Chitosan-pectin synergistic interaction and gelation

Mixed gels of chitosan-pectin were prepared by varying the ratio of constituents in the presence of NaCl. Mixed gel at 3% of total polysaccharide concentration with addtion of 12% NaCl showed a synergistic maximum when the ratio of chitosan to pectin was 60: 40. The effect of the polysaccharide concentration, the preparation temperature (T _p), the time of incubation, balk salt concentration, the molecular weight and the degree of deacetylation of chitosan on gelation have been studied. Interaction mechanism between molecules of both polysaccharides was investigated by FT-IR spectrometry. Foundation item: Supported by the National Natural Science Foundation of China (No. 29574173) Biography: He Dong-bao (1945-), male, Associate professor, research direction: natural polysaccharides.     

巷道围岩控制的波动性平衡理论

运用岩石力学的基本理论分析了巷道围岩的变形、强度特性以及支护力作用下围岩各变形区的应力分布特征,首次提出了涵盖巷道围岩-支护相互作用全过程的波动性平衡理论,为巷道围岩尤其是具有较大松动变形区的巷道围岩控制提供了理论依据。     

岩石裂纹演化过程中围压效应的数值模拟

应用岩石破裂过程分析程序分析了侧压对预制两个平行裂纹岩样中岩桥区裂纹的扩展、贯通和相互作用机制的影响,并对岩样。受载状态与其特征应力和峰值强度的关系进行了探讨,模拟结论与相关的实验结果相吻合。     

联合认知系统模型及应用

从工业工程角度分析人文因素和人的认知特点,提出了一种联合认知系统概念模型.并在此基础上论述了设计具有较好人文特性的认知系统所要考虑的因素.最后,给出了一个案例分析.     

水溶液中L-胱氨酸与氯化镁相互作用的热力学参数

在288.15～318.15 K(间隔5 K)下,用分光光度法测定了L-胱氨酸(L-Cystine)在MgCl2水溶液中的溶解度.计算了MgCl2-L-Cystine-H2O体系中L-Cystine的活度系数及盐效应常数kk8,讨论了MgCl2与L-Cystine相互作用的热力学参数.结果表明ks＜0、gEN＜0、hEN＞0、5EN＞0.应用静电相互作用解释了这些参数及其随温度的变化规律.     

论网络广告媒体交互性的双重效应

作为广告媒体的网络 ,其交互性的特点并非只是优势 ,它提高了受众的主动性却削弱了广告发布方的主动性 ,也降低了广告的重复率 ,同时还导致了无意注意渠道的阻塞和暗示作用的丧失 ,因此 ,它给广告效果带来了双重效应     

非等温边界层中相间相互作用实验研究

应用三维粒子动态分析仪(PDA),测量了水平流动非等温边界层中气固两相间相互作用的特性.结果表明,颗粒使气流温度边界层变薄,强化了壁面与气流间的传热;颗粒质量流率对相间作用有较大影响,随颗粒流率的增加,颗粒对气流平均速度和湍流的影响增大.颗粒和气流相互作用在不同方向上呈各向异性;颗粒对气流垂直方向的脉动影响较大;颗粒改变了气流雷诺应力在壁面附近的分布,对湍流的拟序结构产生了较大的影响.     

Zircon SIMS ages and chemical compositions from Northern Dabie Terrain: Its implication for pyroxenite genesis

We present the results of a detailed micro-scale investigation of zircons from pyroxenites, Daoshicong Northern Dabie using a combination of SIMS and ICPMS. The SIMS measurements gave ages of 134—159 Ma. Its average of (144.5± 6.2) Ma is interpreted as the best estimate of the pyroxenite intrusion. The crystallization of zircons continued for quite a long time and underwent slow cooling. The pyroxenites are products of post-collision magmatism. The REE pattern is HREE-enriched, and its HREE concentrations fall between the magmatic and metamorphic range of gneissic zircons from the Dabie area, which indicate the involvement of crust material in its mantle source.     

Oxygen isotope evidence for two-stage water-rock interactions of the Nianzishan A-type granite in NE China

The oxygen isotope ratios of whole-rock, common rock-forming minerals and zircon from Mesozoic A-type granitic pluton at Nianzishan in northeastern China were analyzed by the conventional BrF5 method and the laser-probe technique, respectively. Both whole-rock and rock-forming minerals show large δ18O variations up to 5.5%. with significant oxygen isotope disequilibrium between zircon and the other minerals, whereas the δ18O values of zircon are tightly clustered between 3.12%. and 4.19%. and thus lower than the normal-mantle δ18O values. These results indicate that the Nianzishan A-type granite experienced two-stage water-rock interactions subsequentially. The remarkably low zircon δ18O values are genetically due to sea-water exchange with granite protolith in the first stage, and the oxygen isotope disequilibrium fractionations between zircon and rock-forming minerals are caused by meteoric-hydro thermal alteration in the second stage. It is inferred that the 18O-depleted A-type granitic magma was derived from partial melting of subducted lower oceanic crust which was isotopically exchanged with seawater at high temperatures. In the process of granite emplacement into the upper crust, meteoric-hydrothermal circulation was triggered to overprint crystallizing granite under subsolidus conditions.     

Combustion synthesis and magnetic investigation of nanosized CoFe2O4

Nanosized Co spinel ferrite was prepared by a combustion method. The grain size of resultant ferrite can be controlled by the reaction conditions. Magnetic investigation revealed that the products with an average grain size of 4 nm behave as superparamagnetic materials and have zero coercive force; whereas the samples with an average grain size of 85 nm (near the size of critical single domain) have the maximal coercive force. There were the negative magnetic intergrain interactions which became stronger when the grain size neared that of the single domain.