期刊文献+
共找到29篇文章
< 1 2 >
每页显示 20 50 100
事件层组合特征限定软沉积变形的地震成因——在青岛灵山岛的应用
1
作者 张济东 梁超 +2 位作者 操应长 陈奥 卢银 《地球科学进展》 CAS CSCD 北大核心 2024年第1期96-107,共12页
对软沉积物变形构造的形成过程解析和触发因素识别一直是国内外事件沉积学研究的重点和难点。国内外学者常将地层中保存的软沉积物变形构造的形成归因于地震作用,但缺乏足够的证据来支撑地震震动触发相应的沉积过程与变形机制。由于软... 对软沉积物变形构造的形成过程解析和触发因素识别一直是国内外事件沉积学研究的重点和难点。国内外学者常将地层中保存的软沉积物变形构造的形成归因于地震作用,但缺乏足够的证据来支撑地震震动触发相应的沉积过程与变形机制。由于软沉积物变形构造可以由地震、风暴和非地震参与的液化作用、重力作用及滑坡等因素触发,且可能受瑞利—泰勒不稳定性(因密度差异沿垂向变形)或开尔文—亥姆获兹不稳定性(沿水平方向变形)机制的控制,软沉积物变形构造本身并不能作为特定触发因素的判别标志。此前,通过解析事件层组合特征来揭示与软沉积物变形构造形成相关的沉积过程和变形机制,进而限定变形构造触发因素的方法已成功应用于中东地区死海盆地(死海断裂带)的事件沉积研究中。尝试应用此方法来解析灵山岛灯塔剖面底部软沉积物变形构造的变形机制与触发因素,研究发现灯塔剖面底部的软沉积物变形构造是原位形成与保存的,并被浊流沉积层上覆,且二者之间无背景沉积物。这种独特的事件层组合指示原位变形和异地搬运两种水下沉积过程准同期发生,而能够同时激发这两类物质来源与沉积过程迥异的事件沉积响应的最可能因素是区域强震震动。结合灵山岛研究案例认为,前人所做的模式化的事件沉积成因判别标志不宜直接套用,而控制事件沉积的沉积过程与物理机制具有一定的普适性,应该是事件沉积学研究的关键。 展开更多
关键词 软沉积变形 浊流沉积 地震震动 沉积响应
原文传递
Preparation of yttrium oxide coating with enhanced thermal shock resistance on refractories used for titanium alloy melting and casting 被引量:2
2
作者 ao chen Yan Ma +7 位作者 Zhou-fu Wang Hao Liu Xi-tang Wang Sen-na chen chen-xin Zhang Zi-yi Tang Wei-dong Fu Wei cheng 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2024年第6期1411-1422,共12页
In order to enhance the service life of refractories for melting and casting of titanium alloy,preparation of yttrium oxide coatings on the refractories surface is an effective solution.The improvement of thermal shoc... In order to enhance the service life of refractories for melting and casting of titanium alloy,preparation of yttrium oxide coatings on the refractories surface is an effective solution.The improvement of thermal shock stability of the coating is beneficial to its spalling resistance during the high-temperature service,and the available slurry with good performance is the prerequisite.The effects of the varieties and contents of dispersant(sodium tripolyphosphate,sodium hexametaphosphate,sodium pyrophosphate,citric acid and polycarboxylate ammonium salt)and binder(aluminum dihydrogen phosphate,zirconium acetate and yttria sol)on the stability,rheological and thixotropic properties of yttrium oxide waterbased slurry were investigated,and the effects of slurry composition design on the thermal shock resistance of the coating were focused.The results showed that the introduction of polycarboxylate ammonium salt as dispersant significantly improved the stability of the slurry,and the varieties of the binders had significant effects on the dispersibility of the slurry.When aluminum dihydrogen phosphate and polycarboxylate ammonium salt were used as binder and dispersant,respectively,the slurry had better stability,suitable rheological and thixotropic properties.By using aluminum dihydrogen phosphate as binder,the coating had good thermal shock resistance and no obvious cracks were observed for the coating after thermal shock,which was attributed to the yttrium aluminate binding phase generated in the coating.An effective method was provided for preparing yttrium oxide coatings with enhanced thermal shock resistance applied in the process of titanium alloy melting and casting. 展开更多
关键词 Yttrium oxide-Slurry Stability Rheological property Thixotropic property-Coating Thermal shock resistance
原文传递
Multi-blade rubbing characteristics of the shaft-disk-blade-casing system with large rotation
3
作者 Zhiyuan WU Linchuan ZHao +3 位作者 Han YAN Ge YAN ao chen Wenming ZHANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第1期111-136,共26页
Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the b... Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the blade, while some only consider the whirl of the rotor, neglecting its spin. To address these limitations, this paper proposes a dynamic model with large rotation for the SDBC system. The model incorporates the spin and whirl of the rotor, enabling the realistic reproduction of multiblade rubbing faults. To verify the accuracy of the SDBC model with large rotation and demonstrate its capability to effectively consider the rotational effects such as the centrifugal stiffening and gyroscopic effects, the natural characteristics and dynamic responses of the proposed model are compared with those obtained from reported research and experimental results. Furthermore, the effects of the rotating speed, contact stiffness,and blade number on the dynamic characteristics of the SDBC system with multi-blade rubbing are investigated. The results indicate that the phase angle between the rotor deflection and the unbalance excitation force increases with the increasing rotating speed,which significantly influences the rubbing penetration of each blade. The natural frequency of the SDBC system with rubbing constrain can be observed in the acceleration response of the casing and the torsional response of the shaft, and the frequency is related to the contact stiffness. Moreover, the vibration amplitude increases significantly with the product of the blade number under rubbing, and the rotating frequency approaches the natural frequency of the SDBC system. The proposed model can provide valuable insight for the fault diagnosis of rubbing in bladed rotating machinery. 展开更多
关键词 shaft-disk-blade-casing(SDBC) large rotation spin and whirl multi-blade rubbing rotational effect
在线阅读 下载PDF
Cluster-Based Massive Access for Massive MIMO Systems
4
作者 Shiyu Liang Wei chen +2 位作者 Zhongwen Sun ao chen Bo Ai 《China Communications》 SCIE CSCD 2024年第1期24-33,共10页
Massive machine type communication aims to support the connection of massive devices,which is still an important scenario in 6G.In this paper,a novel cluster-based massive access method is proposed for massive multipl... Massive machine type communication aims to support the connection of massive devices,which is still an important scenario in 6G.In this paper,a novel cluster-based massive access method is proposed for massive multiple input multiple output systems.By exploiting the angular domain characteristics,devices are separated into multiple clusters with a learned cluster-specific dictionary,which enhances the identification of active devices.For detected active devices whose data recovery fails,power domain nonorthogonal multiple access with successive interference cancellation is employed to recover their data via re-transmission.Simulation results show that the proposed scheme and algorithm achieve improved performance on active user detection and data recovery. 展开更多
关键词 compressive sensing dictionary learning multiuser detection random access
在线阅读 下载PDF
下转换铕配合物应用于太阳能电池的研究 被引量:5
5
作者 秦晓婷 张立业 +4 位作者 敖琛 张瑞森 张忠义 赵长玉 刘小鱼 《中国稀土学报》 CAS CSCD 北大核心 2018年第6期659-666,共8页
近些年具有光转换功能的稀土材料应用于太阳能电池的研究受到越来越多的关注。其中,开发出量子产率高、抗光老化性好等特点的光转换材料已有报道,但是把光转换材料实际应用到太阳能电池上还面临许多问题,例如光转换材料的添加方式、添... 近些年具有光转换功能的稀土材料应用于太阳能电池的研究受到越来越多的关注。其中,开发出量子产率高、抗光老化性好等特点的光转换材料已有报道,但是把光转换材料实际应用到太阳能电池上还面临许多问题,例如光转换材料的添加方式、添加比例,制成光转换薄膜的透光性、抗老化性等。研究了光稳定性良好的下转换铕配合物添加到PMMA中制成光转换薄膜,增加太阳能电池表面对紫外光的响应,从而增加太阳能电池的光电转换效率。系统研究了下转换铕配合物在PMMA薄膜中的添加方式、添加比例,在最佳条件下太阳能电池的相对效率提高1. 23%。通过测试下转换铕配合物和光转换薄膜的量子产率,对配合物和光转换薄膜的抗老化性进行了探讨。 展开更多
关键词 下转换 铕配合物 光转换薄膜 太阳能电池 光电转换效率
原文传递
高油酸花生新品种宇花91的选育 被引量:8
6
作者 潘雷雷 姜亚男 +7 位作者 周文杰 姜平平 吴兰荣 陈傲 朱虹 隋炯明 王晶珊 乔利仙 《生物工程学报》 CAS CSCD 北大核心 2019年第9期1698-1706,共9页
