期刊文献+
共找到154篇文章
< 1 2 8 >
每页显示 20 50 100
黑河中游荒漠-绿洲过渡带典型固沙植物周围风沙运动模拟
1
作者 何娜娜 胡广录 +2 位作者 陈坤 靳涛阳 田凯夫 《中国沙漠》 北大核心 2025年第6期300-311,共12页
黑河中游荒漠-绿洲过渡带典型固沙植物梭梭(Haloxylon ammodendron)、沙拐枣(Calligonum mongolicum)、泡泡刺(Nitraria sphaerocarpa)能够有效降低风沙活动强度,减轻荒漠化对绿洲的威胁,在维持绿洲生态系统安全稳定中发挥着重要作用。... 黑河中游荒漠-绿洲过渡带典型固沙植物梭梭(Haloxylon ammodendron)、沙拐枣(Calligonum mongolicum)、泡泡刺(Nitraria sphaerocarpa)能够有效降低风沙活动强度,减轻荒漠化对绿洲的威胁,在维持绿洲生态系统安全稳定中发挥着重要作用。本文利用Fluent软件对梭梭、沙拐枣和泡泡刺周围的风速特征和积沙特征进行数值模拟,并采用野外试验观测数据加以验证。结果表明:(1)单株植物周围的流场可分为遇阻减速区、加速区、静风区和恢复区,并在植物背风面近地表层存在2个涡流区,其中涡流Ⅰ区是主要的积沙区。(2)梭梭、沙拐枣、泡泡刺在背风面1H距离处的最优防护高度分别为1.2~1.5、1.2~1.4、0.1~1.0 m。(3)3种植物在不同高度层的防风效应存在差异,近地表层的防风效果泡泡刺>沙拐枣>梭梭,而在中高空层为梭梭>沙拐枣>泡泡刺。(4)3种植物的阻沙能力表现为泡泡刺>梭梭>沙拐枣。综合3种植物防风固沙效应表现,在风蚀防治的实际应用中,可采用梭梭、沙拐枣与泡泡刺混交的配置方式,以发挥泡泡刺的固沙作用,同时利用梭梭和沙拐枣在中高空层的防风优势。 展开更多
关键词 荒漠-绿洲过渡带 荒漠植物 防风固沙效应 数值模拟 涡流
原文传递
miR-182-5p在膀胱癌中的表达及其机制 被引量:5
2
作者 郝朝辉 张楠 +1 位作者 陈昆 葛雷 《中国肿瘤临床》 CAS CSCD 北大核心 2021年第10期527-532,共6页
目的:探究miR-182-5p及FOXO3在膀胱癌中的表达意义及其参与膀胱癌可能的机制。方法:收集2017年6月至2019年6月64例于郑州人民医院行手术切除膀胱癌患者的组织标本和临床资料,采用RT-qPCR检测膀胱癌组织及膀胱癌细胞中的miR-182-5p和FOXO... 目的:探究miR-182-5p及FOXO3在膀胱癌中的表达意义及其参与膀胱癌可能的机制。方法:收集2017年6月至2019年6月64例于郑州人民医院行手术切除膀胱癌患者的组织标本和临床资料,采用RT-qPCR检测膀胱癌组织及膀胱癌细胞中的miR-182-5p和FOXO3表达,按照其表达水平分为miR-182-5p高表达组和miR-182-5p低表达组、FOXO3高表达组和FOXO3低表达组,采用Western blot实验检测FOXO3蛋白的表达。采用Kaplan-Meier生存曲线分析miR-182-5p和FOXO3与膀胱癌患者预后的相关性。采用双荧光素酶报告实验分析miR-182-5p与FOXO3的靶向关系,并采用实时荧光定量PCR(RT-q PCR)和Western blot检测转染miR-182-5p抑制剂对FOXO3表达的影响;分别采用CCK-8、Transwell实验和流式细胞术检测转染miR-182-5p抑制剂对T24细胞增殖、侵袭和凋亡的影响。结果:miR-182-5p在膀胱癌组织中的表达量为2.27±0.66,显著高于癌旁组织的1.04±0.36,两者比较差异具有统计学意义(P<0.001),与肿瘤大小、TNM分期、淋巴结转移有关(P<0.05);FOXO3在膀胱癌组织中低表达,与肿瘤大小、分化程度、TNM分期及淋巴结转移有关(P<0.05);miR-182-5p高表达组、FOXO3低表达组的患者的生存率显著低于miR-182-5p低表达组、FOXO3高表达组(P=0.038,P=0.004)。T24细胞中miR-182-5p高表达(P<0.05)。抑制miR-182-5p上调FOXO3表达,抑制miR-182-5p表达能抑制T24细胞的增殖和侵袭,促进细胞凋亡(P<0.05)。结论:miR-182-5p在膀胱癌组织中高表达,而FOXO3低表达。miR-182-5p促进膀胱癌细胞的增殖和侵袭,抑制其凋亡,可能与负调控FOXO3有关。 展开更多
关键词 膀胱癌 miR-182-5p FOXO3 增殖 侵袭
暂未订购
Roles of serum uric acid on the association between arsenic exposure and incident metabolic syndrome in an older Chinese population
3
作者 Haiyan Jiang Simei Zhang +8 位作者 Yaoyao Lin Lin Meng Jiayi Li Wenqing Wang Kaixuan Yang Mingjuan Jin Jianbing Wang Mengling Tang kun chen 《Journal of Environmental Sciences》 2025年第1期332-341,共10页
Growing evidences showed that heavy metals exposure may be associated with metabolic diseases.Nevertheless,themechanism underlying arsenic(As)exposure and metabolic syndrome(MetS)risk has not been fully elucidated.So ... Growing evidences showed that heavy metals exposure may be associated with metabolic diseases.Nevertheless,themechanism underlying arsenic(As)exposure and metabolic syndrome(MetS)risk has not been fully elucidated.So we aimed to prospectively investigate the role of serum uric acid(SUA)on the association between blood As exposure and incident MetS.A sample of 1045 older participants in a community in China was analyzed.We determined As at baseline and SUA concentration at follow-up in the Yiwu Elderly Cohort.MetS events were defined according to the criteria of the International Diabetes Federation(IDF).Generalized linear model with log-binominal regression model was applied to estimate the association of As with incident MetS.To investigate the role of SUA in the association between As andMetS,amediation analysiswas conducted.In the fully adjusted log-binominal model,per interquartile range increment of As,the risk of MetS increased 1.25-fold.Compared with the lowest quartile of As,the adjusted relative risk(RR)of MetS in the highest quartile was 1.42(95%confidence interval,CI:1.03,2.00).Additionally,blood As was positively associated with SUA,while SUA had significant association with MetS risk.Further mediation analysis demonstrated that the association of As and MetS risk was mediated by SUA,with the proportion of 15.7%.Our study found higher As was remarkably associated with the elevated risk of MetS in the Chinese older adults population.Mediation analysis indicated that SUA might be a mediator in the association between As exposure and MetS. 展开更多
关键词 Arsenic(As)exposure Metabolic syndrome(MetS) Serum uric acid(SUA) Cohort study Mediation effect Older adults
原文传递
Regulatory Effects of Radix Salviae Miltiorrhizae Water Extract and Semen Ziziphi Spinosae Compound onβ-secretase Activity in Mice Exposed to Aluminum Maltolate
4
作者 Jiaguo LIANG Min WEI +7 位作者 Yuxue HUANG Yu GU Jinmiao WU kun chen Yongqiu QIU Yuncong LU Junchen WEI Shuqiu ZHANG 《Medicinal Plant》 2025年第4期39-42,共4页
