美国TA仪器：Discovery差示量热扫描仪

Discovely DSC是美国TA仪器在差示扫描量热仪领域的最新创新性性产品，它重新定义了性能、质量和实用性。Discovery差示扫描量热仪的特点采用了金属扩散熔合原理制造全新的热电偶，

用差示量热扫描方法研究米粉糊的老化

采用差示量热扫描方法研究米粉糊在低温贮存时的老化情况 ,比较了不同水分含量 (质量分数 )和添加剂对米粉糊抗老化能力的影响 .结果显示 :米粉糊在 4℃下贮存较在 2 5℃下贮存易于老化 .在米粉糊中添加 1 .0 %的蔗糖酯和 1 .0 %的CaCl2 能有效地提高米粉糊在贮存期间的抗老化性能 .

水分含量对西兰花玻璃化转变温度的影响

在低温贮藏和冻干加工中,玻璃化转变温度是一个非常重要的参数。用差示扫描量热仪测量得到不同含水量西兰花和调理西兰花的玻璃化转变温度Tg。研究发现水分质量分数较高时(≥35%),西兰花和调理西兰花发生的是部分玻璃化转变,不同含水量西兰花的部分玻璃化转变温度Tg′基本相同,水分对其影响较小。而水分质量分数较低时(<35%),西兰花可以实现完全玻璃化转变,含水量对西兰花的完全玻璃化转变温度Tg影响很大,Tg随着含水量的减少而升高;拟合得到Tg随水分变化的公式。

不同原料组分的配合饲料比热模型

为了合理控制乳猪饲料调质、制粒的工艺参数，需要掌握不同原料组分对配合饲料在调质、膨化、冷却过程中的传热特性的影响，试验采用差示量热扫描仪测比热的方法，以乳猪配合饲料为例，采用3因素5水平2次正交旋转中心组合试验设计，研究了乳猪饲料配方中质量分数所占比例较大的玉米（46％-70％）、豆粕（9％-18％）和对比热影响较大的热敏性物质乳清粉（2％-10％）对配合饲料比热的影响，结果表明：单一玉米粉、豆粕、乳清粉的比热值均随温度升高而增大，且乳清粉在58.8℃时出现比热峰值；响应面法试验结果表明，影响配合饲料比热（60℃-80℃）的各因素主次关系为：乳清粉〉玉米〉豆粕，交互作用的主次关系为：玉米和豆粕的交互作用〉玉米和乳清粉的交互作用〉乳清粉和豆粕的交互作用。同时通过回归分析和响应面分析，建立了比热与玉米、豆粕、乳清粉质量分数关系的数学模型（R2=0.9822），研究结果表明：所得回归方程拟合情况良好，当配方中玉米质量分数为66％、豆粕12％、乳清粉6％时，配合料的最小比热值为2536J／（kg·K），此模型的建立将为乳猪配合饲料的湿热加工提供技术依据。

猪皮胶原蛋白的提取及其结构表征

采用较简便的酶法从猪皮中提取胶原蛋白,通过SDS-PAGE凝胶电泳、紫外光谱定性分析,证明所提取胶原蛋白为Ⅰ型胶原蛋白,计算得分子量约为320 kD.利用FTIR、DSC进一步测试,实验结果表明胶原蛋白具有完整的三螺旋结构,即具有生物活性.

乳化剂-直链淀粉复合物的形成及其对蛋糕抗老化的影响

当乳化剂加入到含有淀粉的食品中进行蒸煮或烘焙时,淀粉和乳化剂可形成复合物,以起到改善产品品质、延长货架期的作用。文中通过差示扫描量热分析仪(DSC)和蓝值测定几种乳化剂与直链淀粉的络合能力,并就其对蛋糕的品质和老化特性的影响进行研究,结果表明:与淀粉络合能力强的乳化剂生产出来的蛋糕的品质和抗老化性要比络合能力弱的乳化剂好。研究和探讨了乳化剂对浆料比重、蛋糕比容和蛋糕质构的影响,结果表明:乳化剂的加入使浆料比重降低,蛋糕比容增加,硬度降低,回复性、弹性和咀嚼性提高。

