125I放射性溶液活度测量国际比对

2004年6—8月，中国计量科学研究院电离辐射处参加了国际计量局（BIPM）组织的5I放射性溶液活度测量国际关键比对。我们采用KX射线和γ射线的探测效率符合相加原理，选用4π井形NaI晶体测量装置对^125I的活度进行绝对测量。测量结果与平均值相差1．3％．     

~(155)Eu溶液放射性活度的测量

本文介绍了在4πβ—γ符合活度基准装置上对155Eu 活度的精确测量的分析, 并实测了两个不同活度浓度的155Eu 溶液, 其测量不确定度为1-8 % ( 范围因子为99-33) , 还介绍了155Eu 溶液活度测量国内外的结果     

55Fe溶液活度测量国际比对

首次用CIEMAT/NIST方法参加了BIPM(国际计量局)组织的55Fe放射性溶液活度测量国际关键比对,用该方法获得的测量结果与比对结果平均值在0.5%内一致,验证了我国放射性活度国家基准量值的国际等效性.     

139Ce放射性活度的绝对测量

电子俘获核素是放射性同位素进行核衰变的一种形式,利用这一原子核内部的衰变规律,研究这一类放射性核素的绝对测量方法是放射性活度测量的基础工作,我们采用4πβ-γ符合法测量技术对139Ce放射性活度进行了绝对测量,并通过国际比对对测量结果进行验证,获得满意的结果.     

全国放射性核素~(131)I和~(241)A_m活度测量比对

1991年3月～9月中国计量科学研究院(NIM) 和国防科工委放射性计量一级站(RMC) 共同组织了全国放射性核素~(131)I和~(241)Am活度测量比对,共有十四个实验室参加。它们采用九种不同的测量装置给出了三十六个不同的结果,对弱比活度溶液主要使用4πβ-γ符合、4πβ(PC) 计数器、4πβ(LS) 计数器、HPGeγ谱仪、2πα栅网电离室、小立体角装置及EJ-2603、BH-1216相对测量仪;对于较强比活度溶液,一般使用4πγ电离室测量。最后结果及其不确定度用表给出。     

^204T1核素溶液放射性活度国际比对测量

本文介绍１９９４—１９９７年由ＢＩＰＭ组织的２０４Ｔ１核素溶液放射性活度国际比对测量的情况。     

^155Eu溶液放射性活度的测量

本文介绍了在４πβ－γ符合活度基准装置上对＾１５５Ｅｕ活度的精确测量的分析，并实测了两个不同活度浓度的＾１５５Ｅｕ溶液，其测量不确定度为１．８％（范围因子为９９．３３），还介绍了＾１５５Ｅｕ溶液活度测量国内外的结果。     

~(152)Eu、~(58)Co、~(88)Y和~(166m)Ho核素活度测量比对

组织了152 Eu、58Co、88Y和166mHo放射性核素活度测量的国内比对。 15个参加实验室用γ谱仪和 /或 4πβ -γ符合装置等方法测量了由比对溶液制成的点源或溶液样品。介绍比对测量的结果并通过与SIR(国际参考系统 )平均值的比较 ,使国内实验室的测量结果与国际关键比对参考值建立溯源性的联系     

89Sr放射性核素的活度测量

介绍利用液体闪烁计数法对89Sr核素进行绝对测量,解决了零几率外推等问题,合成标准不确定度达到0.62%.为89Sr核素的应用提供可靠的测量方法.     

125I密封籽源水中吸收剂量分布的测量

用热释光剂量计对125I密封籽源在水中的剂量分布进行具有量值溯源性的测量,结果表明,125II密封籽源在水中的剂量分布随着离源距离的增加而快速衰减,同时受照角度对剂量分布也有一定的影响。模拟实验有助于改进放射性籽源植入治疗的剂量准确性和安全性。对测量误差和实验方法也进行了有益的讨论。     

^89Sr放射性核素的活度测量

介绍利用液体烁计数法^89Sr核素进行绝对测量，解决了零几率外推等总理２，合成标准不确定度达到０．６２％，为^89Sr核素的应用提从可靠的测量方法。     

(hfac)Cu(I)(MP) (hfac=hexafluoroacetylacetonate, MP=4-methyl-1-pentene) and (hfac)Cu(I)(DMB) (DMB=3,3-dimethyl-1-butene) for the chemical vapor deposition of copper film

New organometallic precursors for the metal organic chemical vapor deposition (MOCVD) of copper, (hfac)Cu(I)(MP) (hfac=hexafluoroacetylacetonate, MP=4-methyl-1-pentene) and (hfac)Cu(I)(DMB) (DMB=3,3-dimethyl-1-butene) were studied. Copper films could be deposited at the precursor vaporization temperature of 45 and 35°C. The deposition rate was about four to seven times higher than previously reported precursors such as (hfac)Cu(VTMS) (VTMS=vinyltrimethylsilane), (hfac)Cu(ATMS) (ATMS=allyltrimethylsilane) and (hfac)Cu(VCH) (VCH=vinylcyclohexane). The copper films deposited from these two precursors had a resistivity of about 2.0 μΩ cm in the deposition temperature range of 150 to 200°C.     