[Objectives]To explore the effects of Radix Salviae Miltiorrhizae water extract and Semen Ziziphi Spinosae compound on theβ-secretase activity in mice exposed to aluminum maltolate.[Methods]A total of 60 healthy,clea... [Objectives]To explore the effects of Radix Salviae Miltiorrhizae water extract and Semen Ziziphi Spinosae compound on theβ-secretase activity in mice exposed to aluminum maltolate.[Methods]A total of 60 healthy,clean-grade SPF mice were randomly assigned to four groups based on their body weight,with each group consisting of 15 mice.The groups included a control group,a model group,treatment group 1,and treatment group 2.The control group received an equivalent dose of normal saline,while the model group and treatment groups 1 and 2 were intraperitoneally injected with 0.3 mg/kg of aluminum maltolate solution for 60 d.Additionally,treatment groups 1 and 2 were injected with 0.3 mg/kg of Radix Salviae Miltiorrhizae water extract and 0.3 mg/kg of Semen Ziziphi Spinosae compound,respectively,starting from the 31 st day for a total of 30 d.The cognitive functions of mice,specifically their learning and memory capabilities,were assessed using the Y-shaped water maze test at three distinct time points:prior to,during,and following the experimental procedure.Serum samples were collected for the analysis of various biochemical markers,including hemoglobin(Hb),total cholesterol(TC),triglycerides(TG),total protein(TP),alanine aminotransferase(ALT),and blood urea nitrogen(BUN).Additionally,brain tissues were harvested to evaluate the levels of glutathione peroxidase(GSH-PX)and acetylcholinesterase(AChE)in both serum and brain samples.The expression levels ofα-secretase,β-secretase,andγ-secretase in mouse serum were quantified using enzyme-linked immunosorbent assay(ELISA).[Results]According to the final results of the Y-shaped water maze test,the administration of therapeutic drugs to mice resulted in a gradual reduction in both the swimming time and the distance traveled to reach the platform in treatment groups 1 and 2.Additionally,the number of errors made by these treatment groups was significantly greater than that observed in the control group,with statistically significant differences(P<0.01).Among the three groups subjected to subchronic aluminum exposure,statistically significant differences were observed in the levels of Hb,TC,TG,TP,ALT,BUN,brain GSH-PX,and brain AChE(P<0.05).Furthermore,with the increasing duration of therapeutic drug administration,the levels ofβ-secretase in the brains of mice in both the treatment groups and the model group exhibited a significant decrease,while the levels ofα-secretase showed a significant increase.Additionally,the differences were statistically significant when compared to the control group(P<0.05).[Conclusions]Radix Salviae Miltiorrhizae water extract and Semen Ziziphi Spinosae compound will decrease the expression level ofβ-secretase activity in mice exposed to aluminum maltolate. 展开更多
关键词 Radix Salviae Miltiorrhizae water extract Semen Ziziphi Spinosae compound ALUMINUM Β-SECRETASE MICE Learning and memory capability
暂未订购
Ursodeoxycholic acid inhibits the uptake of cystine through SLC7A11 and impairs de novo synthesis of glutathione
5
作者 Fu'an Xie Yujia Niu +19 位作者 Xiaobing chen Xu Kong Guangting Yan Aobo Zhuang Xi Li Lanlan Lian Dongmei Qin Quan Zhang Ruyi Zhang kunrong Yang Xiaogang Xia kun chen Mengmeng Xiao Chunkang Yang Ting Wu Ye Shen Chundong Yu chenghua Luo Shu-Hai Lin Wengang Li 《Journal of Pharmaceutical Analysis》 2025年第1期189-207,共19页
Ursodeoxycholic acid(UDCA)is a naturally occurring,low-toxicity,and hydrophilic bile acid(BA)in the human body that is converted by intestinal flora using primary BA.Solute carrier family 7 member 11(SLC7A11)functions... Ursodeoxycholic acid(UDCA)is a naturally occurring,low-toxicity,and hydrophilic bile acid(BA)in the human body that is converted by intestinal flora using primary BA.Solute carrier family 7 member 11(SLC7A11)functions to uptake extracellular cystine in exchange for glutamate,and is highly expressed in a variety of human cancers.Retroperitoneal liposarcoma(RLPS)refers to liposarcoma originating from the retroperitoneal area.Lipidomics analysis revealed that UDCA was one of the most significantly downregulated metabolites in sera of RLPS patients compared with healthy subjects.The augmentation of UDCA concentration(≥25 mg/mL)demonstrated a suppressive effect on the proliferation of liposarcoma cells.