宇花91是青岛农业大学选育的高油酸花生新品种。以普通油酸含量品种鲁花11号为母本,F435型高油酸花生品种开农1715为父本配置杂交组合。利用PCR产物测序法筛选获得F1代真杂种,对F2代单株提取叶片基因组DNA,利用PCR产物测序法筛选基因型... 宇花91是青岛农业大学选育的高油酸花生新品种。以普通油酸含量品种鲁花11号为母本,F435型高油酸花生品种开农1715为父本配置杂交组合。利用PCR产物测序法筛选获得F1代真杂种,对F2代单株提取叶片基因组DNA,利用PCR产物测序法筛选基因型纯合的单株个体。对当代收获的单株籽粒利用近红外法多粒模型测定油酸、亚油酸含量,筛选油酸含量在80%以上且油酸亚油酸比值在10.0以上的单株种植成株行,随后利用系谱法进行选择育种。宇花91荚果为普通型小果,网纹较细、较明显,百果重148.06 g,百仁重63.31 g,果皮薄,出米率75.15%。籽仁长椭圆形,种皮粉红色、无裂纹,内种皮白色。籽仁蛋白质含量26.57%,脂肪含量52.72%,油酸含量80.40%,亚油酸含量2.50%,棕榈酸含量5.57%,油酸亚油酸比值32.16。苗期生长旺盛,封垄早,结果集中,中抗叶斑病和青枯病。2017年参加山东省夏播多点试验,平均荚果产量215.79 kg/667 m2,比对照花育20号增产15.27%;平均籽仁产量157.33kg/667m2,比对照花育20号增产21.64%。2018年通过国家花生品种登记,登记号:GPD花生(2018) 370210,适于在山东花生产区种植。 展开更多
关键词 花生 高油酸 宇花91 F435 标记辅助选择
原文传递
稀土发光材料Eu(2mCND)4CTAC及薄膜的耐老化性能研究
7
作者 敖琛 张忠义 +4 位作者 秦晓婷 张立业 张瑞森 闫慧忠 赵长玉 《稀土》 EI CAS CSCD 北大核心 2018年第5期94-101,共8页
下转换发光材料稀土铕配合物Eu(2mCND)4CTAC可以有效的将紫外光转换为可见光,将稀土发光材料和有机薄膜载体结合并负载于电池表面后,晶硅太阳能电池的光电转换效率得到了显著提高。光转换薄膜在户外使用时存在着一定的老化现象,这不... 下转换发光材料稀土铕配合物Eu(2mCND)4CTAC可以有效的将紫外光转换为可见光,将稀土发光材料和有机薄膜载体结合并负载于电池表面后,晶硅太阳能电池的光电转换效率得到了显著提高。光转换薄膜在户外使用时存在着一定的老化现象,这不仅严重影响到光转换薄膜的使用寿命,甚至可能对晶硅电池产生负面效应而造成巨大的经济损失。研究了将Eu^3+配合物与PMMA薄膜载体相结合后制备了五种浓度的光转换薄膜,并对光转换材料和光转换薄膜进行了紫外箱加速老化和户外老化实验。实验表明,稀土发光材料的老化性能优良,在5000小时加速老化或1.5年的户外老化后量子产率不变;Eu^3+配合物浓度为1%的薄膜老化性能最好,初始量子产率最高且在老化一段时间后量子产率趋于稳定;光转换薄膜的室内加速老化和户外老化存在一定的时间对应关系。本次研究系统评价了光转换材料和薄膜的老化性能,对预测光转换薄膜的使用寿命具有一定的指导意义。 展开更多
关键词 Eu3+配合物 下转换材料 光转换膜 耐老化性能
原文传递
Strategies of binder design for high-performance lithium-ion batteries:a mini review 被引量:8
8
作者 Yan-Bo Wang Qi Yang +4 位作者 Xun Guo Shuo Yang ao chen Guo-Jin Liang Chun-Yi Zhi 《Rare Metals》 SCIE EI CAS CSCD 2022年第3期745-761,共17页
Developing high-performance lithium-ion batteries (LIBs) with high energy density, rate capability and long cycle life are essential for the ever-growing practical application. Among all battery components, the binder... Developing high-performance lithium-ion batteries (LIBs) with high energy density, rate capability and long cycle life are essential for the ever-growing practical application. Among all battery components, the binder plays a key role in determining the preparation of electrodes and the improvement of battery performance, in spite of a low usage amount. The main function of binder is to bond the active material, conductive additive and current collector together and provide electron and ion channels to improve the kinetics of electrochemical reaction. With the ever-increasing requirement of high energy density by LIBs, technical challenges such as volume expansion and active material dissolution are attracting worldwide attentions, where binder is thought to provide a new solution.There are two main categories (organic solvent soluble binder and water-soluble binder) and abundant polar functional groups providing adhesion ability. It is of great significance to timely summarize the latest progress in battery binders and present the principles for designing novel binders with both robust binding interaction and outstanding electrode stabilization function. This review begins with an introduction of the binding mechanism and the related binding forces, including mechanical interlocking forces and interfacial forces. Then, we discussed four different strategies (the enhancement of binding force,the formation of three-dimensional (3D) network, the enhancement of conductivity and binders with special functions) for constructing ideal binder system in order to satisfy the specific demands of different batteries, such as LIBs and lithium–sulfur (Li–S) batteries. Finally, some prospective and promising directions of binder design are proposed based on the existing and emerging binders and guide the development of the next-generation LIBs. 展开更多
