Strong,Thermally Superinsulating Biopolymer–Silica Aerogel Hybrids by Cogelation of Silicic Acid with Pectin

Silica aerogels are excellent thermal insulators, but their brittle nature has prevented widespread application. To overcome these mechanical limitations, silica–biopolymer hybrids are a promising alternative. A one‐pot process to monolithic, superinsulating pectin–silica hybrid aerogels is presented. Their structural and physical properties can be tuned by adjusting the gelation pH and pectin concentration. Hybrid aerogels made at pH 1.5 exhibit minimal dust release and vastly improved mechanical properties while remaining excellent thermal insulators. The change in the mechanical properties is directly linked to the observed “neck‐free” nanoscale network structure with thicker struts. Such a design is superior to “neck‐limited”, classical inorganic aerogels. This new class of materials opens up new perspectives for novel silica–biopolymer nanocomposite aerogels.     

Novel sponge-like molecularly imprinted mesoporous silica material for selective isolation of bisphenol A and its analogues from sediment extracts

Bisphenol A (BPA) imprinted sponge mesoporous silica was synthesized using a combination of semi-covalent molecular imprinting and simple self-assembly process. The molecularly imprinted sponge mesoporous silica (MISMS) material obtained was characterized by FT-IR, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption measurements. The results show that the MISMS possessed a large specific surface area (850.55 m² g⁻¹) and a highly interconnected 3-D porous network. As a result, the MISMS demonstrated a superior specific adsorption capacity of 169.22 μmol g⁻¹ and fast adsorption kinetics (reaching equilibrium within 3 min) for BPA. Good class selectivity for BPA and its analogues (bisphenol F, bisphenol B, bisphenol E and bisphenol AF) was also demonstrated by the sorption experiment. The MISMS as solid-phase extraction (SPE) material was then evaluated for isolation and clean-up of these bisphenols (BPs) from sediment samples. An accurate and sensitive analytical method based on the MISMS–SPE coupled with HPLC–DAD has been successfully established for simultaneous determination of five BPs in river sediments with detection limits of 0.43–0.71 ng g⁻¹ dry weight (dw). The recoveries of BPs for lyophilizated sediment samples at two spiking levels (50 and 500 ng g⁻¹ dw for each BP) were in the range of 75.5–105.5% with RSD values below 7.5%.     

Effect of ultrasonic power on the stability of low-molecular-weight oyster peptides functional-nutrition W1/O/W2 double emulsion

Ultrasonic-assisted treatment is an eco-friendly and cost-effective emulsification method, and the acoustic cavitation effect produced by ultrasonic equipment is conducive to the formation of stable emulsion. However, its effect on the underlying stability of low-molecular-weight oyster peptides (LOPs) functional-nutrition W₁/O/W₂ double emulsion has not been reported. The effects of different ultrasonic power (50, 75, 100, 125, and 150 W) on the stability of double emulsions and the ability to mask the fishy odor of LOPs were investigated. Low ultrasonic power (50 W and 75 W) treatment failed to form a well-stabilized double emulsion, and excessive ultrasound treatment (150 W) destroyed its structure. At an ultrasonic power of 125 W, smaller particle-sized double emulsion was formed with more uniform distribution, more whiteness, and a lower viscosity coefficient. Meanwhile, the cavitation effect generated by 125 W ultrasonic power improved storage, and oxidative stabilities, emulsifying properties of double emulsion by reducing the droplet size and improved sensorial acceptability by masking the undesirable flavor of LOPs. The structure of the double emulsion was further confirmed by optical microscopy and confocal laser scanning microscopy. The ultrasonic-assisted treatment is of potential value for the industrial application of double emulsion in functional-nutrition foods.     

Adaptive multimode transmission in wireless sensor networks with energy harvesting

Limited energy has always been an important factor restricting the development of wireless sensor networks. The unbalanced energy consumption of nodes will accelerate the death of some nodes. To solve the above problems, an adaptive routing algorithm for energy collection sensor networks based on distributed energy saving clustering (DEEC) is proposed. In each hop of data transmission, the optimal mode is adaptively selected from four transmission modes: single-hop cooperative, multi-hop cooperative, single-hop non-cooperative and multi-hop non-cooperative, so as to reduce and balance the energy consumption of nodes. The performance of the proposed adaptive multi-mode transmission method and several benchmark schemes are evaluated and compared by computer simulation, where a few performance metrics such as the network lifetime and throughput are adopted. The results show that, the proposed method can effectively reduce the energy consumption of the network and prolong the network lifetime; it is superior to various benchmark schemes.     

