微波辅助合成石墨烯/氧化镍复合材料及其表征

本文通过微波辅助的方法,快速而有效地在热膨胀石墨烯(RG)的缺陷上原位合成氧化镍纳米颗粒,形成石墨烯/氧化镍复合材料(RG/NiO)。利用X-射线衍射(XRD),拉曼光谱(Raman),傅里叶变换红外(FTIR),扫描电镜(SEM),透射电镜(TEM),热重-差热(TGA-DSC)对所制备样品的结构、形貌和NiO含量在复合材料中的含量进行表征。结果表明,热膨胀石墨烯层数约7~8层,层间距约为0.35nm,缺陷多,在水热和微波处理后抗氧化性明显变差。复合材料中氧化镍颗粒平均粒径为25nm,均匀而密集地分散在石墨烯平面上,同时在复合材料中的含量为19.8%。     

颗粒气体团簇行为实验研究

颗粒体系由于非弹性碰撞和摩擦等内秉的能量耗散特性,由宏观粒子形成的颗粒气体体系经常会有局部凝聚现象,这是颗粒气体体系与分子气体体系的最大区别之一.理解和预测这一现象的发生将有助于人们对远离平衡态体系的复杂现象,如有序结构、斑图和团簇形成的认知.这种局部凝聚现象可以类比于分子气体中亚稳分解形成的液滴,将气液相分离用于解释和寻求局部凝聚现象的此模型得到了分子动力学模拟的校验.但是实验的校验却由于宏观粒子运动受重力作用的影响难以在实验室中实现.作为实践十号卫星的前期实验,本文利用国家微重力实验室落塔装置,以水平激振装有不同尺寸和数目的颗粒样品,在短时微重力条件下,成功观察到颗粒气体团簇的形成;并将实验结果与颗粒气体类范德瓦耳斯气体分子相分离模型对比,由形成团簇样品的颗粒数密度条件,来实验确定了所选颗粒的恢复系数,得到直径为0.5 mm的钛珠颗粒的恢复系数在0.6—0.8之间,直径为1 mm的钛珠颗粒的恢复系数约为0.8,直径为2.5 mm的钛珠颗粒的恢复系数应大于0.8.     

柱面微通道板的制备及其性能研究

针对未来空间天文学应用的超分辨率光谱成像仪器的需求,对低噪声柱面微通道板（MCP）的制备方法及其性能进行了研究. 提出了一种将光学抛光与热成型相结合的新的柱面MCP制备方法,利用不含放射性元素的低噪声MCP玻璃,制备出曲率半径为400mm、尺寸为30mm′46mm、长径比为80:1、通道直径12.5mm、通道间距15mm的柱面MCP,并将其与感应电荷楔条形阳极（WSA）组成光子计数探测器,对其暗计数率、分辨率进行了检测,暗计数率约为0.1counts/cm2×s.     

孤对电子与赤道取向——sp3d杂化轨道中电子对排列的一种有趣现象

揭示了一种有趣的分子结构现象：在ABn型多原子分子或离子结构中,若中心原子A的轨道杂化方式为sp3d,且价层有孤电子对时,孤电子对总是呈三角双锥的赤道取向;若分子中A、B原子间有重键时,B原子也总是呈赤道取向。探讨了这一现象的内在原因,并通过归纳法论证了这一规律。     

Association Constant Prediction for the Inclusion of α-Cyclodextrin with Benzene Derivatives by an Artificial Neural Network

The association constants (K_a) for the inclusion complexation of -cyclodextrin (-CD) with 72 mono- and 1,4-disubstituted benzenes were predicted successfully by an artificial neural network (ANN) with molar refraction (R_m) and hydrophobic constant () as input parameters, which reflect the volume and hydrophobicity of the substituents respectively. The predictions strongly suggested that the inclusion complexation of -CD with guest molecules was mainly driven by van der Waals forces and hydrophobic interactions     

Study on structures and electron affinities of small potassium–silicon clusters Si n K (n = 2–8) and their anions with Gaussian-3 theory

The neutral Si _n K (n = 2–8) clusters and their anions have been systematically studied by means of the higher level of Gaussian-3 schemes. Equilibrium geometries and electron affinities have been calculated and are discussed for each considered size. For neutral Si _n K clusters, the ground state structure is found to be “attaching structure”, in which the K atom is bound to Si _n clusters. The most stable isomer for their anions, however, is found to be “substitutional structures”, which is derived from Si_(n+1) by replacing the Si atom with a K. The dissociation energies of K atom from the lowest energy structures of Si _n K have also been estimated to examine relative stabilities.     

