枸橼酸镓-~(67)Ga的制备

采用自制的磷酸三丁酯 (TBP)萃淋树脂作交换柱 ,应用反相分配色层法研究了6 7Ga与靶材料中Zn ,Cu ,Ni等元素及活化产物6 5Zn ,56 Co ,57Co的分离 ,建立了一个简便、快速生产枸橼酸镓 6 7Ga的方法。所得6 7Ga的放射性核纯达 99 5% ,每 37MBq6 7Ga中其它金属离子总量不超过2 5μg     

Thin porous nanosheets of NiFe layered-double hydroxides toward a highly efficient electrocatalyst for water oxidation

NiFe layered double hydroxides (NiFe-LDH) are low cost and earth abundant electrocatalysts for oxygen evolution reaction (OER). Herein, the NiFe-LDH nanosheets induced by ZIF-67 (NiFe-LDH/ZIF-67) were prepared via a coupling method of a self-sacrificing template method and a co-precipitation method. Atomic force microscope and field emission transmission electron microscopy analysis indicate that NiFe-LDH/ZIF-67 consist of thin porous nanosheets. X-ray photoelectron spectra analysis show that NiFe-LDH/ZIF-67 contains more oxygen vacancies than pristine NiFe-LDH. The overpotential of NiFe-LDH/ZIF-67 is 222 mV at 10 mA cm⁻² for OER, lower than that of ZIF-67, pristine NiFe-LDH, and the commercial RuO₂, indicating that its high electrocatalytic activity for OER. The high electrocatalytic activity of NiFe-LDH/ZIF-67 may be attributed to its thin porous nanosheet structure, which is derived from the structural influence of ZIF-67 and the coupling effect of a self-sacrificing template method and a co-precipitation method.     

Solution plasma method assisted with MOF for the synthesis of Pt@CoOx@N-C composite catalysts with enhanced methanol oxidation performance

The key to direct methanol fuel cells (DMFCs) is the anode catalyst for methanol oxidation reaction (MOR) which has good catalytic activity and stability. Pt@CoO_x@N-C catalysts were synthesized by compounding Pt nanoparticles and CoO_x with nitrogen-doped porous carbon (N-C). Pt nanoparticles were prepared by solution plasma technique. CoO_x@N-C are derived from zeolitic-imidazolate-framework-67 (ZIF-67) by heat treatment at 700 °C. For MOR, Pt@CoO_x@N-C exhibits an outstanding electrocatalytic performance (mass activity of 2400 mA mg_Pt⁻¹) and stability (70% remained after 300 cycles) under acidic condition, which owing to the synergistic effects among the Pt nanoparticles, CoO_x and nitrogen-doped porous carbon. Pt@CoO_x@N-C shows such mass activity superior to that of Pt/C (460 mA mg_Pt⁻¹) due to the fact that CoO can adsorb –OH in the solution and then assist Pt to oxidize the CO-like intermediates to CO₂ which improves the resistance to CO poisoning of Pt nanoparticles. Therefore, solution plasma method assisted with metal-organic frameworks have good development prospects on synthesis of highly efficient electrocatalysts.     

A~2/O工艺的污泥中生物毒性物质的迁移转化特性

基于建立的固体样品青海弧菌生物毒性检测方法和理化指标分析,考察了A2/O工艺流程中污泥样品的水溶性和脂溶性污染物的生物毒性,结合有机物和重金属离子的含量,分析污染物在水处理过程中的去除特性。结果显示:污泥中脂溶性污染物的生物毒性远远高于水溶性污染物;随着处理工艺的进行,充氧量不断增加,污泥中的水溶性有机物和绝大多数重金属浓度都有所降低,然而其生物毒性却逐渐升高。与此相反,脂溶性污染物的生物毒性逐渐降低。     

CoP@NC electrocatalyst promotes hydrogen and oxygen productions for overall water splitting in alkaline media

Design and synthesis of high-performance bi-functional electrocatalysts can play a crucial role for electrolytic water splitting. Herein, we develop a simple phosphating process to construct cobalt phosphide@nitrogen-doped carbon (CoP@NC) using metal organic frame (MOF) as a precursor and a template. In alkaline solution, CoP@NC-350 exhibits exceptional hydrogen and oxygen evolution reaction performances with over potentials of 75 mV and 268 mV at 10 mA cm^?2, respectively. For a symmetric CoP@NC-350 two-electrode water splitting setup, the potential can be low as 1.69 V to obtain 10 mA cm^?2. Therefore, low-temperature phosphating treatment can be a simple and promising method to produce electrocatalysts for water splitting.     

