荷移分光光度法测定酒石酸美托洛尔

研究了酒石酸美托洛尔与紫色素之间的荷移反应。确定了反应条件,建立了一种测定酒石酸美托洛尔的荷移分光光度法。酒石酸美托洛尔与紫色素在乙醇介质中,室温条件下即可形成稳定的1∶1型荷移络合物,该络合物的最大吸收波长为540 nm,表观摩尔吸光率为6.83×103L.mol-1.cm-1。酒石酸美托洛尔质量浓度在10~80 mg/L范围内服从比耳定律,相关系数为0.9991。相对标准偏差为1.3%(n=11),回收率为99.3%~102.7%。     

关于Hamltion线图的一个结果

设Ｇ是一个简单图，(?)ｅ∈Ｅ（Ｇ），定义ｅ＝ｕｖ在Ｇ中的度ｄ（ｅ）＝ｄ（ｕ）＋ｄ（ｖ），其中ｄ（ｕ）和ｄ（ｖ）分别为ｕ和ｖ的度数。若连通图Ｇ的每个桥都有一个端点度数为１，则称Ｇ是几乎无桥的图。本文的主要结果是：设Ｇ是ｐ≥２阶几乎无桥的简单连通图，且Ｇ≠Ｋ_{１，ｐ－１}若对任何无公共顶点的两边ｅ₀及ｅ₁，ｄ（ｅ₀）＋ｄ（ｅ₁）≥ｐ＋４，则Ｇ有一个Ｄ－闭迹，从而Ｇ的线图Ｌ（Ｇ）是哈密顿的。     

Pressure and temperature induced high spin–low spin phase transition: Macroscopic and microscopic consideration

The behavior under pressure of the high spin–low spin phase transition in the coordination compounds containing 3d ions is analyzed using thermodynamic and microscopic approaches. For thermodynamic approach the mean field model with interactions between spin-crossover molecules is considered. Microscopic model takes into account the interaction of d electrons of the transition metal ions with full symmetric distortions of the ligands. The relationship of the thermodynamic interaction parameters with microscopic ones is installed and shown how the quantum–mechanical interactions form the cooperativity of the system. Within the microscopic model the temperature and pressure dependences of the high spin fraction in 2-D compounds {Fe(3-Fpy)₂[M(CN)₄]} (M=Pd, Pt) are simulated and microscopic parameters are evaluated. It is concluded that different experimental behaviors of the temperature and pressure induced spin transitions are determined by different variations of the inelastic and elastic energies under pressure, and vibrational component of the free energy drives the ST equally with electronic part.     

Site selectivity of dopant cations in Ca3(SiO4)Cl2

A series of static lattice calculations were performed to determine the site selectivity of cations of differing size and valence when substituted onto the Ca sites of the calcium chlorosilicate (Ca₃(SiO₄)Cl₂) lattice, a potential host phase for the immobilisation of halide-rich wastes arising from the pyrochemical reprocessing of plutonium. Atomic-scale simulations indicate that divalent cations are preferentially substituted onto the Ca1 site, whilst tri- and tetravalent cations are preferentially hosted on the Ca2 site, with the Ca1 site favoured for forming the vacancies necessary to charge-balance the lattice as a whole. Multi-defect calculations reveal that the site selectivity of the dopant cations is dependent on their ionic radii; as the ionic radii of the divalent cations increase, substitution onto the preferred site becomes more and more strongly favoured, whereas the inverse is true of the trivalent cations.     

纳米氧化钛团聚结构的研究

爆轰形成的高温、高压持续时间短,使得新生的氧化钛来不及长成较大的晶粒,只能形成大量的类球形纳米微粒。在潮湿的爆生气体环境中,这些纳米氧化钛颗粒间的相互作用(如碰撞、摩擦、挤压、渗透和粘附等)比较剧烈,极易聚集成团聚体。初步分析了以硫酸氧钛为钛源、采用爆轰法合成的纳米氧化钛的团聚结构和分散形态,对经过加热至500℃、保温1 h热处理后的纳米氧化钛的团聚结构也进行了分析。研究结果表明:用爆轰法合成的纳米氧化钛存在软团聚和硬团聚两种形式,而经过热处理(500℃、1 h)的纳米氧化钛的团聚程度得到了一定的改善。此外,还分析了纳米粉体的特性、爆轰特点和爆生气体环境等因素对产生纳米氧化钛团聚结构的影响。     

Controllable synthesis of layered Co–Ni hydroxide hierarchical structures for high-performance hybrid supercapacitors

A facile solvothermal method is developed for synthesizing layered Co–Ni hydroxide hierarchical structures by using hexamethylenetetramine (HMT) as alkaline reagent. The electrochemical measurements reveal that the specific capacitances of layered bimetallic (Co–Ni) hydroxides are generally superior to those of layered monometallic (Co, Ni) hydroxides. The as-prepared Co_0.5Ni_0.5 hydroxide hierarchical structures possesses the highest specific capacitance of 1767 F g⁻¹ at a galvanic current density of 1 A g⁻¹ and an outstanding specific capacitance retention of 87% after 1000 cycles. In comparison with the dispersed nanosheets of Co–Ni hydroxide, layered hydroxide hierarchical structures show much superior electrochemical performance. This study provides a promising method to construct hierarchical structures with controllable transition-metal compositions for enhancing the electrochemical performance in hybrid supercapacitors.     

Comparison and application of the experimental methods for multi-layer prediction of acoustical properties of noise control materials in standing wave-duct systems

A comparison among the existing experimental methods used for measuring and predicting acoustical properties, such as absorption ratio and transmission loss, of noise control materials was accomplished in this paper. Four methods for absorption ratio and five methods for transmission loss, which can be generalized as standing wave ratio method, two-cavity method and two-load method, were performed in a special standing wave-duct with two configurations of two- and four-microphone holders and compared with the theoretical expressions in the literature. Conclusions were drawn that the standing wave ratio method with two and four-microphones was more reliable, faster, and easier to use for measuring absorption ratio and transmission loss, respectively. The two-cavity and two- load methods, which may be used to predict acoustical properties of an exceedingly thick sample or a multi-layered treatment consisting of variant materials, have different conditions of using limits. The two-cavity method, especially, can be easily conducted and is suitable for the materials with properties of symmetry and reciprocity. The two-load method, however, is more cumbersome to apply, due to the fact of its complex calibration and measurement procedure. Furthermore, some prediction examples for a set of multi-layered treatments of materials were executed by a newly proposed approach, so-called experimental hybrid multi-layer prediction. In view of applications, the works done in this paper may be directly applied in standing wave-duct systems or other noise control configurations to measure, predict and/or optimize their in situ designs.