[15N2]-cystine and[13C5]-glutamine isotope tracing revealed that UDCA impairs cystine uptake and glutathione(GSH)synthesis.Mechanistically,UDCA binds to the cystine transporter SLC7A11 to inhibit cystine uptake and impair GSH de novo synthesis,leading to reactive oxygen species(ROS)accumulation and mitochondrial oxidative damage.Furthermore,UDCA can promote the anti-cancer effects of ferroptosis inducers(Erastin,RSL3),the murine double minute 2(MDM2)inhibitors(Nutlin 3a,RG7112),cyclin dependent kinase 4(CDK4)inhibitor(Abemaciclib),and glutaminase inhibitor(CB839).Together,UDCA functions as a cystine exchange factor that binds to SLC7A11 for antitumor activity,and SLC7A11 is not only a new transporter for BA but also a clinically applicable target for UDCA.More importantly,in combination with other antitumor chemotherapy or physiotherapy treatments,UDCA may provide effective and promising treatment strategies for RLPS or other types of tumors in a ROS-dependent manner. 展开更多
关键词 UDCA SLC7A11 CYSTINE GSH Oxidative stress RLPS
暂未订购
In situ synthesis of MnO_(2)micro/nano-adjuvants for enhanced immunotherapy of breast tumors
6
作者 kun chen Huimin Lin +9 位作者 Xin Peng Ziying Wu Jingyue Dai Yi Sun Yaxuan Feng Ziyi Huang Zhiqiang Yu Meng Yu Guangyu Yao Jigang Wang 《Chinese Chemical Letters》 2025年第5期379-386,共8页
This study presents an approach to enhanced cancer immunotherapy through the in situ synthesis of potassium permanganate(KMnO_(4))derived manganese dioxide(MnO_(2))micro/nano-adjuvants.Addressing the limitations of tr... This study presents an approach to enhanced cancer immunotherapy through the in situ synthesis of potassium permanganate(KMnO_(4))derived manganese dioxide(MnO_(2))micro/nano-adjuvants.Addressing the limitations of traditional immunotherapy due to patient variability and the complexity of the tumor microenvironment,our research establishes KMnO_(4)as a potent immunomodulator that enhances the efficacy of anti-programmed death-ligand 1(αPD-L1)antibodies.The in situ synthesized MnO_(2)adjuvants in the tumor exhibit direct interactions with biological systems,leading to the reduction of MnO_(2)to Mn^(2+)within the tumor,and thereby improving the microenvironment for immune cell activity.Our in vitro and in vivo models demonstrate KMnO_(4)’s capability to induce concentration-dependent cytotoxicity in tumor cells,triggering DNA damage and apoptosis.It also potentiates immunogenic cell death by upregulating calreticulin and high mobility group box 1(HMGB1)on the cell surface.The combination of KMnO_(4)withαPD-L1 antibodies substantially inhibits tumor growth,promotes dendritic cell maturation,and enhances CD8^(+)T cell infiltration,resulting in a significant phenotypic shift in tumor-associated macrophages towards a pro-inflammatory M1 profile.Our findings advocate for further research into the long-term efficacy of KMnO_(4)and its application in diverse tumor models,emphasizing its potential to redefine immune checkpoint blockade therapy and offering a new vista in the fight against cancer. 展开更多
关键词 Cancer immunotherapy Potassium permanganate Manganese dioxide Nanoadjuvants In situ synthesis
原文传递
Elimination of Buried Interface Defects for Highly Efficient and Stable Wide-Bandgap Perovskite Solar Cells
7
作者 kun chen Yu chen +4 位作者 Yang Shen Weijian Tang Xiaojia Zheng WenHua Zhang Shangfeng Yang 《Chinese Journal of Chemical Physics》 2025年第2期231-239,I0020-I0034,I0040,I0041,共26页
As one of the important components of high-effi-ciency perovskite/silicon series devices,wide-bandgap(WBG)perovskite solar cells(PSCs)have been suffering from serious carrier transport barriers and huge open-circuit v... As one of the important components of high-effi-ciency perovskite/silicon series devices,wide-bandgap(WBG)perovskite solar cells(PSCs)have been suffering from serious carrier transport barriers and huge open-circuit voltage deficit de-rived from non-radiative recombination,especial-ly at the buried interface that are often overlooked.Herein,we combined cationic and anion passiva-tion strategies via ammonium tetra-n-butyl tetrafluoroborate(TBABF_(4))pre-treating the buried interface.Theoretical calculation predicts that the tetrabutylammonium(TBA^(+))organic cations and(tetrafluoroborate)BF_(4)^(−)anions can easily interact with charged interfacial defect.Characterizations further confirm the enhance-ment of carrier transport performance and decrease in defect density upon TBABF4 pre-treat-ment.Consequently,a power conversion efficiency of 21.35%with an ultrahigh filling factor of 84.12%is obtained for 1.68 eV-WBG inverted PSCs.In addition,the device with TBABF4 pre-treatment demonstrates excellent shelf,thermal,and operational stability. 展开更多