乳化剂与直链淀粉相互作用及其对蛋糕品质影响的研究

通过差示扫描量热分析仪(DSC)和蓝值测定几种乳化剂与淀粉的络合能力,并对其对蛋糕的品质和老化特性的影响进行研究,结果表明,与淀粉络合能力强的乳化剂生产出来的蛋糕的品质和抗老化性要比络合能力弱的乳化剂好。研究和探讨了乳化剂对浆料比重、蛋糕比容和蛋糕质构的影响,结果表明,乳化剂的加入使浆料比重降低,蛋糕比容增加,使得保存1d的蛋糕的硬度降低,弹性和咀嚼性提高,乳化剂对蛋糕的回复性也有一定的影响。

多层杨木豆胶胶合板工艺及性能

以豆胶为胶黏剂研究一种新型的多层无醛胶合板,分析热预压温度、热压温度和压力,以及3段式热压工艺对胶合板的胶合强度影响,并用差示扫描量热仪(DSC)对豆胶胶黏剂进行热分析,研究了热压过程中板坯表芯层的热压温度变化规律。结果表明,较佳热压工艺参数为预热压温度100℃、热压温度160℃、3段式热压曲线的最高压力1.6MPa。

挤压法制备复配型粉末乳化剂及其在蛋糕中的应用研究

以淀粉为载体。将几种乳化剂与载体按一定比例一起挤压生产粉末乳化剂。用差示扫描量热分析仪(DSC)分析挤压前后混合物的转交温度和热焓,发现在挤压后比挤压前的焓值小。扫描电镜(SEM)研究乳化剂的微观结构,发现乳化剂像一层薄膜一样均匀的分布在淀粉颗粒表面上。将该粉末乳化剂应用到蛋糕中,发现生产出的蛋糕的品质要比加未挤压乳化剂的好。

渗透性低温保护剂玻璃化转变临界降温速率的实验确定

从Boutron结晶动力学半经验公式出发 ,结合他人的修正结果 ,利用差示量热扫描仪 (DSC)的实验数据 ,不必构造TTT和CCT曲线 ,获得了若干常用低温保护剂实现玻璃化转变的临界降温速率 ,测定了渗透性低温保护剂实现玻璃化转变的临界结晶率 ,修正了临界降温速率的计算公式 ,实验还说明了Bourton模型对非渗透性保护剂降温结晶过程的局限性。

Experimental investigation of crystallization process of nanofluid by DSC

A water-TiO2nanofluid with a weight fraction of 5% and an average particle size of 75 nm is used to investigate the effect of TiO2 nanoparticles on the crystallization and melting behaviors of deionized water by using differential scanning calorimetry（DSC）at four different cooling rates,3,5,7,9 ℃/min.The DSC experimental results show that the water-TiO2 nanofluid has a lower supercooling degree and a faster crystallization rate than the deionized water.With the increase in the cooling rate,the influence of the TiO2 nanoparticles on the supercooling degree of the deionized water becomes greater,but on the crystallization rate it turns lower.During the melting process,compared with the deionized water,the water-TiO2 nanofluid has a lower melting temperature,a less latent heat and a higher melting rate.

马铃薯对小麦面团水分状态的影响规律研究

为了探究马铃薯的添加对小麦面团中水分状态的影响规律,本试验以新鲜马铃薯、马铃薯全粉及小麦粉为原料,采用差示量热扫描仪（DSC）,分析马铃薯的添加量及添加方式对小麦面团水分状态的影响.结果表明,马铃薯全粉的添加量对小麦面团的水分状态具有极显著的影响,随着马铃薯全粉添加量的增加,小麦面团中可冻结水含量降低,水分状态逐渐向不可冻结水迁移.