CO2/CH4 separation using prepared and characterized poly (ether-block-amide)/ZIF-8 mixed matrix membranes

In this study, poly (ether-block-amide) (Pebax-2533) based mixed matrix membranes were prepared by incorporating various contents of synthesized zeolitic imidazole framework (ZIF-8) nanoparticles into the polymer matrix. The membranes were fabricated via a solution casting–solvent evaporation technique. The results of gas permeation through the membranes revealed that the addition of the ZIF-8 into the polymer matrix enhances both permeability and CO₂/CH₄ selectivity values. As an example, for the mixed matrix membrane comprising 25 wt% of ZIF-8, CO₂ permeability and ideal CO₂/CH₄ selectivity values are 269.73 Barrer and 9.31, respectively, while the corresponding values are 187.54 Barrer and 7.25 for the neat membrane.     

Solutions of Yule‐Walker equations for singular AR processes

A study is presented on solutions of the Yule‐Walker equations for singular AR processes that are stationary outputs of a given AR system. If the Yule‐Walker equations admit more than one solution and the order of the AR system is no less than two, the solution set includes solutions which define unstable AR systems. The solution set also includes one solution, the minimal norm solution, which defines an AR system whose characteristic polynomial has either only stable zeros (implying that only one stationary output exists for this system and it is linearly regular) or has stable zeros as well as zeros of unit modulus, (implying that stationary solutions of this system are a sum of a linearly regular process and a linearly singular process). The numbers of stable and unit circle zeros of the characteristic polynomial of the defined AR system can be characterized in terms of the ranks of certain matrices, and the characteristic polynomial of the AR system defined by the minimal norm solution has the least number of unit circle zeros and the most number of stable zeros over all possible solutions.     

ZIF-8原位合成法固定化脂肪酶CRL

以ZIF-8为固定化载体,通过原位合成法固定褶皱假丝酵母脂肪酶(CRL),研究了不同固定化条件对固定化酶活力的影响以及固定化酶的稳定性,并对固定化酶进行了结构表征。结果表明:在10 m L 40 mmol/L硝酸锌溶液、10 m L 160 mmol/L 2-甲基咪唑溶液、2-甲基咪唑溶液初始p H8、酶添加量2.75 mg、-48℃冷冻干燥条件下,获得的固定化酶CRL@ZIF-8蛋白回收率为93%,比活力为1.08 U/mg;底物的分子大小对固定化酶的催化性能有明显影响,在以相对小分子的乙酸对硝基苯酯为底物时,重复使用9次后固定化酶仍保持72.8%的相对活力;通过对固定化酶进行场发射扫描电镜和氮气吸附脱附表征,表明脂肪酶CRL在载体表面和内部均有分布,固定化酶颗粒粒径约400 nm。     

Simple Keynesian input–output structural decomposition analysis using weighted Shapley value resolution

This study proposes a method of input–output structural decomposition analysis (I–O SDA) incorporating simple Keynesian modeling and a two-tier KLEM production function framework. The derived model is based on a well-established macro-economic theory and the well-accepted production function form, which presupposes that I–O SDA not only compares I–O table coefficients but also employs well established economic theory. Additionally, weighted Shapley value is introduced to construct a generalized equation for deriving a set of I–O SDA solutions and to verify that, because this set of solutions satisfies efficiency and aggregation axioms, arbitrary use of ad hoc decomposition forms can be avoided, and residuals can be eliminated. The authors would like to thank the National Science Council of the Republic of China, Taiwan, for financially supporting this research under Contract No. NSC 94-2415-H-006-009.