气体分离膜技术凭借其运行能耗低、无相变过程及环境友好特性,已成为传统分离工艺的替代方案。特别是在“碳中和”战略背景下,开发高效碳捕集技术对减缓气候变化具有关键意义。金属有机框架(MOFs)材料因其独特的结构可设计性与功能多样...气体分离膜技术凭借其运行能耗低、无相变过程及环境友好特性,已成为传统分离工艺的替代方案。特别是在“碳中和”战略背景下,开发高效碳捕集技术对减缓气候变化具有关键意义。金属有机框架(MOFs)材料因其独特的结构可设计性与功能多样性,为构建高性能混合基质膜(Mixed Matrix Membranes,MMMs)提供了全新思路,展现出突破“Trade-off”限制的潜力。系统分析了MOFs基MMMs中研究进展,通过将MOFs材料(具有可调孔结构、超高比表面积及多功能性)与聚合物基质的互补结合,突破聚合物膜的性能极限。首先阐释气体分离膜的基本原理及MOFs的理化特性,继而深入解析MOFs基MMMs的设计思路。重点探讨其性能、精准可调的孔径分布及CO_(2)选择性吸附机制。针对碳捕集应用,对比评述了ZIF(Zeolitic Imidazolate Framework)、UiO(University of Oslo)和MIL(Materials of Institute Lavoisier)3类MOFs的结构-性能关系。通过对比溶液浇铸、原位生长和界面聚合等制备工艺,揭示了MOFs-MMMs构建过程中的关键工艺路径。结合CO_(2)渗透率、选择性系数等核心指标,剖析了界面缺陷形成、纳米粒子团聚等关键挑战。汇总整理了抗老化膜设计、规模化生产成本评估等最新突破,同时指出当前MOFs在规模化应用中面临合成成本高、长期运行稳定性不足、有机-无机界面的相容性较差等问题。最后提出未来需材料科学、化学工程与环境技术等多学科协同创新,推动MOFs-MMMs技术的工业化进程,提供应对气候变化的先进气体分离解决方案。展开更多
目的:探讨当归多糖对糖尿病大鼠脂代谢及脂肪因子的影响。方法:将经链脲佐菌素(strep-tozotocin,STZ)诱导的2型糖尿病大鼠随机分为模型组、正常组、吡格列酮组及当归多糖低、中、高剂量组,每组10只。模型组、正常组给予生理盐水10 mL/k...目的:探讨当归多糖对糖尿病大鼠脂代谢及脂肪因子的影响。方法:将经链脲佐菌素(strep-tozotocin,STZ)诱导的2型糖尿病大鼠随机分为模型组、正常组、吡格列酮组及当归多糖低、中、高剂量组,每组10只。模型组、正常组给予生理盐水10 mL/kg灌胃,当归多糖各剂量组分别予400、200、100 mg/kg药物灌胃,吡格列酮组给予吡格列酮10 mg/kg灌胃。每日灌胃1次,灌胃4周后观察干预期间及干预后大鼠的一般情况及体质量变化情况,检测大鼠血脂[总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、低密度脂蛋白(low density lipoprotein,LDL)、高密度脂蛋白(high density lipoprotein,HDL)]、脂肪细胞因子[瘦素(leptin,LEP)、脂联素(adiponectin,ADPN)、抵抗素(RSTN)]以及脂肪细胞变化情况。结果:模型组大鼠毛色枯槁,活动量下降,二便增多。经当归多糖干预后各组大鼠与吡格列酮组活动量基本正常、毛色光泽,大小便较模型组好转,较正常组偶有增多。与正常组比较,模型组大鼠体质量增长速度较快;与模型组比较,各药物干预组大鼠体质量增长速度均较慢。药物干预各组均能降低血清TC、TG、LDL,LEP和RSTN含量,提高HDL及ADPN水平;其中当归多糖高剂量组、吡格列酮组与模型组比较差异显著(P<0.01)。当归多糖各剂量组随着给药剂量的增加,脂肪细胞大小均匀,排列逐渐致密整齐,细胞截面基本恢复正常,空泡及囊腔样病变明显减轻。结论:当归多糖能调节2型糖尿病大鼠脂代谢水平,增加血清脂肪因子ADPN含量,降低LEP、RSTN含量,且对脂肪组织有一定的修复和保护作用。展开更多
Optimizing the spatial pattern of carbon sequestration service is essential for advancing regional low-carbon development,accelerating the achievement of the"dual carbon"goals,and promoting the high-quality ...Optimizing the spatial pattern of carbon sequestration service is essential for advancing regional low-carbon development,accelerating the achievement of the"dual carbon"goals,and promoting the high-quality development of ecological environment.The carbon sequestration capacity within the mountain-desert-oasis system(MDOS),a unique landscape pattern,exhibits significant gradient characteristics,and its carbon sink potential can be substantially improved through multi-scale spatial optimization.This study employed the Integrated Valuation of Ecosystem Services and Tradeoff(InVEST)model to estimate carbon storage and sequestration(CSS)in the Gansu section of Heihe River Basin,China,a representative MDOS,based on land use/land cover(LULC)data from 1990 to 2020.The Patch-level Land Use Simulation(PLUS)model was coupled to simulate LULC and estimate carrying CSS under natural development(ND),ecological protection(EP),water constraint(WC),and economic development(ED)scenarios for 2035.Furthermore,the study constructed and optimized the CSS pattern on the basis of economic and ecological benefits,exploring the guiding significance of different scenarios for pattern optimization.The results showed that CSS spatial distribution is closely correlated with LULC pattern,and CSS is expected to improve in the future.CSS showed an overall increase across subsystems during 1990–2020,but varied across LULC types.CSS of construction land in all subsystems exhibited an increasing trend,while CSS of unused land showed a decreasing trend,with specific changes of 1.68×103 and 3.43×105 t,respectively.Regional CSS dynamics were mainly driven by conversions among unused land,cultivated land,and grassland.The CSS pattern of MDOS was divided into carbon sink