微波高温加热法分解贝壳制取葡萄糖酸钙

贝壳中含有90%以上的碳酸钙,但没有得到充分利用,往往将其当作废物扔掉,不仅浪费了资源,而且对环境的污染也越来越严重。国内利用贝壳加工饲料添加剂,不仅产量较少,产品的附加价值也不高。本文介绍了以贝壳为原料,采用微波高温加热的方法将贝壳分解成氧化钙,并进一步将氧化钙制备成葡萄糖酸钙的过程;详细说明了实验原理、操作方法、最佳煅烧温度以及煅烧时间等条件的选择。结果表明,采用微波高温加热的方法,在1 000℃、煅烧1 h可以得到高纯CaO。对其深加工可制成优质葡萄糖酸钙,解决了环境污染问题,并带来了经济效益。     

超高碱值润滑油清净剂的合成研究

以重烷基苯磺酸、氢氧化钙、氧化钙和二氧化碳为原料,甲醇为促进剂,甲苯为溶剂,采用多步碳酸化法制备超高碱值的烷基苯磺酸钙,考察了促进剂的种类、二氧化碳的通气速率、甲醇的用量等对产品的技术指标及过滤情况的影响。合成工艺的较佳条件：促进剂为D、甲醇用量为28 g、二氧化碳通入速率为300 mL/min、二氧化碳通入量为12 L.     

长流程反渗透系统的腐殖酸污染分析

通过单一污染物试验,分析了腐殖酸对长流程反渗透系统的污染过程,指出了腐殖酸污染会导致系统工作压力上升,透盐率下降及前后段通量失衡的现象.复合污染试验表明,钙离子与腐殖酸的络合效应使系统达到固定污染效果所需的运行时间大大缩短,且系统透盐率高于单一污染.     

BCP/COL/HCA骨组织工程支架的仿生制备

通过仿生合成、冷冻干燥及交联处理方法,制备出一种以双相磷酸钙、胶原和碳酸羟基磷灰石三组分为主要成分的新型三维骨组织工程支架。采用SEM、EDX和FTIR等测试技术对支架的性能特征进行分析。结果表明：制备的复合支架具有三维多孔的有序结构。双相磷酸钙作为力学支撑骨架有助于胶原网络基质形成特定的形状并使之具有一定的力学强度。在矿化过程中,羟基磷灰石矿物晶体在胶原的反应成核位点通过化学键合作用进行自组装。交联的胶原及其仿生矿化形成的碳酸羟基磷灰石可使支架具有良好的生物学性能,有望成为广阔临床应用前景的骨组织工程植入材料。     

AW玻璃基骨水泥的制备及其结构性能表征

以AW生物玻璃与柠檬酸／磷酸氢钾复合固化液混合制得玻璃基生物骨水泥（GBC）,利用XRD、FTIR和SEM对GBC的产物晶相、化学组成和显微结构进行了分析,并对其力学性能进行了测试。结果表明,GBC在固化反应后就已经有羟基磷灰石（HA）晶相生成;随着GBC在SBF中浸泡时间的延长,又生成了少量碳酸钙晶体,且HA晶相数量增多,抗压强度在7d时达到最大值,骨水泥呈现多孔结构。     

Preparation of calcium aluminate cement by combustion synthesis and application for corundum‐based castables

Calcium aluminate cement was prepared by combustion synthesis with CaO₂, Al, and Al₂O₃ as raw materials. The effects of CaO/Al₂O₃ (C/A) molar ratios in raw materials on the phase compositions and morphologies of calcium aluminate were investigated in detail. It was found that when the C/A reduced from 1.1 to 0.74, the content of CaO·2Al₂O₃ (CA₂) in products increased, whereas contents of CaO·Al₂O₃ (CA) and 12CaO·7Al₂O₃ (C₁₂A₇) decreased; when the C/A was 0.8, the phase composition of product (CS71) was equal to that of Secar71. Additionally, the crystallines of CA and CA₂ in the product were reduced when the C/A molar ratio was decreased. And then, the bulk density, apparent porosity, permanent linear change, cold crushing strength (CCS), and cold modulus of rupture (CMOR) of the corundum‐based castables bonded with CS71, Secar7 were compared. The castables bonded with CS71 demonstrate obviously improved CCS, CMOR, and volume stability.     

