in the present study. Expression of the Apaf-1 gene in these samples was analyzed by semi-quantitative RT-PCR. Loss of heterozygosity (LOH) was used to determine whether there was loss of Apaf-1 gene in domain of 12q22-23 in the samples. Promoter methylation of Apaf-1 gene in the samples was analyzed by methylation specific (MSP) PCR. RESULTS: The expression of Apaf-1 mRNA in gastric cancer tissue samples was 51%. The LOH frequency of D12S346, D12S1706, D12S327, D12S1657 and D12S393 was 33%, 8%, 58%, 12% and 42%, respectively. Fifty percent LOH was found at two sites and 17% LOH at three sites. Apaf-1 mRNA expression decreased significantly in 13 cases (rs = 0.487, P = 0.003). The rate of Apaf-1 promoter methylation was 49% in gastric cancer tissue samples and 23% in para-cancerous tissue samples. Promoter methylation occurred significantly in 16 of 18 gastric cancer tissue samples with decreased expression of Apaf-1 mRNA rs = 0.886, P = 10-6). CONCLUSION: The expression of Apaf-1 gene is low in gastric cancer tissues. Methylation of Apaf-1 gene promoter and LOH in domain of 12q22-23 are the main reasons for the expression and altered expression of Apaf-1 gene. 展开更多
关键词 胃癌 甲基化 蛋白酶基因 症状
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Formation of Liquid Pools Entrapped within Solid Grains of ZA27 Alloys during Partial Remelting 被引量:6
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作者 Tijun CHEN Yuan HAO jun sun 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第6期481-483,共3页
The investigations were performed into the formation processes of liquid pools entrapped within solid grains of three ZA27 alloys, produced respectively by either grain refinement, or traditional permanent casting or ... The investigations were performed into the formation processes of liquid pools entrapped within solid grains of three ZA27 alloys, produced respectively by either grain refinement, or traditional permanent casting or mechanical stirring, during partial remelting at semisolid temperature of 460℃. The results show that the rapid coalescence of primary grains due to merging of secondary arms during the initial stage of partial remelting is the main cause for the formation of the entrapped liquid pools. This coalescence resulted in that a high quality of eutectics, especially the 77 phase, was entrapped within the grains, and then remelted to form liquid pools during the subsequent heating. In addition, the growth of the η phase decomposed from the primary α' phase and β phase and the subsequent remelting is another cause for the refined and permanent mould casting alloys. Furthermore, the agglomeration of the solid grains also resulted in the entrapment of liquid in the interior of grains. 展开更多
关键词 THIXOFORMING ZA27 alloy Partial remelting Microstructure
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Zircon U–Pb dating and whole-rock elemental geochemistry of the Shazi anatase deposit in Qinglong,Western Guizhou,SW China 被引量:4
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作者 jun sun Zhao Jingyu Aiguo Nie 《Acta Geochimica》 EI CAS CSCD 2017年第2期329-338,共10页
The Shazi deposit is a large-scale anatase deposit in Qinglong, Guizhou Province. Zircon grains from this deposit yielded a zircon U–Pb age of *259 Ma, representing the formation age of the deposit's parent rocks... The Shazi deposit is a large-scale anatase deposit in Qinglong, Guizhou Province. Zircon grains from this deposit yielded a zircon U–Pb age of *259 Ma, representing the formation age of the deposit's parent rocks.This age is identical to the eruption age of the Emeishan large igneous province, indicating a synchronous magmatic event. The rare-earth-element patterns of laterite samples were similar to those of the weathered basalt sample, and sub-parallel to those of the Emeishan high-Ti basalts,implying a genetic relationship between the laterite and the basalt. The Chemical Index of Alteration values of laterite ranged from 96 to 98, suggesting a high degree of weathering. SiO_2, MgO, and alkaline metal elements decreased with increasing degree of weathering, while Al_2O_3, Fe_2O_3,and TiO_2 increased. We found the highest TiO_2 in laterite and the lowest in pillow basalts, indicating that Ti migrated from basalt to laterite.Our U–Pb dating and whole-rock elemental geochemistry analyses suggest that the Emeishan basalt is the parent rock of the Shazi anatase ore deposit.Based on our analysis, we propose a metallogenic model to explain the ore-forming process, in which the karst terrain formed by the Emeishan mantle plume and the subsequent basaltic magma eruption were the key factors in the formation the Shazi anatase ore deposit. 展开更多
关键词 元素地球化学 锐钛矿 贵州省 年龄 锆石 PB 中国西南 全岩
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