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CD155、TIGIT在胃肠神经内分泌肿瘤中的表达及与临床病理特征的关系
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作者 谢伟 余松 +7 位作者 侯能易 严力 曹钦兴 旦真甲 袁兴梅 陆河江 刘杰 庞明辉 《世界华人消化杂志》 CAS 2024年第2期123-133,共11页
背景胃肠神经内分泌肿瘤(gastrointestinal neuroendocrine neoplasms,GI-NENs)临床表现多样,部分具有高侵袭性及转移性,预后差.收集我院诊治的GI-NENs患者的临床病理资料,免疫组化检测CD155、T细胞免疫球蛋白和ITIM结构域蛋白(T cell i... 背景胃肠神经内分泌肿瘤(gastrointestinal neuroendocrine neoplasms,GI-NENs)临床表现多样,部分具有高侵袭性及转移性,预后差.收集我院诊治的GI-NENs患者的临床病理资料,免疫组化检测CD155、T细胞免疫球蛋白和ITIM结构域蛋白(T cell immunoreceptor with Ig and ITIM domains,TIGIT)的表达量,探讨其与临床病理和预后的关系,为患者的治疗提供一个新的方向.目的探讨CD155、TIGIT在GI-NENs中的表达量与临床病理特征的关系.方法收集2016-11/2020-08经我院诊治的168例GI-NENs患者的临床病理资料.免疫组化检测CD155、TIGIT的表达量,探讨其与临床病理和预后的关系.结果CD155和TIGIT在病理分级高的GI-NENs组织中,表达量也较高,差异有统计学意义(P<0.05);CD155表达量与年龄、肿瘤位置、肿瘤最大直径、病理分级、T分期、淋巴结转移、远处转移、TNM分期、Ki-67指数有关(P<0.05);TIGIT表达量与肿瘤最大直径、病理分级、T分期、淋巴结转移、TNM分期、Ki-67指数有关(P<0.05);CD155和TIGIT表达量高的患者预后较表达量低者差,差异有统计学意义(P<0.05).结论CD155和TIGIT表达量在不同分级、分期的GI-NENs患者存在差异,可能参与了GI-NENs的发生及进展的调控过程,高表达可能提示预后不佳. 展开更多
关键词 胃肠神经内分泌肿瘤 CD155 TIGIT 预后
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Argatroban promotes recovery of spinal cord injury by inhibiting the PAR1/JAK2/STAT3 signaling pathway
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作者 Chenxi Zhao Tiangang Zhou +9 位作者 Ming Li jie liu Xiaoqing Zhao Yilin Pang Xinjie liu Jiawei Zhang Lei Ma Wenxiang Li Xue Yao Shiqing Feng 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第2期434-439,共6页
Argatroban is a synthetic thrombin inhibitor approved by U.S.Food and Drug Administration for the treatment of thrombosis.However,whether it plays a role in the repair of spinal cord injury is unknown.In this study,we... Argatroban is a synthetic thrombin inhibitor approved by U.S.Food and Drug Administration for the treatment of thrombosis.However,whether it plays a role in the repair of spinal cord injury is unknown.In this study,we established a rat model of T10 moderate spinal cord injury using an NYU Impactor ModerⅢand performed intraperitoneal injection of argatroban for 3 consecutive days.Our results showed that argatroban effectively promoted neurological function recovery after spinal cord injury and decreased thrombin expression and activity in the local injured spinal cord.RNA sequencing transcriptomic analysis revealed that the differentially expressed genes in the argatroban-treated group were enriched in the JAK2/STAT3 pathway,which is involved in astrogliosis and glial scar formation.Western blotting and immunofluorescence results showed that argatroban downregulated the expression of the thrombin receptor PAR1 in the injured spinal cord and the JAK2/STAT3 signal pathway.Argatroban also inhibited the activation and proliferation of astrocytes and reduced glial scar formation in the spinal cord.Taken together,these findings suggest that argatroban may inhibit astrogliosis by inhibiting the thrombin-mediated PAR1/JAK2/STAT3 signal pathway,thereby promoting the recovery of neurological function after spinal cord injury. 展开更多
关键词 ARGATROBAN ASTROGLIOSIS JAK/STAT signaling pathway protease-activated receptor-1 spinal cord injury THROMBIN vimentin
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Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n
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作者 Sheng-Da Tang Yong-Hao Chen +72 位作者 Jing-Yu Tang Rui-Rui Fan Qiang Li Gong Li Dong liu Zheng-Yao Jin Xing-Zhu Cui Tian-Xiang Chen Yi-Wei Yang Rong liu Han Yi Yang Li Zhen Yang Qi An Hao-Fan Bai Jiang-Bo Bai jie Bao Ping Cao Qi-Ping Chen Zhen Chen Zeng-Qi Cui An-Chuan Fan Chang-Qing Feng Fan-Zhen Feng Ke-Qing Gao Min-Hao Gu Chang-Cai Han Zi-jie Han Guo-Zhu He Yong-Cheng He Yang Hong Yi-Wei Hu Han-Xiong Huang Wei-Hua Jia Hao-yu Jiang Wei Jiang Zhi-jie Jiang Ling Kang Bo Li Chao Li Jia-Wen Li Xiao Li jie liu Shu-Bin liu Guang-Yuan Luan Chang-Jun Ning Bin-Bin Qi jie Ren Zhi-Zhou Ren Xi-Chao Ruan Zhao-Hui Song Kang Sun Zhi-Xin Tan Li-Jiao Wang Peng-Cheng Wang Zhao-Hui Wang Zhong-Wei Wen Xiao-Guang Wu Xuan Wu Li-Kun Xie Yong-Ji Yu Guo-Hui Zhang Lin-Hao Zhang Mo-Han Zhang Qi-Wei Zhang Xian-Peng Zhang Yu-Liang Zhang Yue Zhang Zhi-Yong Zhang Mao-Yuan Zhao Lu-Ping Zhou Zhi-Hao Zhou Ke-Jun Zhu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第1期178-187,共10页
Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental compositi... Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications. 展开更多
关键词 CSNS White neutron beam NRTA Nuclide identification Nondestructive method
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Dynamic thermo-mechanical responses of road-soft ground system under vehicle load and daily temperature variation
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作者 Chuxuan Tang jie liu +3 位作者 Zheng Lu Yang Zhao Jing Zhang Yinuo Feng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1722-1731,共10页
A complete road-soft ground model is established in this paper to study the dynamic responses caused by vehicle loads and/or daily temperature variation.A dynamic thermo-elastic model is applied to capturing the behav... A complete road-soft ground model is established in this paper to study the dynamic responses caused by vehicle loads and/or daily temperature variation.A dynamic thermo-elastic model is applied to capturing the behavior of the rigid pavement,the base course,and the subgrade,while the soft ground is characterized using a dynamic thermo-poroelastic model.Solutions to the road-soft ground system are derived in the Laplace-Hankel transform domain.The time domain solutions are obtained using an integration approach.The temperature,thermal stress,pore water pressure,and displacement responses caused by the vehicle load and the daily temperature variation are presented.Results show that obvious temperature change mainly exists within 0.3 m of the road when subjected to the daily temperature variation,whereas the stress responses can still be found in deeper places because of the thermal swelling/shrinkage deformation within the upper road structures.Moreover,it is important to consider the coupling effects of the vehicle load and the daily temperature variation when calculating the dynamic responses inside the road-soft ground system. 展开更多
关键词 Dynamic response Vehicle load Daily temperature variation Thermo-poroelastic medium Coupling effects
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Rapid report of source parameters of 2023 M6.2 Jishishan,Gansu earthquake sequence
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作者 ZhiGao Yang jie liu +2 位作者 YingYing Zhang Wen Yang XueMei Zhang 《Earth and Planetary Physics》 EI CAS CSCD 2024年第2期436-443,共8页
The M6.2 earthquake in Jishishan,Gansu Province,on December 18,2023,caused extraordinary earthquake disasters.It was located in the northern part of the north−south seismic zone,which is a key area for earthquake moni... The M6.2 earthquake in Jishishan,Gansu Province,on December 18,2023,caused extraordinary earthquake disasters.It was located in the northern part of the north−south seismic zone,which is a key area for earthquake monitoring in China.The newly built dense strong motion stations in this area provide unprecedented conditions for high-precision earthquake relocation,especially the earthquake focal depth.This paper uses the newly built strong motion and traditional broadband seismic networks to relocate the source locations of the M3.0 and above aftershocks and to invert their focal mechanisms.The horizontal error of earthquake location is estimated to be 0.5−1 km,and the vertical error is 1−2 km.The focal depth range of aftershocks is 9.6−14.6 km,distributed in a 12-km-long strip with SSE direction.Aftershocks in the south are more concentrated horizontally and vertically,while aftershocks in the north are more scattered.The focal mechanisms of the