测量误差(error of measurement)

测量结果与被测量真值之差。测量结果是量的实验表现,通常只是对测量所得被测量值的近似或估计。真值是量的定义的完整体现,只有通过完善的测量才能求得,它反映了人们力求接近的理想、目标或客观真理,本质上是不能确定的,实际上用的是约定真值,须以测量不确定度来表征其所处的范围。所以,作为测量结果与真值之差的测量误差,也是不能确定或确切获知的,随着科学技术水平和人们认识水平的提高,可以尽量减小或对它进行控制,但不可能完全消除。从理论上和实践上研究测量误差,分析其来源、表现形式及性质,正确处理测量的数据,目的是…     

Studies of Structure Evolution of Nanostructured Hf_(11)Ni_(89) Alloy

A nanostructured Hf11Ni89 ribbon sample was prepared by melt-spinning. It was found that the as-quenched sample is composed of a major HfNi5 compound nanophase and an interfacial magnetic Ni(Hf) solid solution phase. The structure evolution of the sample was studied by using X-ray difFraction (XRD), transmission electron microscopy (TEM), difFerential scanning calorimetry (DSC), resistivity and magnetothermal analysis. Upon heating, a second precipitation process of the Ni(Hf) phase prior to grain growth wa5 detected by means of both structural analysis and physical property measurements. The measurement results are discussed based on the relationship between microstructure and physical properties.     

Effects of Pressure on the Solidification Microstructure of Mg_(65)Cu_(25)Y_(10) Alloy

The Mg65Cu25Y10 melts were quenched at a temperature of 973 K under various pressures in the range of 2-5 GPa and ambient pressure. The microstructure of the solidified specimens has been investigated by X-ray diffraction, transmission electron microscope and electron probe microanalysis. Experimental results show that the pressure has a great influence on the solidification microstructure of the Mg65Cu25Y10. At ambient pressure, the solidification products are Mg2(Cu,Y) and a very small amount of Y2O3 inclusion. As the pressure is above 2 GPa, a new Cu2(Y,Mg) phase appears, while Y2O3 is not observed at the pressure of 3, 4 and 5 GPa. When the pressure increases from 2 GPa to 5 GPa, the grain sizes of Mg2(Cu,Y) and Cu2(Y,Mg) decrease from 125, 96 nm to 80, 7 nm, respectively. The mechanisms for the effects of the pressure on the phase evolution and microstructure during solidification process of Mg65Cu25Y10 alloy have been discussed.     

Ellipsometric study of dielectric functions of Mg(1-y)Ca(y)H(x) thin films (0.03≤y≤0.17)

Mg(1-y)Ca(y)H(x) (0.03≤y≤0.17) alloy thin films covered with thin Pd were hydrogenated using 4% H(2) in Ar under atmospheric pressure at room temperature. The complex dielectric functions (ε=ε(1) + iε(2)) in the range of 0.75 to 5.0 eV of these hydrides were evaluated with spectroscopic ellipsometry. The imaginary part of the dielectric function ε(2) was composed of one Drude and three Lorentz oscillator terms whose peak positions were about 1.2 eV (L(1)), 2.8 eV (L(2)), and 5.2 eV (L(3)). The L(3) term observed in all hydrides is attributed to optical absorption of MgH(2) with E(g)=5.16 eV. The Drude term, which may be due to unhydrogenated Mg-metal, was observed in the hydrides with a low Ca composition y of less than 0.04. The L(1) term was observed in the hydrides with a Ca composition of more than 0.05, while the L(2) term was observed for more than 0.11. These L(1) and L(2) terms were estimated from a variation with hydrogenation of ellipsometric angle Ψ which is due to optical absorption of CaH(2-α) (L(1)) and MgCaH(3.72) (L(2)).     

