异相法降解制备低分子量壳聚糖

在前人降解壳聚糖的方法的基础上 ,通过异相法用 H2 O2 、Na NO2 降解壳聚糖得到了一系列分子量从几千到几万的低分子量壳聚糖 ,并就降解过程中反应温度、反应物浓度等条件对最终产物分子量的影响作了深入讨论 ,还就降解前后壳聚糖分子结构的变化、结晶状态的变化作了测试。结果表明 ,在 4 0℃左右 ,H2 O2 用量 2 .5 % ,约 2 4 h可以将原分子量 60万的壳聚糖降低到 2～ 4万 。

异相晶核法液相合成金红石型TiO_2纳米晶

分别以 Sn Cl2 · 2 H2 O和 Sn Cl4 · 5H2 O为锡源 ,采用胶溶晶核法 ,经沉淀和胶溶过程 ,在液相中一步合成了金红石型 Ti O2 .详细考察了各种胶溶条件对产物结构的影响 ,并通过两种锡源实验结果的比较对异相晶核法中两种锡源的成晶机理进行了分析 .所合成的金红石型 Ti O2 晶粒度为 2 0～ 50 nm,两种方法获得完全金红石型 Ti O2 所需引入 Sn O2 的最低物质的量的分数分别为 1 0 %和 8% .

包覆型绿色合成纳米铁异相Fenton法处理柴油废水

以海藻酸钙包覆的绿色合成纳米铁(CA-ELE-Fe NPs)作为异相Fenton氧化催化剂去除废水中的柴油,考察了CA-ELE-Fe NPs投加量、H_2O_2浓度、阴离子表面活性剂十二烷基硫酸钠(SDS)浓度、溶液初始pH、柴油初始浓度、反应温度等对反应过程的影响.研究结果表明,当柴油废水质量浓度为0.050g·L^(-1),CA-ELE-Fe NPs(以Fe计)投加量为0.440 g·L^(-1),H_2O_2浓度为0.010 mol·L^(-1),SDS投加量为0.005 g·L^(-1),pH值为3.0,振荡速度为250 r·min^(-1),反应温度为30℃时,柴油的去除率可达到80.24%.

聚丙烯纤维水相异相接枝马来酸酐

本文研究了用水相异相法在聚丙烯纤维上接枝马来酸酐 ,用称重法测定接枝率。结果认为 ,随着反应中使用的马来酸酐和过硫酸铵浓度的提高 ,所得产物的接枝率显著提高 ,而反应温度和反应时间的影响则是开始随温度升高和时间延长接枝率上升 ,达到最大值后下降。在本实验中 ,各种反应条件下 ,都可以得到超过 1

无机-有机复合粒子制备方法综述

无机-有机复合粒子作为一种新型复合材料,结合了无机物和有机物的特点,已广泛应用于生物、医学、化工、电子、军事等领域。主要介绍无机-有机复合粒子制备方法——机械研磨法、异相凝集法、相分离法和单体聚合法。

去杂方法及试剂的选用原则

去杂方法及试剂的选用原则李小玲化学教学去除杂质的题目是常见的，但大多数学生对于混合物分离及除杂质的题目往往难以掌握，现将我个人的一点看法通过实例来说明：１、异相法：所谓异相法，就是需提纯的混合物和选用的去杂试剂分属于不同的相。其优点在于反应充分，反应...

羧甲基壳聚糖合成条件的优化及产物结构表征

通过异相法的方法合成了絮凝剂羧甲基壳聚糖,根据羧甲基壳聚糖对废水中Cd2+的去除率,利用四因素三水平正交实验优化了羧甲基壳聚糖的合成条件。正交实验的结果表明优化反应条件为:反应时间7h,反应温度为50℃,氯乙酸对壳聚糖的质量比为1.25,氢氧化钠对壳聚糖的质量比为1.0。在此优化条件下得到的羧甲基壳聚糖产品对Cd2+的最大去除率可达99.7%,用IR和1HNMR对相应的产品进行了结构表征,结果表明羧甲基化反应发生在C2位上NH2处的程度高于C6位的OH。

壳聚糖季铵盐晶体的制备及其抑菌、柔软剂性能

采用异相法制备了水溶性的羟丙基三甲基氯化铵壳聚糖 (HACC)晶体 ;测定了它对枯草芽孢杆菌等微生物生长的抑制效果 ;并研究了由HACC复配而成的微乳液在织物柔软处理中的应用性能。