main shock and aftershocks are relatively consistent,and the P-axis orientation is consistent with the regional strain direction.There is a seismic blank area of M3.0 and above,about 3−5 km between the main shock and aftershocks.It is suggested that the energy released by the main shock rupture is concentrated in this area.Based on the earthquake location and focal mechanism of the main shock,it is inferred that the Northern Lajishan fault zone is the seismogenic structure of the main shock,and the main shock did not occur on the main fault,but on a secondary fault.The initial rupture depth and centroid depth of the main shock were 12.8 and 14.0 km,respectively.The source rupture depth may not be the main reason for the severe earthquake disaster. 展开更多
关键词 Jishishan earthquake earthquake relocation focal mechanism strong motion data
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Coherent optical frequency transfer via 972-km fiber link
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作者 邓雪 张翔 +8 位作者 臧琦 焦东东 王丹 刘杰 高静 许冠军 董瑞芳 刘涛 张首刚 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期277-282,共6页
We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase lockin... We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase locking loop in the conventional active phase control scheme,the passive phase noise cancellation is realized by feeding double-trip beat-note frequency to the driver of the acoustic optical modulator at the local site.This passive scheme exhibits fine robustness and reliability,making it suitable for long-distance and noisy fiber links.An optical regeneration station is used in the link for signal amplification and cascaded transmission.The phase noise cancellation and transfer instability of the 972-km link is investigated,and transfer instability of 1.1×10^(-19)at 10^(4)s is achieved.This work provides a promising method for realizing optical frequency distribution over thousands of kilometers by using fiber links. 展开更多
关键词 optical frequency transfer fiber link phase noise cancellation
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Fabrication of Graphene/Cu Composite by Chemical Vapor Deposition and Effects of Graphene Layers on Resultant Electrical Conductivity
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作者 Xinyue liu Yaling Huang +2 位作者 Yuyao Li jie liu Quanfang Chen 《Journal of Harbin Institute of Technology(New Series)》 CAS 2024年第1期16-25,共10页
Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the pro... Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil. 展开更多
关键词 chemical vapor deposition(CVD) Gr/Cu Gr/Cu/Gr graphene layers graphene volume fraction electrical conductivity
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Computer-assisted three-dimensional individualized extreme liver resection for hepatoblastoma in proximity to the major liver vasculature
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作者 Wen-Li Xiu jie liu +7 位作者 Jing-Li Zhang Jing-Miao Wang Xue-Feng Wang Fei-Fei Wang jie Mi Xi-Wei Hao NanXia Qian Dong 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第4期1066-1077,共12页
BACKGROUND The management of hepatoblastoma(HB)becomes challenging when the tumor remains in close proximity to the major liver vasculature(PMV)even after a full course of neoadjuvant chemotherapy(NAC).In such cases,e... BACKGROUND The management of hepatoblastoma(HB)becomes challenging when the tumor remains in close proximity to the major liver vasculature(PMV)even after a full course of neoadjuvant chemotherapy(NAC).In such cases,extreme liver resection can be considered a potential option.AIM To explore whether computer-assisted three-dimensional individualized extreme liver resection is safe and feasible for children with HB who still have PMV after a full course of NAC.METHODS We retrospectively collected data from children with HB who underwent surgical resection at our center from June 2013 to