硅铝比对钙镁耦合作用降低煤灰熔融性的影响研究

利用化学试剂配制不同硅铝比的模拟煤灰,探究不同硅铝比模拟灰的流动温度随灰中钙镁配比的变化规律;并借助XRD、SEM-EDX分析矿物转化过程,初探钙镁耦合作用发生机理.结果表明:随着硅铝比的增加,钙镁耦合作用降低煤灰熔融性的强度先增大后减弱,且在Si/Al为1.5时最大;钙长石与镁橄榄石发生低温共熔是钙镁耦合作用降低煤灰熔融性的主要原因.Si/Al为1.0和4.0时,随着模拟灰中镁钙比的增大,钙长石低温共熔体系及辉石类矿物低温共熔体系的建立,使得煤灰流动温度一直下降,未表现出耦合作用.钙镁含量相同的灰渣中,随硅铝比的增加,灰渣由片块状向团聚状、絮状转变;SEM-EDX分析结果与XRD分析结果一致.     

氧化钙添加剂对碳酸钠活化粉煤灰的影响及机理

碳酸钠焙烧粉煤灰是一种反应温度低、氧化铝溶出率高,且可同步实现铝、硅高效分离的活化方式,然而该活化过程中所需助剂耗量较大,成为其大规模产业化应用的瓶颈.借鉴高温(1200~1300 ℃)碱石灰烧结活化粉煤灰工艺,在中温(600~1000 ℃)条件下,采用正交实验和单因素实验方法,分别研究了氧化钙添加对碳酸钠焙烧活化粉煤灰后氧化铝溶出率的影响.结果表明,在中温条件下可通过添加一定比例的氧化钙来部分替代碳酸钠,当m(CFA:Na2CO3:CaO)=1:0.6:0.2时,即可使粉煤灰中的氧化铝溶出率达90%以上.通过傅里叶变换红外光谱(FT-IR)、X射线衍射分析(XRD)进一步研究发现,氧化钙之所以可以部分替代碳酸钠,主要是由于低聚合度的硅酸钙形成所导致的.     

硅钙基固废原料配比及蒸养条件对硅酸钙板力学性能的影响

研究协同利用硅钙渣、粉煤灰、水泥和脱硫石膏制备硅酸钙板时,原料配比、蒸养条件对硅酸钙板力学性能、水化产物的影响,并利用XRD、IR和SEM表征了原料的协同水化历程和水化产物的微观结构和表面形貌.试验结果表明:最佳原料配比为硅钙渣60%、粉煤灰24%、水泥10%和脱硫石膏6%;最佳蒸压养护条件为蒸养温度180℃,恒温蒸养时间8 h,硅酸钙板抗折强度满足国家标准强度的D1.3的Ⅱ级要求;随着蒸养温度升高,原料水化依次生成C-S-H凝胶、托贝莫来石和针状硬硅钙石,大量托贝莫来石和硬硅钙石的生成使得硅酸钙板的强度得以提升.     

Exploiting Peptidomimetics to Synthesize Compounds That Activate Ryanodine Receptor Calcium Release Channels

Ryanodine receptor (RyR) Ca²⁺‐release channels are essential for contraction in skeletal and cardiac muscle and are prime targets for modification of contraction in disorders that affect either the skeletal or heart musculature. We designed and synthesized a number of compounds with structures based on a naturally occurring peptide ( A peptides) that modifies the activity of RyRs. In total, 34 compounds belonging to eight different classes were prepared. The compounds were screened for their ability to enhance Ca²⁺ release from isolated cardiac sarcoplasmic reticulum (SR) vesicles, with 25 displaying enhanced Ca²⁺ release. Competition studies with the parent peptides indicated that the synthetic compounds act at a competing site. The activity of the most effective of the compounds, BIT 180, was further explored using Ca²⁺ release from skeletal SR vesicles and contraction in intact skeletal muscle fibers. The compounds did not alter tension in intact fibers, indicating that (as expected) they are not membrane permeable, but importantly, that they are not toxic to the intact cells. Proof in principal that the compounds would be effective in intact muscle fibers if rendered membrane permeable was obtained with a structurally related membrane‐permeable scorpion toxin (imperatoxin A), which was found to enhance contraction.