Controlled Synthesis of Branched Polystyrene via Free Radical Polymerization of Novel Chain Transfer Monomer

Cui-Ping Li,Jia-Qiang Wang,Jun Lin,Yan Shi,Zhi-Feng Fu 한국고분자학회 2011 Macromolecular Research Vol.19 No.8

The free radical polymerization of styrene was carried out in the presence of a new found chain transfer monomer, p-vinyl benzene sulfonyl chloride (VBSC), which possesses both a chain transfer group and a polymerizable double bond. Branched polystyrene was formed during the polymerization, as indicated by multi-peaks gel permeation chromatography (GPC) curves of the products, the increase in the number-average molecular weight and molecular weight distribution along with monomer conversions. The structure of the obtained polystyrene was analyzed by 1H nuclear magnetic resonance (NMR) spectroscopy. The results showed that with increasing VBSC in the feed, the degree of branching and VBSC unit in the copolymer increased and a shortest polystyrene arm arose from the highest VBSC content in the feed, suggesting that the composition and structure of the branched polystyrenes could be tuned by the amount of VBSC in the feed. By tracing the structure change in the copolymer at various stages of polymerization, the main polymerization process can be regarded as the copolymerization of VBSC with styrene first and then chain transfer to polymeric radical to form branched polystyrene. This strategy is facile and less expensive than the other method.

Controlled Synthesis of Branched Polystyrene via RAFT Technique in the Presence of Chain Transfer Monomer p-Vinyl Benzene Sulfonyl Chloride

Cui-Ping Li,Jia-Qiang Wang,Yan Shi,Zan Liu,Jun Lin,Zhi-Feng Fu 한국고분자학회 2012 Macromolecular Research Vol.20 No.8

Branched polystyrene was first obtained via a reversible addition-fragmentation chain transfer (RAFT)process in the presence of chain transfer monomer p-vinyl benzene sulfonyl chloride (VBSC) in benzene at 60 oC with 2-(ethoxycarbonyl)prop-2-yl dithiobenzoate as the RAFT agent and 2,2-azobisisobutyronitrile as an initiator. During the RAFT polymerization, VBSC played the role of branching agent. It could not only copolymerized but also acted as a chain transfer agent due to the polymerizable vinyl group and sulfonyl chloride chain transfer group in the VBSC. Gel permeation chromatography (GPC) traces demonstrated that the number-average molecular weights and molecular weight distributions increased along with monomer conversion. Compared with the RAFT process without VBSC, the resulting polymers had broad molecular weight distributions and the sulfonyl functionality of the resultant polymer at the branching point, indicating the formation of branched polystyrene. The structure of the obtained polystyrene was further analyzed by proton nuclear magnetic resonance (1H NMR) spectroscopy. The findings indicated that the branched polystyrene was mainly formed via the RAFT copolymerization of VBSC and styrene firstly to form polystyrene bearing pendant sulfonyl chloride group, and then the pendant sulfonyl chloride group acted as the chain transfer agent to generate the branched structure. In addition, the degree of branching and VBSC unit in copolymer increased along with the VBSC in the feed, implying that composition and structure of the branched polystyrenes could be tuned by the amount of VBSC in the feed.

Variable Research on Engineering Characteristics of Soybean Urease Reinforced Sand

Meng Cui,Huihui Xiong,Jun-jie Zheng,Suying Lv,Mingjuan Cui,Xiao Fu,Shangyu Han 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

In this study, based on soybean urease and standard sand, the unconfined compressive strength test and permeability test of four variables of urease concentration, urea concentration, calcium chloride concentration and sodium alginate content under different combinations of values were carried out, and the range analysis and variance analysis of test data were carried out. On this basis, the coupling model of unconfined compressive strength and permeability coefficient of soybean urease reinforced sand was established based on four test variables. It was found that the engineering characteristics of soybean urease reinforced sand were significantly affected by the combination of variable values. The maximum value of unconfined compressive strength under the test combination condition was 6.5 times of the minimum value, and the minimum value of permeability coefficient was only 1/4 of the maximum value. The primary and secondary order of influence variables of unconfined compressive strength was: urea concentration > calcium chloride concentration > urease concentration > sodium alginate content, and the primary and secondary order of influence variables of permeability coefficient was: urea concentration > calcium chloride concentration > sodium alginate content > urease concentration. The influence of urea concentration on unconfined compressive strength and permeability coefficient was obvious, and the influence of the other three variables was not obvious. In addition, it was confirmed that the established coupling model of unconfined compressive strength and permeability coefficient of soybean urease reinforced sand had high correlation coefficient and significant linear regression, which can be used for subsequent research and engineering application.

