期刊文献+
共找到7,152篇文章
< 1 2 250 >
每页显示 20 50 100
视差立体图像中的∑面描述 被引量:2
1
作者 汪明霓 《杭州电子工业学院学报》 2002年第6期35-39,共5页
首先阐述了视差立体图像设计中的同步生成算法和异步生成算法的概念,描述了∑面原始模板的代码生成过程,分析和综合了∑面原始模块的各种来源,包括程序生成、现成图案的改造和图案的双向重复,最后讨论了一种特殊的视差立体图像———浮画。
关键词 视差立体图像 ∑面 浮画 异步生成算法 同步生成算法
下载PDF
我国大豆生产波动动因分析——基于省际面板模型的实证研究 被引量:6
2
作者 李维刚 张晓东 +1 位作者 宋继华 孙丹 《农业经济与管理》 CSSCI 北大核心 2023年第2期48-63,共16页
在我国大豆生产波动频繁的情况下,找出影响大豆单产、种植面积的影响因素是实现“提单产、稳面积”的首要举措。研究采用1999~2020年21个省份面板数据,在分析大豆单产、种植面积的变化趋势基础上,根据大豆单产增减趋势,把大豆产区划分... 在我国大豆生产波动频繁的情况下,找出影响大豆单产、种植面积的影响因素是实现“提单产、稳面积”的首要举措。研究采用1999~2020年21个省份面板数据,在分析大豆单产、种植面积的变化趋势基础上,根据大豆单产增减趋势,把大豆产区划分成增产区、减产区和波动区,采用改进的面板数据模型分别对三个产区的大豆单产和种植面积的影响因素进行实证分析。结果表明,机械化收割、产研结合、农药投入、小型拖拉机的投入是影响不同区域大豆单产的显著因素;机械化耕作是提升所有区域种植面积的显著因素,玉米种植面积、化肥投入、农药投入、灌溉条件、科研资金与人员投入、产研结合、机械化收割是影响不同区域大豆种植面积显著因素。根据分析,提出了相应政策建议。 展开更多
关键词 大豆生产 大豆单产 大豆种植
下载PDF
两面针总碱抗胃溃疡作用研究 被引量:15
3
作者 庞辉 何惠 +3 位作者 简丽娟 高志睿 韦奇 贾晓栋 《中药药理与临床》 CAS CSCD 北大核心 2007年第1期38-39,共2页
目的:研究两面针总碱对实验性胃溃疡的保护作用及其机制。方法:灌服两面针总碱7天后,用无水乙醇、束缚一冷冻法和幽门结扎法造胃溃疡模型,测量溃疡指数、胃液量、游离酸、总酸度、胃蛋白酶活性以及胃粘膜MDA含量、超氧化物歧化酶(SOD)... 目的:研究两面针总碱对实验性胃溃疡的保护作用及其机制。方法:灌服两面针总碱7天后,用无水乙醇、束缚一冷冻法和幽门结扎法造胃溃疡模型,测量溃疡指数、胃液量、游离酸、总酸度、胃蛋白酶活性以及胃粘膜MDA含量、超氧化物歧化酶(SOD)活性、NO含量。结果:两面针组能使三种模型溃疡指数降低,对胃液量、游离酸、总酸度无明显影响,可降低胃液胃蛋白酶活性,使胃粘膜MDA含量降低,SOD活性和NO含量升高。结论:两面针总碱具有抗溃疡作用。 展开更多
关键词 针总碱 胃溃疡 保护作用 游离酸 总酸度
下载PDF
处理走航式海洋多参数剖面测量系统(MVP)温度和电导率滞后效应的方法 被引量:8
4
作者 任强 于非 +2 位作者 刁新源 司广成 魏传杰 《海洋科学》 CAS CSCD 北大核心 2014年第8期59-66,共8页
走航式海洋多参数剖面测量系统(moving vessel profiler,MVP)是一种集成程度和自动化程度都较高的海洋调查设备,能对海洋多要素进行同时观测,获得水平方向的高分辨率数据资料。由于温度和电导率传感器响应时间的不匹配,MVP下放速度过快... 走航式海洋多参数剖面测量系统(moving vessel profiler,MVP)是一种集成程度和自动化程度都较高的海洋调查设备,能对海洋多要素进行同时观测,获得水平方向的高分辨率数据资料。由于温度和电导率传感器响应时间的不匹配,MVP下放速度过快(峰值速度4 m/s)而造成非常明显的盐度尖峰现象。本研究结合Fofonoff(F)法、时间常数指数递归数字滤波(Giles and McDougall,GM)法和Grose提出的盐度尖峰订正方案,提出了一种新的方法,即MCT(match conductivity and temperature response time)法,通过对压力、温度和电导率传感器进行响应时间的匹配来减弱盐度尖峰。将SBE-9型CTD资料作为标准,发现订正后的资料与CTD盐度曲线的互相关系数为0.917,误差比订正前减小80%。对比35°N断面修正前后的盐度资料,订正后温盐跃层处出现的低盐区域消失。MVP的应用比常规海洋调查仪器CTD对于海洋现象的观测更有优势。 展开更多
关键词 走航式海洋多参数剖测量系统MVP 盐度尖峰 MCT(match CONDUCTIVITY and temperature RESPONSE time)'~r
下载PDF
辽朝南面官研究——以碑刻资料为中心 被引量:39
5
作者 杨军 《史学集刊》 CSSCI 北大核心 2013年第3期3-19,共17页
碑刻资料证明,辽朝南面官的结衔总计包括10个方面的内容,依次为:功臣号、职、阶、官、散官、宪、勋、爵、邑(封)、赐。职是实职,官代表品级,其他皆为虚衔。官员在职、阶、官、勋四个方面的升迁并不同步,但官与职大致存在对应关系。根据... 碑刻资料证明,辽朝南面官的结衔总计包括10个方面的内容,依次为:功臣号、职、阶、官、散官、宪、勋、爵、邑(封)、赐。职是实职,官代表品级,其他皆为虚衔。官员在职、阶、官、勋四个方面的升迁并不同步,但官与职大致存在对应关系。根据碑刻复原的辽代南面官的散官系统,既不同于唐代的实职官,也不同于北宋前期的寄禄官。从门下省、尚书省及六部等机构的属官多作为官称而非职名来看,辽朝并未实行三省六部制,南面朝官的主要权力机构为枢密院和中书省。 展开更多
关键词 结衔
下载PDF
Interfacial Modification of NiO_(x)by Self-assembled Monolayer for Efficient and Stable Inverted Perovskite Solar Cells 被引量:1
6
作者 Xin Yu Yandong Wang +5 位作者 Liufei Li Shantao Zhang Shuang Gao Mao Liang Wen-Hua Zhang Shangfeng Yang 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2024年第4期553-562,I0080-I0091,I0095,共23页
NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy leve... NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy levels and possible redox reactions at the NiO_(x)/perovskite interface severely limit the performance of NiO_(x) based inverted perovskite solar cells.Herein,we introduce a p-type self-assembled monolayer between NiO_(x)and perovskite layers to modify the interface and block the undesirable redox reaction between perovskite and NiO_(x)The selfassembled monolayer molecules all contain phosphoric acid function groups,which can be anchored onto the NiOr surface and passivate the surface defect.Moreover,the introduction of self-assembled monolayers can regulate the energy level structure of NiO_(x),reduce the interfacial band energy offset,and hence promote the hole transport from perovskite to NiO_(x)layer.Consequently,the device performance is significantly enhanced in terms of both power conversion efficiency and stability. 展开更多