水性颜料体系无树脂色浆的制备与应用

中性墨水属于热力学上不稳定的颜料悬浮体系,选择低黏度、高稳定性的色浆是保证墨水体系分散稳定性的重要手段之一。基于此,以颜料炭黑和酞菁蓝为着色剂,配合超分散剂(EK43)与协同增效剂(BM10),制备了两款适用于中性墨水体系的无树脂色浆。首次从色浆粒径与体系分散稳定性角度出发,确定了EK43、BM10用量以及最佳研磨时间,并对其理化性能、稳定性与书写性能进行分析测试。结果表明:在黑色浆中添加质量分数10.0%的EK43、2.5%的BM10,研磨时间为90 min;在蓝色浆中添加质量分数8.0%的EK43、2.0%的BM10,研磨时间为120 min时,两种色浆的粒径与分散稳定性均达到最佳。所制备的无树脂色浆颜料固含量高、黏度较低、储存稳定性好、着色力强,以其调配的中性墨水书写性能良好,且具有较好的离心稳定性和耐热稳定性。     

An Open‐Circuit Voltage and Power Conversion Efficiency Study of Fullerene Ternary Organic Solar Cells Based on Oligomer/Oligomer and Oligomer/Polymer

Variations in the open‐circuit voltage (V _oc) of ternary organic solar cells are systematically investigated. The initial study of these devices consists of two electron‐donating oligomers, S2 (two units) and S7 (seven units), and the electron‐accepting [6,6]‐phenyl C71 butyric acid methyl ester (PC₇₁BM) and reveals that the V _oc is continuously tunable due to the changing energy of the charge transfer state (E _ct) of the active layers. Further investigation suggests that V _oc is also continuously tunable upon change in E _ct in a ternary blend system that consists of S2 and its corresponding polymer (P11):PC₇₁BM. It is interesting to note that higher power conversion efficiencies can be obtained for both S2:S7:PC₇₁BM and S2:P11:PC₇₁BM ternary systems compared with their binary systems, which can be ascribed to an improved V _oc due to the higher E _ct and an improved fill factor due to the improved film morphology upon the incorporation of S2. These findings provide a new guideline for the future design of conjugated polymers for achieving higher performance of ternary organic solar cells.

     

300 MW等级燃煤机组煤粉炉与循环流化床锅炉汞排放特性比较

选取某地330 MW煤粉炉(PC炉)和350 MW循环流化床锅炉(CFB)的燃煤电厂进行汞排放特性的研究。采用30B法和安大略法对两个燃煤电厂的除尘器入口、除尘器出口、脱硫塔出口和湿式电除尘器出口的烟气进行了取样和汞浓度分析,采集了入炉煤和副产物底渣、飞灰及脱硫石膏样品。通过样品中汞含量的分布,探讨了PC炉与CFB锅炉机组现有污染物控制设备对汞的协同脱除作用。结果表明,350 MW CFB电厂除尘器出口烟气平均汞浓度降低至0.43μg/m~3,布袋除尘器对汞的捕获效率达到98.9%,相应的燃烧副产物中飞灰是汞的主要富集对象。对于330 MW PC炉电厂,除尘器入口和除尘器出口烟气汞浓度均高于350 MW CFB电厂,烟气汞浓度从除尘器入口、除尘器出口到脱硫塔出口依次降低,在脱硫塔出口烟气汞浓度降低至0.42μg/m~3,静电除尘器和湿式脱硫塔对烟气汞的捕获效率分别为75.0%和22.4%,相应的产物中飞灰和脱硫石膏中汞都有一定程度的富集。     

三项指数和四次均值的精确计算公式(2)

本文进一步深入研究了三项指数和四次均值的计算问题.运用指数和的相关性质并结合求解同余方程组的方法与技巧,利用两种不同的方法获得了两个精确的均值计算公式,揭示了三项指数和的计算与同余方程组解的个数之间的本质联系,推广了已有的结果.     

二项指数和四次混合均值的计算

本文研究了二项指数和四次均值的计算问题.利用初等数论及代数数论的方法获得了一个精确的计算公式以及一个转换公式,推广了已有的结果,揭示了均值计算与同余方程组的本质联系.     

所有极大子群都为SMSN-群的有限群

若有限群G的每个2-极大子群在G中次正规,则称G为SMSN-群.本文研究了有限群G的每个真子群是SMSN-群但G本身不是SMSN-群的结构,利用局部分析的方法,获得了这类群的完整分类,推广了有限群结构理论的一些成果.