包覆型ZrO_2(3Y)粉体研制

用微波法制备单分散、纳米水合二氧化锆，利用异相成核工艺在水合二氧化锆粒子表面均匀包覆一层Y（OH）3，制备出包覆型ZrO2（3Y）粉体先驱体．最后对煅烧ZrO2（3Y）粉体进行相结构分析，发现在室温下包覆型ZrO2（3Y）粉体中无m－ZrO2存在．结果表明；利用包覆的方法能将Y2O3均匀地加入到ZrO2中，提高ZrO2（3Y）粉体中亚稳定t－ZrO2的含量．

表面包覆Al(OH)_3改性石墨的研究

采用异相成核法在天然鳞片石墨水悬浮液中 ,使硫酸铝水解 ,在石墨表面包覆一层Al(OH) 3对石墨进行表面改性处理。介绍了包覆条件对石墨表面改性的影响 ,对改性后的石墨进行了形貌观察、接触角测定、差热 -热重分析。研究结果表明 :在适当的条件下 ,可在石墨表面形成Al(OH) 3包覆层 ,pH值为 4 .0时 ,包覆效果最好 ;

Fabrication of a monoclinic/hexagonal junction in WO_3 and its enhanced photocatalytic degradation of rhodamine B

A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction（XRD）,scanning electron microscopy（SEM）,high-resolution transmission electron microscopy（HRTEM）,X-ray photoelectron spectroscopy,and N2 adsorption-desorption were used to characterize the crystalline phase,morphology,particle size,chemical composition,and surface area of the WO3 samples.The formation of hexagonal（h-WO3） and monoclinic（m-WO3） crystal structures of WO3 at different temperatures or different times was confirmed by XRD.m-WO3 is formed at 600 ℃,while m-WO3 starts to transform into h-WO3 at 800℃.However,h-WO3,which forms at 800℃,may transform into m-WO3 by increasing the calcination temperature to 1000℃.SEM results indicate that m-WO3 particles exhibit a bulky shape with heavy aggregates,while h-WO3 particles exhibit a rod-like shape.Moreover,m-WO3 crystals are sporadically patched on the surface of the h-WO3 rod-like particles,resulting in the exposure of both m-WO3 and h-WO3 on the surface.It is observed that the monoclinic phase（m-WO3）/hexagonal phase（h-WO3） junction was fabricated by tuning the calcination temperature and calcination time.The relative ratios between m-WO3 and h-WO3 in the phase junction can readily be tailored by control of the calcination time.The photocatalytic activities of WO3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant.A higher photocatalytic activity was observed in the WO3 sample with the m-WO3/h-WO3junction as compared with the sample with only m-WO3.The improvement of photocatalytic activity can be attributed to the reduction of the electron-hole recombination rate owing to the formation of the phase junction,whose presence has been confirmed by HRTEM and photoluminescence spectra.

Phase field method simulation of faceted dendrite growth with arbitrary symmetries

A numerical simulation based on a regularized phase field model is developed to describe faceted dendrite growth morphology. The effects of mesh grid, anisotropy, supersaturation and fold symmetry on dendrite growth morphology were investigated, respectively. These results indicate that the nucleus grows into a hexagonal symmetry faceted dendrite. When the mesh grid is above 640×640, the size has no much effect on the shape. With the increase in the anisotropy value, the tip velocities of faceted dendrite increase and reach a balance value, and then decrease gradually. With the increase in the supersaturation value, crystal evolves from circle to the developed faceted dendrite morphology. Based on the Wulff theory and faceted symmetry morphology diagram, the proposed model was proved to be effective, and it can be generalized to arbitrary crystal symmetries.

Parallel EOI algorithm with different insertion schemes

A parallel embedding overlapped iterative (EOI) algorithm about classicimplicit equations with asymmetric Saul'yev schemes (CIS-EOI) to solve one-dimensional diffusionequations is discussed to improve the properties of the segment classic implicit iterative (SCII)algorithm. The structure of CIS-EOI method is given and the stability of scheme and convergence ofiteration are proved by matrix method. The property of gradual-approach convergence is alsodiscussed. It has been shown that the convergent rate is faster and the property of gradual-approachconvergence also becomes better with the increasing of the net point in subsystems than with theSCII algorithm. The simulation examples show that the parallel iterative algorithm with a differentinsertion scheme CIS-EOI is more effective.