低能X射线空气比释动能国际关键比对

为促进我国在低能X射线空气比释动能计量领域内的量值统一并达到国际等效,中国计量科学研究院(NIM)于2018年采用平板自由空气基准电离室复现低能X射线空气比释动能,并通过传递电离室Radcal-RC6M在国际计量局(BIPM)低能X射线辐射场中开展了间接比对,其比对结果在合成标准不确定度为0.37%范围内与国际计量局等效一致,该比对结果已纳入国际计量局的关键比对数据库(KCDB)。     

钼锝发生器平衡活度的在线测量系统

本文介绍了钼锝发生器平衡活度的线测量方法,描述了系统原理框图及工作流程,给出了应用于淋洗的详细气－液结构。     

Equations of state for the thermodynamic properties of R32 (difluoromethane) and R125 (pentafluoroethane)

Thermodynamic properties of difluoromethane (R32) and pentafluoroethane (R125) are expressed in terms of 32-term modified Benedict-Webb-Rubin (MBWR) equations of state. For each refrigerant, coefficients are reported for the MBWR equation and for ancillary equations used to fit the ideal-gas heat capacity and the coexisting densities and pressure along the saturation boundary. The MBWR coefficients were determined with a multiproperty fit that used the following types of experimental data: PVT: isochoric, isobaric, and saturated-liquid heal capacities; second virial coefficients; and properties at coexistence. The respective equations of stale accurately represent experimental data from 160 to 393 K and pressures to 35 MPa for R32 and from 174 to 448 K and pressures to 68 MPa for R125 with the exception of the critical regions. Both equations give reasonable results upon extrapolation to 500 K and 60 MPa. Comparisons between predicted and experimental values are presented.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado. U.S.A.     

Investigation of Cs(I) and Sr(II) removal using nanoporous bentonite

ABSTRACT

Bentonites are types of clays made up the dominant constituent of montmorillonite. Four types of nano-porous and nano-structured commercial bentonite clays were studied in detail for their physicochemical and mineralogical properties vs. Cs and Sr adsorption. The instrumental analyses to study samples were X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET) surface area measurements, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetry (TG). The XRF and peaks of XRD patterns at 2θ?=?8, 19.9, 35, 55, and 62 clearly indicated that the main component of the bentonite samples was montmorillonite. The BET analysis showed that B1 has the highest specific surface area among the other samples which its single and multiple point BET surface area were equal to 84.85 and 85.94?m²?g^?1, respectively. These values represents the amount of montmorillonite and adsorption capacity of samples. The physicochemical, structural and morphological characteristics of different samples were investigated through instrumental analysis. The results of separation processes of Cs(I) and Sr(II) showed 59.75 and 45.5% adsorption capacities for B3 and B2 which were the highest values among the others. The results lead to the conclusion that samples B3 had a good adsorption capacity to remove Cs(I) and Sr(II).     

An International Comparison of Absolute Radiant Power Measurement Capabilities

We report the results of an intercomparison of monochromatic radiant power measurement capabilities recently completed by 11 national laboratories. The intercomparison radiometers, distributed in pairs, included an amplifier with six decades of precision gain and one of two types of silicon photodiode (pn or np-type construction). Eleven of the laboratories measured the absolute responsivity of the radiometers at 633 nm and nine at 488 nm. The standard deviation of the overall difference was 0.36% at both wavelengths. The agreement between the various participating laboratories and NIST was within the measurement accuracy stated by the participants.     

Surface tension of pentafluoroethane (HFC-125)

A set of accurate surface-tension data for HFC-125 has been obtained experimentally with both an absolute capillary rise technique and a differential capillary rise technique in the temperature range of 233.15–333.15 K. The purity of the experimental HFC-125 sample is 99.98 wt%. The two sets of experimental results with an absolute capillary rise method agree well with each other and, also, with the experimental results with a differential capillary rise method. The absolute deviations of experimental results with these two methods are within 0.01 mN · m^–1. The relative deviation are within 0.2%. A van der Waals surface-tension correlation is also proposed.