测量结果(result of ameasurement)

由测量所得到的被测量值,即通过测量而得到的属于被测量或认作被测量的值。使用这一术语时,应表明它所指的是承值,还是未修正结果,或是已修正结果。示值是由计量器具所指示的被测量值;未修正或已修正结果是考虑到有系统误差存在,而未作修正或已作修正的测量结果。当计量器具只有单个示值时,该承值就是未修正结果;当有几个示值时,宋修正结果可由这几个承值的算术平均值求得。系统误差中的已定或表面系统误差,其大小与符号均为已知,从而可以修正。修正后剩余的是只能估计其界限的未定系统误差,常归纳到测量不确定度中去。测量结果…     

Surface Layer of Ni_(68)P_(18)Cr_(14) Amorphous Alloy

In Ni_(68)P_(18)Cr_(14) amorphous alloy, the dominant component elements Ni and P were in lower contentin the surface layer, while Cr was enriched. There was a P enrichment region just below the surfaceoxide layer, which was supposed to enhance the surface segregation of Cr. Nickel was less oxidizedthan Cr.     

量值(value of a quantity)

由数值和计量单位的乘积所表示的量的大小。量值是量的表示形式。一般说来，任何可测的量都是由数值和计量单位两部分组成，如5．Mm或534cm，15kg或15000g等。没有计董单位的纯数不能表示量，就计量学而言，毫无意义，数值大不等于量大，反之，数值小也不等于星小。表示量值时要采用法定计量单位，所选用的单位大小也要适中，使数值的位数不宜太多。量值(value of a quantity)     

Intercalation of n-alkylamines into α-tin(IV) bis(hydrogenphosphate)

The intercalation reaction of n-alkylamines from methyl- to hexadecylamine into -tin(IV) bis(hydrogenphosphate) has been investigated. The reaction was conducted by mixing the phosphate and solutions of the amines dissolved in water or benzene. The amine/ phosphate molar ratios in the reaction mixtures were 0.43, 0.85, 1.71 and 3.41. The nitrogen/phosphorus atomic ratio in the intercalation compound was not changed by the amine/phosphate molar ratio. The interlayer distances of the intercalates obtained in the reaction mixtures with molar ratios of 3.41 and 1.71 increased with an increase in the number of carbon atoms in the alkyl chain of the amine. The slope of the straight line obtained in plot of interlayer distance versus number of carbon atoms in the alkyl chain of the amine indicates that the amine molecules form a double layer in the interlayer space of the phosphate and are inclined at an approximate angle of 67.7° to the phosphate layer. The interlayer distances of the intercalates of butyl- to nonylamines obtained at the molar ratio of 0.85 are smaller than those of the corresponding compounds from the molar ratios of 3.41 and 1.71, while those of decyl- to hexadecylamine intercalates lie on the previously discussed line. This behaviour is interpreted by assuming kink formation in the short alkyl chains between the phosphate layers.     

Work Functions of Pd_(83.5)Si_(16.5)and Cu_(70)Ti_(30)Glassy Alloys

The work functions before and aftercrystallization of two glassy alloys,Pd_(83.5)Si_(16.5) andCu_(70)Ti_(30) have been measured by means of the con-tact potential difference method in the secondaryelectron field at room temperature under 10~(-5) Pavacuum.The results show that the work functionsof both glassy alloys are higher than those of thecorresponding crystalline alloys.     

Thermal Stability of Amorphous Hydride Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45)

The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed.     

Scaffolds of poly (ε-caprolactone) with whiskers of hydroxyapatite

Scaffolds of Poly (ε-caprolactone)/hydroxyapatite were produced and studied for tissue engineering applications. The materials were selected due to its biodegradability (PCL) and bioactivity (HA), and above all their biocompatibility toward the human tissue. The composites produced were characterized by SEM, XRD, and EDS. By analyzing these characterizations it was possible to obtain further information about the composition and morphology aspects of all portions of the composite scaffold.     

An SANS Study of Decomposition Kinetics in Amorphous Cu_(12.5)Ni_(10)Zr_(41)Ti_(14)Be_(22.5)

Phase decomposition in amorphous Cu12.5Ni10Zr411Ti14Be22.5 alloy as annealed in the super-cooled liquid range was studied by applying small angle neutron scattering (SANS). As annealed between 600 K and 700 K, the alloy was observed to decompose into two new amorphous phases,with the second phase precipitates embedded in the matrix of the first. Long time annealing of the alloy results in crystallization in addition to evolution of the decomposed microstructure.The kinetic diagram of the decomposition and crystallization for this alloy is given. The second phase precipitates have several nanometers in size and occupy a quite low volume fraction. The decomposition of the supercooled liquid in overall temperature range exhibits the features of spinodal reaction.     