关键词 Perovskite solar cell NiO_(x) Self-assembled monolayer Interfacial engineering Stability
下载PDF
肺表面活性蛋白D与呼吸道合胞病毒感染 被引量:2
7
作者 朱亚非 包玲 《医学研究生学报》 CAS 北大核心 2014年第9期998-1001,共4页
肺表面活性蛋白(surfactant protein,SP)-D在机体肺部防御和先天性免疫方面发挥着重要作用。目前的研究表明,SP-D参与儿童呼吸道合胞病毒(respiratory syncytial virus,RSV)感染的发生、发展,提示SP-D可能成为治疗肺部炎症性疾病的有效... 肺表面活性蛋白(surfactant protein,SP)-D在机体肺部防御和先天性免疫方面发挥着重要作用。目前的研究表明,SP-D参与儿童呼吸道合胞病毒(respiratory syncytial virus,RSV)感染的发生、发展,提示SP-D可能成为治疗肺部炎症性疾病的有效手段。文中就SP-D结构、功能及其与RSV关系、对肺部炎症性疾病治疗方面作一综述,旨在为RSV感染的治疗提供依据。 展开更多
关键词 肺表活性蛋白D 生理功能 呼吸道合胞病毒感染
下载PDF
面条机搅拌杯多重倒扣成型注塑模具设计 被引量:18
8
作者 赵战锋 《工程塑料应用》 CAS CSCD 北大核心 2016年第8期73-77,共5页
针对某面条机搅拌杯产品存在多重倒扣难以脱模的问题,设计了单型腔模具结构。采用圆周式薄片侧浇口,并实现了流道废料自动切除。针对产品不同部位的脱模要求设计了不同的脱模机构:型腔侧扣位采用前模抽芯机构进行脱模,型芯侧外侧面多重... 针对某面条机搅拌杯产品存在多重倒扣难以脱模的问题,设计了单型腔模具结构。采用圆周式薄片侧浇口,并实现了流道废料自动切除。针对产品不同部位的脱模要求设计了不同的脱模机构:型腔侧扣位采用前模抽芯机构进行脱模,型芯侧外侧面多重扣位采用哈夫滑块抽芯机构进行脱模,型芯侧内侧面多重扣位采用斜顶机构进行脱模,产品的完全顶出采用推件板顶出方式顶出脱模。结合一侧哈夫滑块抽芯时,需先行将螺纹镶件抽出的特点,在该哈夫滑块的结构基础上,设计了复合式斜导柱+弯销+螺纹滑块脱模机构,实现了产品上各局部扣位的脱模。设计的模具完成了所有的侧抽芯脱模动作,实现了自动化注塑生产。 展开更多
关键词 条机搅拌杯 注塑模具设计 侧抽芯 脱模 哈夫滑块 多重倒扣 自动化注塑
下载PDF
汉语“面”的词缀化考察 被引量:3
9
作者 冯凌宇 《古汉语研究》 CSSCI 北大核心 2008年第3期72-76,共5页
"面"作为方位词缀,其词缀化的主要历程包括两个方面:(1)"面"义由实到虚:面部→平面、方面→方向、方位→"词缀",(2)"方+面"结构由松到紧:短语→复合词→派生词。而随着与各种方位语素的结合,&q... "面"作为方位词缀,其词缀化的主要历程包括两个方面:(1)"面"义由实到虚:面部→平面、方面→方向、方位→"词缀",(2)"方+面"结构由松到紧:短语→复合词→派生词。而随着与各种方位语素的结合,"面"最终成为词缀。而词汇化过程中,概念"从隐含到呈现"规律是双音"方+面"增多的主要动因。 展开更多
关键词 方位词 词缀化
下载PDF
利用Micorsoft VisualJ^(++)使Web页面丰富多彩
10
作者 张天庆 于中华 唐常杰 《计算机应用》 CSCD 1997年第3期68-68,共1页
本文通过介绍利用MicrosoftJ++生成Javaapplets,并使之与COM(ComponentObjectModel)集成。
关键词 WEB页 Javaapplets COM 程序语言
下载PDF
Why the abnormal phenomena of D-band center theory exist?A new BASED theory for surface catalysis and chemistry
11
作者 Zelong Qiao Run Jiang +1 位作者 Jimmy Yun Dapeng Cao 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第9期44-53,共10页
Since the D-band center theory was proposed,it has been widely used in the fields of surface chemistry by almost all researchers,due to its easy understanding,convenient operation and relative accuracy.However,with th... Since the D-band center theory was proposed,it has been widely used in the fields of surface chemistry by almost all researchers,due to its easy understanding,convenient operation and relative accuracy.However,with the continuous development of material systems and modification strategies,researchers have gradually found that D-band center theory is usually effective for large metal particle systems,but for small metal particle systems or semiconductors,such as single atom systems,the opposite conclusion to the D-band center theory is often obtained.To solve the issue above,here we propose a bonding and anti-bonding orbitals stable electron intensity difference(BASED)theory for surface chemistry.The newly-proposed BASED theory can not only successfully explain the abnormal phenomena of D-band center theory,but also exhibits a higher accuracy for prediction of adsorption energy and bond length of intermediates on active sites.Importantly,a new phenomenon of the spin transition state in the adsorption process is observed based on the BASED theory,where the active center atom usually yields an unstable high spin transition state to enhance its adsorption capability in the adsorption process of intermediates when their distance is about 2.5Å.In short,the BASED theory can be considered as a general principle to understand catalytic mechanism of intermediates on surfaces. 展开更多
