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1.
~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.  相似文献   

2.
惰性气体氦由~3He和~4He两种稳定同位素组成。大气中氦的含量为 7×10~(-7)(重量),其中~3He与~4He之比为1.2×10~(-6)。因此想从自然界获得有实用价值的~3He十分困难。现在各国都不再从大气氦中波集~3He,而是从生产氚的副产物中获得~3He。近年来,~3He在各个研究领域里的应用日益重要,如~He中子计数管,以~3He作工作物质的氦-氖激光器,以及~3He在低温物理中的应用需要大量的高纯,高浓度的~3He。热扩散法是分离气体同位素的基本方法之一。由于~He、~He分子量的相对差较大,有比较大的热扩散  相似文献   

3.
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。  相似文献   

4.
充氘钯空心阴极灯中放电气体的质谱研究杨原,王小如(厦门大学化学系,厦门,361005)关键词充氘钯阴极,辉光放电,氦-4质谱钯吸附氢气及氘气的研究已有报道[1],在一定操作条件下,钯吸附氘后还可能产生异常效应[2]。金属空心阴极灯已被广泛地应用于物理...  相似文献   

5.
吕功煊  甄文龙 《分子催化》2017,31(4):299-304
我们报道了在可见光照射下,半导体硫化镉(GdS)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.  相似文献   

6.
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.  相似文献   

7.
松辽盆地非生物成因气的探讨   总被引:80,自引:0,他引:80  
松辽盆地为—克拉通内裂谷盆地。基底、地壳及超壳深大断裂发育。沿深大断裂发生的沉积同期和后期的岩浆活动活跃,存在着非生物成因天然气及其伴生资源的供给条件。非生物成因甲烷沿深大断裂分布,δ~(13)C为-12.8‰至-24.2‰;甲烷同系物碳同位素组成δ~(13)C值反序排列,即δ~(13)C_1>δ~(13)C_2>δ~(13)C_3;氦同位素显示了含幔源氦的同位素组成特征,~3He/~4He=2.34—2.97×10~(-6);上述事实表明,松辽盆地可能存在非生物成因天然气及其伴生资源,是裂谷型沉积盆地资源评价的重要内容。  相似文献   

8.
解决全球能源问题的聚变反应堆一直备受关注,其中由欧盟、俄罗斯、中、韩、印、日等多方合作的ITER(International Thermonuclear Experimental Reactor)计划便是一个代表性的进展标志.ITER实验包层工作组将液态锂铅实验包层模块列为重点开发对象,中国提出的双功能锂铅实验包层模块DFLL-TBM(Dual FunctionLithium Lead-Test Blanket Module)是主要研究方案之一,液态锂铅集氚增殖剂、冷却剂和中子倍增剂于一身,可采用鼓泡器方式实现氚的提取.有关含氚固体废物的回收早有报道,但主要集中于贮氢材料中氚的同位素交换和氘氚化锂残渣中的氚回收,而高温液态合金中氚的回收还未见报道.如果要将液相锂铅中的氚滞留量降低到包层设计的要求,则必须使其上方的氚分压不超过107Pa,采用单纯的氦吹洗或真空脱气难以满足要求,102Pa是它们所能达到的最低极限压力,这是因为在低氚浓度下,由液相转入气相的氚速率是受氚在液相、气相及气-液界面的扩散过程所限制.为了提高从锂铅合金中回收氚的效率,减小氚在液相和气相的分子扩散阻力及气体在液相的滞留时间,本文采用氦吹洗气以及其与氢、氘的混合气作为交换载带气,利用同位素效应(isotopic effect),对液态锂铅合金中的微量氚开展实验回收的预先研究,期望对今后包层氚提取系统(TES)的工程化设计与建造提供技术支持.研究结果显示:随着交换温度的升高,氚的回收率明显增加,并且温度越高,第一次解吸的氚量越大.623K时,同位素交换效果较差,氚回收率较低;723K时经过6次交换后氚的回收率为78.2%;823K时交换一次氚的回收率就可达到66.3%.在相同温度下,氚回收率随交换次数的增加而增加,但经过6次交换后,曲线趋于平坦,氚回收率似乎在接近80%左右形成最大值.此外,单独使用氦吹洗气,氚回收率不到30%;添加0.1%的氘比氢的回收率要略高一些,这是因为充氚结束后的锂铅合金处于平衡状态,并非饱和状态,要交换出合金内的氚,必须预先吸附一定量的载带气,使其达到交换温度下的气体平衡离解压力,方可将合金中的氚交换出来.在较高的交换温度下,氚比氘、氘比氢更容易从锂铅中解析出来,这与气相色谱法分离氢同位素的原理是一致的.但过度增加载带气中氘的比例,反而降低了氚回收率,这是因为随着氘分压的增大,吸附质之间的同位素效应将减弱.总之,采用氦与0.1%氘组成的混合吹洗气,利用同位素交换效应对锂铅合金中的微量氚进行回收是有效的,氚回收效率接近80%;交换温度和交换次数对氚回收率的影响显著,在载带气相同的情况下,温度越高,交换次数越多,氚回收率越高.  相似文献   

