相变微胶囊调温织物的制备及其热性能研究

为了研制一种具有蓄热调温功能的织物,采用原位聚合法制备了以正十八烷为芯材,以三聚氰胺-甲醛-尿素树脂为壁材的相变材料微胶囊。利用扫描电子显微镜(SEM)和差示扫描量热仪(DSC)研究微胶囊的表面形态和储热性能。采用干法涂层工艺将不同质量分数的相变微胶囊整理到丙纶SMS复合织物上,并对其进行外貌、热性能及蓄热调温性能测试。研究结果表明:相变微胶囊表面光滑平整,熔融热焓为228.1J/g。整理后的复合织物表面附着有微胶囊,织物的熔融热焓值随着整理液中微胶囊含量的增加而增大,且降温速率明显减缓,具有良好的蓄热调温功效。     

相变微胶囊/SMS智能调温织物的制备及性能研究

为了研究不同浓度相变微胶囊对整理织物调温性能的影响,首先以正十八烷为芯材,三聚氰胺-尿素-甲醛(MUF)树脂为壁材,采用原位聚合法合成三聚氰胺-尿素-甲醛/正十八烷微胶囊,并利用扫描电镜(SEM)对其形貌和粒径进行分析。然后,采用涂层工艺将不同浓度相变微胶囊整理到SMS织物上,形成相变调温织物,通过SEM、红外测温仪、织物透气量仪、织物强力仪等测试手段,探讨相变微胶囊整理对织物表面形貌、调温、透气性和力学性能的影响。结果表明:相变微胶囊呈球形,表面光滑,粒径分布均匀。经相变微胶囊整理后,织物的升降温速率均明显变缓,具有优良的蓄热调温功能;断裂强力和断裂伸长率均有提高。整理后智能调温织物虽透气性有一定程度的下降,但服用性未受到明显影响。     

蜜胺树脂/硬脂酸丁酯相变微胶囊的制备

以硬脂酸丁酯为芯材,蜜胺树脂为壁材,采用原位聚合法制备相变微胶囊.采用IR,ESEM及DSC对相变微胶囊进行了结构、形貌以及热性能表征,并讨论了乳化剂种类以及预聚体滴加速率对相变微胶囊形貌的影响.结果表明:微胶囊呈球形,平均粒径小于10μm.乳化剂采用TA与司班-80复配,复配质量比为5∶1,预聚体的滴加速率为0.8～1 2mL/min时微胶囊形貌最好.微胶囊相变潜热可达68.36J/g,并且相变微胶囊经反复发生相变过程,质量损失小,相变储热效果明显.     

石墨烯相变调温抗静电复合材料的制备与性能研究

为了制备相变调温抗静电复合材料,以正十八烷和正十六烷为芯材,密胺树脂为壁材,原位聚合法制备相变调温微胶囊,然后以浸轧工艺将其与石墨烯共同对涤棉织物进行整理。采用差示扫描量热法和扫描电镜等手段对相关性能进行测定。结果表明:经整理后的涤棉织物相对温度缓冲系数为1.16,熔融热为63.20J/g,凝固热为-62.56J/g,抗静电性能达到B级标准。     

蓄热调温石蜡/P(MMA-co-AA)相变微胶囊的制备及性能研究

采用界面聚合法制备了石蜡/P(MMA-co-AA)的相变储热微胶囊.采用光学显微镜、FT-IR、DSC、TGA、紫外分光光度计等对微胶囊进行了测试与表征.着重研究了芯壁比对热性能及渗透性能的影响,并对储热调温效果进行了评价.结果表明,微胶囊呈规则的球形,平均粒径为32μm,具有良好的热稳定性,相变温度为60℃,相变潜热...     

氧化石墨烯改性密胺树脂/石蜡相变微胶囊的制备及性能

通过原位聚合法制备了氧化石墨烯(GO)改性的密胺树脂(MF)/石蜡相变微胶囊。采用红外光谱、扫描电镜、差示扫描量热分析、热重分析等手段分析了相变微胶囊的微观结构及热性能,研究了GO含量对相变微胶囊形貌、包覆率和渗漏率的影响。研究结果表明,制备的相变微胶囊为较规则的球形,GO的加入并没有改变壁材或芯材的化学结构;GO改性使相变微胶囊的包覆率由91.39%提高至94.08%,增大了相变微胶囊的储能能力;GO改性相变微胶囊的防渗性能得到大幅提升,250h时的渗漏率由9.43%下降至2.68%,下降了71.6%,相变微胶囊的使用寿命得到提高。     

新型相变储能微胶囊的制备与表征

蓄热调温纺织品是一种新型的智能纺织品,大多采用相变材料(PCM),要求PCM稳定性好、安全、无毒副作用,并有较好的可后整理性能.采用新型微胶囊成形方法,利用核壳聚合原理,制备出直径≤2μm、包覆容量为46%的相变储能微胶囊,并用扫描电镜(SEM)和热分析(DSC)对微胶囊形状及热性能进行表征,为解决智能纺织品用相变材料及其实用化提供了新途径.     