关键词 Surface chemistry Surface catalysis D-band center theory Bonding orbital Anti-bonding orbital
下载PDF
Optical facet coatings for high-performance LWIR quantum cascade lasers atλ∼8.5μm
12
作者 MA Yuan LIN Yu-Zhe +5 位作者 WAN Chen-Yang WANG Zi-Xian ZHOU Xu-Yan ZHANG Jin-Chuan LIU Feng-Qi ZHENG Wan-Hua 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2024年第4期497-502,共6页
We report on the performance improvement of long-wave infrared quantum cascade lasers(LWIR QCLs)by studying and optimizing the anti-reflection(AR)optical facet coating.Compared to the Al2O3 AR coat⁃ing,the Y_(2)O_(3)A... We report on the performance improvement of long-wave infrared quantum cascade lasers(LWIR QCLs)by studying and optimizing the anti-reflection(AR)optical facet coating.Compared to the Al2O3 AR coat⁃ing,the Y_(2)O_(3)AR coating exhibits higher catastrophic optical mirror damage(COMD)level,and the optical facet coatings of both material systems have no beam steering effect.A 3-mm-long,9.5-μm-wide buried-heterostruc⁃ture(BH)LWIR QCL ofλ~8.5μm with Y_(2)O_(3)metallic high-reflection(HR)and AR of~0.2%reflectivity coating demonstrates a maximum pulsed peak power of 2.19 W at 298 K,which is 149%higher than that of the uncoated device.For continuous-wave(CW)operation,by optimizing the reflectivity of the Y_(2)O_(3)AR coating,the maximum output power reaches 0.73 W,which is 91%higher than that of the uncoated device. 展开更多
关键词 quantum cascade lasers long-wave infrared optical facet coatings catastrophic optical mirror damage
下载PDF
Interface engineering via temperature-dependent self-transformation on SnS_(2)/SnS for enhanced piezocatalysis
13
作者 Wenrou Tian Jun Han +4 位作者 Najun Li Dongyun Chen Qingfeng Xu Hua Li Jianmei Lu 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第9期166-179,共14页
Heterojunction has been widely used in vibration-driven piezocatalysis for enhanced charges separation,while the weak interfaces seriously affect the efficiency during mechanical deformations due to prepared by tradit... Heterojunction has been widely used in vibration-driven piezocatalysis for enhanced charges separation,while the weak interfaces seriously affect the efficiency during mechanical deformations due to prepared by traditional step-by-step methods.Herein,the intimate contact interfaces with shared S atoms are ingeniously constructed in SnS_(2)/SnS anchored on porous carbon by effective interface engineering,which is in-situ derived from temperature-dependent self-transformation of SnS_(2).Benefiting from intimate contact interfaces,the piezoelectricity is remarkably improved due to the larger interfacial dipole moment caused by uneven distribution of charges.Importantly,vibration-induced piezoelectric polarization field strengthens the interfacial electric field to further promote the separation and migration of charges.The dynamic charges then transfer in porous carbon with high conductivity and adsorption for significantly improved piezocatalytic activity.The degradation efficiency of bisphenol A(BPA)is 6.3 times higher than SnS_(2) and H_(2) evolution rate is increased by 3.8 times.Compared with SnS_(2)/SnS prepared by two-step solvothermal method,the degradation efficiency of BPA and H2 evolution activity are increased by 3 and 2 times,respectively.It provides a theoretical guidance for developing various multiphase structural piezocatalyst with strong interface interactions to improve the piezocatalytic efficiency. 展开更多