关键词 Wide-bandgap Buried interface Carrier transport Stablility Defect passiva-tion
在线阅读 下载PDF
The miR-6779/XIAP axis alleviates IL-1β-induced chondrocyte senescence and extracellular matrix loss in osteoarthritis
8
作者 Zongchao Li Aonan Dai +8 位作者 Xiaoxiang Fang Kexing Tang kun chen Peng Gao Jingyue Su Xin chen Shengwu Yang Zhenhan Deng Liangjun Li 《Animal Models and Experimental Medicine》 2025年第4期662-673,共12页
Background:Osteoarthritis(OA)is a long-term degenerative joint disease worsen-ing over time.Aging and chondrocyte senescence contribute to OA progression.MicroRNAs have been confirmed to regulate different cellular pr... Background:Osteoarthritis(OA)is a long-term degenerative joint disease worsen-ing over time.Aging and chondrocyte senescence contribute to OA progression.MicroRNAs have been confirmed to regulate different cellular processes.They con-tribute to OA pathology and may help to identify novel biomarkers and therapies for OA.Methods:This study used bioinformatics and experimental investigations to analyze and validate differentially expressed miRNAs in OA that might affect chondrocyte apoptosis and senescence.Results:miR-6779 was found to be significantly down-regulated in OA.Seventy-six of the predicted and miR-6779 targeted genes and the OA-associated disease genes overlapped,and these were enriched in cell proliferation,cell apoptosis,and cell cycle.miR-6779 overexpression remarkably attenuated IL-1βeffects on chon-drocytes by reducing MMP3 and MMP13 levels,promoting cell apoptosis,suppress-ing cell senescence,and increasing caspase-3,caspase-9 and reducing P16 and P21 levels.miR-6779 targeted inhibition of X-linked inhibitor of apoptosis protein(XIAP)expression.XIAP knockdown partially improved IL-1β-induced chondrocyte senes-cence and dysfunction.Lastly,when co-transfected with a miR-6779 agomir,the XIAP overexpression vector partially attenuated the effects of miR-6779 overexpression on chondrocytes;miR-6779 improved IL-1β-induced senescence and dysfunction in chondrocytes through targeting XIAP.Conclusion:miR-6779 is down-regulated,and XIAP is up-regulated in OA cartilage and IL-1β-treated chondrocytes.miR-6779 inhibits XIAP expression,thereby promot-ing senescent chondrocyte cell apoptosis and reducing chondrocyte senescence and ECM loss through XIAP. 展开更多
关键词 CHONDROCYTE miR-6779 OSTEOARTHRITIS SENESCENCE X-linked inhibitor of apoptosis protein
暂未订购
Low-Carbon Economic Dispatch of Electric-Thermal-Hydrogen Integrated Energy System Based on Carbon Emission Flow Tracking and Step-Wise Carbon Price
9
作者 Yukun Yang Jun He +2 位作者 Wenfeng chen Zhi Li kun chen 《Energy Engineering》 2025年第11期4653-4678,共26页
To address the issues of unclear carbon responsibility attribution,insufficient renewable energy absorption,and simplistic carbon trading mechanisms in integrated energy systems,this paper proposes an electricheat-hyd... To address the issues of unclear carbon responsibility attribution,insufficient renewable energy absorption,and simplistic carbon trading mechanisms in integrated energy systems,this paper proposes an electricheat-hydrogen integrated energy system(EHH-IES)optimal scheduling model considering carbon emission stream(CES)and wind-solar accommodation.First,the CES theory is introduced to quantify the carbon emission intensity of each energy conversion device and transmission branch by defining carbon emission rate,branch carbon intensity,and node carbon potential,realizing accurate tracking of carbon flow in the process of multi-energy coupling.Second,a stepped carbon pricing mechanism is established to dynamically adjust carbon trading costs based on the deviation between actual carbon emissions and initial quotas,strengthening the emission reduction incentive.Finally,a lowcarbon economic dispatch model is constructed with the objectives of minimizing operation cost,carbon trading cost,wind-solar curtailment penalty cost,and energy loss.Simulation results show that compared with the traditional economic dispatch scheme 3,the proposed schemel reduces carbon emissions by 53.97%and wind-solar curtailment by 68.89%with a 16.10%increase in total cost.This verifies that the model can effectively improve clean energy utilization and reduce carbon emissions,achieving low-carbon economic operation of EHH-IES,with CES theory ensuring precise carbon flow tracking across multi-energy links. 展开更多