氧化石墨烯改性密胺树脂/石蜡相变微胶囊的制备及性能EI北大核心CSCD

通过原位聚合法制备了氧化石墨烯(GO)改性的密胺树脂(MF)/石蜡相变微胶囊。采用红外光谱、扫描电镜、差示扫描量热分析、热重分析等手段分析了相变微胶囊的微观结构及热性能,研究了GO含量对相变微胶囊形貌、包覆率和渗漏率的影响。研究结果表明,制备的相变微胶囊为较规则的球形,GO的加入并没有改变壁材或芯材的化学结构;GO改性使相变微胶囊的包覆率由91.39%提高至94.08%,增大了相变微胶囊的储能能力;GO改性相变微胶囊的防渗性能得到大幅提升,250h时的渗漏率由9.43%下降至2.68%,下降了71.6%,相变微胶囊的使用寿命得到提高。     

新型相变储能微胶囊的制备与表征

蓄热调温纺织品是一种新型的智能纺织品，大多采用相变材料（PCM），要求PCM稳定性好、安全、无毒副作用，并有较好的可后整理性能。采用新型微胶囊成形方法，利用核壳聚合原理，制备出直径≤2μm、包覆容量为46％的相变储能微胶囊，并用扫描电镜（SEM）和热分析（DSC）对微胶囊形状及热性能进行表征，为解决智能纺织品用相变材料及其实用化提供了新途径。     

核壳结构吸水性树脂的制备及性能研究

采用饥饿态半连续加料方法,对反相悬浮聚合制备核壳结构聚丙烯酸钠高吸水性树脂进行了研究。结果表明,该法制备的产品各项性能均优于溶液聚合法和一般反相悬浮聚合法制备的产品。     

Preparation and characterization of LiNiVO4 powder and non-stoichiometric LiNixVyOz films

Inverse spinel type structured oxide, LiNiVO₄, was synthesized by using solid-state method and the crystalline powder was characterized by Rietveld refinement and X-ray photoelectron spectroscopy. Non-stoichiometric lithium nickel vanadate thin films were prepared by physical vapour deposition technique. The amorphous films were characterized by Rutherford back-scattering spectroscopy (RBS), nuclear reaction analysis (NRA), Auger electron spectroscopy (AES), X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analytical methods. Films crystal growth at various temperatures was also studied by XRD and SEM. The HRTEM analysis of sputtered film shows nanocrystalline domains of NiO and LiNiVO₄ phases with characteristic lattice parameters of the host compound and the results correlate well with the XRD data. Electrochemical properties of the films were discussed.     

Optical and electrical H/sub 2/- and NO/sub 2/-sensing properties of Au/In/sub x/O/sub y/N/sub z/ films

In this paper, we describe the optical and electrical gas-sensing properties of In/sub x/O/sub y/N/sub z/ films with an ultrathin gold promoter overlayer. We have fabricated In/sub x/O/sub y/N/sub z/ films with a nanocrystalline porous structure by RF-sputtering in Ar/N/sub 2/ followed by an annealing process. Gold particles with 20-30-nm diameter have been formed on top of the In/sub x/O/sub y/N/sub z/ films by dc sputtering and an annealing process. We have investigated the optical H/sub 2/and NO/sub 2/-sensing properties (change of absorbance) and also the electrical sensing effect (change of electrical resistance) for these two gases. A combined optical/electrical sensor for H/sub 2//NO/sub 2/ is proposed.     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Preparation and investigation of VOx thin films of n- and p-types

In this work we present first results on the synthesis of vanadium oxide semi-transparent conducting thin films of p- and n-types. The films were deposited by thermal evaporation method in vacuum, on: silicon, glass, sapphire, and gold substrates. Temperature of substrate during deposition was set around 250 °C. As deposited films were of a p-type of conductivity. Thermal annealing at 420 °C of as-deposited films in air at atmospheric pressure resulted in a change in the conductivity type.Optical, electrical and thermal properties of the deposited films were studied. The topography of the films was studied using AFM microscope. P-N structures were created using VO_x films on silicon and glass substrates. Electrical measurements had shown a non-linear behaviour of the samples.     

