半导体CdS悬浮体系中可见光催化产氢同时生成氦-3（英文）

我们报道了在可见光照射下,半导体硫化镉(CdS)悬浮体系在催化分解水制氢同时会伴随着少量氦-3和氦-4产生.结果表明,在温和条件下自水中的质子通过低能核反应(LENR)产生氦-3和氦-4的是可能的.     

天然气中氦同位素的质谱分析

本文着重介绍使用自制的装置净化天然气,净化后氦氖的组分占99%。以空气氦为标准样,采用同位素峰高比测定天然气中~2He/~4He值。当VG5400质谱计内的氦量大于4×10~(-7)cm~3·STP·He时,其灵敏度稳定,约10~(-4)A/cm~3·STP·He,17天内的~3He/~4He值精确度为1.32%。此外,简要讨论了同位素质谱峰高比测定法的条件和~(20)Ne/~4He值对~3He/~4He测量结果的影响。     

类氦离子1,3P激发态Schrodinger方程的直接解

利用相关函数（CF）-超球谐（HH）-广义Laguerre(GLF)方法直接求解类氦离子n1,3P（n=1,2,3）低躺激发态的Schrodinger方程,得氦原子的本征能量分别为-2.13317Eh (13P),-2.12383Eh(11P),-2.05810Eh(23P),-2.05516Eh(21P),-2.03235Eh(33P)和-2.03109Eh(31P),它们与文献值在........第6位上很好地吻合。这说明CFHHGLF方法也适用于类氦离子1,3P激发态。还给出了总角动量L=1的对称超球谐基函数和有关矩阵元的解析式。     

氦检测器气相色谱法快速测定高纯氦中痕量组分

国内外曾有多人进行过氦离子化检测器气相色谱法分析高纯氦中痕量组分的方法和仪器的研究。迄今尚没有见到在一台仪器上,使用一只检测器,在五分半钟内分析氦中痕量Ne、H_2、Ar、O_2、N_2、CO、CH_4,CO_2、N_2O的报道。本工作在研制出二分半钟分离Ne、H_2、Ar、O_2、N_2、CH_4的高效色谱柱后,又制     

氦液滴中羰基硫分子的光解动力学

用时间切片速度成像方法研究了氦液滴中羰基硫(COS)分子的光解动力学. 从共振增强(2+1)电离的CO光谱中发现在氦液滴环境中解离产物CO的转动冷却比振动冷却更有效.利用速度成像采集到的CO (v=0)和CO (v=1)的影像在角分布上都呈现出各向同性的特点. 产物平动能分布的结果表明尽管大部分的平动能都被超流体环境所弛豫, 但振动激发态产物CO (v=1) 的平均平动能比振动基态产物CO (v=0) 的平均平动能高.对羰基硫分子在氦液滴中的光解动力学机理进行了讨论.     

中国一些地区温泉中天然气的地球化学特征及碳、氦同位素组成

中国一些地区温泉气的主要组分是CO_2或N_2,烷烃气含量低或无,同时含极微量的氦。温泉气的δ~(13)C_1主频率峰在-20‰至-22‰,说明温泉气的甲烷主要是无机成因的。温泉气的δ~(13)C_(CO_2)主频率峰在-4‰至-8‰,反映温泉气的CO_2也主要是无机成因的。δ~(13)C_(CO_2)值与CO_2含量正相关,其回归方程为δ~(13)C_(CO_2)(‰)≈0.966lgCO_2-6.354,δ~(13)C_(CO_2)值与N_2含量负相关,其回归方程为δ~(13)C_(CO_2)(‰)≈-3.193-0.109 N_2。根据氦同位素组成特点,可划分出幔源温泉气和壳源温泉气,前者R/R_a>1,后者R/R_a<1。     

最弱受约束电子势模型理论下使用双广义拉盖尔多项式计算氦原子基态能量

计算了在最弱受约束电子势模型理论下使用双广义拉盖尔多项式的氦原子基态能量. 给出了氦原子基态能量期望值的表达式. 通过搜索它的极小, 找到了氦原子基态能量的极小值. 将我们的结果与双灼(zeta)函数的Hartree-Fock(HF)方法的结果进行比较后发现, 我们的结果略优于双灼(zeta)函数的Hartree-Fock(HF)方法的结果. 如此表明线性组合技术可以应用在最弱受约束电子势模型理论中.     

