A Completely Biodegradable Poly[(L‐lactide)‐co‐(ε‐caprolactone)] Elastomer Reinforced by in situ Poly(glycolic acid) Fibrillation: Manufacturing and Shape‐Memory Effects

A new completely biodegradable shape‐memory elastomer consisting of PLLCA reinforced by in situ PGA fibrillation is described. The manufacturing processes and shape‐memory effects of the composites are discussed. DMA results reveal a strong interface interaction between in situ PGA fibrillation and PLLCA. Compared with the SMP‐based composites that are commonly used, the shape‐memory test shows that in situ PGA fibrillation can improve the recovery properties of PLLCA; in fact, the shape‐recovery rate increases from 80.5 to 93.2%.

     

高粘度指数α-烯烃合成油的制备

以三氯化铝为催化剂,高纯度低碳α-烯烃为原料合成了α-烯烃合成油。考查了反应温度、催化剂用量以及反应压力对产品收率及性质的影响。得到了最佳的反应条件:反应温度为100℃、催化剂用量为5%(质量分数,原料烯烃)、反应压力为0.6~0.8MPa。合成油产品粘度指数为131、凝点-48℃、闪点285℃、燃点293℃。     

Content and Service Protection for the Ubiquitous TV Based on Network Convergence

Today, the ubiquitous multimedia services are becoming more and more popular. However, the secure solutions that confirm the content and service security in these services are still open issues because of various network convergences and device interconnections. This paper investigates an ubiquitous multimedia service architecture and proposes a secure solution for it. In this service architecture, the multimedia content is encoded with scalable video coding and broadcasted via digital video broadcasting for handheld terminals (DVB-H) to mobile terminals, the access right is transmitted by global system for mobile (GSM/GPRS) channel, and the media content and access right can also be transferred from mobile terminals to home TV through WiFi based Wireless Local Area Network. The proposed secure solution supports three kinds of business models by using various content encryption modes and secure transmission protocols. The solution’s security is evaluated and discussed. Since few work has been done to solve this problem, the work proposed in this paper is expected to attract more researchers. Additionally, the solution is also potential for other ubiquitous services.     

建筑用水性有机硅-聚氨酯嵌段共聚物防水剂

以端羟基聚二甲基硅氧烷(PDMS)与氨烃基硅烷偶联剂(DB-912)为原料,合成了端氨烃基聚二甲基硅氧烷低聚物(NS),以此为扩链剂,自乳化法制备了水性有机硅-聚氨酯嵌段共聚物(WPSUR),考察了扩链剂类型、NS的相对分子质量对乳液粒径与薄膜拒水性的影响。     

复位性能参数在加固计算分析中的应用

提出复位性能的基本概念及其主要参数后,通过对某抗弯承载力不足的钢筋混凝土框架结构进行五种不同加固用钢量下的复位性能分析,将复位能力系数引入到加固计算分析中,初步探讨了加固用钢量对加固后框架结构复位性能的影响,得到了一些基本结论。     

城市规划语境下城市自组织及其系统探讨

文章基于自组织理论．旨在化解城市规划的他组织属性与城市的自组织本质问的对立关系．提高城市规划的科学性。立足城市规划范畴．从自组织的典型特征及其与他组织的辩证关系对城市自组织进行了辨析．得出规划行为中也有自组织成分的结论,并提出城市规划的自组织与城市内部力量的自组织成正相关i进而构建城市自组织系统．将城市规划的自组织界定为城市自组织的外延部分。最终,提出通过构建开放系统．界定体系范畴、强调对过程的规划来实现城市规划技术体系的自组织完善。     

Surface phase transformation of ZrO2 in VOx/ZrO2 catalysts for boosting propane nonoxidative dehydrogenation

The nanocatalysts of VO_x deposited on ZrO₂ supports with single monoclinic (ZrO₂-M), tetragonal (ZrO₂-T), and binary monoclinic-tetragonal (ZrO₂-MT) phase were synthesized. VO_x/ZrO₂-MT catalysts exhibit better performance during propane nonoxidative dehydrogenation than VO_x/ZrO₂-M and VO_x/ZrO₂-T catalysts. Among VO_x/ZrO₂-MT catalysts, the conversion and deactivation rate constant of VO_x/ZrO₂-M₃₁T₆₉ catalyst is 35.2% and 0.22 h⁻¹, respectively. The promoting role of ZrO₂-MT is revealed by experiments and theoretical calculations. The MT-mixed phase structure in VO_x/ZrO₂-MT catalyst improves the structural properties and dispersion of VO_x. The tetragonal-monoclinic transformation on the ZrO₂-MT surface facilitates VO_x reduction and produces additional V³⁺ active sites. The highly dispersed V³⁺ sites on the ZrO₂-MT surface accelerate C H bond breaking and boost the desorption of propylene, which is the key reason for enhancing activity and stability during the reaction, respectively. Insight into the role of surface phase transformation of ZrO₂-MT is expected to obtain high-efficient catalysts further.     

Evaluation of Pickering emulsions stabilized with nano-cellulose and nano-chitin treated with deep eutectic solvent

Developing bio-friendly and degradable Pickering emulsifiers as surfactants to replace traditional surfactants with bio-toxicity is imperative in the food, coating, cosmetics, and pharmaceutical industries. Nanocellulose and chitin can be used directly as an emulsifier to prepare Pickering o/w emulsions. As the concentration of nanoparticles increases, the stability of the emulsion also increases, and an overly large nanoparticle aspect ratio is not conducive to the stabilization of the emulsion. In comparison, nanocellulose-prepared Pickering emulsion has improved stability. Of these, nanocellulose prepared by DES with a molar ratio of 3:1 to LA:CC has been shown to have the best stability when used to equilibrate the oil/water mass ratio of 2/8. The Zeta potential is −38.4 mV, and the size of the droplets is the most uniform. With a mean droplet diameter of 770 nm. This study had certain research significance and reference value for the development of bio-friendly surfactants.     

Emerging Synthetic Methods and Applications of MOF-Based Gels in Supercapacitors,Water Treatment,Catalysis, Adsorption,and Energy Storage

Metal–organic frameworks (MOFs), which are synthesized through the self-assembly of organic ligands and inorganic metals, have drawn considerable research interest owing to their unique properties and attractive structures. Many studies on various MOF derivatives, such as MOFs and cellulose aerogels, hydrogel composite materials, and bimetallic-centered MOF materials, have provided the potential for wide application of MOFs. However, MOFs mostly exist in the form of powder particles, which are difficult to form. In addition, MOFs have problems with structural instability. MOF-based gels can overcome this problem. MOF-based gels also have significant advantages in secondary processing. In this review, synthetic methods for MOF-based gels, particularly the synergistic effect with other materials, are introduced. The applications of MOF-based hydrogels and aerogels in supercapacitors, water treatment, catalysis, adsorption, and energy storage are also discussed.     

鸡蛋壳制备乳酸钙工艺条件的研究

本试验对鸡蛋壳制备乳酸钙的工艺进行了研究。结果表明最佳条件为:鸡蛋壳在900℃下灰化110min,4g灰分加水50ml制成石灰乳,石灰乳中加入13mol/L乳酸14ml发生中和反应,经过滤、结晶、过滤后干燥制得白色粉末产品。产率为75.6%,乳酸钙含量为88.1%。