关键词 Carbon emission streams integrated energy systems stepped carbon price low carbon economic dispatch wind-solar accommodation
在线阅读 下载PDF
Topology transformation of the zeolite catalysts to enhance electronic metal-support interactions and hydrogen spillover effects for hydrogenation of aromatic-rich oil to high-density aviation fuels
10
作者 Xiaoqi Zhang Kai Meng +10 位作者 He Liu Bernard Wiafe Biney Yiqiang Qi kunyu Xu Jiang Wu Liying Xie Xiaoyu Li Yueliang Liu kun chen Zongxian Wang Aijun Guo 《Journal of Energy Chemistry》 2025年第7期1026-1037,共12页
Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst an... Metal-support interactions and hydrogen spillover effects in heterogeneous catalysts play a crucial role in aromatic hydrogenation reactions;however,these effects are limited by the metal dispersion on the catalyst and the number of acceptable H*receptors.This study prepares highly dispersed Ni nanoparticles(NPs)catalysts on a Beta substrate via precursor structure topology transformation.In contrast to traditional support materials,the coordination and electronic structure changes between the Ni NPs and the support were achieved,further optimizing the active interface sites and enhancing hydrogen activation and hydrogenation performance.Additionally,the-OH groups at the strong acid sites in zeolite effectively intensified the hydrogen spillover effect as receptors for H^(*)migration and anchoring,accelerating the hydrogenation rate of aromatic rings.Under solvent-free conditions,this catalyst was used for the hydrogenation reaction of aromatic-rich oils,directly producing a C_(8)-C_(14)branched cycloalkanes mixture with an aromatic conversion rate of>99%.The cycloalkanes mixture produced by this method features high density(0.92 g/mL)and a low freezing point(<-60℃),making it suitable for use as high-density aviation fuel or as an additive to enhance the volumetric heat value of conventional aviation fuels in practical applications. 展开更多
关键词 Metal-support interaction Hydrogen spillover ZEOLITE Aromatic-richoil High-density aviation fuels
在线阅读 下载PDF
Research Progress and Prospect of Biofeedback Technology Combined with Occupational Therapy in Hand Function Rehabilitation after Stroke
11
作者 Guokai Gu Guodi Wen +4 位作者 Yuhao Li Ya Kong kun chen Debin Li Xiao chen 《Journal of Clinical and Nursing Research》 2025年第12期146-151,共6页
Hand function impairment after stroke has become a key and difficult issue in clinical rehabilitation due to complex neural innervation and a long recovery cycle.Biofeedback technology combined with occupational thera... Hand function impairment after stroke has become a key and difficult issue in clinical rehabilitation due to complex neural innervation and a long recovery cycle.Biofeedback technology combined with occupational therapy can make up for the limitations of single therapy and provide a new solution for hand function rehabilitation after stroke.This paper systematically sorts out the theoretical basis and clinical research progress of biofeedback technology combined with occupational therapy in hand function rehabilitation after stroke,and looks forward to the future development direction,aiming to provide reference for clinical rehabilitation practice and scientific research. 展开更多
关键词 STROKE Hand function rehabilitation Biofeedback technology Occupational therapy NEUROPLASTICITY
暂未订购
Effect of cooling rate on dendritic segregation and solidification structure of a Ni–Cr–Co–Mo based alloy
12
作者 kun chen Xi-kou He +2 位作者 Zheng-dong Liu Yue Zheng Jing Ma 《Journal of Iron and Steel Research International》 2025年第10期3555-3572,共18页
The cooling rate of the center and edge of vacuum induction melting(VIM)or vacuum arc remelting(VAR)ingots exhibit substantial difference,leading to markedly distinct dendritic structures and precipitates.The current ... The cooling rate of the center and edge of vacuum induction melting(VIM)or vacuum arc remelting(VAR)ingots exhibit substantial difference,leading to markedly distinct dendritic structures and precipitates.The current lack of precise predictions for dendritic segregation and the distribution of precipitates in ingot makes it difficult to determine the annealing and homogenization heat treatment process.Thus,clarifying the impact of cooling rate on the solidification behavior of alloy is significantly important.The dendritic structure and precipitation characteristics of as-cast C-HRA-3 Ni–Cr–Co–Mo-based heat-resistant alloy were investigated using Thermo-Calc thermodynamic calculations,scanning electron microscopy