Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents th...Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents them from being scaled-up,limiting their commercial applications.Herein,an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles(TONPs)by one-pot method.Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its an tiferromag netism.At low temperatures,Mn-PtCo TONPs are ferromag netic,and the coercivity in creases gradually with in creasi ng Mn contents.At room temperature,the Mn-PtCo TONPs display superparamag netic behavior,which is greatly helpful for in dustrial recycling.Mn doping can not only modify the electronic structure of PtCo TONPs but also enhanee electrocatalytic performance for methanol oxidation reaction.The maximum specific activity of Mn-PtCo-3 reaches 8.1 A`m^-2,3.6 times of commercial Pt/C(2.2 A·m^-2)and 1.4 times of PtCo TONPs(5.6 A`m^-2),respectively.The mass activity decreases by only 30%after 2,000 cycles,while it is 45%and 99%(nearly inactive)for PtCo TONPs and commercial Pt/C catalysts,respectively.展开更多
Using a stiffness matrix method, we in- vestigate the propagation behaviors of elastic waves in one-dimensional （1D） piezoelectric/piezomagnetic （PE/PM） phononic crystals （PCs） with line defects by calculating e...Using a stiffness matrix method, we in- vestigate the propagation behaviors of elastic waves in one-dimensional （1D） piezoelectric/piezomagnetic （PE/PM） phononic crystals （PCs） with line defects by calculating energy reflection/transmittion coefficients of quasi-pressure and quasi-shear waves. Line defects are created by the re- placement of PE or PM constituent layer. The defect modes existing in the first gap are considered and the influences on defect modes of the material properties and volume fraction of the defect layers, the type of incident waves, the location of defect layer and the number of structural layers are discussed in detail. Numerical results indicate that defect modes are the most obvious when the defect layers are inserted in the middle of the perfect PCs; the types of incidence wave and material properties of the defect layers have important effects on the numbers, the location of frequencies and the peaks of defect modes, and the defect modes are strongly de- pendent on volume fraction of the defect layers. We hope this paper will be found useful for the design of PE/PM acoustic filters or acoustic transducer with PCs structures.展开更多
This paper is concerned with the decay of Saint-Venant end effects for plane deformations of piezoelectric （PE）-piezomagnetic （PM） sandwich structures, where a PM layer is located between two PE layers with the sa...This paper is concerned with the decay of Saint-Venant end effects for plane deformations of piezoelectric （PE）-piezomagnetic （PM） sandwich structures, where a PM layer is located between two PE layers with the same material properties or reversely. The end of the sandwich structure is subjected to a set of self-equilibrated magneto-electro-elastic loads. The upper and lower surfaces of the sandwich structure axe mechanically free, electrically open or shorted as well as magnetically open or shorted. Firstly the constitutive equations of PE mate- rials and PM materials for plane strain are given and normalized. Secondly, the simplified state space approach is employed to arrange the constitutive equations into differential equations in a matrix form. Finally, by using the transfer matrix method, the characteristic equations for eigen- values or decay rates axe derived. Based on the obtained characteristic equations, the decay rates for the PE-PM-PE and PM-PE-PM sandwich structures are calculated. The influences of the electromagnetic boundary conditions, material properties of PE layers and volume fraction on the decay rates are discussed in detail.展开更多
Physical models of ion diffusion at different interfaces are reviewed. The use of impedance spectroscopy （IS）, nuclear magnetic resonance （NMR）, and secondary ion mass spectrometry （SIMS） techniques are also dis...Physical models of ion diffusion at different interfaces are reviewed. The use of impedance spectroscopy （IS）, nuclear magnetic resonance （NMR）, and secondary ion mass spectrometry （SIMS） techniques are also discussed. The diffusion of ions is fundamental to the operation of lithium-ion batteries, taking place not only within the grains but also across different interfaces. Interfacial ion transport usually contributes to the majority of the resistance in lithium-ion batteries. A greater understanding of the interfacial diffusion of ions is crucial to improving battery performance.展开更多