9.
低能氮离子诱发丙酮与重水溶液的反应机理   总被引:1,自引:0,他引:1  
利用氮气火花放电产生离子,其中的正离子在阴极位降的加速下“注入”到丙酮的重水溶液中,诱发其中的化学反应.利用气相色谱 质谱(GC MS)分析离子注入后的样品,证实有氘代产物(CH3COCH2D)、氘羟基取代产物(CH3COCH2OD)生成,这表明低能N+诱发重水溶液中的反应主要是由于重水分子分解产生的自由基引起的,其中氘自由基和氘羟基自由基起重要作用;同时,产物中还检测到氘代乙酸(CH3COOD)和氘氨基丙酮(CH3COCH2ND2),说明反应是在氧化性氛围中进行的,氮离子俘获重水中的氘形成氘氨基可能是氘氨基取代产物生成的主要原因,也是氮“沉积”在溶液中的重要形式.这些结果对初步揭示低能离子诱发水溶液的反应机理具有一定的意义.  相似文献   

10.
以苯酚为原料,氘代碘甲烷与氘代醋酸酐为氘代试剂.经过氘代甲基化、傅克酰基化、克脑文盖尔缩合、芳构化、还原及氘代乙酰化反应得到氘代标记的阿戈美拉汀(1).该合成路线简洁,原料易得、反应条件易于控制,总收率为15.2%,化学纯度为99.97%,氘代丰度大于98%.目标化合物结构经质谱、核磁共振等表征确定可用于其药代动力学研究.  相似文献   

11.
吕功煊  张文妍 《分子催化》2017,31(5):401-410
报道了曙红、氯铂酸钾、氧化石墨烯和三乙醇胺混合物悬浮体系在可见光照射条件下将钾嬗变为钙的现象.在大于440 nm光照的条件下,反应体系可以产生大量的氢气,同时体系中的部分钾原子转变为钙元子.在反应过程中,悬浮混合物中的钙元素浓度持续增加,同时伴随发生质子的还原为氢和部分质子反应为氦3和氦4的反应.分析表明,在自然界的某种环境和条件下,钙有可能通过在温和条件下的低能核反应(LENR)经历钾的嬗变生成,这个过程可能与光催化产氢过程中生成的负氢有关.  相似文献   

12.
The preparation of a set of standards for the calibration of the analysis of deuterium using the2H/3He, p/4He reaction is described. Important considerations in the selection of a suitable standard are that it should be stable under irradiation and be simple to prepare with ready control of the amount of analyte. These requirements were met by Ca/OH/2 which was prepared by the replacement of hydrogen with its isotope in known proportions in the reaction of CaO with water.  相似文献   

13.
Analysis of isotopes of hydrogen and helium without radioactive components by quadrupole mass spectrometry (QMS) has been investigated for measuring the purity of deuterium for injection into the Tokamak of Strong Field. External radioactive source24Na is used to imitate accompanying ionizing radiation of T2. A threshold magnitude of exposure dose power is found, the exceeding of which leads to the increase of detection limit and systematic errors of isotopic analysis. QMS is used at medium resolution of 300 to determine compositions of3He in HD/H3 and4He in D2/H2D, and to quantify impurities in the mass range from 1 to 22 amu. Analysis of4He–D2 mixtures demonstrates the capability to measure isotopic composition with accuracy from 0.2 to 0.5%, depending on the samle-to-reference ratio of inlet pressure.  相似文献   

14.
The 3He nuclear magnetic shieldings were calculated for single helium atom, its dimer, simple models of fullerene cages (He@Cn), and single wall carbon nanotubes. The performances of several levels of theory (HF, MP2, DFT‐VSXC, CCSD, CCSD(T), and CCSDT) were tested. Two sets of polarization‐consistent basis sets were used (pcS‐n and aug‐pcS‐n), and an estimate of 3He nuclear magnetic shieldings in the complete basis set limit using a two‐parameter fit was established. Theoretical 3He results reproduced accurately previously reported theoretical values for helium gas, dimer, and helium probe inside several fullerene cages. Excellent agreement with experimental values was achieved. 3He nuclear magnetic shieldings of single helium atom approaching various points of benzene ring were tested, and an impact of 3He confinement within fullerene cages of different size on the 3He chemical shift was determined. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