A Facile Route for Synthesis of LiFePO_4/C Cathode Material with Nano-sized Primary Particles

A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw materials. Then, as-prepared LiH2PO4, reduced iron powder andα-D-glucose were ball-milled, dried and sin-tered to prepare LiFePO4/C. X-ray diffractometry was used to characterize LiH2PO4, ball-milled product and LiFePO4/C. Differential scanning calorimeter-thermo gravimetric analysis was applied to investigate possible reac-tions in sintering and find suitable temperature for LiFePO4 formation. Scanning electron microscopy was em-ployed for the morphology of LiFePO4/C. As-prepared LiH2PO4 is characterized to be in P21cn（33） space group, which reacts with reduced iron powder to form Li3PO4, Fe3（PO4）2 and H2 in ball-milling and sintering. The appro-priate temperature for LiFePO4/C synthesis is 541.3-976.7 ℃. LiFePO4/C prepared at 700 ℃ presents nano-sized primary particles forming aggregates. Charge-discharge examination indicates that as-prepared LiFePO4/C displays appreciable discharge capacities of 145 and 131 mA·h·g^-1 at 0.1 and 1 C respectively and excellent discharge ca-pacity retention.

Microstructure and dielectric properties of Ca-Al-B-Si-O glass/Al_2O_3 composites with various alkali oxides contents

The effects of alkali oxides （Na2O and K2O addition on both the sintering behavior and dielectric properties of Ca-AI-B-Si-O glass/Al2O3 composites were investigated by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimeter （DSC）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of alkali oxides in the glass causes the decrease of [SiO4], which results in the decrease of the continuity of glass network, and leads to the decrease of the softening temperature Tf of the samples and the increasing trend of crystallization. And that deduces corresponding rise of densification, dielectric constant, dielectric loss of the low temperature co-fired ceramic （LTCC） materials and the decrease of its thermal conductivity. By contrast, the borosilicate glass/A1203 composites with 1.5% （mass fraction） alkali oxides sintered at 875 ℃ for 30 rain exhibit better properties of a bulk density of 2.79 g/cm3, a porosity of 0.48%, a 2 value of 2.28 W/（m.K）, a er value of 7.82 and a tand value of 9.1 × 10-4 （measured at 10 MHz）.

Effect of ZrO_2 Crystalline Phase on the Performance of Ni-B/ZrO_2 Catalyst for the CO Selective Methanation

Amorphous Ni-B/ZrO2 catalysts were prepared by coprecipitation-chemical reduction with KBH4 aqueous solution,and various crystalline phase ZrO2(amorphous-ZrO2,tetragonal-ZrO2 and monoclinic-ZrO2) supported Ni-B catalysts were obtained by thermal treatment in 5%H2-N2 stream at different temperature.The effect of ZrO2 polymorphs and the treatment temperature on the catalytic performance for the CO selective methanation were investigated,and the catalysts were characterized by N2 physisorption,Powder X-ray diffraction(XRD), Temperature-Programmed Desorption(CO-TPD and H2-TPD),and Differential Scanning Calorimeter(DSC).The treatment temperature affected strongly the crystalline structure of ZrO2,and the CO methanation activity and selectivity of the Ni-B/ZrO2 catalysts were significantly influenced by the crystalline phase of ZrO2.Of the three forms of ZrO2 polymorphs(amorphou-ZrO2,tetragonal-ZrO2 and monoclinic-ZrO2),the amorphous-ZrO2 supported nickle catalyst showed highest CO methanation activity,attributing in large part to the largest specific surface area and the optimum CO/H2 absorption intensity of the Ni-B/amorphous-ZrO2 catalyst.