observations,and electron probe microanalyzer.Based on high temperature observation system,the effects of cooling rate on the dendritic structure,dendritic segregation,and precipitation in this alloy were explored.The results showed that the precipitates in the as-cast C-HRA-3 alloy primarily consist of blocky Ti(C,N)phases,large-sized Ti(C,N)–M_(6)C–M_(23)C_(6) symbiotic phases and M_(6)C–M_(23)C_(6) carbides,and small-sized dispersed M_(6)C and M_(23)C_(6) carbides surronding these symbiotic phases.The primary constituent elements of these precipitates are Mo,Cr,C,and Ti,which predominantly concentrate in the interdendritic regions of the as-cast alloy.There is a clear power-law relationship between the secondary dendrite arm spacing and the cooling rate.The dendritic segregation ratio of Mo,Cr,and Ti exhibits a piecewise functional relationship with the cooling rate,under equiaxed dendritic solidification condition.These predictive models and theoretical analyses were validated using numerical simulations and experimental results from the 200 kg grade VIM electrode. 展开更多
关键词 Ni-Cr-Co-Mo based heat resistant alloy Cooling rate SOLIDIFICATION Diffusion Prediction model
原文传递
Atomic vacancy engineering of Co(OH)F nanoarray toward high-performance ammonia electrosynthesis with waste plastics upgrading
13
作者 Mingdan Wang Qianyu Zhang +4 位作者 kun chen Cong Lin Huigang Wang Yanying Zhao Pengzuo chen 《Journal of Energy Chemistry》 2025年第10期558-565,共8页
Developing energy-efficient nitrite-to-ammonia(NO_(2)RR)conversion technologies while simultaneously enabling the electrochemical upcycling of waste polyethylene terephthalate(PET)plastics into highvalue-added chemica... Developing energy-efficient nitrite-to-ammonia(NO_(2)RR)conversion technologies while simultaneously enabling the electrochemical upcycling of waste polyethylene terephthalate(PET)plastics into highvalue-added chemicals is of great significance.Herein,an atomic oxygen vacancy(V_(o))engineering is developed to optimize the catalytic performance of V_(o2)-Co(OH)F nanoarray towards the NO_(2)RR and PET-derived ethylene glycol oxidation reaction(EGOR).The optimal V_(o2)-Co(OH)F achieves an ultralow operating potential of -0.03 V vs.RHE at -100 mA cm^(-2)and a remarkable NH_(3)Faradaic efficiency(FE)of 98.4% at -0.2 V vs.RHE for NO_(2)RR,and a high formate FE of 98.03% for EGOR.Operando spectroscopic analysis and theoretical calculations revealed that oxygen vacancies play a crucial role in optimizing the electronic structure of V_(o2)-Co(OH)F,modulating the adsorption free energies of key reaction intermediates,and lowering the reaction energy barrier,thereby enhancing its overall catalytic performance.Remarkably,the V_(o2)-Co(OH)F-based NO_(2)RR||EGOR electrolyzer realized high NH_(3)and formate yield rates of 33.9 and 44.9 mg h^(-1)cm^(-2)at 1.7 V,respectively,while demonstrating outstanding long-term stability over 100 h.This work provides valuable insights into the rational design of advanced electrocatalysts for co-electrolysis systems. 展开更多
关键词 Atomic vacancy Co(OH)F Nanoarray Ammonia electrosynthesis Waste plastics upgrading Co-electrolysis system
在线阅读 下载PDF
Enhancing microseismic event detection with TransUNet:A deep learning approach for simultaneous pickings of P-wave and S-wave first arrivals
14
作者 kun chen Meng Li +5 位作者 Xiaolian Li Guangzhi Cui Jia Tian JiaLe Li RuoYao Mu JunJie Zhu 《Artificial Intelligence in Geosciences》 2025年第1期282-298,共17页
Microseismic monitoring is essential for understanding subsurface dynamics and optimizing oil and gas pro-duction.However,traditional methods for the automatic detection of microseismic events rely heavily on characte... Microseismic monitoring is essential for understanding subsurface dynamics and optimizing oil and gas pro-duction.However,traditional methods for the automatic detection of microseismic events rely heavily on characteristic functions and human intervention,often resulting in suboptimal performance when dealing with complex and noisy data.In this study,we propose a novel approach that leverages deep learning frame to extract multiscale features from microseismic data using a TransUNet neural network.Our model integrates the ad-vantages of Transformer and UNet architectures to achieve high accuracy in multivariate image segmentation and precise picking of P-wave and S-wave first arrivals simultaneously.We validate our approach using both synthetic and field microseismic datasets recorded from gas storage monitoring and roof fracturing