关键词 Piezocatalysis SELF-TRANSFORMATION Phase junction Interfacial field Polarized field
下载PDF
《庄子·秋水》“旋其面目”考辨 被引量:2
14
作者 郭剑英 《湖南工业大学学报(社会科学版)》 2010年第1期124-126,共3页
《庄子·秋水》篇中的"旋其面目"一语,"旋"当训"还",系还返、回复之义;"面目"指与神情有关的面容。"旋其面目",即是回复其面容。"面目"不表"脸"或"头&... 《庄子·秋水》篇中的"旋其面目"一语,"旋"当训"还",系还返、回复之义;"面目"指与神情有关的面容。"旋其面目",即是回复其面容。"面目"不表"脸"或"头"义,"旋其面目"不能解为"转过脸"或"转过头来";河伯"顺流而东行,至于北海","北海"即黄河所入之海,在黄河入海口之东;河伯"东面而视",所视即为"北海",也用不着"转过脸"或"转过头来"。 展开更多
关键词 《庄子·秋水》 旋其 北海
下载PDF
Versatile fluidity test model for cast superalloys and comparison between IN718 and IN939
15
作者 Jun ZHANG Zi-qi JIE +1 位作者 Miao-nan LIU Min GUO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第9期2881-2888,共8页
A spiral fluidity test model of superalloys with 10 mm in height and 3 mm in thickness was designed to evaluate the fluidity of two distinct Ni-based superalloys IN718 and IN939.The factors influencing fluidity are as... A spiral fluidity test model of superalloys with 10 mm in height and 3 mm in thickness was designed to evaluate the fluidity of two distinct Ni-based superalloys IN718 and IN939.The factors influencing fluidity are ascertained through comparative analysis utilizing methodologies such as JMat Pro,differential scanning calorimetry and high-temperature confocal laser scanning microscopy.The results show that under identical testing conditions,the fluidity of the IN939 superalloy surpasses that of the IN718 superalloy.When subjected to the same temperature,the melt viscosity and surface tension of IN939 superalloy are considerably reduced relative to those of IN718 superalloy,which is beneficial to improving the melt fluidity.Furthermore,the liquidus temperature and solidification range for the IN939 superalloy are both smaller compared with those of the IN718 superalloy.This condition proves advantageous in delaying dendrite coherency,thereby improving fluidity. 展开更多
关键词 FLUIDITY solidification range SUPERALLOYS surface tension VISCOSITY
下载PDF
Preparation and interface state of phosphate tailing-based geopolymers
16
作者 ZHANG Shou-xun XIE Xian +4 位作者 XIE Rui-qi TONG Xiong WU Yu-yao LI Jia-wen LI Yue 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第6期1900-1914,共15页
The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geop... The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geopolymers with compressive strength of 38.8 MPa were prepared by using phosphate tailings as the main raw material,fly ash as the active silicon-aluminum material,and water glass as the alkaline activator.The solid content of phosphate tailings and fly ash was 60% and 40%,respectively,and the water-cement ratio was 0.22.The results of XRD,FTIR,SEM-EDS and XPS show that the reactivity of phosphate tailings with alkaline activator is weak,and the silicon-aluminum material can react with alkaline activator to form zeolite and gel,and encapsulate/cover the phosphate tailings to form a dense phosphate tailings-based geopolymer.During the formation of geopolymers,part of the aluminum-oxygen tetrahedron replaced the silicon-oxygen tetrahedron,causing the polycondensation reaction between geopolymers and increasing the strength of geopolymers.The leaching toxicity test results show that the geopolymer has a good solid sealing effect on heavy metal ions.The preparation of geopolymer from phosphate tailings is an important way to alleviate the storage pressure and realize the resource utilization of phosphate tailings. 展开更多
