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以四水硝酸钙[Ca(NO3)2·4H2O]、磷酸氢二铵[(NH4)2HPO4]、十二水合砷酸钠[Na3AsO4·12H2O]为原料,在200℃下水热反应8h制得掺砷羟基磷灰石[Ca10(PO4)6-x(AsO4)x(OH)2].考察了反应液中不同砷含量对合成砷羟基磷灰石结构的影响.采用X射线衍射分析(XRD)、扫描电镜结合电子能谱分析(SEM/EDS)、傅立叶变换红外光谱分析(FTIR)等测试手段对产物的晶相、化学组成和形貌进行分析.结果表明:As取代部分磷(P)进入羟基磷灰石的晶格中,没有改变其晶体结构,但羟基磷灰石的晶胞参数发生了变化,随着As含量的增加,砷羟基磷灰石的晶体尺寸呈增大的趋势,晶体形状为短棒状. 相似文献
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以FeCl3·6H2O,FeCl2·4H2O为原料,通过水热法制备磁性四氧化三铁粒子.并以合成的磁性四氧化三铁粒子,Na3PO4 ·12H2O和Ca(NO3)2 ·4H2O为原料,在80 ℃恒温水浴条件下,采用共沉淀法制备磁性羟基磷灰石.通过X射线衍射(XRD),红外(FTIR)对制备样品的结构和化学组成进行表征,并用Materials Studio 4.0(MS)模拟软件,对制备的样品进行结构分析.结果表明,四氧化三铁取代羟基磷灰石中平行于c轴的OH进入羟基磷灰石晶格中,从而引起羟基磷灰石 (210)和(212)晶面发生变化,但所得的样品具备羟基磷灰石的晶体结构特征和化学组成. 相似文献
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层状溶致液晶中纳米羟基磷灰石的合成 总被引:3,自引:0,他引:3
在一定的pH值条件下,将Ca(NO3)2和(NH4)2HPO4分别溶于C34H62O11(聚乙二醇辛基苯基醚)/C8H17OH/H2O体系层状溶致液晶溶剂层中,混合并经陈化即可在溶剂层中生成具有一定微观形貌的羟基磷灰石纳米粒子(HA),其直径可以达到10 nm,长度在100 nm以下.产物在不同温度下焙烧,分别用FTIR,XRD和TEM等对产物的结构及形貌进行分析表征.对不同反应物浓度条件下所得HA的微观形貌进行分析对比,并提出了改善团聚的有效措施. 相似文献
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论述了共沉淀法制备羟基磷灰石粉体的过程,以Ca(OH)2和H3PO4为原料,控制适当Ca/P的比、H3PO4的滴加速率、溶液的pH值、反应温度和时间以及煅烧温度等条件,采用电子显微镜、X射线衍射仪和红外光谱仪对目标产物的结构和粒度进行了分析。结果表明,溶液在40℃下反应6 h,煅烧温度为900℃,产物用无水乙醇洗涤可获得纯度、结晶度、颗粒度和分散性均较好的羟基磷灰石粉体。 相似文献
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采用共沉淀法,以Ca(NO3)2.4H2O和(NH4)2HPO4为反应体系,分别添加硫酸软骨素、琼脂糖和天门冬氨酸作为模板剂,引入生物矿化作用,合成了不同形貌的纳米羟基磷灰石粉体。采用X射线衍射法和透射电子显微镜分析了合成产物的晶相结构和粉体形貌。结果表明3种模板剂作用下合成的样品都是纯相的纳米羟基磷灰石。在添加硫酸软骨素(≥0.2%,质量分数,下同)或琼脂糖(1.0%)的条件下,当反应体系钙磷比(钙与磷的摩尔比)为1.67,反应pH值为11.0,纳米羟基磷灰石的形貌分别是梭形短片状和纤维丝状。当天门冬氨酸浓度为2.0%时,若反应体系钙磷比为1.62,反应pH值为10.0,其形貌为类球状;若反应体系钙磷比为1.72,反应pH值为8.5,其形貌则为片状。 相似文献
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纳米羟基磷灰石的超声波辅助水热合成及其表征 总被引:1,自引:0,他引:1
以CaCO3和Ca(H2PO4)2.H2O[钙磷比n(Ca)/n(P)=1.67]的混合物为前驱体,在超声波辅助下,水热法制备了纳米羟基磷灰石(n-HAP)。利用X射线衍射仪、透射电子显微镜、傅里叶红外吸收光谱仪对其进行了表征。分析了pH值、反应温度、水热合成时间以及超声波频率等对羟基磷灰石纳米晶体结构和形貌的影响。结果表明,随着水热合成温度的提高、时间的延长,有利于n-HAP晶体发育完整;提高前驱物pH值可以显著促使产物粒径变小,当水热合成温度为200°C,反应时间8 h,pH=11时,n-HAP为横向尺寸在40~50 nm的六方柱状晶体。红外谱图分析表明,有少量的CO32-进入n-HAP晶体,此种方法制备的羟基磷灰石在结晶形态、组成、结构上更与人骨接近,更适合作为生物医学材料。 相似文献
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以五氧化二磷、无水乙醇、硝酸钙为原料,通过溶胶-凝胶法制备羟基磷灰石涂层.选用2mm/s的速度浸渍提拉载玻片,在载玻片上进行涂膜,经60℃干燥后在650℃保温3h,可在载玻片上得到羟基磷灰石涂层.研究结果表明:制备溶胶合适的配比为nCa(NO3)2·4H2O:nP2O5=10:3,即Ca/P原子比=5:3(约等于1.67). 相似文献
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纳米羟基磷灰石(nano-HAP)的制备工艺在有效控制晶形、尺寸、稳定性等方面尚不成熟,阻碍了它的应用发展。采用化学沉淀法,以Ca(NO3)2.4H2O和(NH4)2HPO4为主要原料合成nano-HAP,在一定工艺条件下通过添加表面活性剂改善制备效果,用XRD、TEM、IR等检测手段表征产物,研究了聚乙二醇-400、聚乙二醇-6000、聚乙烯醇和吐温-80等4种表面活性剂对产物的形貌、粒径、结晶度、分散性等的影响。结果表明:在实验条件下,添加聚乙二醇-400的制备效果最佳,可得平均粒径约为20 nm、结晶度高、稳定性好的高纯nano-HAP针状晶体。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation
of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from
the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out. 相似文献
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The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003 相似文献