in a coal seam.The robustness of the proposed method has been verified in the testing of synthetic data with various levels of Gaussian and real background noises extracted from field data.The comparisons of the proposed method with UNet and SwinUNet in terms of the model architecture and classification performance demonstrate the Tran-sUNet achieves the optimal balance in its architecture and inference speed.With relatively low inference time and network complexity,it operates effectively in high-precision microseismic phase pickings.This advancement holds significant promise for enhancing microseismic monitoring technology in hydraulic fracturing and reser-voir monitoring applications. 展开更多
关键词 Deep learning Microseismic event detection TransUNet Image segmentation Attention mechanism
暂未订购
Remission of iron overload in adipose tissue of obese mice by fatty acid-modified polyoxovanadates
15
作者 kun chen Yu-Rong Qin +1 位作者 Sheng-Qiu Liu Rou-Ling chen 《Rare Metals》 2025年第1期461-471,共11页
Iron overload has been evidenced to contribute to obesity-associated metabolic disorders,including insulin resistance.Strategies to reduce iron levels might help manage the metabolic complications associated with obes... Iron overload has been evidenced to contribute to obesity-associated metabolic disorders,including insulin resistance.Strategies to reduce iron levels might help manage the metabolic complications associated with obesity.Here,it is demonstrated that the specific accumulation of oleic acid-modified polyoxovanadates(OPOVs)in adipose tissue leads to the reduction of iron concentrations in adipocytes in mice fed with a high-fat diet(HFD).Conjugation of oleic acids to polyoxovanadates enables tissue-specific depletion of iron from white adipose tissue(WAT)by OPOVs,protecting mice from HFD-induced obesity and obesity-associated metabolic deteriorations.Glucose tolerance and insulin sensitivity are improved in OPOV-treated mice,which demonstrates that the OPOV-induced iron depletion can reverse the metabolic degeneration caused by HFD-induced obesity.Furthermore,a decrease in expression of the marker genes of iron overload suggests the participation of OPOVs in maintaining iron homeostasis and a potential medical application of vanadium clusters in targeting the iron overload caused by obesity.These findings underscore the potential of vanadate-based clusters tailored to address the complex interplay between iron metabolism and metabolic health. 展开更多
关键词 POLYOXOVANADATES Lipophilic conjugation Obesity Iron overload Insulin resistance
原文传递
Heavy Si isotope compositions of subduction zone fluids controlled by fluid-rock interaction and fluid evolution
16
作者 kun chen Yi-Xiang chen +3 位作者 Hui-Min Yu Hans-Peter Schertl Tatsuki Tsujimori Sergei Skuzovatov 《Geoscience Frontiers》 2025年第4期215-224,共10页
Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility ... Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids.The Rio San Juan Complex(RSJC)in the northern Dominican Republic hosts both P-and R-type jadeitites and jadeite-rich rocks,which provide ideal samples for addressing such issues.Here,we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks.Most samples show similar REE patterns,trace element distributions and δ^(18)O values to those of plagiogranite protoliths,indicating the predominance of R-type origin in RSJC.The P-type samples exhibit slightly higherδ^(30)Si values(−0.15‰to 0.25‰)than that of R-type samples(−0.20‰to 0.08‰),which place above the igneous array.The low(^(87)Sr/^(86)Sr)_(i)(0.70346 to 0.70505)and highεNd(t)values(4.6 to 6.8)of the P-type jadeitites and quartzites,along with relatively lowδ^(18)O values(4.7‰to 6.4‰)of their forming fluids,indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment.However,the estimated jadeitite-and quartzite-forming fluids exhibit distinctδ^(30)Si values(0.76‰to 0.99‰and-0.48‰to-0.08‰,respectively),implying an evolution of the fluids that modified the Si isotopic compositions.Since fluid metasomatism and related desilication process could have lowered the whole-rock δ^(30)Si values,the heavy Si isotope compositions of the R-type samples are produced from the external fluids.Combing Rayleigh distillation and binary mixing simulations,we propose that fluids derived from altered oceanic crust obtained high δ^(30)Si values after crystallization of minerals enriched in light Si isotopes.The P-type jadeitites are formed through direct precipitation from this fluid.As the plagiogranite protoliths were continuously replaced by this fluid,the formed R-type samples(jadeitites and quartzites)also exhibit high δ^(30)Si values.Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins. 展开更多