中国行政区域划分研究—基于聚类分析与支持向量机方法的讨论

Gao Hao,Cui Jun-fu 중국지역학회 2016 중국지역연구 Vol.3 No.2

Any economic and social activities are inseparable from a specific area, and in different regions often mean different development policies. China attaches great importance to the division of the region to a certain area in order to develop targeted policies. Currently, all provinces in China are divided into eastern, central, and western regions, 11 provinces in eastern region, 12 provinces in western region, and 8 provinces in central region. Since the founding, especially since the reform and opening up, China’s regional policy has undergone so many alternates between comprehensive development and focusing development, each policy adjustments have had a significant impact on the development of the relation region. Compared to the current administrative division, this article uses clustering methods to classify China provinces, and support vector machine for testing. The study found that three regions administrative division of China currently used cannot adapt to the actual development of the current situation, we must make the appropriate adjustments in order to provide a basis for the development of more targeted regional policy. 任何经济社会活动都离不开特定的区域, 处于不同的区域往往意味着不同的发展政策。为增强宏观调控的有效性, 在中国的经济社会发展中非常重视将某一个地区划分到一类区域当中, 从而对该区域制定有针对性的政策。目前, 中国将所有省份分为东部、中部、西部三个区域, 东部11个省份, 西部12个省份, 中部8个省份。建国以来, 特别是改革开放以来, 中国的区域政策经历了重点发展、全面发展、重点发展与全面发展相结合等多次政策交替变换, 每次政策调整均对相应区域的发展产生了重大影响。本文使用聚类方法对中国省份进行了分类, 与目前东中西行政区域划分进行对比分析, 并使用支持向量机进行检验。研究发现, 中国目前采用的东中西行政区域划分已经不能适应目前的实际发展状况, 必须进行相应的调整, 以便为制定更有针对性的区域政策提供参考。

Mineralization of calcium phosphate in reverse microemulsion

Xiang-Dong Kong,Xiao-Dan Sun,Jun-Biao Lu,Fu-Zhai Cui 한국물리학회 2005 Current Applied Physics Vol.5 No.5

In the present study, reverse microemulsion was prepared to regulate the mineralization of calcium phosphate. Calcium chlorideand sodium hydrogen phosphate aqueous solution were, respectively, dropped into the mixture of Span 80, Tween 80, andn-heptaneto get two kinds of emulsions.n-Buranol was used to adjust the emulsions to transparent state. Calcium phosphate was prepared byadding phosphate microemulsion to Calcium microemulsion. Heating method was used to induce the phase separation. After beingwashed with acetone and ethanol, the mineralized deposition were studied with scanning electron microscopy (SEM), X-ray dirac-tion (XRD) and transmission electron microscopy (TEM). The results indicated that the minerals in the deposition were mainlymonetite (DCPA) and the nanosized needle-like DCPA exhibited the preferential orientation along 200 direction..

An integrated strategy for production of four anthocyanin compounds from Ribes nigrum L. by deep eutectic solvents and flash chromatography

Ping Kou,Yu-Fei Kang,Li-Tao Wang,Li-Jun Niu,Ying Xiao,Na Guo,Qi Cui,Yanyan Liu,Yu-Jie Fu 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

This study explored an integrated strategy for extraction and preparative separation of four anthocyaninsfrom Ribes nigrum L. using DES-based microwave assisted extraction andflash chromatography. Theextraction yield of anthocyanins reached 2.03 mg/g after optimization. An efficient preparativeseparation process of four main anthocyanins by macroporous resin andflash chromatography wasestablished afterwards. The yields of D3G, D3R, C3G and C3R reached 0.32 mg/g, 0.47 mg/g, 0.18 mg/g and0.43 mg/g with the purities of more than 95%, respectively. The developed procedure represents anefficient and convenient alternative for the systematic utilization of natural products from plantmaterials.

