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基于并行协同粒子群优化算法和PC集群的无功优化 被引量:13
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作者 李英 江全元 +2 位作者 l.jiang Q. H. WU 曹一家 《电力系统自动化》 EI CSCD 北大核心 2010年第19期42-47,80,共7页
针对大规模电力系统无功优化高维度、非线性、不连续的问题,提出一种并行协同粒子群优化算法。该算法基于消息传递接口技术,采用二级并行的方案求解无功优化问题。第1级并行是通过控制变量分组,将原优化问题分解成几个相互关联的子优化... 针对大规模电力系统无功优化高维度、非线性、不连续的问题,提出一种并行协同粒子群优化算法。该算法基于消息传递接口技术,采用二级并行的方案求解无功优化问题。第1级并行是通过控制变量分组,将原优化问题分解成几个相互关联的子优化问题,每一个子优化问题对应一个子粒子群,各子粒子群相互协同,共同求取最优解。第2级并行是指用粒子群优化算法求解子优化问题时使用多个进程并行求解,进程间采用对等模式分配计算任务,提高了优化效率。此外,为了增强粒子群优化算法的全局寻优能力,在优化过程中对其参数进行了动态调整。通过在PC集群上对IEEE118节点系统和IEEE300节点系统进行仿真计算,验证了该算法能取得较好的优化结果,具有较高的加速比和可扩展性,能满足大规模电力系统无功优化的需要。 展开更多
关键词 无功优化调度 并行计算 消息传递接口 协同进化 粒子群优化算法 PC集群
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High throughput synthesis enabled exploration of CoCrFeNi-based high entropy alloys 被引量:4
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作者 l.Zhao l.jiang +9 位作者 l.X.Yang H.Wang W.Y.Zhang G.Y.Ji X.Zhou W.A.Curtin X.B.Chen P.K.liaw S.Y.Chen H.Z.Wang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第15期269-282,共14页
To accelerate the exploration,screening,and discovery of structural high-entropy alloys with targeted properties,the newly developed High-Throughput Hot-Isostatic-Pressing based Micro-Synthesis Approach(HT-HIP-MSA)is ... To accelerate the exploration,screening,and discovery of structural high-entropy alloys with targeted properties,the newly developed High-Throughput Hot-Isostatic-Pressing based Micro-Synthesis Approach(HT-HIP-MSA)is employed to efficiently synthesize and characterize 85 combinatorial alloys in a 13-principal element alloying space.These Co Cr Fe Ni-based high entropy alloys span 1 quaternary,9 quinary,and 36 senary alloy systems,and their composition-structure-property relationships are characterized and analyzed experimentally and computationally.From the single-phase FCC CoCrFeNi alloy base,with Mn,Cu,Ti,Nb,Ta,Mo,W,Al,and Si as principal element alloying additions,we find(1)the extended Mn solubility in the single-phase FCC CoCrFeNi-Mn_(x) alloys,(2)the destabilizing behavior for most of the quinary and senary alloys,and(3)the distinctive solid-solution-strengthening effects in the alloys.In combining the computational methods,the HT-HIP-MSA can be systematic and economic to explore and refine the compositions,structures,and properties of structural high-entropy alloys. 展开更多
关键词 High-entropy alloys HIGH-THROUGHPUT Composition-structure-property
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Detonation initiation developing from the Richtmyer-Meshkov instability 被引量:4
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作者 H.H.Teng Z.l.jiang Z.M.Hu lHD.Institute of Mechanics,CAS.Beijing 100080,China 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第4期343-349,共7页
