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以糯米浆为有机调控物质,二氧化碳提供碳源仿生制备出多种形貌的碳酸钙晶体.探索了矿化时间、钙离子浓度对碳酸钙晶体形貌和晶型的影响.采用扫描电子显微镜(SEM)、傅里叶红外光谱仪(FT-IR)和X射线衍射仪(XRD)对制备的碳酸钙表观形貌及结构进行表征.扫描电镜结果表明:以糯米浆为有机调控物质,钙离子浓度和矿化时间对碳酸钙晶体的形貌有一定的影响;XRD及FT-IR图谱表明制备的碳酸钙晶型为方解石和球霰石. 相似文献
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以聚乙烯醇(PVA)和聚苯乙烯磺酸钠(PSSS)分别与十六烷基三甲基溴化铵(CTAB)组成混合模板,在CaCl2、Na2CO3体系中调控合成CaCO3晶体.考察了不同CTAB浓度及结晶温度对碳酸钙晶体的影响.通过扫描电子显微镜(SEM)、红外光谱(FT-IR)及X射线衍射(XRD)等技术对晶体的形貌和结构进行了表征,并对不同形貌碳酸钙的形成机理进行了探讨.结果表明:在PVA和CTAB模板中,5℃为方解石椭球状聚集体,25℃时为菊花状、立方状的方解石和球霰石的混晶,90℃时得到针状文石晶簇.以PSSS和CTAB模板调控下的碳酸钙,5℃时为球状的方解石和球霰石的混晶,25℃为颗粒均匀的球形球霰石,90℃时得到了花朵状文石.不同形貌及晶型碳酸钙的生成源自聚合物与CTAB组成复合物结构的差异. 相似文献
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根据生物矿化原理,通过CO2的缓慢扩散,在硫酸软骨素(CSB)/L-谷氨酸二元体系中,与富集在有机/无机界面钙离子的结合,合成了不同形貌的碳酸钙.系统地研究了室温下各种因素对碳酸钙晶体形貌和晶型的影响.产物用XRD、SEM和FT-IR进行表征,FT-IR和XRD分析表明:所得的晶体为方解石的晶型,SEM表明体系中CSB的浓度,pH值,CSB/L-谷氨酸的浓度比对碳酸钙形貌起着重要作用.通过改变实验条件得到了椭球型,哑铃型等形貌碳酸钙晶体,并对其可能的形成机理进行了分析. 相似文献
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以硫酸镍(NiSO4·7H2O)为镍源,尿素为pH调节剂,采用表面活性剂辅助的水热法成功制备出了枝状Ni2P微晶.X-射线粉末衍射(XRD)、场发射扫描电子显微镜(FESEM)和紫外-可见分光光度计(UV-Vis)对所得产物进行表征.结果表明,所得产物为纯六方相的磷化镍(Ni2P),其形貌为有明显主干和高度有序分支的树枝状结构.其中,表面活性剂(SDBS)在枝状Ni2P微晶的整个生长过程中起到模板作用.对所得产品光催化性能研究发现,枝状Ni2P微晶能够很好地光催化降解亚甲基蓝溶液,降解率较高. 相似文献
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Dual mineralization on a porous membrane was carried out using an electrochemical approach. The porous membrane was interposed between a pair of glass cells, and calcium chloride (CaCl2) and sodium hydrogenphosphate (Na2HPO4) solutions were separately injected into the cells. After inserting platinum electrodes into the cells, an alternating current with a sine waveform was applied for a given period of time. The resulting membrane was removed from the glass cells and rinsed with ultrapure water. The minerals formed on the membrane were analyzed by using spectroscopic methods such as scanning electron microscopy (SEM), infrared (IR) spectroscopy, and X-ray diffraction (XRD) and identified to be dicalcium phosphate and hydroxyapatite. It was noted that dicalcium phosphate formed on one side of the membrane, while hydroxyapatite was formed on the other side. Thus, dual mineralization could be successfully achieved on both sides of the porous membrane under an alternating current. This process of dual mineralization is very useful for the formation of versatile organic–inorganic hybrids and also for the regulation of the polymorphs on either side of a membrane. 相似文献
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The influence of calcium to phosphate (Ca/P) molar ratio on the extent of mineralization in a model (poly)acrylamide gel was investigated under simulated physiological conditions. We hypothesized that the optimal growth of hydroxyapatite crystals will take place at the stoichiometric Ca/P molar ratio of 1.67. Phosphate ions were incorporated during the polymerization of the gel and mineralization was initiated by submersion of the gel in calcium acetate solution. Ca/P molar ratios were varied in the range of 0.5–5.0. The mineralized gel was characterized by Raman spectroscopy, scanning electron microscopy (SEM) and mineral weight fraction analysis via ashing. Raman spectra captured across the bulk of the gels indicated the presence of mineral at the core section. The phosphate symmetric stretching peak was observed in the range of 955–960 cm−1 which is characteristic of hydroxyapatite. SEM images showed that crystals formed at Ca/P=2.0 were denser and larger in size than at other molar ratios. In agreement with SEM images, the dry weight fraction of mineral reached the maximum at the molar ratio of 2.0 and the