关键词 phosphate tailing GEOPOLYMER interface state toxicity leaching
下载PDF
Microenvironment and electronic state modulation of Pd nanoparticles within MOFs for enhancing low-temperature activity towards DCPD hydrogenation
17
作者 Zhiyuan Liu Changan Wang +8 位作者 Ping Yang Wei Wang Hongyi Gao Guoqing An Siqi Liu Juan Chen Tingting Guo Xinmeng Xu Ge Wang 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第9期112-122,共11页
Precise control of the local environment and electronic state of the guest is an important method of controlling catalytic activity and reaction pathways.In this paper,guest Pd NPs were introduced into a series of hos... Precise control of the local environment and electronic state of the guest is an important method of controlling catalytic activity and reaction pathways.In this paper,guest Pd NPs were introduced into a series of host UiO-67 MOFs with different functional ligands and metal nodes,the microenvironment and local electronic structure of Pd is modulated by introducing bipyridine groups and changing metal nodes(Ce_(6)O_(6) or Zr_(6)O_(6)).The bipyridine groups not only promoted the dispersion Pd NPs,but also facilitated electron transfer between Pd and UiO-67 MOFs through the formation of Pd-N bridges.Compared with Zr6 clusters,the tunability and orbital hybridisation of the 4f electronic structure in the Ce_(6) clusters modulate the electronic structure of Pd through the construction of the Ce-O-Pd interfaces.The optimal catalyst Pd/UiO-67(Ce)-bpy presented excellent low-temperature activity towards dicyclopentadiene hydrogenation with a conversion of>99% and a selectivity of>99%(50℃,10 bar).The results show that the synergy of Ce-O-Pd and Pd-N promotes the formation of active Pd^(δ+),which not only enhances the adsorption of H_(2) and electron-rich C=C bonds,but also contributes to the reduction of proton migration distance and improves proton utilization efficiency.These results provide valuable insights for investigating the regulatory role of the host MOFs,the nature of host-guest interactions,and their correlation with catalytic performance. 展开更多
关键词 Interface regulation Pd^(δ+) MICROENVIRONMENT Electronic state HYDROGENATION
下载PDF
In-situ thermal Raman mapping and stress analysis of CNT/CF/epoxy interfaces
18
作者 HE Jing-zong CHEN Shi +2 位作者 MA Zheng-kun LU Yong-gen WU Qi-lin 《新型炭材料(中英文)》 SCIE EI CAS CSCD 北大核心 2024年第4期703-714,共12页
A study of the interfacial behavior and internal thermal stress distribution in fiber-reinforced composites is essential to assess their performance and reliability.CNT/carbon fiber(CF)hybrid fibers were constructed u... A study of the interfacial behavior and internal thermal stress distribution in fiber-reinforced composites is essential to assess their performance and reliability.CNT/carbon fiber(CF)hybrid fibers were constructed using electrophoretic deposition.The interfacial properties of CF/epoxy and CNT/CF/epoxy composites were statistically investigated and compared using