Grafting of sulfamethoxazole on acrylic acid−vinyl methyl ketone copolymer using the schiff base reaction−application as a drug delivery system

A series of poly(acrylic acid-co-methylvinylketone–graft–sulfamethoxazole)(AVMDS) species was synthesized for drug carrier applications. The synthesis involved two steps: copolymerization of acrylic acid(AA) with methyl vinyl ketone(MVK) through the free radical route and subsequent grafting of the sulfamethoxazole (SMX) onto the copolymer via the Schiff base reaction of the primary amine of SMX with the carbonyl groups of the MVK units. The structures and properties of the materials were characterized by nuclear magnetic resonance(NMR), X-ray diffraction(XRD), differential scanning calorimetry(DSC), and scanning electronic microscopy (SEM). An in-vitro cytotoxicity test of the drug-carrier systems via MTT assay revealed no significant cytotoxic effect at concentrations up to 100?µg?·?ml^?1. The dynamic release of SMX from these systems through a retro-imidation reaction (inverse Schiff base reaction) was investigated in depth, where the diffusion through the polymer matrix, the enhancement of the water solubility of SMX, the influence of the initial drug concentration, the pH of the medium, and the effect of the degree of swelling of the polymer matrix on the release dynamics were evaluated. The AVMGS4 and AVMGS1 drug carrier systems containing 3.58 and 1.18?wt% of SMX were the best performing systems.     

热烧结矿竖式冷却过程传热特性

 与传统环冷相比，烧结竖冷拥有漏风率低、换热效率高的优势。为此利用竖冷试验装置，在某烧结厂取热风与热烧结矿研究了竖式冷却过程气固对流换热特性。研究表明，烧结矿竖式冷却过程中影响传热特性的主要因素为冷却风的流量及温度。烧结矿和冷却风对流换热系数随着烧结矿温度的升高而增大，且随着冷却风流量的增大以及冷却风温度的降低，对流换热系数也随之增大。基于白金汉定理，结合试验数据拟合得出了描述烧结矿与冷却风传热特性的准数关联式，其模拟性较好且平均相对误差为7.25%。     

Ultrathin perovskite based solar cells with the efficiency enhanced by charge transfer process

We report a new approach of improving the solar cells efficiency based on ultrathin perovskite films. We propose the addition of CuPc compound to perovskite active layer for enhanced charge generation and transfer process by charge transfer process between CuPc and perovskite. The performance of the devices with and without addition of CuPc was studied in respect to thickness of the active layer. The thickness was varied by the change of the spin coating speed in the range of 4000, 7000 and 10000 rpm, different concentration of CuPc also been studied. The process of charge carrier recombination, crystallinity and Raman characteristics of the obtained films was studied. The perovskite device with an active layer of MAPbI₃ mixed with CuPc spin coated with the speed of 10000 rpm with thickness of about 150 nm demonstrated the efficiency of 12.7%. The ultrathin mixed perovskite film (10000 rpm perovskite film of 15% CuPc) based device presents 33% thickness and 85% efficiency of common pure perovskite device (4000 rpm pure perovskite film).     

Chemical Bonding by the Chemical Orthogonal Space of Reactivity

The fashionable Parr–Pearson (PP) atoms-in-molecule/bonding (AIM/AIB) approach for determining the exchanged charge necessary for acquiring an equalized electronegativity within a chemical bond is refined and generalized here by introducing the concepts of chemical power within the chemical orthogonal space (COS) in terms of electronegativity and chemical hardness. Electronegativity and chemical hardness are conceptually orthogonal, since there are opposite tendencies in bonding, i.e., reactivity vs. stability or the HOMO-LUMO middy level vs. the HOMO-LUMO interval (gap). Thus, atoms-in-molecule/bond electronegativity and chemical hardness are provided for in orthogonal space (COS), along with a generalized analytical expression of the exchanged electrons in bonding. Moreover, the present formalism surpasses the earlier Parr–Pearson limitation to the context of hetero-bonding molecules so as to also include the important case of covalent homo-bonding. The connections of the present COS analysis with PP formalism is analytically revealed, while a numerical illustration regarding the patterning and fragmentation of chemical benchmarking bondings is also presented and fundamental open questions are critically discussed.     