Detonation initiation resulting from the Richtmyer-Meshkov instability is investigated numerically in the configuration of the shock/spark-induced-deflagration interaction in a combustive gas mixture. Two-dimensional ... Detonation initiation resulting from the Richtmyer-Meshkov instability is investigated numerically in the configuration of the shock/spark-induced-deflagration interaction in a combustive gas mixture. Two-dimensional multi-species Navier-Stokes equations implemented with the detailed chemical reaction model are solved with the dispersion-controlled dissipative scheme. Numerical results show that the spark can create a blast wave and ignite deflagrations. Then, the deflagration waves are enhanced due to the Richtmyer-Meshkov instability, which provides detonation initiations with local environment conditions. By examining the deflagration fronts, two kinds of the initiation mechanisms are identified. One is referred to as the deflagration front acceleration with the help of the weak shock wave, occurring on the convex surfaces, and the other is the hot spot explosion deriving from the deflagration front focusing, occurring on the concave surfaces. 展开更多
关键词 Hot spot Deflagration front acceleration Detonation initiation Richtmyer-Meshkov instability
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FedTC:A Personalized Federated LearningMethod with Two Classifiers
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作者 Yang liu Jiabo Wang +4 位作者 Qinbo liu Mehdi Gheisari Wanyin Xu Zoe l.jiang Jiajia Zhang 《Computers, Materials & Continua》 SCIE EI 2023年第9期3013-3027,共15页
Centralized training of deep learning models poses privacy risks that hinder their deployment.Federated learning(FL)has emerged as a solution to address these risks,allowing multiple clients to train deep learning mod... Centralized training of deep learning models poses privacy risks that hinder their deployment.Federated learning(FL)has emerged as a solution to address these risks,allowing multiple clients to train deep learning models collaborativelywithout sharing rawdata.However,FL is vulnerable to the impact of heterogeneous distributed data,which weakens convergence stability and suboptimal performance of the trained model on local data.This is due to the discarding of the old local model at each round of training,which results in the loss of personalized information in the model critical for maintaining model accuracy and ensuring robustness.In this paper,we propose FedTC,a personalized federated learning method with two classifiers that can retain personalized information in the local model and improve the model’s performance on local data.FedTC divides the model into two parts,namely,the extractor and the classifier,where the classifier is the last layer of the model,and the extractor consists of other layers.The classifier in the local model is always retained to ensure that the personalized information is not lost.After receiving the global model,the local extractor is overwritten by the globalmodel’s extractor,and the classifier of the globalmodel serves as anadditional classifier of the localmodel toguide local training.The FedTCintroduces a two-classifier training strategy to coordinate the two classifiers for local model updates.Experimental results on Cifar10 and Cifar100 datasets demonstrate that FedTC performs better on heterogeneous data than current studies,such as FedAvg,FedPer,and local training,achieving a maximum improvement of 27.95%in model classification test accuracy compared to FedAvg. 展开更多