关键词 Subduction zone fluid Si isotopes JADEITITE Fluid-rock interaction
在线阅读 下载PDF
Exploring Lifshitz transition and superconductivity in 3R-NbS_(2) under pressure
17
作者 kun chen Xindeng Lv +2 位作者 Simin Li Yanping Huang Tian Cui 《Chinese Physics B》 2025年第3期161-166,共6页
The interplay between electronic topological phase transitions and superconductivity in the field of condensed matter physics has consistently captivated researchers.Here we have succeeded in modulating the Lifshitz t... The interplay between electronic topological phase transitions and superconductivity in the field of condensed matter physics has consistently captivated researchers.Here we have succeeded in modulating the Lifshitz transition by pressure and realized superconductivity.At 25.7 GPa,superconductivity with a transition temperature of 1.9 K has been observed in 3R-NbS_(2).The Hall coefficient changes from negative to positive at 14 GPa,indicating a Lifshitz transition in 3R-NbS_(2),and the carrier concentration continues to increase with increasing pressure.X-ray diffraction results indicate that the appearance of superconductivity cannot be attributable to structural transitions.Based on theoretical calculations,the emergence of a new band is attributed to the Lifshitz transition and the new band coincides with the Fermi surface at the pressure of 30 GPa.These findings provide new insights into the relationship between the Lifshitz transition and superconductivity. 展开更多
关键词 high pressure SUPERCONDUCTIVITY Lifshitz transition 3R-NbS_(2)
原文传递
High-quality and High-yield Cultivation Techniques for Summer Soybean
18
作者 Huajun SUN kun chen Ruhong FU 《Agricultural Biotechnology》 2025年第3期29-32,共4页
Soybeans are rich in protein,fats,vitamins,and minerals,serving as an important source of plant-based protein for humans.Summer soybean is widely cultivated in China,and improving its yield and quality is of great sig... Soybeans are rich in protein,fats,vitamins,and minerals,serving as an important source of plant-based protein for humans.Summer soybean is widely cultivated in China,and improving its yield and quality is of great significance for ensuring food security and promoting agricultural economic development.This paper elaborated on the high-quality and high-yield cultivation techniques for summer soybean,including variety selection,seed treatment,field selection and land preparation,sowing techniques,field management,pest and disease control,and harvesting,aiming to provide scientific cultivation guidance for summer soybean growers to achieve both superior quality and high yield. 展开更多
关键词 Summer soybean High quality High yield Cultivation technique
在线阅读 下载PDF
六针缝合法在腹腔镜下插入式输尿管膀胱再植术中的应用 被引量:2
19
作者 张楠 陈昆 +6 位作者 郭亮 马曜辉 葛雷 郝朝辉 韩前河 胡建庭 单中杰 《中国内镜杂志》 北大核心 2017年第3期94-98,共5页
目的探讨六针缝合法腹腔镜下插入式输尿管膀胱再植术的安全性及有效性。方法回顾性分析2012年3月-2015年9月16例腹腔镜下6(4+2)针缝合法插入式输尿管膀胱再植术的手术视频、临床资料。统计分析手术时间、术中出血量、术后引流量、引流... 目的探讨六针缝合法腹腔镜下插入式输尿管膀胱再植术的安全性及有效性。方法回顾性分析2012年3月-2015年9月16例腹腔镜下6(4+2)针缝合法插入式输尿管膀胱再植术的手术视频、临床资料。统计分析手术时间、术中出血量、术后引流量、引流管拔除时间、术后住院时间以及术后输尿管反流、狭窄等并发症发生率。结果 16例手术顺利完成,无中转开放病例。手术时间60~125 min,平均85 min。术中出血量20~50 ml,平均32 ml。术后引流量60~400 ml,平均106 ml。引流管拔除时间3~6 d,平均4.2 d。术后住院时间7~10 d,平均8.5 d。16例均获随访,随访时间6~18个月,平均12个月。无吻合口狭窄病例,1例有轻度反流,随访18个月未见加重。结论六针缝合法腹腔镜下插入式输尿管膀胱再植术安全、有效。手术时间明显缩短、没有增加吻合口狭窄及输尿管反流等并发症的发生率,有可能降低吻合口狭窄的发生率。 展开更多
关键词 输尿管膀胱再植 腹腔镜 输尿管膀胱连接部梗阻 泌尿外科
暂未订购
单核细胞趋化蛋白1在前列腺癌进展中的调节作用 被引量:3
20
作者 陈昆 韩前河 +2 位作者 张楠 单中杰 管庆军 《中国现代医学杂志》 CAS 2018年第27期22-28,共7页
目的探讨单核细胞趋化蛋白1(MCP-1)在前列腺癌进展中的作用。方法采用免疫组织化学(简称免疫组化)检测MCP-1和血管紧张素Ⅱ1型受体(AT1R)在前列腺癌细胞系LNCa P,C4-2和C4-2AT6中的表达。ELISA检测AngⅡ和CV11974(AT1R阻断剂)对前列腺... 目的探讨单核细胞趋化蛋白1(MCP-1)在前列腺癌进展中的作用。方法采用免疫组织化学(简称免疫组化)检测MCP-1和血管紧张素Ⅱ1型受体(AT1R)在前列腺癌细胞系LNCa P,C4-2和C4-2AT6中的表达。ELISA检测AngⅡ和CV11974(AT1R阻断剂)对前列腺癌细胞系中MCP-1生成的影响。在C4-2AT6细胞中,ELISA检测AngⅡ和LY294002(PI3K抑制剂)对MCP-1生成的影响,Western blot检测AngⅡ和CV11974对Akt蛋白磷酸化水平(p-Akt)的影响,免疫组化检测TCV116(AT1R阻断剂)对C4-2AT6细胞中MCP-1和F4/80+表达的影响。免疫组化检测前列腺癌患者组织中MCP-1和CD68的表达。结果 MCP-1和AT1R在前列腺癌细胞系LNCaP,C4-2和C4-2AT6中均表达,且在C4-2AT6中表达最高。在C4-2和C4-2AT6细胞中,AngⅡ能够增加MCP-1生成(P <0.05),而CV11974则能够逆转AngⅡ介导的MCP-1生成增加(P <0.05)。在C4-2AT6细胞中,LY294002逆转了AngⅡ介导的MCP-1生成增加(P <0.05),CV11974能够逆转AngⅡ介导的p-Akt增加。TCV116可降低C4-2AT6细胞中MCP-1和F4/80+的表达(P <0.05)。前列腺癌患者组织中MCP-1和CD68的表达与前列腺癌的恶性程度有关,格里森分数越高,MCP-1和CD68的表达越高。结论 MCP-1可通过AT1R-PI3K/Akt信号通路在前列腺癌恶性进展中发挥重要作用。 展开更多
关键词 单核细胞趋化蛋白1 血管紧张素Ⅱ1型受体 前列腺癌
暂未订购
上一页 1 2 8 下一页 到第
使用帮助 返回顶部