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1.
毫米波用六角铁氧体多晶材料   总被引:1,自引:0,他引:1  
冯全源  任朗 《功能材料》2000,31(1):48-49
用普通陶瓷工艺制备了BaAlxFe12-xO19六角铁氧体多晶材料,随着X的增加,饱和磁化强度减小,居里温度下降,磁晶各向异性场增加。其结果可以通过假设Al^3+取代了2a位和12K点阵位上的Fe^3+来解释。  相似文献   

2.
从理论和实验上分析了Fe^3+和Fe^2+对(BiA)YIG薄膜的生长感各向异性的贡献,掺Bi导致的生长磁感生各向异性,来源于Ei^3+改变了Fe^3+的零场劈裂,其大小取决于Bi^3+含量及在十二面体位的择优分布,高价离子和氧空位形成的Fe^2+在八面体位的择优分布,对生长感生磁各向异性也有贡献。  相似文献   

3.
ZnxFe3—xO4的制备及性能   总被引:4,自引:0,他引:4  
采用合适加剂在碱性溶液中制备了FeZn铁氧体,研究了其形成机理及磁性能,提出FeZn铁氧体的形成机理为:An^2++2Fe^3++80H^-→ZnFe2O4+4H2O Fe^2++2Fe^2++80H^-→Fe3O4+4H2O。  相似文献   

4.
提出了乳状液膜体系自湿法冶锌系统中经一级同时分离镓和锗的新方法,建立了用P204和C5-7羟肟酸协同载体,pH=3.2的NH4F溶液为内水相试剂,使Ge^4+以溶液状态而Ga^3+则以Ga(OH)3沉淀同步迁移进入内水相并分别回收的液膜体系,研究了影响Ga^3+、Ge^4+迁移的各种因素,经正交实验确定了分离镓和锗的最佳液膜组成及操作条件,并用加入铁粉法除去了杂质Fe^3+和Cu^2+对Ga^3+  相似文献   

5.
退火对氧敏CeO2—x薄膜结构及电子组态的影响   总被引:1,自引:0,他引:1  
用射频磁控溅射法制备了CeO2-x高温氧敏薄膜,用Ce3d的XPS谱计算了Ce^3+浓度,研究了退火条件对氧敏CeO2-x薄膜的晶体结构及电子组态的影响,XRD和AFM分析表明,薄膜经973K至1373退火后,形成了CaF2型结构的CeO2-x其晶粒大小明显依赖于退火条件和膜厚,退火温度在973K至1173K时(200)晶面是择优取向的,在1373退化4h后,可得到热力学稳定的CeO2-x在退火前  相似文献   

6.
镍内电极多层陶瓷电容器介质材料的研究   总被引:8,自引:0,他引:8  
通过(BaO+CaO)/(TiO2+ZrO2)略大于1的Ba-TiO3系材料进行受主离子Ca^2+、Mg^2+、Fe^3+、Mn^2+和Zn^2+掺杂试验,使瓷料在还原性气氛中与镍电极共烧,获得介电常数为15000、绝缘电阻率达到10^12Ω.cm的抗还原陶瓷。  相似文献   

7.
立方A^4+M^5+2O7型化合物与新型负热膨胀材料   总被引:1,自引:0,他引:1  
概述了立方A^4+M^5+2O7型化合物的结构特点,讨论了AV2-xPxO7型(A=Zr或Hf;x=0.1~1.2)及其部分取代的A^4+1-yB^4+yV2-xPxO7型(B=Ti,Ce,Th,U,Mo,Pt,Pb,Sn,Ge或Si;y=0.1~0.4)和A^4+1-yC^1+yD^3+yV2-xPxO7型(C为碱金属元素,D为稀土金属元素)材料的负热膨胀性能。  相似文献   

8.
卞建江  钟永贵 《材料导报》2000,(Z10):155-157
研究了B位分别掺杂Sn^4+、Zr^4+、Ce^4+对(Pb0.45Ca0.25)(Fe1/2Nb1/2)O3(PCFN)陶瓷的烧结行为、微观结构及微波介电性能的影响。实验结果表明,掺杂样品能在相对较低的温度下烧结(1200℃/2h),B位大半径离子的掺入使介电常数降低,适量的B位掺杂能不同程度的改进PCFN陶瓷的综合微波介电性能。用这种材料做成的带通滤波器在中心频率为928.4MHz下,插入损耗为2.469dB,满足插入损耗应小于3dB的要求,在移动通信中有着实际应用前景。  相似文献   

9.
本文详细地研究了BaYF5和KCaF3基质中Eu^2+、Ce^3+浓度对其发光的影响,发现两基质中Eu^2+、Ce^3+的猝灭浓度都较低;提出了Eu^2+、Ce^3+的浓度猝灭机理,计算了猝灭浓度和临界距离,并与实验结果进行了比较。  相似文献   

10.
制备了可用于蓝色TFEL的粉末发光材料MGa2S4:Ge(M=Ca,Sr)地其昌体结构进行了X射线分析,测量并其激光光谱和发射光谱,研究了Ce^3+浓度的变化对CaGa2S4:Ce和SrGa2S4:Ce的激光光谱,发射光谱、色纯工及发光强度的影响,同时研究了基质组分的改变对发光特性的影响,结果表明,CaGa2S4:Ce和SrGa2S4:Ce的可发射纯蓝色光,色纯度好,对CaGa2S4:Ce来说,实  相似文献   

11.
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.  相似文献   

12.
13.
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……  相似文献   

14.
A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.  相似文献   

15.
On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……  相似文献   

16.
Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.  相似文献   

17.
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill.  相似文献   

18.
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...  相似文献   

19.
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from  相似文献   

20.
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.  相似文献   

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