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1.
Photoemission studies of the electronic structure of the vicinal SiC(100) 4° surface, which was grown using a new substrate atom substitution method, and the Cs/SiC(100) 4° interface have been performed for the first time. The modification of spectra of the valence band and C 1s and Si 2p core levels in the process of formation of the Cs/SiC(100) 4° interface was analyzed. The suppression of the surface SiC state with a binding energy of 2.8 eV and the formation of a cesium-induced state with a binding energy of 10.5 eV were observed. The modification of the complex component structure in the spectrum of C 1s core level has been detected and examined for the first time. It was found that Cs adsorption on the vicinal SiC(100) 4° surface results in intercalation of graphene islands on SiC(100) 4° with Cs atoms.  相似文献   

2.
Correlation of the molecular structure and utilizing measurements of the electrical conductivity, activation energy of conduction of 4,4 bis(2-thenylideneamino)biphenyl (SB) and 4,4 bis(thenyl-diphenylphosphinylmethyleneamino)biphenyl (OPSB) compounds have been carried out. The results of the activation energies, obtained from the electrical conductivity measurements, as well as the energy gaps calculated from ultraviolet (u.v.) and visible spectra in the solid state indicate that the investigated compounds behave like semiconducting materials. The delocalized -electrons in addition to the lone pairs of electrons on the nitrogen atoms of the two compounds as well as the donor effect of diphenylphosphinyl groups of OPSB compound were considered as the main sources participating in the conduction processes.  相似文献   

3.
半导体级:纯度99.999%典型分析(重t计)钙,lpPb;镁,0 .02ppb;乍吕lppb,铁,SPPb物理性质分子量16匀。89;冰点(1大气压)一70 .0“C;蒸汽压(20oC),0.26巴(绝对值);液态密度(ZooC),1.45克/毫升;沸点(1大气压),57.6oC;无色;有刺激性和窒息性气味安全 ·警告:有毒、腐蚀性物质 危害性 八小时工作时间内空气中最大允许浓度为svpm。液体在容器中呈部分真空时,蒸汽压为0.26巴(绝对值)。其蒸汽比空气重,在湿空气中冒烟。与水能激烈反应(可能爆炸)。对皮肤和眼睛能引起严重的化学烧伤。 安全预防措施(参阅BZH。的贮存与处理说明,见本刊1984,腿3,尸.…  相似文献   

4.
5.
甲烷(CH_4)     
规格(查阅现行产品样本) 甲烷级 95%典型分析(体积)二氧化碳3.5%氧0 .15%氮0 .3%乙烷一水一丙烷一化学纯级 99%仪表级99.7%研究级99.9%0。02%.6%.1PPm25PPmO。18PPPm0 .25PPin16 PPxli40一50PPm1。7PPmgPPm1 4PPmn nVSPPm物理性质分子量16。04比容(20OC,1大气压)1479毫升/克沸点(z大气压)一i6r.soC凝固点(1大气压)一182.6oC气体密度(20aC,1大气压)0.676克/升临界温度一82.1”C在空气中的可燃范围5.3%~15%(体积)比重(空气=l)0.555无色低浓时感知不到气味,超过S000ppm时有芳香油型气味化学纯级甲烷中使用添味剂(四氢鹰吩)安…  相似文献   

6.
录像机的灵活运用(4)16、使盒式机具有高性能的令人惊奇的音响——高保真录像机电视机接收的声音和FM广播一样,音质很好,但是录在带子上时就有相当程度的劣化。原因如下:要想得到良好地声音效果,磁带的运行速度要尽量快一些,磁带的接触或运行系统不能有毛病。...  相似文献   

7.
规格(查阅现行产品样本)化学纯级,纯度99.7%。物理性质(纯四氟化碳)分子量, 88。01,(ZoOC,1大气压)(1大气压),(1大气压),128274.7毫升/克,0 OC液体密度(一80OC),1.32克/毫升,蒸汽密度(沸点),7.62克/升,临界温度,一45.7OC;比重(空气=1),3.03,容点比沸凝固点无色,一184。0“C,轻微醚味,在空气中不燃烧。 安全曹告:窒息性气体 危害性 八小时工作时间内空气中最大允许含量未定,但可以认为属于低毒性物质。窒息性气体。根据不适当的气味可报警。比空气重。钢瓶中压缩气体压力约114巴(表压)。在高温下分解为毒性化合物,该化合物遇潮气时具有…  相似文献   

