超细碳酸钙生产中碳化工序控制因素的分布

就超细碳酸钙工业生产中碳化工序一些影响产品粒径及晶形的因素进行分析，并从中选择最佳的工艺控制条件。     

炸药结晶晶形控制技术研究进展

介绍了HMX、RDX等炸药在传统晶形控制方面的研究进展,阐述了超临界结晶技术、超声波的引入和添加晶形控制剂在炸药晶形控制中的作用机理及其在炸药中的研究进展。     

晶形控制剂在苦味酸钾合成中的应用

为确定苦味酸钾(KPA)中晶形控制剂的用量,选择官能团中含有活泼H原子的非离子型表面活性剂作为KPA的晶形控制剂,研究了其水溶液的表面张力和临界胶团浓度.通过对在不同条件下得到的KPA进行XRD研究,确定了KPA晶体成长过程中对晶体形状影响较大的晶面.结果表明,通过加入晶形控制剂能显著降低最强衍射峰,影响KPA的主导晶面,对KPA晶体的晶形起到控制作用.通过对晶形控制剂表面张力的测量,选择合适的晶形控制剂和用量,能够制得颗粒状KPA晶体.     

炸药纳微米结晶品质控制技术研究

为研究纳微米炸药的结晶习性及晶形控制技术,结合经典结晶理论和无序结晶理论,从晶体生长热力学及动力学角度研究纳微米炸药重结晶的特性。通过控制溶剂—非溶剂法细化炸药过程中晶体生长的条件,介入模板粒子,均可有效地控制纳微米炸药粒子的晶形及粒径。     

粒径和晶形对ε-HNIW感度的影响

采用溶剂-反溶剂重结晶工艺制备出3种不同粒径和晶形的ε-型HNIW,用激光粒度仪和偏光显微镜-扫描电镜(SEM)对样品的粒度和形貌进行表征,并测试了撞击、摩擦感度和热分解性能。结果表明,随着粒径的减小,HNIW的撞击感度显著降低,热稳定性缓慢降低,但摩擦感度增加;粒度分布越宽,撞击感度与大颗粒感度值相当,摩擦感度与细颗粒感度值相当;粒径分布窄时,颗粒晶形越规整,撞击和摩擦感度越低,热稳定性越好。影响HNIW撞击、摩擦和热分解的主要因素依次是粒径、粒度分布和晶形。     

浅析超细碳酸钙的几项主要指标

根据对超细碳酸钙制备研究和应用推广试验的体会和经验，阐述了对超细碳酸钙粒径、晶形、比表面积、吸油值、主含量等几项指标的认识，指出超细碳酸钙的重点发展方向是专用化、系列化、多品种化、功能化。应根据用途的不同，对粒径大小、晶体形状、比表面积、吸油值、主含量等提出具有针对性、各具特色的要求。     

混合碱液法生长氧化锌晶体的晶形、表面形貌及光致发光性质(英文)

以氢氧化钠和氢氧化锂作为助熔剂,采用常压混合碱液法成功生长了各种形貌的ZnO晶体。以Bravais-Friedel-Donnay-Harker法则为指导,获得了ZnO晶体的几种理论结构晶形;在考虑晶体内部结构和生长实验中外部生长条件下,得到了晶体的实验晶形。采用光学显微镜、扫描电子显微镜和原子力显微镜对六方片状晶体的表面形貌进行了研究。结果表明:晶体的理论结构晶形和实验晶形吻合良好;晶体具有二维螺旋生长的机制。此外,晶体在325 nm光激发的室温光致发光光谱显示,在380 nm处存在1个强的紫外发射峰和位于652 nm处的弱且窄的红光发射峰,说明生长的六方片状ZnO晶体结晶质量优良。     

纳米TiO_2晶形对合成革用阴离子水性聚氨酯性能的影响

用纳米微粒直接分散法制备了纳米TiO2/水性聚氨酯复合膜,考察了纳米TiO2晶形(金红石型和锐钛矿型)对复合膜性能的影响。黏度分析表明,金红石型纳米TiO2增黏效果较好。粒径、SEM和AFM分析表明,添加纳米TiO2不影响聚氨酯乳液的稳定性,复合粒子仍然以纳米级存在,两种晶形的纳米TiO2均能均匀分散于复合膜中,并对复合膜表面的平整度无影响;接触角和卫生性能测试表明,两种晶形的复合膜都没有防水性,添加锐钛矿型纳米TiO2复合膜的卫生性能较好;机械性能和抗菌性测试表明,添加锐钛矿型纳米TiO2的复合膜具有更好的力学性能和抗菌性能。     