Simulation of Isotopic Angular Effects under Ion Bombardment of a~(92)Mo-~(100)Mo Target

Under 5 keV Ar ion bombardment of a 92Mo-100Mo target, we have investigated isotopic angular effects by means of the static and the dynamic Monte Carlo programs. Our calculated results are in quantitative agreement with the measured and other calculated results. The conclusion consistences among theories. simulations and measurements are also discussed.     

Laboratory of Solid State Microstructures(LSSMS)

1. General Survey The Laboratory of Solid State Microstruc-tures (LSSMS) of Nanjing University islocated in the centre of the historic cityNanjing. It is one of the major labs establi-shed with the approval and special grantfrom the National Planning Commissionof China in 1984, based on the Instituteof Solid State Physics of Nanjing University. The research direction of LSSMS focuses     

Visible photoluminescense of the (112¯0), (101¯1) and (0001) surfaces of ZnO nanofilms

Thin ZnO nanofilms 25 nm thick with (0001), $\left(11\overline{2}0\right)$ and $\left(10\overline{1}1\right)$ as surfaces were grown epitaxially on the NaCl (111) and (001) surfaces. The room temperature photoluminescence (PL) spectrum from the $\left(11\overline{2}0\right)$ nanofilm has a sharp UV emission but negligible green emission, indicating that it has good quality and low defect density. However, the PL spectra from the $\left(10\overline{1}1\right)$ and (0001) surface nanofilms have a broad green emission, and that of the $\left(10\overline{1}1\right)$ surface is stronger than the (0001) surface. The result supports that the surface oxygen vacancies are the probable origins of the green emission.     

High-resolution Fourier-transform emission spectroscopy of the A(1)II-X(1)Σ(+) system of AIH

The emission spectrum of the A(1)II-X(1)Σ(+) system of AIH, excited in a hollow-cathode discharge lamp, has been observed at high resolution with a Fourier-transform spectrometer. The rotational lines in the 0-0 and the 1-1 bands have been measured with a precision of ±0.001 cm(-1). The present measurements provide a considerable improvement overthe previous data of Zeeman and Ritter [Can. J. Phys. 32, 555 (1954)]. The present data, combined with the previous high-resolution measurements of the 1-0 vibration-rotation band by White et al. [J. Chem. Phys. 99, 8371 (1993)] and the J = 1-0 pure rotational line of Goto and Saito [Astrophys. J. 452, L147 (1995)] have been used to determine improved molecular constants for the A(1)!! state.     

An XPS study of interaction of neptunyl(V) in aqueous solution with goethite (α-FeOOH)

Sorption and physicochemical state of Np on the goethite (-FeOOH) surface were studied. The oxidation state of Np on the -FeOOH surface was studied by the liquid extraction. The neptunium complexes formed on the surface were studied by X-ray photoelectron spectroscopy. The ionic and elemental composition of the goethite surface and NpO ₂ ⁺ complexes with -FeOOH were determined from the XPS data. No Np(IV) and Np(VI) compounds were detected. Neptunyl(V) Np(V)O ₂ ⁺ forms complexes with the surface groups of -FeOOH. The equatorial plane of these complexes is occupied by the oxygen atoms of -FeOOH and water and/or carbonate group CO ₃ ^2– .Translated from Radiokhimiya, Vol. 46, No. 6, 2004, pp. 503–506.Original Russian Text Copyright © 2004 by Yu. Teterin, Kalmykov, Novikov, Sapozhnikov, Vukcevic, A. Teterin, Maslakov, Utkin, Khasanova, Shcherbina.     

Characterization of ThMn_(12)-structure Stability

A series of YTi(Fe_(1-x)_(11)alloy withx=0.00,0.01,0.03,0.04,0.05,0.07 and 0.10 hasbeen investigated by measurement of the structuralproperties and ~(57)Fe Mssbauer experiments.Thepure ThMn_(12)-structure phase exists at x≤0.03 andis absent at x>0.03.The reasons for lower satura-tion magnetization and lower energy product of theThMn_(12)-structure compounds were given.Thecrystal structure relations