关键词 Lithium-ion batteries BINDER Binding mechanism Binder design
原文传递
任务类型感知的无线传感器网络数据融合调度算法 被引量:7
9
作者 邹洪森 李良 +3 位作者 奥琛 张普宁 王峥 李宁 《科学技术与工程》 北大核心 2019年第30期247-257,共11页
针对数据融合调度能量与时延优化问题,提出一种任务类型感知的无线传感网数据融合调度算法。通过传感器节点多功率、多信道的方式,利用最大独立集思想,构建基于数据融合主干树的网络拓扑结构,从而根据调度优先级,通过近似贪婪算法实现... 针对数据融合调度能量与时延优化问题,提出一种任务类型感知的无线传感网数据融合调度算法。通过传感器节点多功率、多信道的方式,利用最大独立集思想,构建基于数据融合主干树的网络拓扑结构,从而根据调度优先级,通过近似贪婪算法实现簇内数据融合调度,同时结合稀疏系数感知任务类型,减少传输数据量,进而利用簇头节点在网络中的等级,实现簇间数据融合调度。结果表明:所提算法在减少簇头节点数据传输量,降低节点能耗的同时,缩短了数据融合时延,提高了网络寿命。 展开更多
关键词 无线传感网 数据融合 任务类型 稀疏系数 时延优化
在线阅读 下载PDF
High uniformity and stability of 1S1R directly stacked for high-density cross-point memory applications 被引量:2
10
作者 Zhi-Ying Yu Jia-Yi Zhao +4 位作者 Guo-Kun Ma ao chen Da-Lei chen Yi-Heng Rao Hao Wang 《Rare Metals》 SCIE EI CAS CSCD 2022年第11期3671-3676,共6页
In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path cur... In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path current.The fabricated 1S1R exhibits stable direct current(DC)endurance(>200 cycles),suitable memory window(>40),matched selectivity(>40)and high uniformity of switching parameters. 展开更多
关键词 Ti STABILITY HIGH
原文传递
Surveillance Video Portrait Recognition Preprocessing Technology for Police Actual Combat 被引量:1
11
作者 Yao chen ao chen +1 位作者 Zhiwei Jiang Jianfu Zhong 《Open Journal of Applied Sciences》 2019年第5期394-402,共9页
With the continuous development of technology, face recognition technology has played an important role in police work. In order to get a clear face image, image preprocessing technology is needed. This paper mainly p... With the continuous development of technology, face recognition technology has played an important role in police work. In order to get a clear face image, image preprocessing technology is needed. This paper mainly proposes illumination compensation technology and reconstruction technology based on symmetry. 展开更多
关键词 WIENER Filter Logarithmic Transformation WAVELET Transform SYMMETRY GRADIENT DESCENT
在线阅读 下载PDF
PGK1-coupled HSP90 stabilizes GSK3βexpression to regulate the stemness of breast cancer stem cells
12
作者 Wei Tang Yu Wu +5 位作者 Xin Qi Rilei Yu Zhimin Lu ao chen Xinglong Fan Jing Li 《Cancer Biology & Medicine》 SCIE CAS CSCD 2022年第4期486-503,共18页
Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanism... Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanisms of GSK3βprotein expression remain elusive.Methods:Co-immunoprecipitation and mass spectral assays were performed to identify molecules binding to GSK3β,and to characterize the interactions of GSK3β,heat shock protein 90(Hsp90),and co-chaperones.The role of PGK1 in Hsp90 chaperoning GSK3βwas evaluated by constructing 293T cells stably expressing different domains/mutants of Hsp90α,and by performing a series of binding assays with bacterially purified proteins and clinical specimens.The influences of Hsp90 inhibitors on breast cancer stem cell stemness were investigated by Western blot and mammosphere formation assays.Results:We showed that GSK3βwas a client protein of Hsp90.Hsp90,which did not directly bind to GSK3β,interacted with phosphoglycerate kinase 1 via its C-terminal domain,thereby facilitating the binding of GSK3βto Hsp90.GSK3β-bound PGK1 interacted with Hsp90 in the“closed”conformation and stabilized GSK3βexpression in an Hsp90 activity-dependent manner.The Hsp90 inhibitor,17-AAG,rather than HDN-1,disrupted the interaction between Hsp90 and PGK1,and reduced GSK3βexpression,resulting in significantly reduced inhibition ofβ-catenin expression,to maintain the stemness of breast cancer stem cells.Conclusions:Our findings identified a novel regulatory mechanism of GSK3βexpression involving metabolic enzyme PGK1-coupled Hsp90,and highlighted the potential for more effective cancer treatment by selecting Hsp90 inhibitors that do not affect PGK1-regulated GSK3βexpression. 展开更多
