微波法合成含1,1’-联萘骨架的对称酰胺型开链冠醚

在微波辐射条件下高效合成了3种含1,1’-联萘骨架的对称酰胺型开链冠醚,产物结构经IR,1 H-NMR进行了表征.结果表明,该方法具有反应步骤短,时间短,产率高等优点,是合成含1,1’-联萘骨架的对称酰胺型开链冠醚的有效方法之一.     

Restoration of rat calvarial defects by poly（lactide-co-glycolide）/ hydroxyapatite scaffolds loaded with bone mesenchymal stem cells and DNA complexes

A composite construct comprising of a bone mesenchymal stem cell (BMSC) sheet, plasmid DNA, encoding human bone morphogenic protein-2 (hBMP-2), and poly(lactide-co-glycolide)/hydroxyapatite (PLGA/HA) sponge was designed and employed in the restoration of rat calvarial defects. To improve gene transfection efficiency, a cationic chitosan derivative, N,N,N,-trimethyl chitosan chloride (TMC), was employed as the vector. The TMC/DNA complexes had a transfection efficiency of 13% in rat BMSCs, resulting in heterogeneous hBMP-2 expression in a 10-d culture period in vitro. In vivo culture of the composite constructs was performed by implantation into rat full-thickness calvarial defects, using constructs lacking pDNA-hBMP-2 or BMSC sheets as controls. Significantly higher heterogeneous expression of hBMP-2 was detected in vivo at 2 weeks for the cell sheet/DNA complex/scaffold constructs, compared with the constructs lacking pDNA-hBMP-2 or BMSC sheets. New bone formation was evident as early as 4 weeks in the experimental constructs. At 8 weeks, partial bridging of calvarial defects was observed in the experimental constructs, which was significantly better than the constructs lacking pDNA-hBMP-2 or BMSC sheets. Therefore, the combination of the PLGA/HA scaffold with BMSC sheets and gene therapy vectors is effective at enhancing bone formation.     

Cesaro函数空间CESp的依测度收敛的Opial性质和强端点

依测度收敛的Opial性质为函数空间所特有,验证了Cesaro函数空间CESp(1＜p＜∞)有依测度收敛的Opial 性质,证明了(A)z∈S(CESp)都是B(CESp)的强端点,进而证明了CESp?(1＜p＜∞)是中点局部一致凸的.     

改进的热平衡积分法的细化

文章讨论了改进的热平衡积分法的细化.将求解区间[0,s]均匀分划,在所得的子区间内选取适当的近似解析解形式,运用改进的热平衡积分法进行求解.通过讨论得知:细化的改进热平衡积分法能很好地提高所求解的精度.     

用数轴法判断中心原子的杂化类型

提出了用数轴判断中心原子轨道杂化方式的方法、应用及规律.     

高平市城乡统筹发展道路初探

统筹城乡发展已成为各级政府工作的重点,文章通过认识高平市城乡发展的现状,在深刻分析高平市城乡统筹发展的动力和背景基础上,提出了特色城镇化、社会主义新农村建设、乡村精简化、资源开发、现代产业发展的城乡一体化战略,并指出要构建城乡一体化发展的支撑体系以促进城乡一体化快速发展。     

佳禾沟泥石流堆积物的粒度与强度关系分析

佳禾沟位于云南省维西县中路乡佳禾村,历史上曾多次发生不同规模的泥石流,并造成了人员伤亡和财产损失。通过对沟道流域沿线不同位置取样,用泥石流颗粒标度分析法并结合强度实验,发现佳禾沟泥石流松散堆积物的颗分参数μ与P(D_2)之间存在线性关系,这说明μ影响了泥石流的启动;物源区中的细颗粒的迁移、上游泥石流部分物质的随机性停歇和沟道支沟和主沟陡坡物质的随机性补给导致了颗分参数(μ,D_c)的波浪式发展。黏聚力c与μ之间的关系为线性关系,c随着μ的增加而增加。这说明细颗粒的组成控制了黏聚力c的大小,因此推断黏聚力受到细颗粒之间的胶结作用和静电作用等因素的影响。内摩擦角φ与Dc之间的关系为负线性相关,而φ随着D_c的增加而变小,粗颗粒决定了φ的发展。因此,在相同条件下,较大的μ和较小的D_c组合的土体,其强度较大;这从定量的角度上验证了颗粒级配与土体强度的关系。以上结论是否适用于其他流域需进一步验证。此外,还应结合颗粒形状,土动力学,渗透理论分析泥石流发生机理。     

THE COMPARISON OF STRENGTH PROPERTY BETWWEEN KRAFT PULP AND ALKALINE SULFITE-ANTHRAQUINONE PULP FOR THICKER CELL WALL FIBER MATERIALS

INTRODUCTIONMany studies on the strengths of AS-AQ pulp have been carried out. Generally speaking, except lower tear strength, other strength properties of AS-AQ pulp are similar to those of KP. Some even higher than KP[1,2]. Macleod[3] find that the difference in tear strength between the AS-AQ pulp and KP of aspen can be decreased about bleaching. McDonough et al[4] point out that at the same beating degree, the tear strength of AS-AQ pulp is lower than that of KP, but at the …     

通电多层板在磁场中的振动

给出了有外加电流通过时，多层弹性导电板在外磁场中弯曲振动的基本方程。对于结构为中面对称的多层板作了较多的讨论。     

成对电有机合成

举例总结了近几年成对电有机合成的发展情况,阐述成对电有机合成是一种节能、经济的技术。指出在精细化工和石油化工中都应努力开发这种技术。