Bile Acid Transporters Are Expressed and Heterogeneously Distributed in Rat Bile Ducts

Zhu-lin Luo,Long Cheng,Tao Wang,Li-jun Tang,Fu-zhou Tian,Ke Xiang,Lin Cui 거트앤리버 소화기연관학회협의회 2019 Gut and Liver Vol.13 No.5

Background/Aims: Cholangiocytes are capable of reabsorbing bile salts from bile, but the pathophysiological significance of this process is unclear. To this end, we detected the expression and distribution of bile acid transport proteins in cholangiocytes from normal rat liver and analyzed the possible pathophysiological significance. Methods: Bile duct tissues of Sprague-Dawley rats were isolated by enzymatic digestion and mechanical isolation, and then divided into large and small bile duct tissues. Immunohistochemistry, real-time polymerase chain reaction and Western blotting were used to determine the expression of the apical sodium-dependent bile acid transporter (ASBT), ileal bile acid binding protein (IBABP), and basolateral organic solute transporter α (Ostα) in the biliary tract system of rats. Differences in the expression and distribution of these proteins were analyzed. Results: In cholangiocytes, ASBT and IBABP were mainly expressed in cholangiocytes of the large bile ducts, in which the expression of both was significantly higher than that in the small ducts (p<0.05). Ostα was simultaneously expressed in cholangiocytes of both the large and small bile ducts, showing no significant difference in expression between the two groups of bile ducts (p>0.05). Conclusions: Bile acid transporters are expressed and heterogeneously distributed in rat bile ducts, indicating that bile acid reabsorption by cholangiocytes might mainly occur in the large bile ducts. These findings may help explore the physiology of bile ducts and the pathogenesis of various cholangiopathies.

Open source board based acoustofluidic transwells for reversible disruption of the blood–brain barrier for therapeutic delivery

Ke Wang,Chao Sun,Povilas Dumčius,Hongxin Zhang,Hanlin Liao,Zhenlin Wu,Liangfei Tian,Wang Peng,Yongqing Fu,Jun Wei,Meng Cai,Yi Zhong,Xiaoyu Li,Xin Yang,Min Cui 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Blood–brain barrier (BBB) is a crucial but dynamic structure that functions as a gatekeeper for the central nervous system (CNS). Managing sufficient substances across the BBB is a major challenge, especially in the development of therapeutics for CNS disorders. Methods To achieve an efficient, fast and safe strategy for BBB opening, an acoustofluidic transwell (AFT) was developed for reversible disruption of the BBB. The proposed AFT was consisted of a transwell insert where the BBB model was established, and a surface acoustic wave (SAW) transducer realized using open-source electronics based on printed circuit board techniques. Results In the AFT device, the SAW produced acousto-mechanical stimulations to the BBB model resulting in decreased transendothelial electrical resistance in a dose dependent manner, indicating the disruption of the BBB. Moreover, SAW stimulation enhanced transendothelial permeability to sodium fluorescein and FITC-dextran with various molecular weight in the AFT device. Further study indicated BBB opening was mainly attributed to the apparent stretching of intercellular spaces. An in vivo study using a zebrafish model demonstrated SAW exposure promoted penetration of sodium fluorescein to the CNS. Conclusions In summary, AFT effectively disrupts the BBB under the SAW stimulation, which is promising as a new drug delivery methodology for neurodegenerative diseases.

From 3D to 4D printing: approaches and typical applications

Ye Zhou,Wei Min Huang,Shu Feng Kang,Xue Lian Wu,Hai Bao Lu,Jun Fu,Haipo Cui 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

With the additional dimension, 4D printing is emerging as a novel technique to enable configuration switching in 3D printed items. Inthis paper, four major approaches, namely self-assembly of elements, deformation mismatch, bi-stability, and the Shape memory effect(SME), are identified as the generic approaches to achieve 4D printing. The main features of these approaches are briefly discussed. Utilizingthese approaches either individually or in a combined manner, the potential of 4D printing to reshape product design is demonstratedby a few example applications.