关键词 Distributed machine learning federated learning data hetero-geneity non-independent identically distributed
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Synthesis of morphology-controlled silver nanostructures by electrodeposition 被引量:1
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作者 C.l.liang K.Zhong +8 位作者 M.liu l.jiang S.K.liu D.D.Xing H.Y.li Y.Na W.X.Zhao Y.X.Tong P.liu 《Nano-Micro Letters》 SCIE EI CAS 2010年第1期6-10,共5页
Nanostructured silver was obtained by potentiostatic electrolysis.The effects of ionized surfactant(sodium dodecanesulphonate)and the substrate(Cu and Ti)on the morphology of depositions were investigated.It is found ... Nanostructured silver was obtained by potentiostatic electrolysis.The effects of ionized surfactant(sodium dodecanesulphonate)and the substrate(Cu and Ti)on the morphology of depositions were investigated.It is found that morphologies of silver nanostructures can be simply controlled via change of the substrate.Spherical Ag nanoparticles with narrow size distribution were obtained by electrodeposition in Ag NO3-SDS aqueous solution on copper substrate.In the case of titanium substrate,silver dendrite structures were obtained.Despite of different morphologies,XRD and TEM results showed that the as-prepared samples belong to face-centered cubic silver structure with good crystallinity.The formation mechanism of different silver nanostructures was discussed. 展开更多
关键词 ELECTRODEPOSITION Silver nanopartilces Silver nano dentrites
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Effects of cyclic loading on temperature evolution of ULTIMET superalloy: experiment and theoretical modeling 被引量:1
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作者 l.jiang H.Wang 《中国有色金属学会会刊:英文版》 EI CSCD 2002年第4期734-747,共14页
High speed, high resolution infrared thermography, as a non contact, full field, and nondestructive technique, was used to study the temperature variations of a cobalt based ULTIMET alloy subjected to cyclic fatigue. ... High speed, high resolution infrared thermography, as a non contact, full field, and nondestructive technique, was used to study the temperature variations of a cobalt based ULTIMET alloy subjected to cyclic fatigue. During each fatigue cycle, the temperature oscillations, which were due to the thermal elastic plastic effects, were observed and related to stress-strain analyses. The change of temperature during fatigue was utilized to reveal the accumulation of fatigue damage. A constitutive model was developed for predicting the thermal and mechanical responses of ULTIMET alloy subjected to cyclic deformation. The model was constructed in light of internal state variables, which were developed to characterize the inelastic strain of the material during cyclic loading. The predicted stress-strain and temperature responses were found to be in good agreement with the experimental results. 展开更多
关键词 超级合金 热分析 疲劳 ULTIMET 理论模型
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新型杂化有机硅技术及其应用
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作者 S.Thumm D.Sielemann +3 位作者 C.Stanica ljiang 张奔(译) 罗艳(校) 《国际纺织导报》 2008年第10期40-40,42-44,共4页