溴染料敏化担载Pt石墨烯催化可见光制氢、氘和氦

3He是理想的核聚变燃料,但是地球上3He的储量十分有限,大约只有500 kg.我们报道了在可见光光照条件下,溴染料敏化担载Pt石墨烯催化水还原为氢气过程中伴生少量氘和氦的实验现象.结果表明在温和条件下自水中的质子生产氘和氦的是可能的.     

应用交流脉冲氦离子化检测器于气相色谱法测定变压器油中溶解气及水分

用自制的交流脉冲氦离子化检测器于气相色谱法测定变压器油中溶解气及水分.该检测器采用双向交流脉冲高压电源放电,避免了阳极溅射消耗和阴极污染问题.在未加任何净化、氦气纯度99.999%情况下,用气相色谱法测定了变压器油中7种溶解气体(H2,CO,CH4,CO2,C2H4,C2H6及C2H2),其检出限(3S/N)在0.1×10-6uL·L-1以下.检测器与程序升温、双柱切换等操作过程配合良好,而且可同时检测油中微水.     

大型氦低温制冷系统的自主研发之路

以氦的独特性质,特别是在低温下表现出的不同状态：常态氦与超流氦,分析氦作为低温制冷剂的原因。其次,引出氦低温制冷系统在我国国计民生中的重要应用（主要包括国家能源和科技发展、氦资源保障、洁净氢能开发等方面）。正因为其重要地位,中国科学院理化技术研究所从2009年开始进行大型低温氦制冷系统的自主研发。简述了理化所近几年的各项研究成果,以及产业化公司的成立、设备应用及出口情况。最后,展望了未来的发展道路：全面突破氦低温制冷技术,打破国际垄断,实现国产大型低温制冷装备对国家战略发展的有力支撑。     

Helium-3 activation analysis of oxygen in silicon nitride films on silicon wafers

Oxygen in silicon nitride films on silicon wafers was analyzed by activation with the¹⁶O(³He, p)¹⁸F reaction. By³He bombardment of samples propertly arranged under consideration of the¹⁸F recoil effect, total oxygen was reliably determined and its predominant part was estimated to be located whether on film surface, in film interior, or on film-substrate interface. Sample films with 0.1 to 2 μm thicknesses were found to contain 0.2 to 2 μg/cm² of oxygen in locations varying with preparation conditions. This method has been compared with ESCA and other methods for surface analysis.     

Extraterrestrial3 He in marine polymetallic nodules: A potential method for measuring growth rate of nodules

The comparative measurements of helium isotope compositions between marine polymetallic nodules and their surrounding sediments, their magnetic fractions and bulk from C-C Zone of the East Pacific Basin are reported. The⁴He content and³He/⁴He ratio of polymetallic nodules and their surrounding sediments are extremely high; the³He,⁴ He concentrations and most³He/⁴He ratios of magnetic fractions in nodules and sediments are apparently higher than those in bulk. The helium isotope data points of nodules and sediments are all distributed along or closely to the mixing curve of the interplanetary dust particles (IDPs) and the terrigenous sediments in the chart of³He-³He/⁴He. In the same sampling site, the³He/⁴He ratios of nodules and their surrounding sediments are very similar, and the changes of both ratios are synchronous. It shows that the high³He/⁴He ratios in nodules and sediments may all result from IDPs. So, if the flux of extraterrestrial³He into the nodules and sediments is constant, the growth rate of polymetallic nodules and the sedimentation rate of sediments can be independently calculated according to the concentra-tion of extraterrestrial³He in nodules and sediments.