An automatic control system for the electrostatic accelerator has been developed by adopting the PLC （Programmable Logic Controller） control technique, infrared and optical-fibre transmission technique and network c...An automatic control system for the electrostatic accelerator has been developed by adopting the PLC （Programmable Logic Controller） control technique, infrared and optical-fibre transmission technique and network communication with the purpose to improve the intelligence level of the accelerator and to enhance the ability of monitoring, collecting and recording parameters. In view of the control system＇ structure, some anti-interference measures have been adopted after analyzing the interference sources. The measures in hardware include controlling the position of the corona needle, using surge arresters, shielding, ground connection and stabilizing the voltage. The measures in terms of software involve inter-blocking protection, soft-spacing, time delay, and diagnostic and protective programs. The electromagnetic compatible ability of the control system has thus been effectively improved.展开更多
Three new transition metal tricyanomethanide complexes [Co（dpdo）（tcm）2] （1）, [Cu（dpdo）（tcm）2] （2） and Cu（dpdo）2（tcm）2 （3） were synthesized and structurally characterized. In compound 1 each Co（II） ...Three new transition metal tricyanomethanide complexes [Co（dpdo）（tcm）2] （1）, [Cu（dpdo）（tcm）2] （2） and Cu（dpdo）2（tcm）2 （3） were synthesized and structurally characterized. In compound 1 each Co（II） ion is coordinated to four disorder tcm anions and one dpdo molecule to give a distorted octahedral geometry. In compound 2 each Cu（II） ion is surrounded by four tcm anions and one dpdo ligand to form a square bipyramidal geometry. Both compounds 1 and 2 display a μ1,5-tcm bridged infinite chain structure. Interestingly, in compound 3 coordination geometry around the central ion is square-planar, each Cu（II） ion is coordinated by two dpdo molecules to form a cationic part, the cationic parts is linked with the free tcm anionic parts via electrostatic attraction, leading to the formation of a mononuclear structure. Magnetic susceptibility measurement in the range 2--300 K indicates that there are antiferromagnetic couplings between adjacent metal ions in 1 （0=--2.33 K, C=2.13 cm3-mol 1oK） and 2 （J= --0.30, g = 2.20） respectively.展开更多
伴随着预测性维护和大数据分析的需求在自动化领域的日益增加,设备级过程数据的重要性也越来越突出。赫优讯推出的设备级物联网嵌入式研发产品net IC IOT,是基于net X 52多协议芯片研发的一款智能DIL-32封装通讯IC,集成通用对象接口,通...伴随着预测性维护和大数据分析的需求在自动化领域的日益增加,设备级过程数据的重要性也越来越突出。赫优讯推出的设备级物联网嵌入式研发产品net IC IOT,是基于net X 52多协议芯片研发的一款智能DIL-32封装通讯IC,集成通用对象接口,通过OPC UA和MQTT实现Io T通讯,并在同一根物理线缆上与实时以太网通讯并行地传输数据。net IC IOT采用net PROXY技术,基于对象的抽象层,面向应用程序开发,并通过net X Studio工程工具进行参数配置。展开更多
目的：探讨振幅整合脑电图（aEEG）在新生儿缺氧缺血性脑病（HIE）早期诊断及预后评估中的意义。方法将2012年1月至2013年12月在河北省儿童医院新生儿科住院的90例足月 HIE 患儿分为轻度、中度和重度3组，分别在出生12 h 内进行 aEEG ...目的：探讨振幅整合脑电图（aEEG）在新生儿缺氧缺血性脑病（HIE）早期诊断及预后评估中的意义。方法将2012年1月至2013年12月在河北省儿童医院新生儿科住院的90例足月 HIE 患儿分为轻度、中度和重度3组，分别在出生12 h 内进行 aEEG 描记，出生3~7 d 行头颅磁共振成像（MRI）检查，分为轻度异常、中度异常和重度异常3组。将 aEEG 监测结果分为正常、轻度异常、重度异常3组，与 HIE 患儿临床分度及头颅 MRI 表现进行相关性分析，并应用患儿出生7 d、14 d 及28 d 新生儿行为神经系统（NBNA）评分、出生12个月中国儿童发展量表婴幼儿智能发育测试对 HIE 患儿进行预后评估。结果1. HIE 患儿90例中轻度 HIE 44例（48.9%），中度 HIE 29例（32.2%），重度 HIE 17例（18.9%）；头颅 MRI 轻度异常49例（54.4%），中度异常23例（25.6%），重度异常18例（20.0%）；aEEG 正常43例（47.8%），轻度异常25例（27.8%），重度异常22例（24.4%）。2. aEEG 分类结果与 HIE 临床分度有相关性（r =0.9707，P ﹤0.001）。aEEG 分类结果与 HIE 患儿头颅 MRI 分度有相关性（r =0.9335，P ﹤0.001）。3. aEEG 重度异常 HIE 患儿 NBNA 评分明显低于轻度异常组[出生7 d：（14.1±4.2）分比（32.2±2.3）分，出生14 d：（17.8±5.6）分比（33.4±2.1）分，出生28 d：（18.9±8.4）分比（34.6±2.6）分]，差异均有统计学意义（P 均﹤0.05）。4. aEEG 重度异常 HIE 患儿12月龄时随访发育商智力发育指数（ MDI）及运动发育指数（ PDI）明显低于轻度异常组[ MDI（65.1±4.1）分比（89.1±6.7）分，PDI（67.5±10.1）分比（90.7±8.3）分]，差异均有统计学意义（P 均﹤0.05）。结论 aEEG可早期判断 HIE 病情程度，对 HIE 临床预后有评估价值。展开更多
基金The work was supported by the National Natural Science Foundation(Nos.51625101,51431009,5180118&and 51701202)the State Key Development Program for Basic Research of China(No.2015CB921401)+3 种基金the Fundamental Research Funds for the Central University Universities of China(No.FRF-TP-16-001C2)the China Postdoctoral Science Foundation(No.2018M632792)Startup Research Fund of Zhengzhou University(No.32210815)Bejing Natural Science Foundation(No.Z180014).