extent of mineralization rapidly declined as the molar ratio diverged from 2.0. Also, the crystallinity of the mineral was optimum at the molar ratio of 2.0. Thus it appears that for effective mineralization, the molar ratio of the two ions needs to be in excess of the stoichiometric requirement, suggesting that ions are expended in processes other than the formation and growth of hydroxyapatite crystals. Therefore, the optimal level of mineralization in biomimetic-based growth of calcium phosphate crystals in sol–gel environment requires consideration of a range of molar ratios as opposed to using the molar ratios corresponding to that of the crystal species intended to grow. 相似文献
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Water soluble matrix (WSM) was extracted from pearls originated from Hyriopsis cumingii in Zhuji, Zhejiang province, China. WSM was regarded as an additive in mineralization experiments in order to study the effect of WSM on CaCO3 crystallization. The experiments were carried out at different pH and temperatures by gas diffusion method and solution titration method, respectively. Scanning electron microscopy (SEM) and Raman spectroscopy (Raman) were used as powerful techniques to analyze the co-effect of pH value, temperature and WSM on crystal growth of CaCO3. The results showed that WSM could induce aragonite at different pH values of mineralization solution, and the pH value had remarkable influence on morphology of calcite rather than aragonite due to distinct supersaturation and ionic strength related to various pH values. At different solution temperatures, WSM had little effect on crystal growth of calcium carbonate while the solution temperature had notable effect on polymorph and morphology of CaCO3 crystals. This work can provide some basic information for the polymorph and morphology control of calcium carbonate. 相似文献
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A modified crystallization process using current‐induced joule heating under vacuum is presented. A thin layer of high temperature resistant tungsten was sputtered on the amorphous silicon as the conducting and annealing medium. The thin film thickness was measured by α‐stepper. The high current density provided effective means in crystallizing the amorphous silicon layer. The crystalline morphology was studied by scanning electron microscopy (SEM) after Secco‐etch, transmission electron microscopy (TEM), and x‐ray diffraction (XRD), under different annealing conditions. The grain size was controlled in the range of 0.1‐0.5 μm and could be increased with annealing time. No tungsten silicide was found. Some defects were formed due to electron‐migration effect near the electrodes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Two kinds of hollow twinning ZnO microstructures were synthesized through a simple hydrothermal method without additional templates or any surfactants. Dumbbell‐like and shuttle‐like ZnO microstructures with hollows were obtained by changing the materials source. The products were characterized by X‐ray power diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high‐resolution transmission electron microscopy (HRTEM). It was found that different precursors may be responsible for the formation of two different morphologies. Based on the time‐dependent experiments, we investigated the growth process of these hollow twinning structures and found the “Ostwald‐ripening process” played an important role. The interesting point of this growth process was that the interface of the two twinning structure performed as the activate center where the Ostwald‐ripening process carried out. We also investigated the luminescent properties of the as‐obtained products by photoluminescence (PL) spectroscopy. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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In the current paper we designed a simple glucose reduction route for synthesis of sheet‐like Cu dendrites on a high yield, using CuSO4 as the starting material. The reaction was carried out at 180 °C for 18 h in the absence of any structure‐directing agent. The product was characterized by X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and electron diffraction (ED). Some factors influencing the shapes of Cu microcrystals, including the reaction temperature, time, and the concentration of the starting CuSO4, were investigated. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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以氧化镁和二氧化硅为原料,采用水热法在不同反应时间下合成了一系列纤蛇纹石纳米管.利用X-射线衍射(XRD)、红外光谱(IR)、扫描电镜(SEM)、高分辨透射电镜(TEM)等手段研究了纤蛇纹石晶体生长和晶体结构随反应时间的变化过程.X-射线衍射和红外光谱分析表明:随着反应时间的增加所得到的纤蛇纹石样品结晶逐渐完善、卷曲程度逐渐增大;电镜分析表明:获得的纳米管的外径和内径分别为15~40 nm和6~9 nm,长度为50~300 nm,出现了双层管式结构.根据实验结果,结合负离子多面体配位生长理论对纤蛇纹石的生长机理研究表明,纤蛇纹石是由片状逐渐卷曲成管状的. 相似文献
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Zhenyuan Ji Jiquan Sun Xiaoping Shen Guoxing Zhu 《Crystal Research and Technology》2013,48(11):1022-1026
A simple and general microwave route is developed to synthesize nanostructured ZnO using Zn(acac)2·H2O (acac = acetylacetonate) as a single source precursor. The reaction time has a great influence on the morphology of the ZnO nanostructures and an interesting spindle‐like nanostructure is obtained. The microstructure and morphology of the synthesized materials are investigated by X‐ray diffraction (XRD), scanning electron microscopy (SEM), field‐emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). It is found that all of them with hexagonal wurtzite phase are of single crystalline structure in nature. Ultraviolet–visible (UV‐vis) absorption spectra of these ZnO nanostructures are investigated and a possible formation mechanism for the spindle‐like ZnO nanostructures is also proposed. 相似文献
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Abstract A biomimetic supported liquid membrane (SLM) system was employed to control the morphology of manganese carbonate. Some interesting
morphologies including nanowire/hollow spheres/twinborn spheres could be readily generated by using EDA (ethylenediamine),
EDTA (ethylenediaminetetracid) or NTA (nitrilotriacetic acid) as cooperative modifiers in the mineralization process, under
the conditions of pH 10, 0.01% of crystal modifier and ambient temperature. The key factor in this system was the cooperative
template effect of SLM and the crystal modifiers. The clarification of fantastic morphogenesis of them could be valuable for
understanding of biomineralization processes.
Index Abstract A biomimetic supported liquid membrane (SLM) system was employed to control the morphology of manganese carbonate. Some interesting
results including nanowires/hollow spheres/twinborn spheres/etc. could be readily generated by using EDA (ethylenediamine),
EDTA (ethylenediaminetetracid) or NTA (nitrilotriacetic acid) as cooperative modifiers in the mineralization process. The
clarification of fantastic morphogenesis of them could be valuable for the understanding of biomineralization processes..
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以正硅酸乙酯(TEOS)和Sr(NO3)2为原料,采用溶胶-凝胶法制备出高纯度的不规则形状硅酸锶粉体。利用X射线衍射仪、扫描电镜和差热-热重分析仪等研究了锶盐种类、水硅比和pH值对硅酸锶粉体的相结构、形貌和纯度的影响,探讨了溶胶-凝胶法制备硅酸锶粉体的反应过程与机理。结果表明:溶胶-凝胶法制备Sr2S iO4粉体的最佳工艺条件为:锶盐选择Sr(NO3)2,n(H2O)∶n(TEOS)∶n(EtOH)为24∶1∶5,pH值为3~4,煅烧温度为800℃。与传统高温固相反应法相比,该方法大幅度降低了煅烧温度,提高了粉体的纯度,同时能够减小最终获得的硅酸锶粉体粒径。 相似文献