     

Extraterrestrial<Superscript>3</Superscript> He in marine polymetallic nodules: A potential method for measuring growth rate of nodules

The comparative measurements of helium isotope compositions between marine polymetallic nodules and their surrounding sediments, their magnetic fractions and bulk from C-C Zone of the East Pacific Basin are reported. The⁴He content and³He/⁴He ratio of polymetallic nodules and their surrounding sediments are extremely high; the³He,⁴ He concentrations and most³He/⁴He ratios of magnetic fractions in nodules and sediments are apparently higher than those in bulk. The helium isotope data points of nodules and sediments are all distributed along or closely to the mixing curve of the interplanetary dust particles (IDPs) and the terrigenous sediments in the chart of³He-³He/⁴He. In the same sampling site, the³He/⁴He ratios of nodules and their surrounding sediments are very similar, and the changes of both ratios are synchronous. It shows that the high³He/⁴He ratios in nodules and sediments may all result from IDPs. So, if the flux of extraterrestrial³He into the nodules and sediments is constant, the growth rate of polymetallic nodules and the sedimentation rate of sediments can be independently calculated according to the concentra-tion of extraterrestrial³He in nodules and sediments.     

3He Impurities in Nearly Frictionless Transport of Solid 4He at Low Temperatures

Glassy matter, when subjected to high shear rates exhibit shear thinning, that is, the viscosity diminishes with increasing shear rate. One possible outcome for the almost vanishing viscosity is nearly frictionless transport, which is possible in solid ⁴He due to the presence of minute concentrations of ³He. The glassy state of solid ⁴He is also relevant to the possible onset of superuidity in solid ⁴He. By treating the solid ⁴He locally as an amorphous matter and using the transition‐rate dependent model together with the specific activation energy, we observe a series of sudden changes of the shearing stresses (which directly relates to the resistance) at corresponding onset temperatures of supersolid ⁴He (ranging from 175 to 1200 mK) for different activation volumes of ³He. Even at higher concentrations of ³He than previous reported (around 1700 ppm), the supersolidity of ⁴He still occurs.     

The determination of trace oxygen in lead by helium-3 and helium-4 activation analysis

The determination of oxygen in lead by³He and⁴He activation analysis was studied. Both methods were applied to the same material containing 0.9 μg·g^?1 of oxygen. The¹⁸F formed from oxygen was separated from matrix activities by extraction of Po with N-benzoyl-N-fenylhydroxylamine, followed by distillation of fluorosilicic acid and precipitation of lead fluorochloride (⁴He activation) or by distillation followed by precipitation (³He activation). The yield of the separation, which amounted on the average to 68%, was determined via the¹⁹F(n,⁴He)¹⁶N reaction. The coefficients of variation were 21 and 45% for⁴He and³He activation analysis, respectively, thus indicating a less homogeneous distribution of the oxygen. Nuclear interferences of sodium and fluorine were shown to be negligible.     

Molecular ramsauer-townsend effect in very low energy He-He scattering

It is shown that a Ramsauer-Townsend effect is possible in very low energy (≈ 2°K) collisions of ⁴He-⁴He - i.e., a deep minimum in the total elastic scattering cross section occurs at this collision energy. It is seen that no such minimum is possible for the other isotopic variants, ³He-³He and ³He-⁴He.     

Semiclassical calculation of vibrational relaxation of CO colliding with 4He and 3He

The rate constant for the deactivation of CO (υ = 1) colliding with ⁴He and ³He is calculated in the range 100–1000 K. Agreement with experiment can be obtained using a hybrid isotropic potential. The isotopic ratio k₁₀(³He) k₁₀(⁴He) is predicted to be strongly temperature dependent at low temperatures.     

Surface potentials and A3He bound state on liquid 4He

Continuous surface potentials are calculated for both ⁴He and ³He at T = OK. Comparison of the derived heats of vaporization with the experimental ones shows good agreement. The energy of a ³He bound state on liquid ⁴He is also calculated: our results, —5.85K, is to be compared with the experimental one, —5.20K.     

Density of states and evaporation rate of helium clusters

The density of states of⁴He clusters is calculated on the assumption that only surface vibrations are thermally excited. Results for mixed³He-⁴He and³He clusters are also given. The Weisskopf procedure is used to calculate the evaporation rates and the cooling laws of helium clusters at low temperatures.