June 2023.We then analyzed the detailed clinical and three-dimensional characteristics of children with HB who still had PMV after a full course of NAC.RESULTS Sixty-seven children diagnosed with HB underwent surgical resection.The age at diagnosis was 21.4±18.8 months,and 40 boys and 27 girls were included.Fifty-nine(88.1%)patients had a single tumor,39(58.2%)of which was located in the right lobe of the liver.A total of 47 patients(70.1%)had PRE-TEXT III or IV.Thirty-nine patients(58.2%)underwent delayed resection.After a full course of NAC,16 patients still had close PMV(within 1 cm in two patients,touching in 11 patients,compressing in four patients,and showing tumor thrombus in three patients).There were 6 patients of tumors in the middle lobe of the liver,and four of those patients exhibited liver anatomy variations.These 16 children underwent extreme liver resection after comprehensive preoperative evaluation.Intraoperative procedures were performed according to the preoperative plan,and the operations were successfully performed.Currently,the 3-year event-free survival of 67 children with HB is 88%.Among the 16 children who underwent extreme liver resection,three experienced recurrence,and one died due to multiple metastases.CONCLUSION Extreme liver resection for HB that is still in close PMV after a full course of NAC is both safe and feasible.This approach not only reduces the necessity for liver transplantation but also results in a favorable prognosis.Individualized three-dimensional surgical planning is beneficial for accurate and complete resection of HB,particularly for assessing vascular involvement,remnant liver volume and anatomical variations. 展开更多
关键词 Children HEPATOBLASTOMA Surgery THREE-DIMENSIONAL COMPUTER-ASSISTED
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Long non-coding RNA-AK138945 regulates myocardial ischemia-reperfusion injury via the miR-1-GRP94 signaling pathway
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作者 Yanying Wang Jian Huang +13 位作者 Han Sun jie liu Yingchun Shao Manyu Gong Xuewen Yang Dongping liu Zhuo Wang Haodong Li Yanwei Zhang Xiyang Zhang Zhiyuan Du Xiaoping Leng Lei Jiao Ying Zhang 《Frigid Zone Medicine》 2024年第1期31-40,共10页
Objective:Myocardial ischemia-reperfusion injury(MIRI)is one of the leading causes of death from cardiovascular disease in humans,especially in individuals exposed to cold environments.Long non-coding RNAs(lncRNAs)reg... Objective:Myocardial ischemia-reperfusion injury(MIRI)is one of the leading causes of death from cardiovascular disease in humans,especially in individuals exposed to cold environments.Long non-coding RNAs(lncRNAs)regulate MIRI through multiple mechanisms.This study explored the regulatory effect of lncRNA-AK138945 on myocardial ischemia-reperfusion injury and its mechanism.Methods:In vivo,8-to 12-weeks-old C57BL/6 male mice underwent ligation of the left anterior descending coronary artery for 50 minutes followed by reperfusion for 48 hours.In vitro,the primary cultured neonatal mouse ventricular cardiomyocytes(NMVCs)were treated with 100μmol/L hydrogen peroxide(H_(2)O_(2)).The knockdown of lncRNA-AK138945 was evaluated to detect cardiomyocyte apoptosis,and a glucose-regulated,endoplasmic reticulum stress-related protein 94(GRP94)inhibitor was used to detect myocardial injury.Results:We found that the expression level of lncRNA-AK138945 was reduced in MIRI mouse heart tissue and H2O2-treated cardiomyocytes.Moreover,the proportion of apoptosis in cardiomyocytes increased after lncRNA-AK138945 was silenced.The expression level of Bcl2 protein was decreased,and the expression level of Bad,Caspase 9 and Caspase 3 protein was increased.Our further study found that miR-1a-3p is a direct target of lncRNA-AK138945,after lncRNA-AK138945 was silenced in cardiomyocytes,the expression level of miR-1a-3p was increased while the expression level of its downstream protein GRP94 was decreased.Interestingly,treatment with a GRP94 inhibitor(PU-WS13)intensified H2O2-induced cardiomyocyte apoptosis.After overexpression of FOXO3,the expression levels of lncRNA-AK138945 and GRP94 were increased,while the expression levels of miR-1a-3p were decreased.Conclusion:LncRNA-AK138945 inhibits GRP94 expression by regulating miR-1a-3p,leading to cardiomyocyte apoptosis.The transcription factor Forkhead Box Protein O3(FOXO3)participates in cardiomyocyte apoptosis induced by endoplasmic reticulum stress through up-regulation of lncRNA-AK138945. 展开更多