8.
Metastability of the K2NiF4 type aluminate LaCaAlO4 and its chromium diluted solid solution LaCaCr x Al1–x O4 (x0.10) was evidenced at 1400C in air, in terms of demixing into the parent structures of the 11 intergrowth, i.e. the perovskite and rocksalt type LaAlO3 (LaCr x Al1–x O3) and CaO, respectively. This behaviour is discussed comparatively with YCaAlCO4 and LaSrAlO4 whose structures are stable under the same thermodynamic conditions. The results of a structure analysis are used to emphasize the role of the nine-fold co-ordination of the (A 3+=Y3+, La3+; A2+=Ca2+, Sr2+) cations as mixing the twelve-fold co-ordination of A 3+ in A 3+AlO3 perovskite and the six-fold one of A 2+ in A 2+O rocksalt. Calcium-oxygen underbonding in the (La, Ca)-O-Al bridge is assumed to trigger the metastability of the intergrowth structure at high temperature.  相似文献   

9.
The upper critical field B c2 of the organic superconductor -(BETS)2GaCl4 has been determined from resistance measurements for orientation of the magnetic field along three perpendicular crystallographic directions. The Ginzburg–Landau coherence length was estimated from the slope of B c2(T) curve near T c as 12.5 nm, 1.6 nm, and 12.5 nm for the a*-, b*-, and c-directions. Angular dependence of the critical field within highly conducting ac plane at 1.5 K was shown to possess two-fold symmetry, which can be related to the band structure anisotropy.  相似文献   

10.
The LiZr2(AsO4)3 arsenate and LiZr2(AsO4) x (PO4)3 ? x solid solutions have been prepared through precipitation followed by heat treatment, and characterized by X-ray diffraction, X-ray structure analysis, IR spectroscopy, and impedance spectroscopy. We have established conditions for the crystallization of the arsenate and a continuous series of arsenate phosphate solid solutions (0 ≤ x ≤ 3), which have been obtained as two polymorphs: monoclinic and hexagonal. Using the Rietveld method, we have refined the crystal structures of the polymorphs of LiZr2(AsO4)3 (sp. gr. P21/n, a = 9.1064(2), b = 9.1906(2), c = 12.7269(3) Å, β = 90.844(2)°, V =1065.03(5) Å3, Z = 4; sp. gr. R $\bar 3$ c, a = 9.1600(4), c = 22.9059(13) Å, V = 1664.44(14) Å, Z = 6) and LiZr2(AsO4)1.5(PO4)1.5. Their structural frameworks are built up of AsO4 tetrahedra—or (As,P)O4 tetrahedra occupied by arsenic and phosphorus atoms at random—and ZrO6 octahedra, with the lithium atoms in between. The ionic conductivity of the materials has been measured. The cation conductivity of monoclinic LiZr2(AsO4) x (PO4)3 ? x with 0 ≤ x ≤ 1 has been shown to exceed the conductivity of lithium zirconium phosphate.  相似文献   

11.
以BaCO_3、BaF_2、H_3BO_3和氧化铕(Eu_2O_3)原料,采用高温固相反应法制备了一系列新型荧光材料Ba_(4-4x) B_(11)O_(20)F∶4xEu~(3+)(x=0.06、0.08、0.10、0.12、0.14)。利用XRD、SEM和荧光分光光度计对粉体结构、形貌和发光性能进行表征,并研究了铕离子(Eu~(3+))掺杂量对Ba_(4-4x)B_(11)O_(20)F∶4xEu~(3+)发光性能的影响。研究结果表明在激发波长为465nm的条件下,材料的发射峰主要位于592、598、616、654和700nm处;随着Eu~(3+)离子浓度的增大,样品的发光强度先增大后减小,最佳掺杂浓度为x=0.12。  相似文献   

12.
AF微距镜头(1)AF微距尼康f60F2.8D是近摄和复制最合适的D型标准微距镜头。可以近摄到约22cm。采用近距离校正方式,可减小各种象差,从无限远至等倍率摄影均能获得鲜明的图像。适合花和植物等的摄影,能清晰地捕捉花瓣及花芯等,最适合着重于质感描写之摄影。装备有缩短对焦时间的对焦控制转换开关。也是广泛地用于风景摄影。快照等一般摄影的镜头。镜头构成:7组8片;最短摄影距离:0219m;滤色镜尺寸:62mm;遮光罩:HN-22(另购);*53000门)F微距尼康fi05FZ.SD是D型望远系列的微距镜头,可近摄到约31cm。采用近距离校正方…  相似文献   