15.
The role of theory level in prediction of benzene magnetic indexes of aromaticity is analysed and compared with calculated nuclear magnetic shieldings of 3He used as NMR probe. Three closely related nucleus‐independent chemical shift (NICS) based indexes were calculated for benzene at SCF‐HF, MP2, and DFT levels of theory and the impact of basis set on these quantities was studied. The changes of benzene NICS(0), NICS(1), and NICS(1)zz parameters calculated using SCF‐HF, MP2 and several density functionals were within 1 to 3 ppm. Similar deviations between magnetic indexes of aromaticity were observed for values calculated with selected basis sets. Only very small effect of polar solvent on benzene aromaticity was predicted. The 3He nuclear magnetic isotropic shielding (σ) and its zz‐components (σzz) of helium atom approaching the centre of benzene ring from above produced similar curves versus benzene‐He distance to NICS parameters calculated for similarly moving Bq ghost atom. We also propose an experimental verification of NICS calculations by designing the 3He NMR measurement for benzene saturated with helium gas or in low temperature matrices.  相似文献   

16.
The 3He nuclear magnetic shieldings were calculated for free helium atom and He–pyrrole, He–indole, and He–carbazole complexes. Several levels of theory, including Hartree–Fock (HF), Second‐order Møller‐Plesset Perturbation Theory (MP2), and Density Functional Theory (DFT) (VSXC, M062X, APFD, BHandHLYP, and mPW1PW91), combined with polarization‐consistent pcS‐2 and aug‐pcS‐2 basis sets were employed. Gauge‐including atomic orbital (GIAO) calculated 3He nuclear magnetic shieldings reproduced accurately previously reported theoretical values for helium gas. 3He nuclear magnetic shieldings and energy changes as result of single helium atom approaching to the five‐membered ring of pyrrole, indole, and carbazole were tested. It was observed that 3He NMR parameters of single helium atom, calculated at various levels of theory (HF, MP2, and DFT) are sensitive to the presence of heteroatomic rings. The helium atom was insensitive to the studied molecules at distances above 5 Å. Our results, obtained with BHandHLYP method, predicted fairly accurately the He–pyrrole plane separation of 3.15 Å (close to 3.24 Å, calculated by MP2) and yielded a sizable 3He NMR chemical shift (about ?1.5 ppm). The changes of calculated nucleus‐independent chemical shifts (NICS) with the distance above the rings showed a very similar pattern to helium‐3 NMR chemical shift. The ring currents above the five‐membered rings were seen by helium magnetic probe to about 5 Å above the ring planes verified by the calculated NICS index. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

17.
Angle-resolved translational energy spectroscopy has been applied to Cs4I + 3 ions that survived 8 keV collisions with a range of collision gas targets, including inert gases and deuterium. The experimental data comprise values of the translational energy loss ΔTR as a function of the (laboratory-frame) scattering angle θ R for each collision gas under conditions such that single-collision events dominated the scattering. The values of ΔTR increase with θ R, in accordance with very general expectations. However for any value of θ R, the values of ΔTR for helium and deuterium as targets were almost indistinguishable from one another but were at least five to six times larger than those for neon and all other collision gases. These data have been shown to be consistent with theoretical considerations based upon conservation of energy and linear momentum. Theoretical approaches include the simple “elasticlimit” model, which makes no mechanistic assumptions, and a particular “binary-model” theory, which excludes electronic excitation as a possibility. Both theories are consistent with the experimental data and interpret the surprisingly large values of ΔTR for low-mass targets in terms of large recoil energies of the target required to ensure conservation of momentum. The most likely alternative candidate as sink for ΔTR is internal excitation of the target, but this possibility was excluded in the present work by choosing ΔTR values less than the lowest excitation energies of the inert gas targets. Moreover, such an interpretation cannot explain the similar results obtained using helium and deuterium, which were markedly different from those obtained for all other collision gases.  相似文献   

18.
《印度化学会志》2021,98(8):100101
Although a helium atom prefers to stay at the centre of a fullerene (C60) cage and a proton binds with one of the carbon atoms from inside, DFT(MN15)/cc-pVTZ and DLPNO-MP2/def2-TZVP calculations show that the helium atom and the proton in HeH+ prefer to stay away from the centre of the cage, weakening the He–H+ covalent bond considerably. Both the helium atom and the proton exhibit noncovalent interactions with the carbon atoms of two pentagons at the opposite ends of the fullerene cage. Our calculations also show that a linear arrangement of H3+ (inside C60), pointing towards the centres of two pentagons opposite to each other, with the proton breaking away from H2, is energetically more favored over the equilateral triangle geometry of free H3+.  相似文献   

19.
The emission systems produced in He(2 3S)/SO2, Ne(3P0,2)/SO2 and Ar(3P0,2)/SO2, afterglows have been investigated in the ultraviolet and visible spectral ranges. In all three afterglows we have identified previously unknown long—wavelenght progressions in the SO(A3Π → X 3 σ?) system and have assigned several new bands in the SO(B 3σ? → X 3σ?)system. Reducing the temperature of the helium gas flowing through a hollow cathode discharge source to 118K effectively removes helium ions from the stream, thus facilitating spectral studies in uncontaminated metastable afterglows. A further effect of cooling the rare gases He, Ne, and Ar is an improvement in the resolution of the emission spectra and an enhanced signal-to-noise ratio. bl  相似文献   

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