关键词 myocardial ischemia reperfusion lncRNA APOPTOSIS microRNAGRP94
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Exploration and Practice of “Construction Engineering Regulations” Course Reform
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作者 jie liu 《Journal of Contemporary Educational Research》 2024年第3期49-54,共6页
Based on the analysis of the existing teaching situation of the“Construction Engineering Regulations”course,this paper divides the course content into three parts according to the course characteristics and content,... Based on the analysis of the existing teaching situation of the“Construction Engineering Regulations”course,this paper divides the course content into three parts according to the course characteristics and content,and explores three corresponding teaching modes.The proportion of student-led relationships in the three teaching modes is 80%,60%,and 90%,respectively,realizing a teaching mechanism centered on students and stimulating students’interest in independent learning.Teaching methods such as problem-oriented learning,group discussion,student reporting,MOOC(massive open online course),case analysis,etc.,have been used to establish a variety of comprehensive examination mechanisms such as quiz games,follow-up tests,and work displays.Practice has shown that after adopting these three teaching modes,classroom teaching efficiency has significantly improved,and students’abilities in exploration,expression,innovation,and team cooperation have also been enhanced. 展开更多
关键词 Construction Engineering Regulations Problem-oriented learning Independent learning
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基于工程教育专业认证构建一致化的教学大纲——以高分子物理课程为例 被引量:1
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作者 陈学琴 姚丽 +4 位作者 刘杰 张群朝 蒋涛 施德安 王国成 《大学化学》 CAS 2023年第3期125-130,共6页
作为课程运行的指挥棒,传统课程大纲难以满足工程教育专业认证的要求,重建课程大纲迫在眉睫。基于工程认证标准,笔者以高分子物理课程为例,制定了标准的教学大纲,实现教学环节、学习活动和评价方式构建一致化。1)根据课程可支撑的毕业... 作为课程运行的指挥棒,传统课程大纲难以满足工程教育专业认证的要求,重建课程大纲迫在眉睫。基于工程认证标准,笔者以高分子物理课程为例,制定了标准的教学大纲,实现教学环节、学习活动和评价方式构建一致化。1)根据课程可支撑的毕业指标点,设立了定位准确、支撑强度合理的课程目标;2)细化了与课程目标对接的课程内容和教学环节;3)设置了课程考核方式和评分标准,科学量化学生学习效果。该标准化课程大纲不仅为达成课程目标提供了保障,而且为建立其他课程大纲树立了典范。 展开更多
关键词 工程教育专业认证 高分子物理 教学大纲 构建一致化 形成性评价
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基于微流控技术平台的Pt基三元电催化剂高通量合成和筛选 被引量:1
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作者 胡洋 刘斌 +5 位作者 徐路遥 董自强 仵亚婷 刘杰 钟澄 胡文彬 《物理化学学报》 SCIE CAS CSCD 北大核心 2023年第3期58-67,共10页
高性能铂基电催化剂的高效合成和筛选对于加速其在各个领域的进一步发展和应用具有重要意义。微流控高通量技术在铂基电催化剂的合成参数优化应用方面具有巨大的潜力。然而,缺少性能评估的微流控高通量合成无法最大限度地发挥其优势。... 高性能铂基电催化剂的高效合成和筛选对于加速其在各个领域的进一步发展和应用具有重要意义。微流控高通量技术在铂基电催化剂的合成参数优化应用方面具有巨大的潜力。然而,缺少性能评估的微流控高通量合成无法最大限度地发挥其优势。在这项工作中,我们构建了将材料的高通量合成与高通量筛选相结合的多功能平台。该平台的微流控芯片可以生成三种不同前驱体金属离子的20级浓度梯度。微反应器阵列具有100个微通道,用于材料合成和电化学表征。利用该平台我们合成了5组铂基三元电催化剂(共计100种不同的组分),并进行了电化学表征,直接确定了Pt基三元电催化剂对析氧反应的最佳组成。这表明我们所构建微流控高通量平台具有高效性和灵活性,可大大缩短了新材料开发和材料性能优化的周期。 展开更多
关键词 高通量方法 电催化剂 微流控技术 电化学表征 析氧反应
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重塑位于火山曲线右支的弱吸附金属单原子位点的配位环境及电子结构
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作者 贡立圆 王颖 +8 位作者 刘杰 王显 李阳 侯帅 武志坚 金钊 刘长鹏 邢巍 葛君杰 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第7期352-360,共9页