铵浸法由白云石制备高纯度碳酸钙和氧化镁

通过对煅烧后的白云石中所含的氧化钙和氧化镁，分别采用氯化铵溶液和硫酸铵溶液进行浸提，使其中的钙、镁得到较好的分离。氯化钙浸提液用碳化法在不同的晶体控制剂的作用下，制备出了不同粒径的球形和立方体形的高纯度碳酸钙。硫酸镁浸提液采用碳酸铵沉淀法制备出了高纯度高活性的氧化镁。并对反应过程中的温度、浓度、晶形控制剂的种类等影响因素进行了研究，确定了反应的最佳条件，提高了资源的利用率。     

纳米碳酸钙合成研究

采用传统的鼓泡碳化法，用50℃热水快速消化石灰，精制石灰乳冷却到20℃以下碳化，制备纳米碳酸钙。研究了碳化过程中粘度和pH的变化，以及陈化和添加晶形控制剂对纳米碳酸钙晶形的影响。通过陈化一二次碳化法制备了晶形比较完整的纳米碳酸钙，从而降低了纳米碳酸钙的吸油量。通过添加不同的晶形控制剂，可以制备立方体形、立方柱形、棒状和菱形纳米碳酸钙。     

The influence of Li-based catalysts/additives on cBN crystal morphologies synthesized under HPHT

In this paper, various cubic boron nitride (cBN) crystal morphologies were synthesized using hexagonal boron nitride (hBN) as raw materials and Li₃N, LiH, and LiNH₂ as catalysts/additives under high pressure and high temperature (HPHT).These crystal shapes contain thick-plate, spherical, octahedral or hex-octahedral, flat cone and flaky hexagonal morphologies. The reasons of various crystal shapes synthesized can be summarized as follows: various catalysts/additives take on distinct properties under HPHT, which have crucial effects on the cBN crystal morphologies synthesized. Catalyst Li₃N tends to grow cBN with thick-plate morphology, catalyst LiH would induce the growth of cBN tending to integrated octahedral morphology, and catalyst LiNH₂ would play diverse roles for cBN crystal morphologies in various systems.     

Thermal and morphological studies on γ‐Fe2O3 polystyrene composites and the affect of additives

γ‐Fe₂O₃polystyrene (PS) composite films were prepared by a gel‐casting technique to obtain monodisperse composite films. To understand the effect of additives on the prepared composite films, additives such as rice husk ash and thiourea were made to disperse into the PS matrix. The as‐prepared γ‐Fe₂O₃ PS composite films, along with their additives, were subjected to characterization and study by X‐ray diffraction, scanning electron microscopy, thermal, IR, and dielectric measurement techniques. These studies showed monodisperse and chemically homogenous composite films with an increase in thermal behavior. An interesting self‐assembly of rod‐like nanoparticles of γ‐Fe₂O₃ particles into the polymer matrix, which formed spherical packets, was observed for the γ‐Fe₂O₃PS composite film. The electrical behavior of these films was interesting, as some showed conduction whereas others showed an increase in dielectric behavior. This nature was explained by the dielectric measurements. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 778–788, 2004     

Effect of additives on release profile of leuprolide acetate in an in situ forming controlled‐release system: In vitro study

In situ forming drug delivery system is prepared by phase inversion technique using poly (D ,L ‐lactic‐co‐glycolide) and leuprolide acetate dissolved in N‐methyl‐2‐pyrrolidone. The effects of ethyl heptanoate and glycerol additives are important determinant as rate modifying agents on the drug release kinetics in biodegradable in situ forming porous systems of poly(D ,L ‐lactide‐co‐glycolide) (PLGA) in N‐methyl‐2‐pyrrolidone (NMP). The release performance and porous structure morphology are investigated by scanning electron microscopy and UV–visible spectroscopy techniques to study the effect of additives. The experimental results exhibit the crucial role of ethyl heptanoate and glycerol at different loadings (1, 3, and 5% w/w) on release profile of leuprolide acetate loaded on poly(D ,L ‐lactide‐co‐glycolide)hydroxylated (PLGA‐H). Both additives at different concentrations reduce the burst effect, while increasing duration of drug release. Ethyl heptanoate, however, shows stronger effect than glycerol. The results of morphological studies show that ethyl heptanoate reduces the porosity of the polymer surface and interconnected tear‐like structures of the bulk disappear while the sponge‐like structures are observed. In this system glycerol reduces the surface porosity intensively, while the interconnected tears change into channel‐like structures. Therefore, morphological results confirm the effect of additives on leuprolide release profile. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Measurement of Polarization Parameters Impacting on Electrodeposit Morphology. II: Conventional Zinc Electrowinning Solutions

A new technique for measuring effects of polarization modifiers on nucleation potential and plating potential in polycrystalline electrodeposition was presented in Part I of this series (J. Appl. Electrochem. 32(2002) 1101–1107). This paper presents the results of application of the proposed technique to conventional zinc electrowinning. Strong correlations are observed between deposit metallographic structure and the polarization characteristics. The results demonstrate that the new galvano-staircase method can be used to predict long-term (i.e. substrate-independent) deposit morphology, based on relatively rapid electrochemical measurements. With sufficient knowledge of the system, beneficial changes can be specified for additives, particularly long term averages. However even interactive, control on an hourly basis should be possible.     