Fabrication and characterization of NiO/ZnO/ITO p-i-n heterostructure

Transparent oxide semiconductors (TOSs) are promising materials for a variety of optoelectronic applications such as UV detectors. While several TOS-based p-n and p-i-n diodes have been recently reported, the high reverse dark current still poses a major issue. In this work, we report on a NiO/ZnO/ITO p-i-n heterostructure with reduced dark current level suitable for practical applications. Ion beam-assisted e-beam evaporation was used to deposit both p-type NiO and intrinsic ZnO layers, while a conventional sputtering system was used to prepare the ITO layer. Samples with sputtered ZnO layer were also fabricated for comparison. The diodes demonstrated clear rectifying I-V characteristics with a current rectification ratio up to 10⁴ at bias voltages of ± 1 V. The lowest level of reverse dark current (∼ 10 nA/cm² at − 5 V) is observed in samples with ZnO deposited by ion beam-assisted e-beam evaporation. In comparison, diodes with sputtered ZnO layer show two orders of magnitude higher dark current. Analysis of the quasi-static J-V characteristics, including time dependence behavior, shows that the dark current can be attributed to thermal generation of charge carriers via deep defects states in the ZnO layer and charge injection from the contacts. Electrical and optical properties of the TOS films are presented and discussed along with deposition conditions and device performance.     

Effect of Bi/Pb ratio and annealing temperature onTc and formation of high-Tc phase in Bi-Pb-Sr-Ca-Cu-O superconductor

We studied the effect of Bi/Pb ratio and annealing temperature onT _c and formation of the high-T _c ; phase in Bi-Pb-Sr-Ca-Cu-O superconductor by the three-step reaction process. The optimum Bi/Pb ratio is about 1.80.3 and the optimum annealing temperature is about 845–855°C. It is found that a variate high-T _c phase existed at the higher annealing temperature. The zero-resistance temperature of the variate high-T _c phase decreased when the annealing temperature increased, although the phase is isostructural with the 110 K phase.     

Analysis of phenothiazine and its derivatives using LC/electrochemistry/MS and LC/electrochemistry/fluorescence

The on-line electrochemical conversion of phenothiazine and its derivatives after liquid chromatographic separation has been studied by mass spectrometry and fluorescence spectroscopy. In an electrochemical cell consisting of porous glassy carbon, the phenothiazines are readily converted to oxidized products, which can be detected by on-line fluorescence spectroscopy and mass spectrometry. The method allows rapid investigations on the electrochemical oxidation pathways, as demonstrated for phenothiazine itself. The phenothiazine derivatives are transferred into their strongly fluorescent sulfoxides. Based on this reaction, an LC/electrochemistry/fluorescence method was developed that allows for limits of detection between 5 x 10(-9) and 4 x 10(-8) mol/L and limits of quantification between 2 x 10(-8) and 1 x 10(-7) mol/L for the individual phenothiazines. The linear ranges comprised three decades starting at the limit of quantification.     

Properties of composite BxCyNz nanotubes and related heterojunctions

We review the stability and electronic properties of composite B_xC_yN_z nanotubes, including BN-, BC₂N- and B-doped carbon nanotubes. We show in particular that BC₂N systems are driven towards the segregation of pure C and BN sections. The same process of segregation into BC₃ islands is evidenced in the case of B-doped carbon nanotubes. These spontaneous segregation processes lead to the formation of quantum dots or nanotube heterojunctions with potential important technological applications.     

非晶Tb/Fe/Dy和Fe/Tb/Fe/Dy纳米多层膜磁性能及超磁致伸缩性能(英文)

研究非晶Tb/Fe/Dy(样品A)和Fe/Tb/Fe/Dy(样品B)纳米多层膜超磁致伸缩性能和磁性能.磁滞回线表明样品A的垂直磁各向异性而样品B有面向磁各向异性,样品B比样品A更好的磁性能.样品B有很好的低场超磁致伸缩性能,在外磁场为0.12T情况下样品B的超磁致伸缩性能是样品A的五倍,即从16ppm变为82ppm.     

Fabrication and electrical properties of Al/phenolsulfonphthalein/n-Si/AuSb structure

The current-voltage (I-V), capacitance-voltage (C-V) and capacitance-frequency (C-f) characteristics of Al/phenolsulfonphthalein (PSP)/n-Si/AuSb structure were investigated at room temperature. A modified Norde's function combined with conventional forward I-V method was used to extract the parameters including barrier height and the series resistance. The barrier height and series resistance obtained from Norde's function were compared with those from Cheung functions, and it was seen that there was a good agreement between the barrier height values from both method. It was also seen that the values of capacitance were almost independent of frequency up to a certain value of frequency, whereas at high frequencies the capacitance decreased quickly. The higher values of capacitance at low frequencies were attributed to the excess capacitance resulting from the interface states in equilibrium with the n-Si that can follow the alternating current (a.c) signal.