functional region(CSFR),low carbon conservation region(LCCR),low carbon economic region(LCER),and economic development region(EDR).Water resources coordination served as the basis of pattern optimization,while the four dimensions—ecological carbon sink,low-carbon maintenance,agricultural carbon reduction and sink enhancement,and urban carbon emission reduction—framed the optimization framework.ND,EP,WC,and ED scenarios provided guidance as the basic reference,optimal benefit,"dual carbon"baseline,and upper development limit,respectively.Additionally,the detailed CSS sub-partitions of MDOS covered most potential scenarios of such ecosystems,demonstrating the applicability of these sub-partitions.These findings provide valuable references for enhancing CSS and hold important significance for low-carbon territorial spatial planning in the MDOS.展开更多
Physical layer security is an important method to improve the secrecy performance of wireless communication systems.In this paper,we analyze the effect of employing channel correlation to improve security performance ...Physical layer security is an important method to improve the secrecy performance of wireless communication systems.In this paper,we analyze the effect of employing channel correlation to improve security performance in multiple-input multipleoutput(MIMO)scenario with antenna selection(AS)scheme.We first derive the analytical expressions of average secrecy capacity(ASC)and secrecy outage probability(SOP)by the first order Marcum Q function.Then,the asymptotic expressions of ASC and SOP in two specific scenarios are further derived.The correctness of analytical and asymptotic expressions is verified by Monte Carlo simulations.The conclusions suggest that the analytical expressions of ASC and SOP are related to the product of transmitting and receiving antennas;increasing the number of antennas is beneficial to ASC and SOP.Besides,when the target rate is set at a low level,strong channel correlation is bad for ASC,but is beneficial to SOP.展开更多
文摘气体分离膜技术凭借其运行能耗低、无相变过程及环境友好特性,已成为传统分离工艺的替代方案。特别是在“碳中和”战略背景下,开发高效碳捕集技术对减缓气候变化具有关键意义。金属有机框架(MOFs)材料因其独特的结构可设计性与功能多样性,为构建高性能混合基质膜(Mixed Matrix Membranes,MMMs)提供了全新思路,展现出突破“Trade-off”限制的潜力。系统分析了MOFs基MMMs中研究进展,通过将MOFs材料(具有可调孔结构、超高比表面积及多功能性)与聚合物基质的互补结合,突破聚合物膜的性能极限。首先阐释气体分离膜的基本原理及MOFs的理化特性,继而深入解析MOFs基MMMs的设计思路。重点探讨其性能、精准可调的孔径分布及CO_(2)选择性吸附机制。针对碳捕集应用,对比评述了ZIF(Zeolitic Imidazolate Framework)、UiO(University of Oslo)和MIL(Materials of Institute Lavoisier)3类MOFs的结构-性能关系。通过对比溶液浇铸、原位生长和界面聚合等制备工艺,揭示了MOFs-MMMs构建过程中的关键工艺路径。结合CO_(2)渗透率、选择性系数等核心指标,剖析了界面缺陷形成、纳米粒子团聚等关键挑战。汇总整理了抗老化膜设计、规模化生产成本评估等最新突破,同时指出当前MOFs在规模化应用中面临合成成本高、长期运行稳定性不足、有机-无机界面的相容性较差等问题。最后提出未来需材料科学、化学工程与环境技术等多学科协同创新,推动MOFs-MMMs技术的工业化进程,提供应对气候变化的先进气体分离解决方案。
文摘目的:探讨当归多糖对糖尿病大鼠脂代谢及脂肪因子的影响。方法:将经链脲佐菌素(strep-tozotocin,STZ)诱导的2型糖尿病大鼠随机分为模型组、正常组、吡格列酮组及当归多糖低、中、高剂量组,每组10只。模型组、正常组给予生理盐水10 mL/kg灌胃,当归多糖各剂量组分别予400、200、100 mg/kg药物灌胃,吡格列酮组给予吡格列酮10 mg/kg灌胃。每日灌胃1次,灌胃4周后观察干预期间及干预后大鼠的一般情况及体质量变化情况,检测大鼠血脂[总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、低密度脂蛋白(low density lipoprotein,LDL)、高密度脂蛋白(high density lipoprotein,HDL)]、脂肪细胞因子[瘦素(leptin,LEP)、脂联素(adiponectin,ADPN)、抵抗素(RSTN)]以及脂肪细胞变化情况。结果:模型组大鼠毛色枯槁,活动量下降,二便增多。经当归多糖干预后各组大鼠与吡格列酮组活动量基本正常、毛色光泽,大小便较模型组好转,较正常组偶有增多。与正常组比较,模型组大鼠体质量增长速度较快;与模型组比较,各药物干预组大鼠体质量增长速度均较慢。药物干预各组均能降低血清TC、TG、LDL,LEP和RSTN含量,提高HDL及ADPN水平;其中当归多糖高剂量组、吡格列酮组与模型组比较差异显著(P<0.01)。当归多糖各剂量组随着给药剂量的增加,脂肪细胞大小均匀,排列逐渐致密整齐,细胞截面基本恢复正常,空泡及囊腔样病变明显减轻。结论:当归多糖能调节2型糖尿病大鼠脂代谢水平,增加血清脂肪因子ADPN含量,降低LEP、RSTN含量,且对脂肪组织有一定的修复和保护作用。
基金funded by the Gansu Provincial Department of Education's University Teacher Innovation Fund Project(2025A-001)the Gansu Provincial Philosophy and Social Science Planning Project(2024YB088).