关键词 Glycogen synthase kinase-3β(GSK3β) heat shock protein 90(Hsp90) phosphoglycerate kinase 1(PGK1) hsp90 inhibitors breast cancer stem cell
暂未订购
Stress effect on lattice thermal conductivity of anode material NiNB_(2)O_(6)for lithium-ion batteries
13
作者 陈奥 童话 +4 位作者 吴成伟 谢国锋 谢忠祥 向长青 周五星 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第5期43-48,共6页
The thermal transport properties of NiNB_(2)O_(6)as anode material for lithium-ion battery and the effect of strain were studied by machine learning interatomic potential combined with Boltzmann transport equation.The... The thermal transport properties of NiNB_(2)O_(6)as anode material for lithium-ion battery and the effect of strain were studied by machine learning interatomic potential combined with Boltzmann transport equation.The results show that the lattice thermal conductivity of NiNB_(2)O_(6)along the three crystal directions[100],[010],and[001]are 0.947 W·m^(-1)·K^(-1),0.727 W·m^(-1)·K^(-1),and 0.465 W·m^(-1)·K^(-1),respectively,indicating the anisotropy of the lattice thermal conductivity of NiNB_(2)O_(6).This anisotropy of the lattice thermal conductivity stems from the significant difference of phonon group velocities in different crystal directions of NiNB_(2)O_(6).When the tensile strain is applied along the[001]crystal direction,the lattice thermal conductivity in all three directions decreases.However,when the compressive strain is applied,the lattice thermal conductivity in the[100]and[010]crystal directions is increased,while the lattice thermal conductivity in the[001]crystal direction is abnormally reduced due to the significant inhibition of compressive strain on the group velocity.These indicate that the anisotropy of thermal conductivity of NiNB_(2)O_(6)can be enhanced by the compressive strain,and reduced by the tensile strain. 展开更多
关键词 nickel niobate lattice thermal conductivity uniaxial strain machine learning potential
原文传递
Performance and stability-enhanced inorganic perovskite light-emitting devices by employing triton X-100
14
作者 ao chen Peng Wang +4 位作者 Tao Lin Ran Liu Bo Liu Quan-Jun Li Bing-Bing Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第4期629-632,共4页
Significantly enhanced electroluminescence performance and stability of all-inorganic perovskite light-emitting devices(PeLEDs) have been achieved by adding triton X-100 into the perovskite precursors.The small perovs... Significantly enhanced electroluminescence performance and stability of all-inorganic perovskite light-emitting devices(PeLEDs) have been achieved by adding triton X-100 into the perovskite precursors.The small perovskite grains arranged tightly and formed large grains as the triton X-100 were introduced.Thus the nonradiative defects originated from Pb atoms at the grain boundaries were highly passivated by triton X-100 and resulted in the promotion of PeLED performance,including a turn-on voltage of 3.2 V,a brightness of 63500 cd/m^(2),a current efficiency of 17.4 cd/A,and a prolonged lifetime of 2 h in air. 展开更多
关键词 electroluminescence performance STABILITY perovskite light-emitting devices(Pe LEDs) triton X-100
原文传递
Hemilabileα-Diimine Nickel Catalyzed Olefin Polymerization
15
作者 Muhammad Asadullah Khan Yue Liu +2 位作者 Wenmin Pang ao chen Min chen 《Chinese Journal of Chemistry》 2025年第5期517-523,共7页