金属单原子位点独特的电子结构使其在燃料电池阴极氧还原催化反应(ORR)的应用引起广泛兴趣.金属单原子中心作为催化剂的活性位点遵循Sabatier原则,即位于火山型曲线右侧的金属中心与ORR中间产物的结合能力弱,使中间产物难以被位点活化,... 金属单原子位点独特的电子结构使其在燃料电池阴极氧还原催化反应(ORR)的应用引起广泛兴趣.金属单原子中心作为催化剂的活性位点遵循Sabatier原则,即位于火山型曲线右侧的金属中心与ORR中间产物的结合能力弱,使中间产物难以被位点活化,与之相反,左侧的位点则与中间产物的结合力太强,使中间产物难以脱附.因此,构建中间产物结合强度适中的位点可以提高催化剂活性.研究表明,通过改变金属中心的配位环境可以调控金属的电子结构,进而调节对ORR中间产物的吸附能力,提高催化剂活性.例如,对于位于火山曲线左侧的FeN4位点,通过在配位原子中引入高电负性的基团,如OH,S,Cl,减弱其对ORR中间产物的结合强度,使其活性向右侧活性顶点移动.然而,目前还没有提出有效的策略来改善火山曲线右侧位点的弱吸附能力.例如,Pd和Pt的纳米催化剂具有较高的ORR活性,而其单原子MN4位点却对ORR呈惰性,原因为高电负性的N使M具有较高的电荷密度,使其对中间产物的吸附能力太弱而位于火山曲线的最右边,具有较差的本征活性.为了缓解此类金属与配位N之间的不匹配的问题,我们提出通过利用电负性低的C(χp=2.55)代替N(χp=3.04)配位,以提升弱吸附位点的本征活性.本文制备了Ir-N-C,Pd-N-C,Pt-N-C,Ir-C,Pd-C和Pt-C六种催化剂;X射线衍射、透射电极和球差电镜结果表明,催化剂不含金属颗粒;同步辐射结果表明,催化剂呈M-N/C配位形式存在,且价态为氧化态.飞行时间二次离子质谱法(ToF-SIMS)测试可以检测到MNXCY和MCX的位点结构,结合同步辐射结果,认为活性位点分别是IrNXC((4-X)),IrC4,PdN_(2)CX和PdN3CX,PdC4,PtN3C1和PtN4,PtC4.电化学结果表明,相比N配位的催化剂,C配位的催化剂具有更高的半波电位、起始电位及本征活性,表明C配位更适合配位金属Ir,Pd和Pt,证明本文策略的可行性.为了进一步研究催化活性提升的原因,本文采用密度泛函理论计算探究催化机理,根据实验结果(X射线吸附光谱和ToF-SIMS)模拟了催化剂的活性位点结构,并计算反应中间产物的吸附能ΔGOH*.将ΔGOH*作为横坐标,反应的起始电位即催化活性作为纵坐标,绘制图谱得到火山型曲线.结果表明,相比N配位的金属位点,C配位的金属位点向强吸附端移动并靠近活性顶点,与实验结果一致,说明催化活性的提升是因为配位环境的改变改善了位点吸附能力.随后,通过计算活性位点的Bader电荷密度探究配位环境对电子结构的调控.结果显示,低电负性的C由于吸电子能力弱于高电负性的N,使MCX位点具有较低的Bader电荷密度,从而具有较强的中间产物吸附能力,进而提高催化活性.综上,本文提出了一个普遍性的原则,通过利用低电负性的元素配位调节具有弱结合能的金属(不仅是Ir,Pd,Pt)位点活性,为不同性质的金属匹配合适的配位环境,以实现高催化活性. 展开更多
关键词 氧还原反应 单原子催化剂 配位环境 电子结构 反应中间产物吸附能
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可逆交联瓶刷状聚己内酯的合成及性能
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作者 宋冠军 冷雪菲 +2 位作者 缪鹏程 刘杰 李杨 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2023年第12期16-24,共9页
通过原子转移自由基聚合(ATRP)得到聚甲基丙烯酸羟乙酯(PHEMA),以PHEMA的羟基为引发剂通过开环聚合得到了瓶刷状聚己内酯。通过凝胶渗透色谱和核磁共振波谱确定聚合物的结构,证明成功合成了瓶刷状聚己内酯且分子量分布较窄(PDI<1.22... 通过原子转移自由基聚合(ATRP)得到聚甲基丙烯酸羟乙酯(PHEMA),以PHEMA的羟基为引发剂通过开环聚合得到了瓶刷状聚己内酯。通过凝胶渗透色谱和核磁共振波谱确定聚合物的结构,证明成功合成了瓶刷状聚己内酯且分子量分布较窄(PDI<1.22)。将得到的瓶刷状聚己内酯与二苯基甲烷二异氰酸酯(MDI)进行交联得到了一系列含有动态共价氨酯键的可逆交联瓶刷状聚己内酯网络。通过傅里叶变换红外光谱仪、差示扫描量热仪、动态力学热分析仪、万能拉伸机等对交联后的聚合物进行了结构表征和性能分析。交联后的聚合物断裂伸长率随臂长的增加显著提高,最高可达344.4%;材料表现出明显的应力松弛行为,符合阿伦尼乌斯公式规律。材料破碎后仍可热压成型,拉伸强度和断裂伸长率均可恢复至80%以上。 展开更多
关键词 聚己内酯 瓶刷聚合物 可逆交联 氨酯键
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连续流技术在光氧化还原催化转化的最新进展
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作者 袁鑫 范海滨 +5 位作者 刘杰 覃龙州 王剑 段秀 邱江凯 郭凯 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第7期175-194,共20页
光氧化还原催化转化因其具备绿色、温和、可持续和原子经济性高等方面的优势,近年来被广泛应用于构建有机合成和药物分子骨架.光子被称为绿色“无痕”试剂,可以提供能量进而引发化学反应.光化学过程通常涉及分子分解、分子激发态的重排... 光氧化还原催化转化因其具备绿色、温和、可持续和原子经济性高等方面的优势,近年来被广泛应用于构建有机合成和药物分子骨架.光子被称为绿色“无痕”试剂,可以提供能量进而引发化学反应.光化学过程通常涉及分子分解、分子激发态的重排或发色团激发引起的电子转移(光氧化还原催化)等过程.20世纪80年代,太阳光能作为“绿色化学”的有力工具被用于构建新型分子骨架.随后,可见光被人们广泛应用于有机合成,且陆续有新的研究结果报道.然而,众多研究表明光氧化还原催化中仍然存在一些基本限制.近年来,连续流反应技术成为一种引人注目且功能强大的工具,该技术可以克服间歇反应器在反应过程中存在的局限.连续流反应技术的引入可以有效解决传统有机光化学合成中的许多问题,实现不同类型的光化学转化.本综述系统地分析了传统光化学釜式反应器存在的限制:第一,根据布格-朗伯-比尔定律,传统的光催化反应的透光率随着反应路径长度的增加衰减较为明显.因而在使用较大的间歇式光反应器进行规模化放大实验时,需要增加光照强度来克服光子衰减效应,但容易过度照射反应体系,进而引起反应体系受热不均造成反应效率下降和副产物增多等问题;第二,间歇式的光化学反应装置容易受混合效果的影响,进行非均相反应时往往反应效率不高.总结分析了连续流反应技术解决传统光反应中问题的成功关键在于连续流反应技术具有更好的混合能力、更优的传质传热效率以及更容易规模化放大的优势.基于光催化剂的类型包括传统金属催化剂、有机光催化剂以及非均相光催化剂,对近五年连续流技术在光氧化还原催化转化中的应用进行了分类及讨论.针对不同反应条件包括光催化剂、多相反应和多步骤等体系中连续流反应器的装置材料和光源和溶剂等方面内容,探讨了连续流反应技术在不同的光催化反应中的影响因素以及反应机理.本文还提出了目前微流场技术中仍需要解决的问题:(1)开发更高效的光催化剂;(2)反应过程中固体堵塞及后处理系统的问题;(3)实现大规模生产所需要的变革.在此基础上,对连续流技术在光氧化还原催化转化的研究前景进行了展望,如多步骤连续流以及连续流技术在生物和聚合物材料方面的应用. 展开更多
关键词 光氧化还原催化 连续流技术 过渡金属光敏剂 有机光催化剂 非均相光催化剂
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A literature review of MOF derivatives of electromagnetic wave absorbers mainly based on pyrolysis 被引量:3
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作者 Qiuyi Wang jie liu +2 位作者 Yadong Li Zhichao Lou Yanjun Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第3期446-473,共28页