在改进纺织品功能和节约工艺成本的同时,提高纺织品应用安全性一直是新型纺织助剂的发展目标。具有革命意义的杂化有机硅最新一代产品以其独特的方式兼备上述标准。将3个正在申请专利的新型杂化有机硅改性剂用于进行具有最佳柔软性的氟... 在改进纺织品功能和节约工艺成本的同时,提高纺织品应用安全性一直是新型纺织助剂的发展目标。具有革命意义的杂化有机硅最新一代产品以其独特的方式兼备上述标准。将3个正在申请专利的新型杂化有机硅改性剂用于进行具有最佳柔软性的氟碳整理和牢度改进的超亲水柔软剂领域,以展示此新一代有机硅柔软剂的优点。 展开更多
关键词 杂化有机硅 氟碳整理 柔软剂
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铌微合金化钢中硅对再结晶和沉淀之间交互作用的影响
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作者 ljiang 韦菁(译) 段玉玲(校) 《钢铁译文集》 2005年第1期19-25,共7页
研究了三种舍Nb约0.035%的微合金化钢在非再结晶温度(Tnr)期间,Si对再结晶和沉淀之间交互作用的影响。在0.01%~0.48%的Si浓度范围内,通过扭转试验测定Tnr。结果发现,Tnr随Si含量的增加而升高,但在长的道次间隔时间时呈现... 研究了三种舍Nb约0.035%的微合金化钢在非再结晶温度(Tnr)期间,Si对再结晶和沉淀之间交互作用的影响。在0.01%~0.48%的Si浓度范围内,通过扭转试验测定Tnr。结果发现,Tnr随Si含量的增加而升高,但在长的道次间隔时间时呈现饱和。此外,高的应变减轻Si对Tnr的影响。这是因为,添加的Si使Nb(C,N)沉淀加速。 展开更多
关键词 铌微合金化钢 非再结晶温度 扭转试验 再结晶动力学
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Server-Aided Multi-Secret Sharing Scheme for Weak Computational Devices
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作者 En Zhang Xintao Duan +4 位作者 Siuming Yiu Junbin Fang Zoe l.jiang Tsz HonYuen Jie Peng 《Computers, Materials & Continua》 SCIE EI 2018年第9期401-414,共14页
In the setting of(t,n)threshold secret sharing,at least t parties can reconstruct the secret,and fewer than t parties learn nothing about the secret.However,to achieve fairness,the existing secret sharing schemes eith... In the setting of(t,n)threshold secret sharing,at least t parties can reconstruct the secret,and fewer than t parties learn nothing about the secret.However,to achieve fairness,the existing secret sharing schemes either assume a trusted party exists or require running multi-round,which is not practical in a real application.In addition,the cost of verification grows dramatically with the number of participants and the communication complexity is O(t),if there is not a trusted combiner in the reconstruction phase.In this work,we propose a fair server-aided multi-secret sharing scheme for weak computational devices.The malicious behavior of clients or server providers in the scheme can be verified,and the server provider learns nothing about the secret shadows and the secrets.Unlike other secret sharing schemes,our scheme does not require interaction among users and can work in asynchronous mode,which is suitable for mobile networks or cloud computing environments since weak computational mobile devices are not always online.Moreover,in the scheme,the secret shadow is reusable,and expensive computation such as reconstruction computation and homomorphic verification computation can be outsourced to the server provider,and the users only require a small amount of computation. 展开更多
关键词 SECRET SHARING server-aided NON-INTERACTIVE FAIRNESS
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Future Physics Programme of BESⅢ 被引量:538
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作者 M.Ablikim M.N.Achasov +147 位作者 P.Adlarson S.Ahmed M.Albrecht M.Alekseev A.Amoroso F.F.An Q.An Y.Bai O.Bakina R.Baldini Ferroli Y.Ban K.Begzsuren J.V.Bennett N.Berger M.Bertani D.Bettoni F.Bianchi J Biernat J.Bloms I.Boyko R.A.Briere l.Calibbi H.Cai X.Cai A.Calcaterra G.F.Cao N.Cao S.A.Cetin J.Chai J.F.Chang W.l.Chang J.Charles G.Chelkov Chen G.Chen H.S.Chen J.C.Chen M.l.Chen S.J.Chen Y.B.Chen H.Y.Cheng W.Cheng G.Cibinetto F.Cossio X.F.Cui