Towards antihydrogen confinement with the ALPHA antihydrogen trap

ALPHA is an international project that has recently begun experimentation at CERN’s Antiproton Decelerator (AD) facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms with the ultimate goal of precise spectroscopic comparisons with hydrogen. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.     

安徽两淮煤田天然气资源简评

本文讨论了两淮煤田煤化作用与岩浆热之间的关系,表明有机质二次生气在淮南复向斜和肖西复向斜有聚集的可能。此外,本文讨论了两淮的煤矿瓦斯资源,煤层瓦斯量丰富,它的回收问题应引起足够的重视     

On the Most Powerful Chemical Traps for Bis(methoxycarbonyl)carbene (=2‐Methoxy‐1‐(methoxycarbonyl)‐2‐oxoethylidene)

The efficiency and validity of different chemical substrates for trapping bis(methoxycarbonyl)carbene (=2‐methoxy‐1‐(methoxycarbonyl)‐2‐oxoethylidene; 1 ) is dependent on the conditions of carbene generation. On conventional photolysis of dimethyldiazomalonate (=2‐diazopropanedioic acid dimethyl ester; 2 ) by long‐wave UV light (through a Pyrex filter, λ>290 nm), the most powerful trap for carbene 1 in the series of substrates Me₂S, MeOH, cyclohexane, and pyridine is Me₂S (with an efficiency ratio of ca. 6 : 4 : 2 : 1, resp.). When short‐wave decomposition of diazomalonate 2 is employed (through a quartz filter, λ>210 nm), more reliable and useful chemical traps for bis(methoxycarbonyl)carbene ( 1 ) are pyridine and cyclohexane, whose adducts with 1 are rather stable under short‐wave‐irradiation conditions. Application of alcohols for the trapping of 1 proves to be preferential when simultaneous monitoring of carbene and oxoketene formation during photolysis is necessary.     

塔里木盆地大北地区巴什基奇克组成岩相测井识别

依据成岩序列和成岩阶段划分原理,结合储层岩心观察、铸体薄片、阴极发光,扫描电镜、X射线衍射等资料,对塔里木盆地大北地区巴什基奇克组成岩相定量划分及测井表征进行研究。结果表明:塔里木盆地大北地区巴什基奇克组划分为强压实相、不稳定组分溶蚀相、钙质胶结相、构造裂缝相4种成岩相类型;将综合成岩系数作为成岩相表征的参数,相比前人的研究方法能够很好地解决成岩相定量划分的问题;综合成岩系数的测井资料计算可以实现测井资料模块化处理定量识别成岩相;提出的成岩相识别新方法与岩心分析资料形成良好的印证,方法准确可靠。     

激子复合区随温度移动对OLED磁效应的影响

制备了DCM掺杂层靠近阴极的双发光层有机发光器件ITO/CuPc/NPB/Alq3（发射绿光）/Alq3：DCM（发射红光）/LiF/Al,并在不同温度下测量了该器件和无DCM掺杂的单发光层参考器件的磁电致发光（Magneto-ElectroLuminescence,MEL）和磁电导（Magneto-Conductance,MC）.在注入相同电流密度下,发现双发光层器件MEL的高场（B50mT）效应随温度降低呈现先减小后增大的非单调变化,这与单发光层参考器件的单调递增变化明显不同.同时测量了不同温度下的电致发光光谱,发现双发光层器件的533nm和600nm两个特征峰的强度随温度变化出现了此消彼长的现象,表明激子复合区域随温度变化发生了移动.通过分析工作温度对器件各发光层中的三重态激子对间相互作用及载流子迁移率的影响,对双发光层器件中MEL的高场效应随温度的非单调变化进行了定性解释.实验结果进一步验证了在单发光层器件中得到的有机磁效应高场变化的相关结论.     