Growing electromagnetic pollution has plagued researchers in the field of electromagnetic(EM)energy dissipation for many years;it is increasingly important to solve this problem efficiently.Metal-organic frameworks(MO... Growing electromagnetic pollution has plagued researchers in the field of electromagnetic(EM)energy dissipation for many years;it is increasingly important to solve this problem efficiently.Metal-organic frameworks(MOFs),a shining star of functional materials,have attracted great attention for their advantages,which include highly tunable porosity,structure,and versatility.MOF-derived electromagnetic wave(EMW)absorbers,with advantages such as light weight,thin matching thickness,strong capacity,and wide effective bandwidth,are widely reported.However,current studies lack a systematic summary of the ternary synergistic effects of the precursor component-structure-EMW absorption behavior of MOF derivatives.Here we describe in detail the electromagnetic(EM)energy dissipation mechanism and strategy for preparing MOF-derived EMW absorbers.On the basis of this description,the following means are suggested for adjusting the EM parameters of MOF derivatives,achieving excellent EM energy dissipation:(1)changing the metal and ligands to regulate the chemical composition and morphology of the precursor,(2)controlling pyrolysis parameters(including temperature,heating rate,and gas atmosphere)to manipulate the structure and components of derivatives,and(3)compounding with enhancement phases,including carbon nanomaterials,metals,or other MOFs. 展开更多
关键词 metal organic framework microstructure magnetic-dielectric synergy electromagnetic wave absorption
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科学研究的第五范式——以智能驱动的材料设计为例 被引量:2
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作者 Can Leng Zhuo Tang +5 位作者 Yi-Ge Zhou Zean Tian Wei-Qing Huang jie liu Keqin Li Kenli Li 《Engineering》 SCIE EI CAS CSCD 2023年第5期126-137,I0003,I0004,共14页
科学正在进入一个新时代——第五范式——它被认为是知识整合到不同领域的主要特征,是基于无所不在的机器学习系统的计算社区中智能驱动的工作。在此,我们通过在天河一号超级计算机系统上构建的催化材料专门设计的典型平台案例,生动地... 科学正在进入一个新时代——第五范式——它被认为是知识整合到不同领域的主要特征,是基于无所不在的机器学习系统的计算社区中智能驱动的工作。在此,我们通过在天河一号超级计算机系统上构建的催化材料专门设计的典型平台案例,生动地阐明了第五范式的本质,旨在促进第五范式在其他领域的培养。第五范式平台主要包括模型自动构建(原始数据提取)、指纹自动构建(神经网络特征选择)以及跨学科知识串联的重复迭代(“火山图”)。与分解一起进行的是对迭代中实现的体系结构的性能评估。通过讨论,第五范式的智能驱动平台可以极大地简化和改进研究中极其繁琐和具有挑战性的工作,并通过补偿机器学习中缺少样本和替代一些由于计算资源不足而导致的数值计算来实现数值计算与机器学习之间的相互反馈,从而加速探索过程。在数据驱动的学科中,跨学科专家的协同作用和对动态数据需求的急剧增长仍然是一个挑战。我们相信,对第五范式平台的一瞥可以为其在其他领域的应用铺平道路。 展开更多
关键词 机器学习 自动构建 天河一号 数据驱动 神经网络 动态数据 知识整合 科学研究
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SbMYB3 transcription factor promotes root-specific f lavone biosynthesis in Scutellaria baicalensis 被引量:2
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作者 Yumin Fang jie liu +8 位作者 Minmin Zheng Sanming Zhu Tianlin Pei Mengying Cui Lijing Chang Hanwen Xiao Jun Yang Cathie Martin Qing Zhao 《Horticulture Research》 SCIE CSCD 2023年第2期160-169,共10页
Scutellaria baicalensis Georgi produces abundant root-specific f lavones(RSFs),which provide various benefits to human health.We have elucidated the complete biosynthetic pathways of baicalein and wogonin.However,the ... Scutellaria baicalensis Georgi produces abundant root-specific f lavones(RSFs),which provide various benefits to human health.We have elucidated the complete biosynthetic pathways of baicalein and wogonin.However,the transcriptional regulation of f lavone biosynthesis in S.baicalensis remains unclear.We show that the SbMYB3 transcription factor functions as a transcriptional activator involved in the biosynthesis of RSFs in S.baicalensis.Yeast one-hybrid and transcriptional activation assays showed that SbMYB3 binds to the promoter of flavone synthase II-2(SbFNSII-2)and enhances its transcription.In S.baicalensis hairy roots,RNAi of SbMYB3 reduced the accumulation of baicalin and wogonoside,and SbMYB3 knockout decreased the biosynthesis of baicalein,baicalin,wogonin,and wogonoside,whereas SbMYB3 overexpression enhanced the contents of baicalein,baicalin,wogonin,and wogonoside.Transcript profiling by qRT–PCR demonstrated that SbMYB3 activates SbFNSII-2 expression directly,thus leading to more abundant accumulation of RSFs.This study provides a potential target for metabolic engineering of RSFs. 展开更多
关键词 abundant von SPECIFIC