文摘Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents them from being scaled-up,limiting their commercial applications.Herein,an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles(TONPs)by one-pot method.Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its an tiferromag netism.At low temperatures,Mn-PtCo TONPs are ferromag netic,and the coercivity in creases gradually with in creasi ng Mn contents.At room temperature,the Mn-PtCo TONPs display superparamag netic behavior,which is greatly helpful for in dustrial recycling.Mn doping can not only modify the electronic structure of PtCo TONPs but also enhanee electrocatalytic performance for methanol oxidation reaction.The maximum specific activity of Mn-PtCo-3 reaches 8.1 A`m^-2,3.6 times of commercial Pt/C(2.2 A·m^-2)and 1.4 times of PtCo TONPs(5.6 A`m^-2),respectively.The mass activity decreases by only 30%after 2,000 cycles,while it is 45%and 99%(nearly inactive)for PtCo TONPs and commercial Pt/C catalysts,respectively.
基金supported by the National Natural Science Foundation of China(11102122)
文摘Using a stiffness matrix method, we in- vestigate the propagation behaviors of elastic waves in one-dimensional （1D） piezoelectric/piezomagnetic （PE/PM） phononic crystals （PCs） with line defects by calculating energy reflection/transmittion coefficients of quasi-pressure and quasi-shear waves. Line defects are created by the re- placement of PE or PM constituent layer. The defect modes existing in the first gap are considered and the influences on defect modes of the material properties and volume fraction of the defect layers, the type of incident waves, the location of defect layer and the number of structural layers are discussed in detail. Numerical results indicate that defect modes are the most obvious when the defect layers are inserted in the middle of the perfect PCs; the types of incidence wave and material properties of the defect layers have important effects on the numbers, the location of frequencies and the peaks of defect modes, and the defect modes are strongly de- pendent on volume fraction of the defect layers. We hope this paper will be found useful for the design of PE/PM acoustic filters or acoustic transducer with PCs structures.
基金Project supported by the National Natural Science Foundation of China (No. 10972147)
文摘This paper is concerned with the decay of Saint-Venant end effects for plane deformations of piezoelectric （PE）-piezomagnetic （PM） sandwich structures, where a PM layer is located between two PE layers with the same material properties or reversely. The end of the sandwich structure is subjected to a set of self-equilibrated magneto-electro-elastic loads. The upper and lower surfaces of the sandwich structure axe mechanically free, electrically open or shorted as well as magnetically open or shorted. Firstly the constitutive equations of PE mate- rials and PM materials for plane strain are given and normalized. Secondly, the simplified state space approach is employed to arrange the constitutive equations into differential equations in a matrix form. Finally, by using the transfer matrix method, the characteristic equations for eigen- values or decay rates axe derived. Based on the obtained characteristic equations, the decay rates for the PE-PM-PE and PM-PE-PM sandwich structures are calculated. The influences of the electromagnetic boundary conditions, material properties of PE layers and volume fraction on the decay rates are discussed in detail.
基金supported by the Beijing S&T Project,China(Grant No.Z13111000340000)the National Natural Science Foundation of China(Grant Nos.51325206and 11234013)the National Basic Research Program of China(Grant No.2012CB932900)
文摘Physical models of ion diffusion at different interfaces are reviewed. The use of impedance spectroscopy （IS）, nuclear magnetic resonance （NMR）, and secondary ion mass spectrometry （SIMS） techniques are also discussed. The diffusion of ions is fundamental to the operation of lithium-ion batteries, taking place not only within the grains but also across different interfaces. Interfacial ion transport usually contributes to the majority of the resistance in lithium-ion batteries. A greater understanding of the interfacial diffusion of ions is crucial to improving battery performance.