Analysis on Interaction between Genotype of Four Main Flavonoids of Barley Grain and Environment

[Objective] This study aimed to analyze the interaction between genotype of flavonoids of barley grain and environment, to increase the flavonoid content of barley grain in cultivation and breeding. [Method] In this study, the content of cate- chin, myricetin, quercetin and kaempferol of barley grain planted in Kunming, Qujing and Baoshan were determined by HPLC, and the genotype, environment, genotype- environment interaction of the flavonoid content of barley grain were analyzed. [Result] According to the experimental results, the genotype variance, environmental variance and G x E interaction variance of catechin and kaempferol contents show the same trend： genotype variation 〉 environmental variation 〉 G × E interaction variation, which all reach a extremely significant level; the genotype variance, envi- ronmental variance and G × E interaction variance of quercetin and total flavonoid contents show the same trend： genetype variation 〉 G × E interaction variation 〉 environmental variation, which all reach a extremely significant level; the genotype variance and environmental variance of myricetin content both reach a extremely sig- nificant level, while the G × E interaction variance reaches a significant level, showing an order of genotype variation 〉 environmental variation 〉 G × E interaction variation; the genotype variance, environmental variance and G x E interaction vari- ance of total flavonoid content show an order of genotype variation 〉 environmental variation 〉 G × E interaction variation. Among different barley varieties, Ziguang- mangluoerling and Kuanyingdamai in Qujing, Kunming and Baoshan have relatively high content of quercetin, while other barley varieties barely contain any quercetin. The grains of Ziguangmangluoerling and Kuanyingdamai are purple, while the grains of other barley varieties are yellow. [Conclusion] Four main flavonoids and the total flavonoids of barley grain are mainly under genetic control and affected by genetic- environment interactions; the purple barley grains contain high content of quercetin.

Simultaneous separation and determination of four main isoflavonoids in Astragali Radix by an isocratic LC/ESI-MS method

A simple, reliable and rapid isocratic liquid chromatography(LC)-mass spectrometric detection(MS) coupled with electrospray ionization(ESI) method for simultaneous separation and determination of calycosin-7-O-β-D-glucoside, ononin, calycosin and formonometin in Astragali Radix was developed. After the samples were extracted with ethanol, the optimum separation conditions for these analytes were achieved using water and acetonitrile(70:30, v/v) containing 0.2%(v/v) acetic acid as a mobile phase and a 2.0 mm×150 mm Hypersil-Keystone C18 column. Selective ion monitoring(SIM) mode and [M+H]+ ions at m/z 447, 431, 285 and 269 were used for quantitative analysis of four main active components above mentioned. The calibration curves were linear in the range of 0.4-175.0 μg/mL for calycosin-7-O-β-D-glucoside, 0.2-146.0 μg/m L for ononin, 0.4-210.0 μg/mL for calycosin and 0.5-217.0 μg/mL for formonetion, respectively. The limits of quantification(LOQ) and detection(LOD) were 0.4 μg/mL and 0.08 μg/m L for calycosin-7-O-β-D-glucoside, 0.2 μg/mL and 0.06 μg/m L for ononin, 0.4 μg/mL and 0.1 μg/mL for calycosin, 0.5 μg/m L and 0.1 μg/m L formonetion, respectively. The standard recoveries were in the range of 96.5%-104.7%. The developed method has successfully been used for the determination of four main flavonoids in Astragali Radix from various sources and can be used for identification, differentiation and quality evaluation of Astragali Radix.

Simulation of facet dendrite growth with strong interfacial energy anisotropy by phase field method

Numerical simulations based on a new regularized phase-field model were presented, to simulate the solidification of hexagonal close-packed materials with strong interfacial energy anisotropies. Results show that the crystal grows into facet dendrites,displaying six-fold symmetry. The size of initial crystals has an effect on the branching-off of the principal branch tip along the<100> direction, which is eliminated by setting the b/a(a and b are the semi-major and semi-minor sizes in the initial elliptical crystals, respectively) value to be less than or equal to 1. With an increase in the undercooling value, the equilibrium morphology of the crystal changes from a star-like shape to facet dendrites without side branches. The steady-state tip velocity increases exponentially when the dimensionless undercooling is below the critical value. With a further increase in the undercooling value, the equilibrium morphology of the crystal grows into a developed side-branch structure, and the steady-state tip velocity of the facet dendrites increases linearly. The facet dendrite growth has controlled diffusion and kinetics.

