Low-temperature thermal batteries using molten nitrate electrolytes

Journal of Solid State Electrochemistry - In this paper, low-temperature thermal batteries (LTBs) pertain to thermal batteries that have a lower operating temperature (less than...     

Photoinitiation mechanisms and photogelation kinetics of blue light induced polymerization of acrylamide with bicomponent photoinitiators

Blue light induced free radical photopolymerization of acrylamide (AM) was studied using five bicomponent photoinitiators, camphorquinon, riboflavin-5′-phosphate sodium, curcumin, eosin Y, and Ru(bpy)₃Cl₂ (Ru(II)) as photosensitizer, and diphenyliodonium hexafluorophosphate or potassium persulfate as electron acceptor. Fluorescence and UV–vis spectroscopies were used in combination with molecular orbital computations to characterize the photochemical behaviors of the five bicomponent photoinitiators, explore the possible electron transfer pathways of the photoinitiation processes, and quantify photopolymerization efficiencies. Real-time photogelation behavior of poly(AM) was monitored by Photo-differential scanning calorimetry and photo-rheometry. Photogelation kinetic parameters, including dG′ (storage modulus)/dt, dG″ (loss modulus)/dt, time delay of gelation (t_d), and duration of gelation (Δt_gel), were derived from photorheological data analyses and used to identify the best bicomponent photoinitiator candidate for rapid fabrication of blue light induced photopolymerizable hydrogels for biomedical applications.     

A Free‐Blockage Controlled Release System Based on the Hydrophobic/Hydrophilic Conversion of Mesoporous Silica Nanopores

A pH‐responsive free‐blockage release system was achieved through controlling the hydrophobic/hydrophilic conversion of mesoporous silica nanopores. This system further presented pulsatile release with changing pH values between 4.0 and 7.0 for several cycles. This free‐blockage release system could also release antitumor agents to induce cell death after infecting tumor cells and could have the ability of continuous infection to tumor cells with high drug‐delivery efficiency and few side effects.     

Graphene for Cleanup in Trace Analysis of Pyrethroid Insecticides in Cucumber and Spinach

Graphene, a novel class of carbon nanostructure, possesses an ultra-high specific surface area (theoretical value 2,630 m² g⁻¹), and both sides of the planar sheets of graphene are available for molecule adsorption. Graphene has already been used for preconcentration, extraction, and electrochemical selective determination. In this study, we used graphene to clean up pigments in cucumber for analysis, and measured eight pyrethroid model analytes using GC with electron capture detection (ECD). The recoveries of the 8 pyrethroids were 75–116 % with RSDs below 10 %, and LOQs ranged from 2.5 to 10 μg kg⁻¹. Comparative studies showed that graphene was superior to graphitized carbon black for the purification of pigments. We also investigated the ability of graphene to clean up spinach. A promising new adsorbent for pesticide residue analysis was developed. Graphene has significant potential as an effective adsorbent of pigments.

     

自适应演化硬件系统中遗传算法内核设计

根据基于演化的自适应系统的体系架构,将与具体应用相对独立的遗传算法操作部分取出来,结合算法的操作流程,设计了一个与应用无关的、能够独立完成遗传算法操作的GAK(遗传算法内核).采用VHDL(超高速集成电路硬件描述语言)语言描述的状态机来实现该设计,其中种群规模、染色体长度等参数均可配置.采用Xilinx的Vl000FG680、速度等级为-6的EPGA(现场可编程门阵列)来实现GAK,其中染色体长度为8位、适应度值为16位、种群规模为256,此时该设计的综合结果为:占用资源为485个片(Slice),时钟频率为48.51MH.进而在GAK上仿真求解了多项式函数的极值优化问题，从而验证了设计的有效性.     

Global optimization algorithm for a generalized linear multiplicative programming

This article present a branch and bound algorithm for globally solving generalized linear multiplicative programming problems with coefficients. The main computation involve solving a sequence of linear relaxation programming problems, and the algorithm economizes the required computations by conducting the branch and bound search in R ^p , rather than in R ⁿ , where p is the number of rank and n is the dimension of decision variables. The proposed algorithm will be convergent to the global optimal solution by means of the subsequent solutions of the series of linear relaxation programming problems. Numerical results are given to show the feasibility and effectiveness of the proposed algorithm.     

EFFECT OF Z-PINS’ DIAMETER,SPACING AND OVERLAP LENGTH ON CONNECTING PERFORMANCE OF CMC SINGLE LAP JOINT

The effect of through-thickness reinforcement by composite pins (Z-pins) on the static tensile strength and failure mechanisms of the joints made from ceramic matrix composite (CMC) is investigated. Overlap length of the single lap joint is 15 mm, 20 mm, 23 mm, 37 mm, and 60 mm, respectively. The experimental results indicate that the final failure modes of the joints can be divided into two groups, (a) the bond-line stops debonding until crack encounters Z-pins; and then the adherends break at the location of Z-pins, when overlap length is more than 20 mm; (b) the bond-line detaches entirely and Z-pins are drawn from adherends, when overlap length is equal to 15 mm. A simple effcient computational approach is presented for analyzing the benefit of through-thickness pins for restricting failure in the single lap joints. Here, the mechanics problem is simplified by representing the effect of the pins by tractions acting on the fracture surfaces of the cracked bond-line. The tractions are prescribed as functions of the crack displacement, which are available in simple forms that summarize the complex deformations to a reasonable accuracy. The resulting model can be used to track the evolution of complete failure mechanisms, for example, bond-line initial delamination and ultimate failure associated with Z-pin pullout, ultimate failure of the adherends. The paper simulates connecting performance of the single lap joints with different Z-pins’ diameter, spacing and overlap length; the numerical results agree with the experimental results; the numerical results indicate enlarging diameter and decreasing spacing of Z-pins are in favor of improving the connecting performance of the joints. By numerical analysis method, the critical overlap length that lies between two final failure modes is between 18 mm and 19 mm, when Z-pins’ diameter and spacing are 0.4 mm, 5 mm, respectively.     

Poly(9,9′‐diheylfluorene carbazole) Functionalized with Reduced Graphene Oxide: Convenient Synthesis using Nitrogen‐Based Nucleophiles and Potential Applications in Optical Limiting

Covalently functionalized reduced graphene oxide (RGO) sheet was prepared by treating nitrogen‐centered anions generated from poly(9,9′‐diheylfluorene carbazole) (PCF) with GO. The resultant hybrids with different chemical behavior were separated by centrifugation. The covalent modification was fully characterized by IR spectroscopy, UV/Vis spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, TEM, and SEM. It was found that RGO‐PCF‐s, the soluble part, was split into small platelets with a size of about 200 nm, and the hydrophobic polymer PCF became hydrophilic after wrapping by RGO. The content of RGO in RGO‐PCF‐s was about 11.9 %, and the hybrid material showed good dispersion stability in water. Besides, RGO‐PCF‐i, the insoluble part, with larger size, displayed excellent optical‐limiting response, in which both nonlinear absorption and nonlinear scattering play important roles. As nitrogen‐centered anions are an important type of intermediates in chemistry, this one‐step “grafting‐to” strategy could be used to obtain RGO‐based materials with different applications.