H.l.Dai J.P.Dai X.C.Dai A.Dbeyssi D.Dedovich Z.Y.Deng A.Denig Denysenko M.Destefanis S.Descotes-Genon F.De Mori Y.Ding C.Dong J.Dong l.Y.Dong M.Y.Dong Z.l.Dou S.X.Du S.I.Eidelman J.Z.Fan J.Fang S.S.Fang Y.Fang R.Farinelli l.Fava F.Feldbauer G.Felici C.Q.Feng M.Fritsch C.D.Fu Y.Fu Q.Gao X.l.Gao Y.Gao Y.Gao Y.G.Gao Z.Gao B.Garillon I.Garzia E.M.Gersabeck A.Gilman K.Goetzen l.Gong W.X.Gong W.Gradl M.Greco l.M.Gu M.H.Gu Y.T.Gu A.Q.Guo F.K.Guo l.B.Guo R.P.Guo Y.P.Guo A.Guskov S.Han X.Q.Hao F.A.Harris K.l.He F.H.Heinsius T.Held Y.K.Heng Y.R.Hou Z.l.Hou H.M.Hu J.F.Hu T.Hu Y.Hu G.S.Huang J.S.Huang X.T.Huang X.Z.Huang Z.l.Huang N.Huesken T.Hussain W.Ikegami Andersson W.Imoehl M.Irshad Q.Ji Q.P.Ji X.B.Ji X.l.Ji H.l.jiang X.S.jiang X.Y.jiang J.B.Jiao Z.Jiao D.P.Jin S.Jin Y.Jin T.Johansson N.Kalantar-Nayestanaki X.S.Kang R.Kappert M.Kavatsyuk B.C.Ke I.K.Keshk T.Khan A.Khoukaz P.Kiese R.Kiuchi R.Kliemt l. 《Chinese Physics C》 SCIE CAS CSCD 2020年第4期I0001-I0004,1-102,共106页
There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B fac... There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESⅢ, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESⅢ during the remaining operation period of BEPCⅡ. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCⅡ to higher luminosity. 展开更多
关键词 MESON HADRON optimization
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Influence of cement-fly ash-gravel pile-supported approach embankment on abutment piles in soft ground 被引量:20
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作者 D.Xiao G.l.jiang +2 位作者 D.liao Y.F.Hu X.F.liu 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2018年第5期977-985,共9页
Abutment piles in soft ground may be subjected to both vertical and horizontal soil movements resulting from approach embankment loads. To constrain the soil movements, the soft soil ground beneath the approach embank... Abutment piles in soft ground may be subjected to both vertical and horizontal soil movements resulting from approach embankment loads. To constrain the soil movements, the soft soil ground beneath the approach embankment is often improved using composite pile foundations, which aim at mitigating the bump induced by high-speed trains passing through the bridge. So far, there is limited literature on exploring the influence of the degree of ground improvement on abutment piles installed in soft soil grounds. In this paper, a series of three-dimensional (3D) centrifuge model tests was performed on an approach embankment over a silty clay deposit improved by cement-fly ash-gravel (CFG) piles combined with geogrid. Emphasis is placed on the effects of ground replacement ratio (m) on the responses of the abutment piles induced by embankment loads. Meanwhile, a numerical study was conducted with varying ground replacement ratio of the pile-reinforced grounds. Results show that the performance of the abutment piles is significantly improved when reinforcing the ground with CFG piles beneath the approach embankment. Interestingly, there is a threshold value of the replacement ratio of around 4.9% above which the effect of CFG pile foundations is limited. This implies that it is essential to optimize the ground improvement for having a cost-effective design while minimizing the risk of the bump at the end of bridge. 展开更多
