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InrecentyearsThMn12 typeiron richcompoundshavebeenintensivelyinvestigatedduetotheirexcellentpermanent magneticproperties .AlthoughpurebinaryRE Fecom poundsdonotexist,theThMn12 structurecanbestabilizedinpseudobinariesofthetypeREFe12 -xMx,withM =Al,Ti,Cr ,Si ,Mo ,V …  相似文献   

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The room temperature creep behaviors of Mg61Cu28Gd11 and(Mg61Cu28Gd11)99.5Sb0.5 bulk metallic glasses(BMGs) were revealed by means of nanoindentation technique.The creep mechanism was explored by characterization of creep rate sensitivity,creep compliance and retardation spectra.The results showed that the experimental creep curves could be well described by a generalized Kelvin model.The low creep rate sensitivity of both Mg-based BMGs indicated that their room temperature creep was dominated by localized shear flow.In addition,the(Mg61Cu28Gd11)99.5Sb0.5 glassy alloy exhibited lower creep rate sensitivity,creep compliance and milder retardation peak,indicating its higher creep-resistance and less relaxed state.Furthermore,the creep retardation spectrum consisted of two relatively separated peaks with the well defined characteristic relaxation times.  相似文献   

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The distinction between the anaclitic and introjective configuration of personality and psychopathology has potential to inform therapeutic practice. Anaclitic patients, concerned primarily with obtaining and maintaining close and nurturing interpersonal relations, respond differently to brief and longterm treatment, in comparison to their introjective counterparts, who are mainly concerned with securing a positive sense of self. This article reviews research on the therapeutic responses of anaclitic and introjective patients in three settings: (a) in intensive, inpatient psychoanalytically oriented treatment; (b) in psychoanalysis as compared to long-term supportive-expressive therapy; and (c) in manualized brief treatments for depression. Findings indicate that anaclitic patients improve more in long-term supportive expressive therapy than in psychoanalysis. The reverse occurs with introjective patients, who also did particularly poorly in brief manualized treatment for depression. Therapists should take into account the tendency of anaclitic and introjective patients to receive and react differently to different therapeutic situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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用磁控溅射法在 (0 0 1)取向的LaAlO3单晶基片上制备了La0 .6 7Sr0 .33MnO3/La0 .75MnO3/La0 .6 7Sr0 .33MnO3外延三层膜。结果表明 ,与La0 .6 7Sr0 .33MnO3单层膜相比较 ,外延三层膜的X射线衍射图上出现 3级衍射峰 ,每级衍射峰由 3个峰组成 :其中强度最高的衍射峰代表衬底的衍射 ;次强的代表上下两层La0 .6 7Sr0 .33MnO3膜 ;最弱的代表中间La0 .75MnO3层。三层膜的二维原子力表面形貌为均匀的小颗粒状 ,表明其三维形貌为外延岛状柱状晶。这种三层膜的巨磁电阻效应与中间层La0 .75MnO3的厚度有关 ,当中间层厚度为 70nm时 ,其最大磁电阻值可达到 3 2 % ,这个结果优于La0 .6 7Sr0 .33MnO3单层膜的巨磁电阻效应。其可能的原因是电子在界面上的散射、层间的交互作用 ,以及点阵错配导致的内应力的综合结果。  相似文献   

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Magnetocaloric effect and magnetic properties of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 and its hydride La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 were investigated. The Curie temperature of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was increased by hydrogen absorption. XRD patterns showed that the structure of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 remained NaZn13-type. The Curie temperature (TC) of the sample was increased from 174 K to 331 K. The homogeneity of the hydrogen absorption for La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 was proven very well by the random measurement of DSC. The magnetic entropy △SM of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 had peak at 326 K. The peak value of-△SM-was 12.3 and 7.8 J/(kg.K) under magnetic field change of 0-2 T and 0-1 T,respectively,which was comparable with Gd5Si2Ge2. The negative slope and inflection point of the Arrott curve indicated that the first-order magnetic transition of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was reserved after hydrogen absorption.  相似文献   

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Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) is a scintigraphic imaging technique undergoing a rapid growth in the field of oncology. The constant progress of the detectors, either CDET or PET dedicated cameras, allows to obtain in routine conditions images with a 5 mm spatial resolution. Absolute tracer uptake quantification is also possible, which allows to evaluate objectively therapy efficacy. The mechanisms of FDG tissular accumulation are now better understood. Increase of glycolysis and of transmembrane transport of glucose seems to be at the origin of the high tumorous accumulation of FDG. The main current oncologic application of FDG PET is the diagnosis of malignancy of the isolated pulmonary nodules, with a sensitivity of more than 95%, and in the staging of lung cancer where PET shows higher performances than conventional imaging. The same stands in cutaneous melanoma and for malignancies of the digestive tract, either in colorectal, pancreatic or esophageal localizations. In colorectal cancers, the role of PET has for long being recognized in the differential diagnosis between recurrence and postoperative fibrosis. In the head and neck tumors, FDG also allows to differentiate between recurrence and postradiation necrosis. In lymphoma, the most suitable site for biopsy can be identified on a PET scan and therapy efficacy can also be assessed. In breast cancer, the detection of metastases seems to be possible with FDG. In brain and thyroid cancers, the role of FDG PET remains to be further determined. The low uptake of FDG in prostate cancer metastasis is not in favor of its use in this indication. In conclusion, the indications of FDG PET in oncology are now becoming more precise and it can be expected that clinical PET centers will soon appear in France.  相似文献   