Comprehensive Summary For coordination-insertion olefin polymerization,the development of novel transition-metal catalysts has drawn extensive attention in this field.In this contribution,we designed a series of hemil... Comprehensive Summary For coordination-insertion olefin polymerization,the development of novel transition-metal catalysts has drawn extensive attention in this field.In this contribution,we designed a series of hemilabileα-diimine nickel catalysts bearing oxygen atom as neighboring group.The steric hindrance and oxygen atom number of these nickel complexes(Ni1—Ni4)could be adjusted,which influenced ethylene(co)polymerization processes. 展开更多
关键词 Homogeneous catalysis Olefin polymerization Nickel catalyst Hemilabile effects Catalytic activity COPOLYMERS
原文传递
Ethylene (Co)Polymerization Catalyzedby α-Diimine Nickel Catalysts Bearing Ether Substituents
16
作者 ao chen Changle chen +1 位作者 Yue Long Yu chen 《Polymer Science & Technology》 2025年第6期563-568,共6页
The synthesis and design of transition metal catalysts have attracted extensive attention in ethylene polymer-ization.In this work,a series of α-diimine nickel catalysts(Ni1-Ni4)bearing ether substituents were design... The synthesis and design of transition metal catalysts have attracted extensive attention in ethylene polymer-ization.In this work,a series of α-diimine nickel catalysts(Ni1-Ni4)bearing ether substituents were designed and synthesized.The steric hindrance of these catalysts was systematically modulated by varying the ether groups,which directly influenced their ethylene(co)polymerization performances.These catalysts showed exceptionally high activities(up to 10^(7) g·mol^(-1)·h^(-1)).The resulting polyethylene displayed a broad range of branching densities(22 to 92/1000C)and high polymer molecular weights(up to 59.8×10^(4) g·mol^(-1)).Polyethylene produced by Ni1 and Ni2 exhibited outstanding mechanical properties and elastic recovery performance.Furthermore,these catalysts efficiently catalyzed ethylene copolymerization with diverse polar monomers,yielding copolymers with incorporation ratios ranging from 0.24%to 1.43%. 展开更多
关键词 nickel catalysts ether substituent ethylene polymerization COPOLYMERIZATION secondary cooperation
在线阅读 下载PDF
Advancements in electrochemical synthesis:Expanding from water electrolysis to dual-value-added products
17
作者 Genxiang Wang ao chen +5 位作者 Yao chen Fen Qiao Junfeng Wang Nianjun Yang Hao Zhang Zhenhai Wen 《eScience》 2025年第4期1-33,共33页
The application of electrochemical technologies for chemical and fuel synthesis offers a significantly more eco-friendly method than traditional industrial practice.However,electrochemical synthesis in aqueous solutio... The application of electrochemical technologies for chemical and fuel synthesis offers a significantly more eco-friendly method than traditional industrial practice.However,electrochemical synthesis in aqueous solutions often involves a sluggish oxygen evolution reaction(OER)at the anode,yielding products that are less economically viable and leading to inefficient energy use.This challenge has prompted extensive research into replacing the OER with fast,value-added oxidation reactions(OER alternatives)in electrolysis systems.In this review,we summarize the latest research progress in coupled electrochemical systems that integrate OER al-ternatives with reduction reactions,beyond hydrogen evolution reactions,in aqueous solutions to synthesize dual value-added products.After providing a general overview,we start by introducing two key factors:(i)electrolytic devices and(ii)advanced characterization techniques for mechanism investigation.The focus then shifts to catalysts developed so far and their corresponding catalytic mechanisms,and to the electrochemical performance of these hybrid electrolysis systems.Finally,we outline and discuss the challenges and prospects for these inte-grated electrochemical systems to offer insights into future research directions and applications.We envision that this review will provide a panorama of electrolysis systems for dual value-added products,thereby fostering the development of green synthesis with zero carbon emissions. 展开更多