关键词 Abutment pile Soft soilSoil movement Ground improvement Load transfer
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欧美杨单株液流昼夜组成及其影响因素分析 被引量:18
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作者 孔喆 陈胜楠 +2 位作者 律江 陈立欣 张志强 《林业科学》 EI CAS CSCD 北大核心 2020年第3期8-20,共13页
【目的】分析欧美杨107杨昼夜液流特征,量化夜间液流对整日液流的贡献率,探讨昼夜液流对树形因子和环境因子的响应差异,为深入认识树木水分利用策略对环境的响应机制提供理论依据。【方法】以北京市顺义新城滨河森林公园内的树种欧美杨... 【目的】分析欧美杨107杨昼夜液流特征,量化夜间液流对整日液流的贡献率,探讨昼夜液流对树形因子和环境因子的响应差异,为深入认识树木水分利用策略对环境的响应机制提供理论依据。【方法】以北京市顺义新城滨河森林公园内的树种欧美杨107杨为研究对象,在样地内选择8株35年生、长势良好的样木,于2018年7—10月采用热扩散探针对样木进行树干液流变化监测,并同步监测环境因子。【结果】1)欧美杨小、中、大径阶的液流速率呈“昼高夜低”单峰曲线,前半夜液流活动比后半夜活跃;2)各径阶整日液流量为39.04~94.96 g·cm^-2d^-1,夜间液流量为3.34~10.49 g·cm^-2d^-1,夜间液流对整日液流的贡献率在4.2%~16.2%范围内波动,整日液流量与日间液流量(去除夜间液流的日总液流)差异性达极显著水平(P<0.01);3)日间和夜间液流对树形因子的响应关系一致,冠幅与昼夜液流呈显著正相关(P<0.05),对昼夜液流的解释程度分别为80%和77%,树高和胸径对昼夜液流的影响不显著(P>0.05);4)饱和水汽压差(VPD)、太阳总辐射(Ra)、空气温度(T)和风速(W s)是影响欧美杨整日液流量的主要环境因子;影响日间和夜间液流速率的环境因子存在差异,VPD、Ra、T和Ws是影响日间液流速率的主要环境因子,而夜间液流速率主要受VPD和W s影响;W s对昼夜液流速率的影响具有两重性,具体表现为白天促进树干液流速率,夜间抑制树干液流速率;日间液流量与夜间液流量极显著正相关(P<0.01),小、中、大径阶的日间液流量对夜间液流量的解释程度分别为37%、48%和47%。【结论】欧美杨存在明显的夜间液流,估算欧美杨耗水量时,忽略夜间液流会低估日常需水量。液流速率对环境因子的响应存在昼夜差异,估算和模拟树木蒸腾量时,应分日间和夜间考虑环境因子对液流速率的影响。 展开更多
关键词 欧美杨107杨 昼夜树干液流 树形因子 环境响应 夜间液流贡献率
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枯草芽孢杆菌的生物学特性及其在猪生产上的应用进展 被引量:14
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作者 彭孝坤 吕江漫 邓敦 《饲料研究》 CAS 北大核心 2020年第11期154-158,共5页
枯草芽孢杆菌是当前应用最为广泛的饲用益生菌之一,可作为抗生素的有效替代物。枯草芽孢杆菌在改善猪的生长性能、肠道微生态平衡、免疫功能、肉品质和养殖环境等方面发挥重要作用。文章综述枯草芽孢杆菌的生物学特性及其在养猪生产中... 枯草芽孢杆菌是当前应用最为广泛的饲用益生菌之一,可作为抗生素的有效替代物。枯草芽孢杆菌在改善猪的生长性能、肠道微生态平衡、免疫功能、肉品质和养殖环境等方面发挥重要作用。文章综述枯草芽孢杆菌的生物学特性及其在养猪生产中的应用进展,以期为枯草芽孢杆菌的应用和研究提供参考。 展开更多
关键词 枯草芽孢杆菌 生物学特性 应用进展
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应对气候变化与生物多样性保护的国际规则协同:演进、挑战与中国选择 被引量:10
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作者 吕江 《北京理工大学学报(社会科学版)》 CSSCI 北大核心 2022年第2期50-60,共11页
应对气候变化和生物多样性保护乃是当前国际社会面临的两大紧迫任务,特别是随着全球对气候变化认识的不断深入,二者的关联性被越来越多地提及。然而,目前在其规则协同方面,它们却凸显出诸多滞后与不足,进而严重影响到应对气候变化和生... 应对气候变化和生物多样性保护乃是当前国际社会面临的两大紧迫任务,特别是随着全球对气候变化认识的不断深入,二者的关联性被越来越多地提及。然而,目前在其规则协同方面,它们却凸显出诸多滞后与不足,进而严重影响到应对气候变化和生物多样性保护的行动同步。是故,未来国际社会应在整体系统思维的基础上,充分利用碳中和共识的政治推动力,从法律上确立起相互支持原则,以期实现二者的规则协同。对中国而言,则应在碳达峰、碳中和1+N政策体系下充分考虑生物多样性因素,在肯定基于自然的气候解决办法的同时,亦应积极防范应对气候变化与生物多样性保护之间可能产生的规则冲突。 展开更多
关键词 碳中和 气候变化 生物多样性
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高速公路边坡植被修复对土壤微生物群落的影响 被引量:10
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作者 吕江 赵晖 +3 位作者 袁宗浩 潘晓东 孙宏磊 蔡袁强 《福建农林大学学报(自然科学版)》 CSCD 北大核心 2021年第3期420-426,共7页
以千黄高速淳安段为例,利用高通量测序技术比较了地表裸露区域和植被修复区域土壤微生物群落多样性差异.结果表明:(1)植被修复显著提高了土壤有机质含量;(2)地表裸露区域土壤细菌OTU数目和Shannon指数显著低于植被修复区域,两区域之间... 以千黄高速淳安段为例,利用高通量测序技术比较了地表裸露区域和植被修复区域土壤微生物群落多样性差异.结果表明:(1)植被修复显著提高了土壤有机质含量;(2)地表裸露区域土壤细菌OTU数目和Shannon指数显著低于植被修复区域,两区域之间土壤细菌群落结构无显著性差异;(3)地表裸露区域土壤真菌OTU数目显著高于植被修复区域,但是Shannon指数显著低于植被修复区域,两区域之间土壤真菌群落结构具有显著性差异;(4)CCA分析结果显示土壤有机质含量是影响土壤真菌群落结构的主要因素.综合分析表明:植被修复过程中可能会增加土壤有机质含量,进而影响土壤微生物群落结构. 展开更多
关键词 高速公路 土壤微生物 细菌 真菌 高通量测序
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Three-dimensional dynamics of supported pipes conveying fluid 被引量:9