13.
(丰]机械加工性机械的性质机械的接着机械扩粉久气孔率希释剂丰夕卜/一夕卜树脂年夕夕夕树‘脂午久口一夕卜口一夕牛久口一夕卜口一于才沙犷丰七/夕于夕夕你体透过性挥发减量挥发分忌避能气泡率逆IJ形力卜夕夕年七久于、夕犷夕口岁7o牟今又卜7才沙人机械加工性机械性能机械粘合机械加压孔隙率稀释剂二甲酚树脂二甲苯树脂辊溉涂布机辊溉涂布氛灯透气性、挥发损失挥发物,挥发物含量抗鼠咬性孔隙率倒L型压延机浇铸树脂液‘流延薄膜,挤塑薄膜〔美〕模槽,阴模阴模托板急冷供给部(久夕口“因)凝集共重合共重合体凝集力强肠人性共单量体镜面研摩…  相似文献   

14.
葛世名 《照相机》2003,(5):55-55,58
基辅—康泰弗来克斯系列,这类相机属于35mm内测光单镜头反光帘幕快门相机,简写为35mm DF相机(英文SLR);Kiev10,kiev15 TEE,Kiev15 TTL属于此类。Kiev10,kiev15 TEE,Kiev15 TTL成套相机如图1、图2、图3。  相似文献   

15.
许宗馨 《照相机》2014,(4):29-32
正夜色之魅,这是各种光源色彩斑斓的美丽夜景,常常让我们为之振奋,为之倾倒,更难以抑制拍摄的激情,所以夜景是影友们理所当然的风光拍摄对象。与白天的拍摄不同,夜景摄影需要较为独特的技巧,如一般要配用稳定的三脚架、云台;掌握曝光、ISO感光度、抑制噪点、白平衡等,在手持相机拍摄时,配合防抖镜头或用三脚架,以及不同相机个性的合理设定。还有若让夜色光源产生星光效果,除了用星光滤镜、机内滤镜和一些品牌相机的润饰菜单功能外,还可用非圆型光圈叶片设计的镜头,小光圈、长时间曝光直接拍摄形成等等。为了得到高画质的照片,最好用RAW或"RAW+JPEG"格式拍摄,以便拍摄后在机内和在电脑上对白平衡、照片风格和  相似文献   

16.
13·4·4氨瓶水路运输氨瓶经水路运输,必须遵守危险品运输规定。托运前对氨瓶的要求与铁路运输一样。氨瓶装卸应遵守下列要求。1·船舶是否适合装运氨瓶,由船上负责人、港务技术和航行部门,根据液氨的性质确定。客货船原则上不得装运氨瓶,确需装运时应制定“客货船装运限额表”  相似文献   

17.
The reaction of Np(VII) with Ag(I) was studied by spectrophotometry with the aim to evaluate the potential of the Np(VII)/(VI) couple in acid solutions. In perchloric acid solutions with pH 1.5 and 3.05, the potential E is 1.93 and 1.85 V, respectively. Extrapolation to a solution with pH 0 gives 2.20 ± 0.01 V. A close value (E = 2.22 V) is obtained by extrapolating the potential from a 1 M NaOH solution (pH 13.83, E = 0.582 or 0.587 V) to acid solutions (pH 0).  相似文献   

18.
三、混合电路材料混合电路顾名思义是一种半导体集成电路和PCB的特点兼而有之的电子元件。混合电路的线条和间距都比集成电路粗得多,但比PCB细得多。混合电路中也包括一些电阻、电容和二极管。典型的混合电路的面积为100cm~2。它们常用于空间限制不如集成  相似文献   

19.
Brownish crystals of Rb6(V2O3)2(VO)2(PO4)4(HP2−xVxO7) were prepared hydrothermally. The structure was solved from single crystal X-ray diffraction data in the non centrosymmetric orthorhombic space group Pmn21 (No. 31) a=13.5505(2) Å, b=7.1407(2) Å, c=14.7040(2) Å. (R1(Fo)=0.048, wR2(Fo2)=0.111). The structure of Rb6(V2O3)2(VO)2(PO4)4(HP2−xVxO7) is closely related to the previously reported M3(V2O3)(VO)(PO4)2(HPO4) (M=K+, Tl+) with a disordered occupation of the tetrahedral voids by VV and PV atoms.  相似文献   

20.
全孔径volefnungfulaperture镜头光圈开到最大时的入射光瞳直径或有效孔径。镜头速率ObjektivlichtstrkeLensspeed指镜头的最大透光能力。通常用来表示镜头的最大相对孔径(或最小F数)。有效F数wirksameBle...  相似文献   

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