细颗粒湍流聚并的分区法群平衡模拟

通过聚并促进细颗粒(PM_2.5)特别是亚微米颗粒(PM_1.0)团聚长大或被大颗粒捕集,是提高其脱除效率的有效方法之一。本文采用分区法对燃煤电厂尾部烟气中飞灰的聚并进行了群平衡模拟研究。利用圆柱阵列实现的湍流聚并装置,圆柱横向间距为4倍直径时,纵向间距宜在圆柱直径的15~30倍之间,在工程上较为可行的条件下,对于PM_1.0可达到55%或更高的聚并效率。粗颗粒的存在对于细颗粒聚并具有明显的促进作用,聚并停留时间越短,该作用相对越显著。     

RgBF2(+) complexes (Rg = Ar, Kr, and Xe): the cations with large stabilities

Rare gas containing cations with general formula [Rg, B, 2F](+) have been investigated theoretically by second-order Mo?ller-Plesset perturbation, coupled cluster, and complete active space self-consistent field levels of theory with correlation-consistent basis sets. Totally two types of minima, i.e., boron centered C(2) (v) symmetried RgBF(2) (+) (Rg = Ar, Kr, and Xe) which can be viewed as loss of F(-) from FRgBF(2) and linear FRgBF(+) (Rg = Kr and Xe) are obtained at the CCSD(T)∕aug-cc-pVTZ∕SDD and CASSCF(10,8)∕aug-cc-pVTZ∕SDD levels, respectively. It is shown that the RgBF(2) (+) are global minima followed by FRgBF(+) at 170.9 and 142.2 kcal∕mol on the singlet potential-energy surfaces of [Rg, B, 2F](+) (Rg = Kr and Xe) at the CASPT2(10,8) ∕aug-cc-pVTZ∕SDD∕∕CASSCF(10,8)∕aug-cc-pVTZ∕SDD, respectively. The interconversion barrier heights between RgBF(2) (+) and FRgBF(+) (Rg = Kr and Xe) are at least 39 kcal∕mol. In addition, no dissociation transition state associated with RgBF(2) (+) and FRgBF(+) can be found. This suggests that RgBF(2) (+) (Rg = Ar, Kr, and Xe) can exist as both thermodynamically and kinetically stable species, while linear FRgBF(+) (Rg = Kr and Xe) can exist as metastable species compared with the lowest dissociation limit energies just like isoelectronic linear FRgBO and FRgBN(-). From natural bond orbital and atoms-in-molecules calculations, it is found that the positive charge is mainly located on Rg and boron atoms for both types of minima, the Rg-B bonds of ArBF(2) (+), KrBF(2) (+), and XeBF(2) (+) are mostly electrostatic, thus can be viewed as ion-induced dipole interaction; while that of linear FKrBF(+) and FXeBF(+) are covalent in nature. The previous experimental observation of ArBF(2) (+) by Pepi et al. [J. Phys. Chem. B. 110, 4492 (2006)] should correspond to C(2) (v) minimum. The presently predicted spectroscopies of KrBF(2) (+), XeBF(2) (+), FKrBF(+), and FXeBF(+) should be helpful for their experimental identification in the future.     

A dual pathway in the solid-state photoreaction of nitrobenzaldehydes with indole

The solid-state photoreaction of the mixed crystals between nitrobenzaldehydes and indole was found to give nitrophenyl-(bis-3-indolyl)methane ( 3 ) and nitrophenyl-(3-indolyl)methanol ( 4 ). The structure of the ortho isomer 4c was established by X-ray crystallographic analysis. A dual pathway from an oxetane intermediate 5 is proposed for the formation of 3 and 4 .     

Standard Bases of a Vector Space Over a Linearly Ordered Incline

Inclines are additively idempotent semirings, in which the partial order ≤ : x ≤ y if and only if x + y = y is defined and products are less than or equal to either factor. Boolean algebra, max-min fuzzy algebra, and distributive lattices are examples of inclines. In this article, standard bases of a finitely generated vector space over a linearly ordered commutative incline are studied. We obtain that if a standard basis exists, then it is unique. In particular, if the incline is solvable or multiplicatively-declined or multiplicatively-idempotent (i.e., a chain semiring), further results are obtained, respectively. For a chain semiring a checkable condition for distinguishing if a basis is standard is given. Based on the condition an algorithm for computing the standard basis is described.