关键词 ELECTROSYNTHESIS Electrochemical hybrid systems Oxygen evolution reaction alternatives Reduction reactions
原文传递
A simple and efficient in planta transformation method based on the active regeneration capacity of plants 被引量:8
18
作者 Guoguo Mei ao chen +5 位作者 Yaru Wang Shuquan Li Minyi Wu Yilong Hu Xu Liu Xingliang Hou 《Plant Communications》 SCIE CSCD 2024年第4期166-176,共11页
Plant genetic transformation strategies serve as essential tools for the genetic engineering and advanced molecular breeding of plants.However,the complicated operational protocols and low efficiency of cur-rent trans... Plant genetic transformation strategies serve as essential tools for the genetic engineering and advanced molecular breeding of plants.However,the complicated operational protocols and low efficiency of cur-rent transformation strategies restrict the genetic modification of most plant species.This paper de-scribes the development of the regenerative activity–dependent in planta injection delivery(RAPID)method based on the active regeneration capacity of plants.In this method,Agrobacterium tumefaciens is delivered to plant meristems via injection to induce transfected nascent tissues.Stable transgenic plants can be obtained by subsequent vegetative propagation of the positive nascent tissues.The method was successfully used for transformation of plants with strong regeneration capacity,including different genotypes of sweet potato(Ipomoea batatas),potato(Solanum tuberosum),and bayhops(Ipo-moea pes-caprae).Compared with traditional transformation methods,RAPID has a much higher trans-formation efficiency and shorter duration,and it does not require tissue culture procedures.The RAPID method therefore overcomes the limitations of traditional methods to enable rapid in planta transformation and can be potentially applied to a wide range of plant species that are capable of active regeneration. 展开更多
关键词 plant genetic transformation RAPID active regeneration sweet potato POTATO bayhops
原文传递
Deep learning methods for noisy sperm image classification from convolutional neural network to visual transformer:a comprehensive comparative study
19
作者 ao chen chen Li +9 位作者 Md Mamunur Rahaman Yudong Yao Haoyuan chen Hechen Yang Peng Zhao Weiming Hu Wanli Liu Shuojia Zou Ning Xu Marcin Grzegorzek 《Intelligent Medicine》 EI CSCD 2024年第2期114-127,共14页
Background With the gradual increase of infertility in the world,among which male sperm problems are the main factor for infertility,more and more couples are using computer-assisted sperm analysis(CASA)to assist in t... Background With the gradual increase of infertility in the world,among which male sperm problems are the main factor for infertility,more and more couples are using computer-assisted sperm analysis(CASA)to assist in the analysis and treatment of infertility.Meanwhile,the rapid development of deep learning(DL)has led to strong results in image classification tasks.However,the classification of sperm images has not been well studied in current deep learning methods,and the sperm images are often