in-situ thermal Raman mapping by dispersing CNTs as a Raman sensing medium(CNT_(R))in a resin.The associated local thermal stress changes can be simulated by capturing the G'band position distribution of CNT_(R) in the epoxy at different temperatures.It was found that the G'band shifted to lower positions with increasing temperature,reaching a maximum difference of 2.43 cm^(−1) at 100℃.The interfacial bonding between CNT/CF and the matrix and the stress distribution and changes during heat treatment(20-100℃)were investig-ated in detail.This work is important for studying thermal stress in fiber-reinforced composites by in-situ thermal Raman mapping technology. 展开更多
关键词 Thermal Raman mapping Stress distribution Carbon fiber Carbon nanotube Interface
下载PDF
Ultra-soft Desorption Assisted Mass Spectrometry using Picosecond Infrared Laser for the Detection of lons in the Liquid Surface
19
作者 Ziyuan Li Yue Wang +2 位作者 Tiantian Tong Ziwei Chen Shan Xi Tian 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2024年第4期461-464,I0093,共5页
To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to i... To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to isolate the ionic,larger species from the liquid surface,because of the frangible structures and the higher solvation energies of those species.Here we demonstrate a new mass spectrometry in which the ionic species at the liquid surface can be desorbed with ultrasoft infrared picosecond laser pulses while the liquid surface is not breached.This laser desorption assisted mass spectrometry is not only a powerful tool to detect the fragile species but also promising to investigate vibrational energy transfer dynamics in the liquid surface. 展开更多
关键词 Ultrasoft desorption Infrared laser Picosecond pulse Mass spectrometry Liquid surface
下载PDF
In-situ building of multiscale porous NiFeZn/NiZn-Ni heterojunction for superior overall water splitting
20
作者 Ya-xin LI Hong-xiao YANG +4 位作者 Qiu-ping ZHANG Tian-zhen JIAN Wen-qing MA Cai-xia XU Qiu-xia ZHOU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第9期2972-2986,共15页
The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).A sel... The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).A self-supporting,multiscale porous NiFeZn/NiZn-Ni catalyst with a triple interface heterojunction on nickel foam(NF)(NiFeZn/NiZn-Ni/NF)was in-situ fabricated using an electroplating-annealing-etching strategy.The unique multiinterface engineering and three-dimensional porous scaffold significantly modify the mass transport and electron interaction,resulting in superior bifunctional electrocatalytic performance for water splitting.The NiFeZn/NiZn-Ni/NF catalyst demonstrates low overpotentials of 187 m V for HER and 320 mV for OER at a current density of 600 mA/cm^(2),along with high durability over 150 h in alkaline solution.Furthermore,an electrolytic cell assembled with NiFeZn/NiZn-Ni/NF as both the cathode and anode achieves the current densities of 600 and 1000 m A/cm^(2) at cell voltages of 1.796 and 1.901 V,respectively,maintaining the high stability at 50 mA/cm^(2) for over 100 h.These findings highlight the potential of NiFeZn/NiZn-Ni/NF as a cost-effective and highly efficient bifunctional electrocatalyst for overall water splitting. 展开更多
关键词 NiFeZn alloy multiple interface porous structure DEALLOYING overall water splitting
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部