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为了提高La-Mg-Ni基贮氢合金的荷电保持率,本文研究了La/Nd比的变化对La-Mg-Ni基贮氢合金自放电性能的影响。随着Nd替代La量的增加,(LaxNdy)0.9Mg0.10Ni3.09Mn0.12Co0.60Al0.13(x/y=5,4,3,2,1)合金的荷电保持率先增大后减小,当x/y=4时,其荷电保持率达到最大值80.8%(318 K)。合金电极贮存后,FESEM-EDS和XRD分析表明,合金颗粒表面形成了Mg(OH)2和Nd(OH)3。P-C-T曲线和Tafel极化测试表明,随着Nd含量的增加,金属氢化物的稳定性呈现先增加后降低和腐蚀电流先减小后增大的规律。  相似文献   

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Gastric inhibitory polypeptide, originally isolated from porcine intestine, is a gastrointestinal hormone belonging to the vasoactive intestinal peptide (VIP)/glucagon/secretin family. GIP consists of 42 amino acid residues which is derived by proteolytic processing of a GIP precursor. In vivo and in vitro experiments have indicated that GIP auguments glucose-stimulated insulin secretion, suggesting that GIP plays an important role in the regulation of insulin secretion as an incretin. Thus, GIP now is generally referred to as glucose-dependent insulinotropic polypeptide. It is also suggested that GIP may be involved in the pathogenesis of non insulin-dependent diabetes mellitus (NIDDM). GIP exerts its biological actions by binding to its specific receptors, which appear to be coupled to G proteins. We have isolated a cDNA encoding a GIP receptor from a hamster insulinoma(HIT-T15) cDNA library. The hamster GIP receptor is a 462 amino acid protein having seven transmembrane segments. Expression of recombinant of hamster GIP receptors in Chinese hamster ovary (CHO) cells shows that it binds specifically to GIP with high affinity (IC50 = 9.6 nM) and is positively coupled to adenylate cyclase. RNA blot analysis reveals that a 3.8-kb GIP receptor mRNA is expressed at high levels in rat pancreatic islets as well as in HIT-T15 cells.  相似文献   

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本文用TiFe_(0.88)Mn_(0.1)与MlNi_(4.5)Al_(0.5)合金作为分离材料,分离混合气体氢中的氪、氙。实验证明:TiFe_(0.88)Mn_(0.1)与MlNi_(4.5)Al_(0.5)合金中,当放氢量为总储氢量的5%时均能达到<1ppm氪或氙的纯度。MlNi_(4.5)Al_(0.5)合金的分离效果优于TiFe_(0.86)Mn_(0.1)合金。经过二级分离,分离效果将会更好。  相似文献   

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The coprecipitation of cobalt(II) and nickel(II) with iron(III), chromium(III) and aluminum(III) from ammoniacal solutions has been investigated. The coprecipitation behavior was found to be very sensitive to the solution pH and total ammonia concentration. Co(II) and Ni(II) can be precipitated from low ammonia concentration solutions but are readily redissolved at higher ammonia concentrations. The coprecipitate of divalent and trivalent species was found to contain very large amounts of the divalent metals (up to a mole ratio M M(II)/M(III) of 2.5) when aluminum was the trivalent species, whereas with iron(III) or chromium(III), the ratio was only 0.5.  相似文献   

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合成了三种新的异三核配合物,其组成为{Ln2(bpy)4[Cu(opba)](ClO4)2}(ClO4)2。通过元素分析、红外光谱、紫外光谱、差热热重及摩尔电导分析等手段表征了配合物。  相似文献   

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用磁控溅射方法制备了系列 (Fe0 .86 Zr0 .0 33Nb0 .0 33B0 .0 6 8Cu0 .0 1 ) x(Al2 O3) 1 -x颗粒膜样品 ,体积百分比x从 0 .3 3~ 0 .63 ,样品厚度约为10 0nm。室温下在Fe0 .86 Zr0 .0 33Nb0 .0 33B0 .0 6 8Cu0 .0 1 体积百分比x =0 .43时得到 17.5 μΩ·cm的最大饱和霍耳电阻率 ,比纯铁磁金属提高了 3~ 4个量级。对其磁性和微结构进行了研究 ,样品霍耳电阻率随外场的变化曲线 ρxy~H与磁场平行于膜面时的磁化曲线M~H有相似性 ,说明霍尔电阻率 ρxy与磁化强度M相关。样品电阻率 ρxx随金属体积百分比x的减小而增加 ,在x =0 .43附近发生突变 ,从金属导电变为绝缘体。根据微结构和输运性质对可能的机制进行了探讨  相似文献   

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