affected by noise in practical CASA applications.The purpose of this article is to investigate the anti-noise robustness of deep learning classification methods applied on sperm images.Methods The SVIA dataset is a publicly available large-scale sperm dataset containing three subsets.In this work,we used subset-C,which provides more than 125,000 independent images of sperms and impurities,including 121,401 sperm images and 4,479 impurity images.To investigate the anti-noise robustness of deep learning classification methods applied on sperm images,we conducted a comprehensive comparative study of sperm images using many convolutional neural network(CNN)and visual transformer(VT)deep learning methods to find the deep learning model with the most stable anti-noise robustness.Results This study proved that VT had strong robustness for the classification of tiny object(sperm and impurity)image datasets under some types of conventional noise and some adversarial attacks.In particular,under the influence of Poisson noise,accuracy changed from 91.45%to 91.08%,impurity precison changed from 92.7%to 91.3%,impurity recall changed from 88.8%to 89.5%,and impurity F1-score changed 90.7%to 90.4%.Meanwhile,sperm precision changed from 90.9%to 90.5%,sperm recall changed from 92.5%to 93.8%,and sperm F1-score changed from 92.1%to 90.4%.Conclusion Sperm image classification may be strongly affected by noise in current deep learning methods;the robustness with regard to noise of VT methods based on global information is greater than that of CNN methods based on local information,indicating that the robustness with regard to noise is reflected mainly in global information. 展开更多
关键词 Computer-assisted sperm analysis ANTI-NOISE Robustness Deep learning .Image classification Sperm image Conventional noise Adversarial attacks Convolutional neural network Visual transformer
原文传递
Polyolefin vitrimers bearing acetoacetate functionality
20
作者 Zihao Wang Yue Liu +2 位作者 Wenmin Pang ao chen Min chen 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第11期3861-3867,共7页
Polyolefin vitrimers are polymer networks bearing reversible covalent crosslinking points, enabling them to be reprocessed and recycled. In this contribution, a series of polyolefin vitrimers were designed based on th... Polyolefin vitrimers are polymer networks bearing reversible covalent crosslinking points, enabling them to be reprocessed and recycled. In this contribution, a series of polyolefin vitrimers were designed based on the acetoacetate-functionalized polyolefin copolymers, which were produced through the direct copolymerization of ethylene with polar comonomers using a phosphinesulfonate palladium catalyst. The pendant acetoacetate group could mediate several characteristic reactions, such as the Michael addition reaction, ketone-amine condensation and metal coordination reaction. As such, structurally adjustable polyolefin vitrimers can be accessed by introducing various dynamic crosslinking bonds, including disulfide exchange, transamination of vinylogous urethane and labile metal coordination bond. The utilization of different crosslinking reactions and the mole ratio of crosslinkers significantly impact the material properties of the resultant polymers. Specifically, the generated polyolefin vitrimers demonstrated excellent reprocessability and closed-loop recycling properties. The study in this work provides an efficient strategy to access various polyolefin vitrimers. 展开更多
关键词 polyolefin vitrimers acetoacetate group polar monomer olefin copolymerization
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部