基金the special fund of the Education Department of Henan Provice
文摘An automatic control system for the electrostatic accelerator has been developed by adopting the PLC （Programmable Logic Controller） control technique, infrared and optical-fibre transmission technique and network communication with the purpose to improve the intelligence level of the accelerator and to enhance the ability of monitoring, collecting and recording parameters. In view of the control system＇ structure, some anti-interference measures have been adopted after analyzing the interference sources. The measures in hardware include controlling the position of the corona needle, using surge arresters, shielding, ground connection and stabilizing the voltage. The measures in terms of software involve inter-blocking protection, soft-spacing, time delay, and diagnostic and protective programs. The electromagnetic compatible ability of the control system has thus been effectively improved.
基金Project supported by the National Natural Science Foundation of China （No. 20571086）.
文摘Three new transition metal tricyanomethanide complexes [Co（dpdo）（tcm）2] （1）, [Cu（dpdo）（tcm）2] （2） and Cu（dpdo）2（tcm）2 （3） were synthesized and structurally characterized. In compound 1 each Co（II） ion is coordinated to four disorder tcm anions and one dpdo molecule to give a distorted octahedral geometry. In compound 2 each Cu（II） ion is surrounded by four tcm anions and one dpdo ligand to form a square bipyramidal geometry. Both compounds 1 and 2 display a μ1,5-tcm bridged infinite chain structure. Interestingly, in compound 3 coordination geometry around the central ion is square-planar, each Cu（II） ion is coordinated by two dpdo molecules to form a cationic part, the cationic parts is linked with the free tcm anionic parts via electrostatic attraction, leading to the formation of a mononuclear structure. Magnetic susceptibility measurement in the range 2--300 K indicates that there are antiferromagnetic couplings between adjacent metal ions in 1 （0=--2.33 K, C=2.13 cm3-mol 1oK） and 2 （J= --0.30, g = 2.20） respectively.
文摘伴随着预测性维护和大数据分析的需求在自动化领域的日益增加,设备级过程数据的重要性也越来越突出。赫优讯推出的设备级物联网嵌入式研发产品net IC IOT,是基于net X 52多协议芯片研发的一款智能DIL-32封装通讯IC,集成通用对象接口,通过OPC UA和MQTT实现Io T通讯,并在同一根物理线缆上与实时以太网通讯并行地传输数据。net IC IOT采用net PROXY技术,基于对象的抽象层,面向应用程序开发,并通过net X Studio工程工具进行参数配置。
文摘目的：探讨振幅整合脑电图（aEEG）在新生儿缺氧缺血性脑病（HIE）早期诊断及预后评估中的意义。方法将2012年1月至2013年12月在河北省儿童医院新生儿科住院的90例足月 HIE 患儿分为轻度、中度和重度3组，分别在出生12 h 内进行 aEEG 描记，出生3~7 d 行头颅磁共振成像（MRI）检查，分为轻度异常、中度异常和重度异常3组。将 aEEG 监测结果分为正常、轻度异常、重度异常3组，与 HIE 患儿临床分度及头颅 MRI 表现进行相关性分析，并应用患儿出生7 d、14 d 及28 d 新生儿行为神经系统（NBNA）评分、出生12个月中国儿童发展量表婴幼儿智能发育测试对 HIE 患儿进行预后评估。结果1. HIE 患儿90例中轻度 HIE 44例（48.9%），中度 HIE 29例（32.2%），重度 HIE 17例（18.9%）；头颅 MRI 轻度异常49例（54.4%），中度异常23例（25.6%），重度异常18例（20.0%）；aEEG 正常43例（47.8%），轻度异常25例（27.8%），重度异常22例（24.4%）。2. aEEG 分类结果与 HIE 临床分度有相关性（r =0.9707，P ﹤0.001）。aEEG 分类结果与 HIE 患儿头颅 MRI 分度有相关性（r =0.9335，P ﹤0.001）。3. aEEG 重度异常 HIE 患儿 NBNA 评分明显低于轻度异常组[出生7 d：（14.1±4.2）分比（32.2±2.3）分，出生14 d：（17.8±5.6）分比（33.4±2.1）分，出生28 d：（18.9±8.4）分比（34.6±2.6）分]，差异均有统计学意义（P 均﹤0.05）。4. aEEG 重度异常 HIE 患儿12月龄时随访发育商智力发育指数（ MDI）及运动发育指数（ PDI）明显低于轻度异常组[ MDI（65.1±4.1）分比（89.1±6.7）分，PDI（67.5±10.1）分比（90.7±8.3）分]，差异均有统计学意义（P 均﹤0.05）。结论 aEEG可早期判断 HIE 病情程度，对 HIE 临床预后有评估价值。