Optimizing the incorporation of silica nanoparticles in polysulfone/poly(vinyl alcohol) membranes with response surface methodology

The addition of silica nanoparticles and poly(vinyl alcohol) (PVA) to polysulfone (PSF) membranes was used to modify the membrane morphology and enhance membrane performance. The central composite design of the response surface methodology was used to predict the maximum permeability and real salt rejection (R_real) of the PSF membranes. The factors affecting the permeability and R_real values of the PSF membranes were the silica (0–12 wt % PSF) and PVA (0–2 wt % PSF) contents. The optimized responses, membrane permeability, and R_real obtained experimentally were 61.9260 L m⁻² h⁻¹ bar⁻¹ and 97.5850%, respectively, with deviation from the predicted values of 34.72 and 15.84%, respectively. In the further characterization, the contact angle results showed that PVA was important in stabilizing the nanoparticle surfaces to prevent agglomeration in the polymeric matrix. The tensile strength test confirmed that the addition of silica nanoparticles improved the mechanical strength of the PSF membranes. However, the addition of PVA had a weakening effect on the mechanical strength of the PSF membranes. The addition of silica nanoparticles and PVA affected the typical asymmetric structures of the PSF membrane less, as shown in the scanning electron micrographs. This may have been due to the good incorporation of additives in the PSF membranes, as observed from the energy‐dispersive X‐ray and Fourier transform infrared spectroscopy results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 Liver Transpl, 2011. © 2011 AASLD.     

Effect of PEG additives on properties and morphologies of membranes prepared from poly(2,6‐dimethyl‐1,4‐phenylene oxide) by benzyl bromination and in situ amination

This study investigated the effect of PEG additive on the structure formation and permeation properties of membranes. The membranes were prepared from a bromomethylated poly(2,6‐dimethyl‐1,4‐phenylene oxide)/chlorobenzene/ethanol system using the phase inversion method with PEG as an additive. As expected, PEG with a fixed molecular weight (e.g., PEG 600) acted as a pore‐forming agent, and membrane porosity increased as the PEG content of the casting solution increased. However, when the PEG content was fixed, the effect of PEG on the membrane properties and morphology was largely dependent on its molecular weight. It was found that when the molecular weight of PEG was less than 800, it acted as a pore former, but when the molecular weight of PEG was more than 1000, the pore size and porosity of the resulting membrane decreased. These results can be explained by the membrane‐forming system's thermodynamic and kinetic properties, which can be assessed by coagulation value and viscosity. Furthermore, the membranes were characterized for pure water flux and rejection of solute and by SEM observation. The filtration results agreed well with the SEM observations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2414–2421, 2005     

可溶性添加剂对碳酸钙晶型及形貌控制的研究进展

碳酸钙的晶型及形貌直接影响它的性能,涉及到众多的应用领域.本文结合近几年碳酸钙合成的研究进展,综述了可溶性添加剂对碳酸钙晶型及形貌的影响;重点介绍了在碳酸钙的制备过程中常用的可溶性小分子、可溶性大分子及水溶性表面活性剂三类可溶性添加剂对碳酸钙晶型及形貌的影响,并对其作用机理进行了初步探讨,为碳酸钙的工业应用提供了理论指导.     

Studies on γ‐Fe2O3–high‐density polyethylene composites and their additives

γ‐Fe₂O₃–high‐density polyethylene (HDPE) composite films are prepared by a gel‐casting technique. To understand the effect of additives, rice husk ash and thiourea are made to disperse in the HDPE matrix to obtain the composite films with additives. The as‐prepared γ‐Fe₂O₃–HDPE composite films with their additives are subjected to characterization and study through X‐ray diffraction, thermal, scanning electron microscopy, and dielectric measurements. The results are qualitatively treated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1527–1533, 2004     

Studies on polymer latex films: II. Effect of surfactants on the water vapour permeability of polymer latex films

Poly(butyl methacrylate) films have been prepared from surfactant-free latices which had post-added commonly used latex stabilisers. Water vapour transmission rates were used to study film permeability in relation to morphology, which was also studied by freeze fracture replication transmission electron microscopy. The extent of latex coalescence depended upon the chemical nature of the stabiliser employed and at monolayer coverage was not necessarily deleterious to the barrier properties of the films.