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作者 l.Wang T.l.jiang H.l.Dai 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2017年第6期1065-1074,共10页
This paper deals with the three-dimensional dynamics and postbuckling behavior of flexible supported pipes conveying fluid, considering flow velocities lower and higher than the critical value at which the buckling in... This paper deals with the three-dimensional dynamics and postbuckling behavior of flexible supported pipes conveying fluid, considering flow velocities lower and higher than the critical value at which the buckling instability occurs. In the case of low flow velocity, the pipe is stable with a straight equilibrium position and the dynamics of the system can be examined using linear theory. When the flow velocity is beyond the critical value, any motions of the pipe could be around the postbuckling configuration(non-zero equilibrium position) rather than the straight equilibrium position, so nonlinear theory is required. The nonlinear equations of perturbed motions around the postbuckling configuration are derived and solved with the aid of Galerkin discretization. It is found, for a given flow velocity,that the first-mode frequency for in-plane motions is quite different from that for out-of-plane motions. However, the second-or third-mode frequencies for in-plane motions are approximately equal to their counterparts for out-of-plane motions, keeping almost constant values with increasing flow velocity. Moreover, the orientation angle of the postbuckling configuration plane for a buckled pipe can be significantly affected by initial conditions, displaying new features which have not been observed in the same pipe system factitiously supposed to deform in a single plane. 展开更多
关键词 Pipe conveying fluid Three-dimensional dynamics INSTABILITY Natural frequency Postbuckling configuration
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草酸处理对采后‘华优’猕猴桃果实耐冷性的影响 被引量:8
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作者 梁春强 吕茳 饶景萍 《食品科学》 EI CAS CSCD 北大核心 2017年第19期230-235,共6页
采后‘华优’猕猴桃(Actinidia Chinensis‘Huayou’)果实经5 mmol/L草酸浸泡10 min后,置于(0.0±0.5)℃、相对湿度90%~95%低温贮藏90 d。结果表明:草酸处理可以缓解猕猴桃果实的冷害症状,降低猕猴桃果实的冷害率,有效抑制呼吸速率... 采后‘华优’猕猴桃(Actinidia Chinensis‘Huayou’)果实经5 mmol/L草酸浸泡10 min后,置于(0.0±0.5)℃、相对湿度90%~95%低温贮藏90 d。结果表明:草酸处理可以缓解猕猴桃果实的冷害症状,降低猕猴桃果实的冷害率,有效抑制呼吸速率和乙烯释放速率,抑制脂氧合酶活性和丙二醛的积累,维持较高的抗坏血酸过氧化物酶活性和谷胱甘肽还原酶活性,贮藏结束后保持了较高的好果率和较低的质量损失率。这表明草酸处理能缓解‘华优’猕猴桃果实的冷害,提高果实的耐冷性。 展开更多
关键词 猕猴桃 草酸 低温贮藏 耐冷性
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右心声学造影对成人卵圆孔未闭诊断效能及卵圆孔未闭与隐源性缺血性脑卒中的关系 被引量:3
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作者 陈媛 吕江州 刘洋 《黑龙江医药科学》 2023年第1期72-75,共4页
目的:研究右心声学造影对成人卵圆孔未闭(patent foramen ovale,PFO)诊断效能及PFO与隐源性缺血性脑卒中(cryptogenic stroke,CS)的关系。方法:采用随机数字表法,选取我院2021-01~2022-05收治的106例CS患者及107例性别、年龄相匹配的非... 目的:研究右心声学造影对成人卵圆孔未闭(patent foramen ovale,PFO)诊断效能及PFO与隐源性缺血性脑卒中(cryptogenic stroke,CS)的关系。方法:采用随机数字表法,选取我院2021-01~2022-05收治的106例CS患者及107例性别、年龄相匹配的非卒中患者,将其分为两组,分别是CS组106例和对照组107例。先后采用经食管超声心动图((trans esophageal echocardiography,TEE)和右心声学造影检查对照组及CS组PFO发生率,并对PFO发生率及CS危险因素进行分析。结果:右心声学造影检查中,CS组检出阳性58例(54.72%),对该部分患者行TEE检查,结果显示58例患者中,阳性检出例数为54例(50.94%),阴性4例(3.77%),阳性检出率对比无显著差异(P>0.05)。对照组阳性检出例数为2例(1.87%),对该部分患者行TEE检查,结果显示2例患者中,检出阳性1例(0.93%),阴性1例(0.93%),阳性检出率对比无显著差异(P>0.05);但CS组PFO检出率明显高于对照组(P<0.05);静息状态下启动右心声学造影,CS组RLS例数19例(17.92%)多于对照组1例(0.93%)(P<0.05),Valsalva动作后启动右心声学造影,CS组RLS总例数58例(54.72%)明显多于对照组2例(1.87%)(P<0.05),而CS组RLS分级2、3级例数明显较多(P<0.05)。结论:右心声学造影用于诊断PFO效能显著,对于全面评估PFO及查找CS相关发病因素均大有裨益。 展开更多