文摘Optimizing the spatial pattern of carbon sequestration service is essential for advancing regional low-carbon development,accelerating the achievement of the"dual carbon"goals,and promoting the high-quality development of ecological environment.The carbon sequestration capacity within the mountain-desert-oasis system(MDOS),a unique landscape pattern,exhibits significant gradient characteristics,and its carbon sink potential can be substantially improved through multi-scale spatial optimization.This study employed the Integrated Valuation of Ecosystem Services and Tradeoff(InVEST)model to estimate carbon storage and sequestration(CSS)in the Gansu section of Heihe River Basin,China,a representative MDOS,based on land use/land cover(LULC)data from 1990 to 2020.The Patch-level Land Use Simulation(PLUS)model was coupled to simulate LULC and estimate carrying CSS under natural development(ND),ecological protection(EP),water constraint(WC),and economic development(ED)scenarios for 2035.Furthermore,the study constructed and optimized the CSS pattern on the basis of economic and ecological benefits,exploring the guiding significance of different scenarios for pattern optimization.The results showed that CSS spatial distribution is closely correlated with LULC pattern,and CSS is expected to improve in the future.CSS showed an overall increase across subsystems during 1990–2020,but varied across LULC types.CSS of construction land in all subsystems exhibited an increasing trend,while CSS of unused land showed a decreasing trend,with specific changes of 1.68×103 and 3.43×105 t,respectively.Regional CSS dynamics were mainly driven by conversions among unused land,cultivated land,and grassland.The CSS pattern of MDOS was divided into carbon sink functional region(CSFR),low carbon conservation region(LCCR),low carbon economic region(LCER),and economic development region(EDR).Water resources coordination served as the basis of pattern optimization,while the four dimensions—ecological carbon sink,low-carbon maintenance,agricultural carbon reduction and sink enhancement,and urban carbon emission reduction—framed the optimization framework.ND,EP,WC,and ED scenarios provided guidance as the basic reference,optimal benefit,"dual carbon"baseline,and upper development limit,respectively.Additionally,the detailed CSS sub-partitions of MDOS covered most potential scenarios of such ecosystems,demonstrating the applicability of these sub-partitions.These findings provide valuable references for enhancing CSS and hold important significance for low-carbon territorial spatial planning in the MDOS.
基金supported in part by the National Natural Science Foundation of China under Grants NO.61971161 and 62171151in part by the Foundation of Heilongjiang Touyan Team under Grant NO.HITTY-20190009+3 种基金and in part by the Fundamental Research Funds for the Central Universities under Grant NO.HIT.OCEF.2021012supported in part by the Natural Science Foundation of China under Grant NO.62171160in part by the Fundamental Research Funds for the Central Universities under Grant NO.HIT.OCEF.2022055in part by the Shenzhen Science and Technology Program under Grants NO.JCYJ20190806143212658 and ZDSYS20210623091808025.
文摘Physical layer security is an important method to improve the secrecy performance of wireless communication systems.In this paper,we analyze the effect of employing channel correlation to improve security performance in multiple-input multipleoutput(MIMO)scenario with antenna selection(AS)scheme.We first derive the analytical expressions of average secrecy capacity(ASC)and secrecy outage probability(SOP)by the first order Marcum Q function.Then,the asymptotic expressions of ASC and SOP in two specific scenarios are further derived.The correctness of analytical and asymptotic expressions is verified by Monte Carlo simulations.The conclusions suggest that the analytical expressions of ASC and SOP are related to the product of transmitting and receiving antennas;increasing the number of antennas is beneficial to ASC and SOP.Besides,when the target rate is set at a low level,strong channel correlation is bad for ASC,but is beneficial to SOP.