Effects of upholstery materials on the burning behavior of real‐scale residential upholstered furniture mock‐ups

Fire spread and growth on real‐scale four cushion mock‐ups of residential upholstered furniture (RUF) were investigated with the goal of identifying whether changes in five classes of materials (barrier, flexible polyurethane foam, polyester fiber wrap, upholstery fabric, and sewing thread), referred to as factors, resulted in statistically significant changes in burning behavior. A fractional factorial experimental design plus practical considerations yielded a test matrix with 20 material combinations. Experiments were repeated a minimum of two times. Measurements included fire spread rates derived from video recordings and heat release rates (HRRs). A total of 13 experimental parameters (3 based on the videos and 10 on the HRR results), referred to as responses, characterized the measurements. Statistical analyses based on Main Effects Plots (main effects) and Block Plots (main effects and factor interactions) were used. The results showed that three of the factors resulted in statistically significant effects on varying numbers of the 13 responses. The Barrier and Fabric factors had the strongest main effects with roughly comparable magnitudes. Foam was statistically significant for fewer of the responses and its overall strength was weaker than for Barrier and Fabric. No statistically significant main effects were identified for Wrap or Thread. Multiple two‐term interactions between factors were identified as being statistically significant. The Barrier*Fabric interaction resulted in the highest number of and strongest statistically significant effects. The existence of two‐term interactions means that it will be necessary to consider their effects in approaches designed to predict the burning behavior of RUF.     

基于区间犹豫模糊语言集的水资源多目标决策

以鄂北水资源配置工程为对象,研究大型调水工程背景下的多水源多目标优化配置。将鄂北地区水库分为充蓄水库、补偿水库与在线水库等3类,根据各类水库特点对鄂北水资源配置工程进行系统概化,建立以年缺水量最小和调水成本最低为目标函数的多水源多目标优化配置模型。采用权重系数法进行求解得到非劣解集。最后采用基于区间犹豫模糊语言与TOPSIS的多目标决策方法对各方案的缺水量与调水量作出评价并遴选出最优方案。研究结果表明:对鄂北水资源配置工程而言,缺水量与调水量的权重比为7∶3的方案综合评价最优,重视缺水的同时兼顾调水成本;基于区间犹豫模糊语言集与TOPSIS的水资源多目标决策方法经本文实例验证具有较高的稳定性与可行性。     

Achieving High Electroluminescence Efficiency and High Color Rendering Index for All-Fluorescent White OLEDs Based on an Out-of-Phase Sensitizing System

Sensitizing conventional fluorescence (CF) dopants with thermally activated delayed fluorescence (TADF) materials has achieved considerable progress, by which the advantages of TADF materials and CF dopants can be fully harnessed. However, the usually used co-phase configuration of CF dopant-engaged sensitizing systems often encounters exciton loss due to Dexter energy transfer (DET). Herein, an effective out-of-phase configuration is proposed to sensitize CF dopants in the fabrication of white organic light-emitting diodes (WOLEDs). Based on a new efficient sky-blue TADF luminogen DCP-BP-DPAC which has an electroluminescence (EL) peak at 486 nm and an EL efficiency of 26.6%, a green TADF material BDMAC-XT, and a red CF dopant DBP sensitized by BDMAC-XT through an out-of-phase configuration without interlayer, efficient WOLEDs are successfully fabricated. By further adopting orange TBRB or 4CzTPNBu as intermediate sensitizers, more efficient energy transfer to DBP is achieved via Förster energy transfer. Through step-by-step energy transfer and elimination of excess DET process, high-performance all-fluorescent WOLEDs are achieved, providing excellent EL efficiencies over 23.0%, and highly stable white light with a high color rendering index of 87. The outstanding EL performance and high-quality emission color demonstrate the great potential of the proposed out-of-phase design for sensitizing systems of WOLEDs.     

Liquid Phase CO2-Analytics for Standardized Mass Transfer Characterization in Packed Columns

Mass transfer parameters are necessary for the design of absorption and desorption processes in packed columns. To determine the effective interfacial area and liquid side mass transfer parameters, CO₂ absorption and desorption are frequently used. Reliable analytics for concentration determination are essential to obtain correct results. In this work two methods of CO₂ liquid phase analysis are compared: first, the back titration of unreacted NaOH after prior precipitation of the bound CO₂; secondly, the inorganic carbon analysis with a commercial inorganic carbon analyzer.     

超高层劲性结构及大型机械设备立体协同施工技术

基于某超高层建筑群项目的主体施工阶段,对超高层劲性结构建筑群项目施工过程中可能遇到的问题,诸如大型机械立体协同、钢结构与钢筋连接节点优化、钢结构桁架层施工等重难点进行总结分析,并提出相应的解决方案以供探讨,可为同类型工程提供参考经验。     

基于跨临界CO2热泵的茶叶生产能源系统负荷削减潜力

乡村产业中的化石能源设备逐渐被电能技术替代，引起了乡村负荷波动增大、部分时段产生集中高负荷的问题。为了解决以上问题，将低品位清洁能源应用至乡村的茶叶生产中，针对烘茶全过程的工艺要求提出了跨临界CO₂热泵烘茶技术；并以某茶叶生产乡村为对象，对其代表台区的全年日用电量及产茶日负荷进行了分析，得出采用CO₂热泵烘茶后其负荷得到大幅度削减，整体可降低至原负荷的39.6%~46.8%，峰值负荷与平时负荷的比值由原本的13.6降至5.4~6.2。跨临界CO₂热泵应用至农产品生产中可有效缓解乡村供电压力。