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Three-in-one LaNiO_(3) functionalized separator boosting electrochemical stability and redox kinetics for high-performance Li-S battery 被引量:1
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作者 Weiyu Wang Mingxiu Hou +6 位作者 Fangqian Han Di Yu jie liu Qian Zhang Fengli Yu Lei Wang Maoshuai He 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期581-591,I0013,共12页
The lithium-sulfur(Li-S)battery,as one of the energy storage devices,has been in the limelight due to its high theoretical energy density.However,the poor redox kinetics and the"shuttle effect"of polysulfide... The lithium-sulfur(Li-S)battery,as one of the energy storage devices,has been in the limelight due to its high theoretical energy density.However,the poor redox kinetics and the"shuttle effect"of polysulfides severely restrict the use of Li-S batteries in practical applications.Herein,a novel bimetallic LaNiO_(3) functional material with high electrical conductivity and catalytic property is prepared to act as a high-efficiency polysulfide shuttling stopper.The three LaNiO_(3) samples with different physical/chemical characteristics are obtained by controlling the calcination temperature.In conjunction with the high electrical conductivity and excellent catalytic properties of the as-prepared materials,the appropriate chemisorption toward polysulfides offers great potential to enhance electrochemical stability for highperformance Li-S batteries.Particularly,the Li-S cell with the separator modified by such functional material gives a specific capacity of 658 mA h g^(-1) after 500 cycles at a high current density of 2 C.Even with high sulfur loading of 6.05 mg cm^(-2),the Li-S battery still exhibits an areal specific capacity of 2.81 m A h cm^(-2)after 150 cycles.This work paves a new avenue for the rational design of materials for separator modification in high-performance Li-S batteries. 展开更多
关键词 Li-S battery Functional separator Catalytic property Electrochemical stability Redox kinetics
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Ultrasensitive quantification of trace amines based on N-phosphorylation labeling chip 2D LC-QQQ/MS 被引量:1
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作者 Xiqing Bian Yida Zhang +5 位作者 Na Li Menglin Shi Xiaolin Chen Hui-Lu Zhang jie liu Jian-Lin Wu 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2023年第3期315-322,共8页
Trace amines(TAs)are metabolically related to catecholamine and associated with cancer and neurological disorders.Comprehensive measurement of TAs is essential for understanding pathological processes and providing pr... Trace amines(TAs)are metabolically related to catecholamine and associated with cancer and neurological disorders.Comprehensive measurement of TAs is essential for understanding pathological processes and providing proper drug intervention.However,the trace amounts and chemical instability of TAs challenge quantification.Here,diisopropyl phosphite coupled with chip two-dimensional(2D)liquid chromatography tandem triple-quadrupole mass spectrometry(LC-QQQ/MS)was developed to simultaneously determine TAs and associated metabolites.The results showed that the sensitivities of TAs increased up to 5520 times compared with those using nonderivatized LC-QQQ/MS.This sensitive method was utilized to investigate their alterations in hepatoma cells after treatment with sorafenib.The significantly altered TAs and associated metabolites suggested that phenylalanine and tyrosine metabolic pathways were related to sorafenib treatment in Hep3B cells.This sensitive method has great potential to elucidate the mechanism and diagnose diseases considering that an increasing number of physiological functions of TAs have been discovered in recent decades. 展开更多
关键词 Chip 2D LC-QQQ/MS Trace amines DERIVATIZATION HEPATOMA
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