Research on thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane based on differential scanning calorimetry

In order to test the thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane(RDX),the linear temperature rise experiment of RDX was carried out by differential scanning calorimeter under different heating rate conditions.The kinetic calculation of RDX thermal decomposition curve was carried out by Kissinger and Ozawa methods,respectively,and the thermal analysis software was used to calculate the parameters such as self-accelerating decomposition temperature.The results show that the initial decomposition temperature range,decomposition peak temperature range,and decomposition completion temperature range of RDX are 208.4-214.2,225.7-239.3 and 234.0-252.4℃,respectively,and the average decomposition enthalpy is 362.9 J·g^-1.Kissinger method was used to calculate the DSC experimental data of RDX,the apparent activation energy obtained is 190.8 kJ·mol^-1,which is coincident with the results calculated by Ozawa method at the end of the reaction,indicating that the apparent activation energy calculated by the two methods is relatively accurate.When the packaging mass values are 1.0,2.0 and 5.0 kg,respectively,the self-accelerating decomposition temperatures are 97.0,93.0 and 87.0℃,respectively,indicating that with the increase of packaging mass,the self-accelerating decomposition temperature gradually decreases,and the risk increases accordingly.

Thermal behavior and mass spectrometry analysis of N-methyl-N-nitroso-p-toluenesulfonamide

The effect of temperature on the functional groups transition of N-methyl-N-nitroso-p-toluenesulfonamide （Diazald） and thermal decomposition were investigated by Fourier Transform Infrared Spectroscopy （FT-IR） and Differential Scanning Calorimeter （DSC）. The results showed that the functional groups transition of Diazald was temperature dependent, and thermal decomposition of Diazald was accelerated above 47.7℃. The HPLC-ESI-MS method was used for Diazald analysis, which indicated the strong hydrogen bonding between Diazald and water and instability of the NO group.

Physicochemical Characterization and Solubility Enhancement Studies of Mebendazole Solid Dispersions in Solvent Mixtures

Abstract： The objective was to obtain solid dispersion to improve the dissolution rate, solubility and oral absorption of MB （mebendazole）, poor water-soluble drugs. The new formulation was characterized by DSC （differential scanning calorimetry）, PXRD （powder X-ray diffraction）, FT-1R （fourier transform infrared spectroscopy） and STEM （scanning transmission electron microscopy） methods. Solid dispersions of MB with polyvinylpyrrolidone K-30 （PVP K30） were prepared by solvent evaporation method. The solubility of MB （original powder） and that of the solid dispersions was measured at 25℃ in ethanol-water. The aqueous solubility of MB was favoured by the presence of the polymer in solvent mixtures. Combination of solid dispersions with co-solvents increased the water solubility of MB in a larger extent that each method separately. Solubility parameter （o） was used to relate to solubility profiles. MB and the solid dispersions show a solubility curve with a single peak at 51 = 30.78 MPav2. Solid state characterizations indicated that the solid dispersion exist an amorphous material entrapped in polymer matrix getting highest improvement in wettability and solubility.

乳化剂抑制鲜湿面老化机理的研究

本研究探讨两种不同乳化剂的添加量和储藏时间对鲜湿面淀粉热力学行为产生的影响。利用差示量热扫描（DSC）、Avrami方程和Hyper Chem软件对分别添加硬脂酰乳酸钠（SSL）,β-环糊精（β-CD）两种乳化剂的鲜湿面老化动力学方程与分子结构模型进行分析。结果表明抑制老化的最佳添加量为：SSL 0.2%,β-CD 0.10%。乳化剂/鲜湿面体系较空白组具有更加有序致密的结构;乳化剂/鲜湿面体系的老化焓均小于空白组;SSL/鲜湿面体系成核方式（n1）,结晶速率常数（k1）与β-CD/鲜湿面体系成核方式（n2）,结晶速率常数（k2）的变化范围为：n1=0.743-0.759、k1=0.328-0.353、n2=0.748-0.785、k2=0.321-0.356,且乳化剂/鲜湿面的成核方式均不断趋近于自发成核,结晶速率常数均小于空白组;通过Hyperchem软件模拟发现乳化剂能打开并插入淀粉老化过程中形成的双螺旋结构中,牵制直链淀粉并形成无定形区。结果说明添加乳化剂能延缓鲜湿面淀粉的老化,为延长鲜湿面的货架期提供参考。