测井成岩相自动识别及其在鄂尔多斯盆地苏里格地区的应用

以岩性作为测井特征提取及成岩相识别单元,排除岩性差异对测井信息影响,控制识别单元发育成岩相类型。利用黏土矿物含量比值反映孔隙流体酸碱性,提高判别结果的准确性。根据成岩相对孔缝演化作用的最终影响,定义测井成岩相,并利用基于贝叶斯最佳分类的概率神经网络,对比不同测井组合下神经网络对测井成岩相的识别能力。利用所提方法对鄂尔多斯盆地苏里格地区进行成岩相识别。结果表明,测井成岩相识别结果与实际取心鉴别结果的符合率为81%,且识别的溶蚀相发育区域在实际试气中基本为气层及气水同层,无差气层存在。     

Two-step condensation of lattice bosons

We present a theoretical study of Bose-Einstein condensation in highly anisotropic harmonic traps. The bosons are considered to be moving in an optical lattice in an overall anisotropic harmonic confining potential. We find that two-step condensation occurs for lattice bosons at much reduced harmonic potential anisotropy when compared to the case of an ideal Bose gas in an anisotropic harmonic confinement. We also show that when the bosons are in an isotropic harmonic confinement but with highly anisotropic hopping in the optical lattice, two-step condensation does not occur. We interpret some of our results using single boson density of energy states corresponding to the potentials faced by the bosons.     

Trajectory compensation in an autoresonant trap mass spectrometer

The auto-resonant trap mass spectrometer, ART-MS, utilizes electrostatic ion trapping within an anharmonic potential well. Ions are detected after mass selective trap ejection with auto-resonant driving employing only low-power rf electronics. We identify the major limiting factor in the mass resolution of these instruments. Whilst keeping in the spirit of maintaining a rapid scan rate, low cost, lightweight instrument, with minimal required machining tolerances, we introduce a method for much improving the mass resolutions of an ART-MS. The addition of two electrodes has enabled an improvement in the mass resolution by a factor of ～4. The scheme significantly reduces the effects of a finite sized trap and compensates for the influence of radial variation in natural oscillating frequencies within the trap. Compensation can be implemented with a wide range of designs and is not limited by the size of the trap.     

新疆红连地区七克台组储层成岩作用与成岩相

吐哈盆地红连地区中侏罗统七克台组油气勘探潜力巨大。在综合运用普通薄片、铸体薄片和扫描电镜等资料的基础上,系统分析七克台组储集砂岩成岩作用特征,建立成岩演化序列,进而分析成岩相特征及有利成岩相的分布。结果表明：七克台组储集砂岩成岩阶段总体处于中成岩阶段 A－B 期,主要经历了压实作用、胶结作用、溶蚀作用和破裂作用。压实作用、硅质胶结作用、碳酸盐胶结作用对储层起破坏性作用;建设性的成岩作用主要为早期绿泥石环边胶结作用、溶蚀作用和破裂作用。初步进行了成岩相特征的研究,划分出5种成岩相类型,其中环边绿泥石胶结-硅质、高岭石充填-剩余原生粒间孔成岩相和伊利石、方解石充填-剩余原生粒间孔-溶蚀孔成岩相为较有利的成岩相类型。     

Penning traps as a versatile tool for precise experiments in fundamental physics

This review article describes the trapping of charged particles. The main principles of electromagnetic confinement of various species from elementary particles to heavy atoms are briefly described. The preparation and manipulation with trapped single particles, as well as methods of frequency measurements, providing unprecedented precision, are discussed. Unique applications of Penning traps in fundamental physics are presented. Ultra-precise trap-measurements of masses and magnetic moments of elementary particles (electrons, positrons, protons and antiprotons) confirm CPT-conservation, and allow accurate determination of the fine-structure constant α and other fundamental constants. This together with the information on the unitarity of the quark-mixing matrix, derived from the trap-measurements of atomic masses, serves for assessment of the Standard Model of the physics world. Direct mass measurements of nuclides targeted to some advanced problems of astrophysics and nuclear physics are also presented.