Wavelet matrix transform for time-series similarity measurement

A time-series similarity measurement method based on wavelet and matrix transform was proposed,and its anti-noise ability,sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet subspace,and sample feature vector and orthogonal basics of sample time-series sequences were obtained by K-L transform. Then the inner product transform was carried out to project analyzed time-series sequence into orthogonal basics to gain analyzed feature vectors. The similarity was calculated between sample feature vector and analyzed feature vector by the Euclid distance. Taking fault wave of power electronic devices for example,the experimental results show that the proposed method has low dimension of feature vector,the anti-noise ability of proposed method is 30 times as large as that of plain wavelet method,the sensitivity of proposed method is 1/3 as large as that of plain wavelet method,and the accuracy of proposed method is higher than that of the wavelet singular value decomposition method. The proposed method can be applied in similarity matching and indexing for lager time series databases.

高含量羧基键合硅胶的制备及其对Cu^(2+)吸附性能的研究

目的制备两种EDTA键合硅胶(SG-EDTA)并对其Cu2+吸附性能进行研究。方法采用均相法和异相法制备SGEDTA。结果均相法制备SG-EDTA的收率比异相法制备SG-EDTA高;SG-EDTA在p H2时对Cu2+表现出了最大吸附量;从动力学吸附曲线来看,异相法与均相法制备的SG-EDTA对铜离子的吸附行为无明显差异。SG-EDTA在吸附动力学机制方面属于液膜扩散且符合拟二级动力学吸附;热力学吸附过程可用Freundlich热力学模型描述。结论两种方法制备的SGEDTA吸附量分别为1.413、1.457 mmol·g-1。吸附重金属离子后,均相法制备的EDTA键合硅胶较异相法制备的更易洗脱。

Study on pharmacokinetic and tissue distribution ofisovitexin in rats by HPLC

An HPLC method for the determination of isovitexin in rat plasma and different tissues was developed.The separation was achieved on a C_（18）column with a mobile phase consisting of methanol-1% acetum（40：60,v/v）at a detection wavelength of 338 nm and a column temperature of 30℃.Rutin was chosen as the internal standard.The linear range of the standard curves was 0.20-128.75μg/mL in the plasma and 0.024-3.09μg/mL in the tissues.The LOQ was 0.19μg/mL in the plasma and 0.024μg/mL in the tissues.The relative recoveries of isovitexin ranged from 93% to 105% in the plasma and 87% to 112% in the tissues.The intra-and inter-day precisions were all below 8%.The pharmacokinetics and tissue distribution of isovitexin in rats were studied with the method.Blood samples were collected at fixed time intervals after the i.v.injection of isovitexin at a dosage of 18.75,3.75 and 0.75 mg/kg;the tissue samples（brain,liver,kidney,heart,lung,spleen and ovary）were obtained at 10,30,and 60 min after the i.v.injection of isovitexin at a dosage of 18.75 mg/kg.The pharmacokinetics of the isovitexin in three different dosages in the rats fit the two-compartment open model.The isovitexin displayed linear dynamics in the dosage range of 0.75-18.75 mg/kg.The mean value of t_（1/2α）was 1.54-1.84 min,and t_（1/2β）was 36.94-46.27 min at the three dosages.The tissue distribution study showed that the sequence of tissue drug concentration from high to low was kidneyliverlung≈ovaryheart≈spleenbrain.

An unconventional phase field modeling of domains formation and evolution in tetragonal ferroelectrics

Based on characteristic functions of variants, we developed an unconventional phase field modeling for investigating domains formation and evolution in tetragonal ferroelectrics. In order to develop this computational approach, we constructed the anisotropy energy of tetragonal variants, which is used instead of Landau-Devonshire potential in the conventional phase field method, resulting in that much fewer parameters are needed for simulations. This approach is advantageous in simulations of emerging ferroelectric materials. We employ it to study the formation and evolution of domains in tetragonal barium titanate single crystal, as well as the nonlinear behaviors under cyclical stress and electric field loading. A multi-rank laminated ferroelectric domain pattern, 90° domain switching accompanied by polarization rotation, and 180° domain switching accompanied by move of domain wall are predicted. It is found that the speed of 90° domain switching is slower than that of 180° domain switching, due to both polarization and transformation strain changed in 90° domain switching. It also suggests that large strain actuation can be generated in single crystal ferroelectrics via combined electromechanical loading inducing 90° domain switching. The good agreement between simulation results and experimental measurements is observed.