文化再生之发展规划路程--以陕西礼泉县袁家村为例

袁家村从一个物质文化双重匮乏的村子,后以发展文化为基点,为乡村的发展提供了强有力的支撑,使之最终成为现代化文化产业示范基地,打造了全国知名的乡村旅游品牌。在这期间,袁家村经历了寻找文化、复制文化、创造文化、衍生文化四个过程。     

高层智能建筑火灾浅析

火灾对人的生命安全和公共财产造成了极大地威胁。如今,城市中高层智能化建筑物火灾发生的现象比较严重。本文浅析了该类建筑的特点,分析火灾成因以及火灾造成的危害形势,抛砖引玉,希望降低此类火灾发生的频率。     

公路工程沥青路面施工技术探讨

沥青路面是当前公路工程路面施工中比较常用的面层,具有非常广泛的应用性。本文结合相应的工程实例,对公路工程沥青路面施工技术进行了分析和探讨,希望可以为相关工程的施工提供一定的参考。     

Influence of fluoride treatment on surface properties,biodegradation and cytocompatibility of Mg–Nd–Zn–Zr alloy

Fluoride treatment is a commonly used technique or pre-treatment to optimize the degradation kinetic and improve the biocompatibility of magnesium-based implant. The influence of changed surface properties and degradation kinetics on subsequent protein adsorption and cytocompatibility is critical to understand the biocompatibility of the implant. In this study, a patent magnesium alloy Mg–Nd–Zn–Zr alloy (JDBM) designed for cardiovascular stent application was treated by immersion in hydrofluoric acid. A 1.5 μm thick MgF₂ layer was prepared. The surface roughness was increased slightly while the surface zeta potential was changed to a much more negative value after the treatment. Static contact angle test was performed, showing an increase in hydrophilicity and surface energy after the treatment. The MgF₂ layer slowed down in vitro degradation rate, but lost the protection effect after 10 days. The treatment enhanced human albumin adsorption while no difference of human fibrinogen adsorption amount was observed. Direct cell adhesion test showed many more live HUVECs retained than bare magnesium alloy. Both treated and untreated JDBM showed no adverse effect on HUVEC viability and spreading morphology. The relationship between changed surface characteristics, degradation rate and protein adsorption, cytocompatibility was also discussed.     

Bioactivity of porous biphasic calcium phosphate enhanced by recombinant human bone morphogenetic protein 2/silk fibroin microsphere

To prepare a bioactive bone substitute, which integrates biphasic calcium phosphate (BCP) and rhBMP-2/silk fibroin (SF) microsphere, and to evaluate its characteristics. Hydroxyapatite and β-tricalcium phosphate were integrated with a ratio of 60–40 %. RhBMP-2/SF (0.5 μg/1 mg) microsphere was prepared, and its rhBMP-2-release kinetics was assed. After joining pore-forming agent (Sodium chloride, NaCl), porous BCP/rhBMP-2/SF were manufactured, and its characteristics and bioactivity in vitro were evaluated. Mean diameter of rhBMP-2/SF microsphere was 398.7 ± 99.86 nm, with a loading rate of 4.53 ± 0.08 %. RhBMP-2 was released in a dual-phase pattern, of which fast-release (nearly half of protein released) focused on the initial 3 days, and slow-release sustained more than 28 days. With the increase in concentration of NaCl, greater was porosity and pore size, but smaller mechanical strength of BCP/rhBMP-2/SF. Material with 150 % (w/v) NaCl had an optimal performance, with a porosity of 78.83 %, pore size of 293.25 ± 42.77μm and mechanical strength of 31.03 MPa. Proliferation of human placenta-derived mesenchymal stem cells (hPMSCs) on leaching extract medium was similar to the normal medium (P = 0.89), which was better than that on control group (P = 0.03). Activity of alkaline phosphatase on BCP/rhBMP-2/SF surface was higher than on pure BCP at each time point except at 1 day (P < 0.05). RhBMP-2 has a burst release on early times and a sustaining release on later times. BCP/rhBMP-2/SF with 150 % (w/v) pore-forming agent has excellent porosity, pore size and mechanical strength. The biomaterial induces proliferation and differentiation hPMSCs effectively.     

基于6-氨基己酸可降解P(AC/AAE)的合成与表征

以6-氨基己酸(6-AC)、己二酸(AA)和乙二醇(EG)为原料,采用熔融缩聚法合成了可生物降解聚酯酰胺(PEAs),对处理提纯后的共聚物用红外光谱进行了结构表征;利用差示扫描量热法表征了共聚物的熔融过程和结晶过程,并研究了产物的吸水性和水解降解行为。结果表明,红外光谱图中共聚物中酯键吸收峰的强度随着酯含量的增加而增强;聚合物的熔点(Tm)、熔融焓(ΔHm)和结晶温度(Tc)、结晶焓(ΔHc)随着酯含量的增加而明显降低。共聚物的组成对吸水率影响不大,其降解速率随酯含量的增加而加快;共聚物在酸性溶液中降解速率最快,在碱性溶液中降解速率次之,在近于中性溶液中降解速率最慢。     

Stress singularity analysis for orthotropic V‐notches in the generalised plane strain state

The singularity for the V‐notch under the generalised plane deformation is investigated by the combination of the asymptotic analysis with the interpolating matrix method developed by part of the authors before. The displacement asymptotic expansions at the vicinity of the V‐notch vertex are introduced into the equilibrium equations, which are transformed into a set of characteristic ordinary differential equations with respect to the notch singularity orders. The boundary conditions and interfacial compatibility conditions are also represented by the combination of the singularity orders and characteristic angular functions. The determination of the singularity orders and characteristic angular functions are transformed into solving the ordinary differential equations with variable coefficients, which are solved by the interpolating matrix method. The present method is suitable for the singularity analysis for isotropic and orthotropic V‐notches. It is versatile for analysing the stress singularity of single material V‐notches, bi‐material V‐notches, interface edges and cracks. The correctness of the results by the proposed method is ensured by the comparison with the published ones.     

L波段雷达高空气象探测系统的使用

本文对L波段雷达探测系统在使用过程中常常出现的问题进行分析和总结归纳,并根据长期积累的工作经验,对有关问题提出了相应的解决方法。     

T726井石炭系盐膏层钻井完井技术

T726井是中国石化西北分公司在塔河油田西南部边缘地区布置的一口重点评价井。针对塔里木盆地石炭系盐层埋藏深,温度高,地层压力大,极易发生“缩径、坍塌”,造成卡钻,同时由于盐岩层的塑性蠕动,形成不规则井眼,甚至造成套管挤毁变形事故,井身质量难以控制,固井质量难以保证等问题,通过对同类型已钻井进行总结分析,提出了一系列钻井技术措施,并在T726井严格实施。结果表明,施工全过程安全无事故,盐层套管无变形,井身质量和固井质量优良,为以后在该地区石炭系盐膏层安全钻井积累了成功的经验。