混沌理论在建筑设计中的应用

首先明确了混沌理论的含义,然后分析其理论来源及历史,之后从混沌理论内在随机性和初值的敏感性等的本质特征出发,简述在建筑与城市中的体现应用,最后简要指出其在建筑设计方面的意义。     

城市公园有机更新的方法研究——以福安富春公园更新为例

近几年来,随着城市建设进程的加快,一大批始建于20世纪的城市公园面临着改造更新。这些公园虽然大多衰老破败,已无法满足人们日常使用,但是这些公园又多处于旧城的核心区域,交通便捷,游憩设施和植物景观仍然有一定的使用价值,如何改造这些老旧的城市公园,使其焕发出新的生命力,是当前城市公园建设中的迫切问题。该文以福安富春城市公园更新为例,针对城市公园更新的特点,引入有机更新理论,指出城市公园更新必须遵循的整体性、阶段性、延续性、适宜性原则,同时应建立新建、改造、保护于一体的整体更新措施体系。     

Effect of stents coated with a combination of sirolimus and alpha-lipoic acid in a porcine coronary restenosis model

The aim of this study was to evaluate antiproliferative sirolimus- and antioxidative alpha-lipoic acid (ALA)-eluting stents using biodegradable polymer [poly-l-lactic acid (PLA)] in a porcine coronary overstretch restenosis model. Forty coronary arteries of 20 pigs were randomized into four groups in which the coronary arteries had a bare metal stent (BMS, n = 10), ALA-eluting stent with PLA (AES, n = 10), sirolimus-eluting stent with PLA (SES, n = 10), or sirolimus- and ALA-eluting stent with PLA (SAS, n = 10). A histopathological analysis was performed 28 days after the stenting. The ALA and sirolimus released slowly over 30 days. There were no significant differences between groups in the injury or inflammation score; however, there were significant differences in the percent area of stenosis (56.2 ± 11.78 % in BMS vs. 51.5 ± 12.20 % in AES vs. 34.7 ± 7.23 % in SES vs. 28.7 ± 7.30 % in SAS, P < 0.0001) and fibrin score [1.0 (range 1.0–1.0) in BMS vs. 1.0 (range 1.0–1.0) in AES vs. 2.0 (range 2.0–2.0) in SES vs. 2.0 (range 2.0–2.0) in SAS, P < 0.0001] between the four groups. The percent area of stenosis based on micro-computed tomography corresponded with the restenosis rates based on histopathological stenosis in different proportions in the four groups (54.8 ± 7.88 % in BMS vs. 50.4 ± 14.87 % in AES vs. 34.5 ± 7.22 % in SES vs. 28.9 ± 7.22 % in SAS, P < 0.05). SAS showed a better neointimal inhibitory effect than BMS, AES, and SES at 1 month after stenting in a porcine coronary restenosis model. Therefore, SAS with PLA can be a useful drug combination for coronary stent coating to suppress neointimal hyperplasia.     

Anti-adhesive effect of poloxamer-based thermo-sensitive sol-gel in rabbit laminectomy model

Poloxamer-based thermo-sensitive sol-gel has been developed to reduce the incidence of postoperative scar formation at the laminectomy site. The purpose of this study was to evaluate the anti-adhesive effect of poloxamer based thermo-sensitive sol-gel compared to hyaluronate based solution after laminectomy, using a rabbit model. A thermo-sensitive anti-adhesive with a property of sol-gel transition was manufactured by a physical mixture of Poloxamer188/407, Chitosan and Gelatin. The viscosity in different temperatures was assessed. 72 adult New Zealand rabbits underwent lumbar laminectomy and were randomly divided into experimental (treated with the newly developed agent), positive (treated with hyaluronate based solution), and negative control groups. Each group was subdivided into 1 and 4-week subgroups. Gross and histological evaluations were performed to assess the extent of epidural adhesion. The experimental group showed significantly higher viscosity compared to the positive control group and showed a significant increase of viscosity as the temperature increased. Gross evaluation showed no statistically significant differences between the 1- and 4-week subgroups. However, histologic evaluation showed significant differences both in 1- and 4-week subgroups. Although the 4-week histologic results of the experimental and the positive control subgroups showed no significant difference, both subgroups revealed higher value compared to the negative control subgroup with regard to the ratio of adhesion less than 50?%. The new poloxamer based thermo-sensitive agent showed superior efficacy over the hyaluronate based agent at 1?week postoperatively. At 4?weeks postoperatively, there were no statistically significant differences between the two agents, although both showed efficacy over the sham group.     

Design and analysis of a highly efficient coupler between a micro/nano optical fiber and an SOI waveguide

A compact coupling structure is proposed for highly efficient coupling between a micro/nano fiber and a silicon-on-insulator waveguide. The proposed structure is characterized by high coupling efficiency, wavelength insensitivity, large misalignment tolerance, and easy fabrication. Theoretical analysis and numerical simulation results show that coupling efficiency of >90% can be achieved with a taper length of ～4.5 μm.     

Has globalization strengthened South Korea’s national research system? National and international dynamics of the Triple Helix of scientific co-authorship relationships in South Korea

We trace the structural patterns of co-authorship between Korean researchers at three institutional types (university, government, and industry) and their international partners in terms of the mutual information generated in these relations. Data were collected from the Web of Science during the period 1968–2009. The traditional Triple-Helix indicator was modified to measure the evolving network of co-authorship relations. The results show that international co-authorship relations have varied considerably over time and with changes in government policies, but most relations have become stable since the early 2000s. In other words, the national publication system of Korea has gained some synergy from R&D internationalization during the 1990s, but the development seems to stagnate particularly at the national level: whereas both university and industrial collaborations are internationalized, the cross-connection within Korea has steadily eroded.     

All solution processable organic photovoltaic cells using DMDCNQI as an organic N-type buffer layer

Organic photovoltaic cells consisting of ITO/PEDOT-PSS/P3HT:PCBM/TiO(x)/DMDCNQI/Al have been fabricated by using dip-coated DMDCNQI layer as a cathode buffer material. We have investigated the physical effects of charge transfer complex and wettability of DMDCNQI between TiO(x)/P3HT:PCBM layer and Al cathode electrode on the performance of organic photovoltaic cell. The photovoltaic cell fabricated with a dip-coated DMDCNQI layer exhibited almost similar performance compared to the device using conventional evaporated DMDCNQI layer. Especially, the power conversion efficiency of the prepared organic photovoltaic cell using TiO(x)/DMDCNQI layer was improved to 3.1%, which is mainly due to the decrease in the low contact resistance of organic-metal interface.     

羧甲基-β-环糊精减水剂的制备与性能

以β-环糊精和氯乙酸为原料,通过亲核取代反应制备了混凝土减水剂羧甲基-β-环糊精(CM-β-CD),讨论了反应物物质的量比、反应温度和反应时间对CM-β-CD的取代度及应用性能的影响.结果表明,当氯乙酸与β-环糊精物质的量比为6∶1、反应温度为60℃、反应时间为5h时,所得CM-β-CD的取代度最大为0.68.水泥净浆实验表明净浆流动度随着取代度的增加而增加,减水剂的最佳掺量为0.8％,减水率为23.5％.红外光谱(FTIR)和核磁共振光谱(NMR)检测结果表明β-环糊精和氯乙酸发生了反应.