关键词 右心声学造影 成人卵圆孔未闭 隐源性缺血性脑卒中
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Effect of Nitrogen Content on Microstructures and Mechanical Properties of WB_2(N) Films Deposited by Reactive Magnetron Sputtering 被引量:6
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作者 Y.M.liu D.Y.Deng +4 位作者 H.lei Z.l.Pei C.l.jiang C.Sun J.Gong 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2015年第12期1217-1225,共9页
In the present study,WB 2(N) films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure(P (N2)) on the film microstructur... In the present study,WB 2(N) films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure(P (N2)) on the film microstructure and characteristics is studied systematically,including the chemical composition,crystalline structure,residual stress,surface roughness as well as the surface and the cross-section morphology.Meanwhile,nano-indentation and ball-on-disk tribometer are performed to analyze the mechanical and tribological properties of the films.The results show that the addition of nitrogen apparently leads to the change of the structure from(1 0 1) to(0 0 1) orientation then to the amorphous structure with the formation of BN phase.And the addition of nitrogen can greatly refine the grain size and microstructure of the films.Furthermore,the residual stress of the film is also found to change from tensile to compressive stress as a function of P (N2),and the compressive stress increases with P (N2),The WB 2(N) films with small nitrogen content,which are deposited at P (N2) of 0.004 and 0.006 Pa,exhibit better mechanical,tribological and corrosion properties than those of other films.Further increase of nitrogen content accelerates the formation of BN phase and fast decreases the film hardness.In addition,the large N 2 partial pressure gives rise to the target poisoning accompanied by the increase of the target voltage and the decrease of the deposition rate. 展开更多
关键词 Reactive magnetron sputtering NANOCOMPOSITES WB 2(N) films Residual stress Mechanical properties
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桥墩被动防船撞设施发展评述 被引量:1
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作者 王凯 李茜 +1 位作者 宋彦臣 吕奖国 《公路交通科技》 CAS CSCD 北大核心 2024年第1期116-125,共10页
桥梁被动防船撞装置通过缓冲和吸收撞击能量,是保障桥梁在船舶撞击下结构安全的重要措施之一。由于各类防船撞设施的结构差异较大,其防护、维护等功能需求以及对航道环境的影响都存在较大差异。为此,首先梳理了被动防船撞装置的分类方法... 桥梁被动防船撞装置通过缓冲和吸收撞击能量,是保障桥梁在船舶撞击下结构安全的重要措施之一。由于各类防船撞设施的结构差异较大,其防护、维护等功能需求以及对航道环境的影响都存在较大差异。为此,首先梳理了被动防船撞装置的分类方法,针对钢浮箱、复合材料浮箱、钢围堰、普通橡胶护舷等各类防船撞装置的防护性能与研究应用现状进行了分析。结合对国内外35座特大桥梁开展的防撞措施应用状况调查,总结归纳了各类防船撞装置的特点与适用场合,梳理了当前各类防撞装置面临的技术问题。最后,针对未来被动防船撞设施的发展提出了钛钢复合板材和FRP复合钢板等高性能复合金属材料应用、GFRP部件连接新工艺与新形式研发、拦截索网自适应技术及其恒定阻力装置研发等有待进一步研究的问题和展望。调研与分析结果表明:通航孔桥墩以采用直接型防撞装置为主,对于非通航孔桥墩则采用间接型防撞装置,独立防撞钢管桩适用于内河航道非通航孔桥且水中桥墩较少的情形,人工岛目前应用较少。未来被动防船撞措施在强耐久性、高耗能以及受力稳定性方面,仍需进一步深入研究和改进,以提高桥梁被动防船撞措施的防护性能。 展开更多
关键词 桥梁工程 被动防撞设施 应用调查 适用性 船-桥碰撞 展望
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