超细碳酸钙粉体的制备

以CaCl2和(NH4)2CO3为原料,采用气相扩散法合成碳酸钙晶体。通过添加合适的晶形控制剂,选择适当的用量,合成了花生状碳酸钙晶体。用发射扫描电子显微镜(FESEM)和X射线衍射仪(XRD)进行了表征,结果表明,当控制剂柠檬酸钠用量在10 mmol/L时,生成的花生状碳酸钙粒子粒度分布均匀,在700 nm左右,且粒子分散性良好。并对花生状碳酸钙粒子的形成机理进行了探讨。     

硫酸四氨合铜结晶过程的粒度控制技术

氨水和硫酸铜溶液反应形成铜氨溶液,之后与乙醇混合使硫酸四氨合铜以晶体形式析出,过滤、干燥制备硫酸四氨合铜晶体。考察不同操作条件对硫酸四氨合铜晶体粒度分布的影响。结果表明,析出过程中加入合适的表面活性剂对粒度分布有一定影响,混料时以铜氨溶液分散加入到乙醇中效果较好,适当增加乙醇用量和提高搅拌强度有利于得到小粒度产品。     

Binding Mode and Structure–Activity Relationships around Direct Inhibitors of the Nrf2–Keap1 Complex

An X‐ray crystal structure of Kelch‐like ECH‐associated protein (Keap1) co‐crystallised with (1S,2R)‐2‐[(1S)‐1‐[(1,3‐dioxo‐2,3‐dihydro‐1H‐isoindol‐2‐yl)methyl]‐1,2,3,4‐tetrahydroisoquinolin‐2‐carbonyl]cyclohexane‐1‐carboxylic acid (compound (S,R,S)‐ 1 a ) was obtained. This X‐ray crystal structure provides breakthrough experimental evidence for the true binding mode of the hit compound (S,R,S)‐ 1 a , as the ligand orientation was found to differ from that of the initial docking model, which was available at the start of the project. Crystallographic elucidation of this binding mode helped to focus and drive the drug design process more effectively and efficiently.     

Monitoring of degradation of porous silicon photonic crystals using digital photography

We report the monitoring of porous silicon (pSi) degradation in aqueous solutions using a consumer-grade digital camera. To facilitate optical monitoring, the pSi samples were prepared as one-dimensional photonic crystals (rugate filters) by electrochemical etching of highly doped p-type Si wafers using a periodic etch waveform. Two pSi formulations, representing chemistries relevant for self-reporting drug delivery applications, were tested: freshly etched pSi (fpSi) and fpSi coated with the biodegradable polymer chitosan (pSi-ch). Accelerated degradation of the samples in an ethanol-containing pH 10 aqueous basic buffer was monitored in situ by digital imaging with a consumer-grade digital camera with simultaneous optical reflectance spectrophotometric point measurements. As the nanostructured porous silicon matrix dissolved, a hypsochromic shift in the wavelength of the rugate reflectance peak resulted in visible color changes from red to green. While the H coordinate in the hue, saturation, and value (HSV) color space calculated using the as-acquired photographs was a good monitor of degradation at short times (t < 100 min), it was not a useful monitor of sample degradation at longer times since it was influenced by reflections of the broad spectral output of the lamp as well as from the narrow rugate reflectance band. A monotonic relationship was observed between the wavelength of the rugate reflectance peak and an H parameter value calculated from the average red-green-blue (RGB) values of each image by first independently normalizing each channel (R, G, and B) using their maximum and minimum value over the time course of the degradation process. Spectrophotometric measurements and digital image analysis using this H parameter gave consistent relative stabilities of the samples as fpSi > pSi-ch.     

飞秒激光加工单晶金刚石制备正前角磨削工具

目的制造一种磨粒有序排布、具有正前角的无结合剂端面金刚石磨削工具。方法采用波长为1030 nm、脉宽为250 fs的钛蓝宝石飞秒激光对单晶金刚石(SCD)进行烧蚀加工,首先研究加工工艺参数(特别是烧蚀轨迹间距)对金刚石加工效率及表面质量的影响。采用预先设计的激光扫描路径,基于优化后的工艺参数在SCD表面加工出微磨粒阵列结构,各磨粒呈方锥台形结构,其顶部倾斜角约为100°。在此基础上,对微磨粒阵列进行烧蚀加工,将所有微磨粒顶部的倾斜角减小至小于90°。结果当激光烧蚀轨迹间距为10.0μm时,烧蚀加工表面RMS粗糙度最小。确定了一种微磨粒边缘倾斜角小于90°且磨粒有序排布的新型无结合剂金刚石端面磨削工具的激光制备方法和工艺,采用该工艺加工的磨削工具表面质量好,轮廓精度高,磨粒平均正前角约为9.80°。结论采用飞秒激光可以高质量、高效率地制备出磨粒有序排布的新型正前角无结合剂金刚石端面磨削工具,该工具有望在硬脆材料磨削中减小磨削力,提高材料表面完整性。     

电化学沉积法制备氢氧化镁晶体的影响因素研究

以MgCl_2溶液作为电解质,利用电化学沉积方法制备了Mg(OH)_2晶体.研究了电流密度、MgCl_2浓度、沉积时间等因素对沉积产物生长速率、结晶度、微观形貌和孔径分布的影响.结果表明:上述各因素均不影响沉积产物(Mg(OH)_2)的物相组成;电流密度的增大加快了Mg(OH)_2的生长速率,但同时降低了Mg(OH)_2晶体的结晶度,增大了产物中的孔隙率与大孔体积;MgCl_2浓度对Mg(OH)_2结晶度及晶体颗粒大小的影响较小,存在使Mg(OH)_2生长速率达到最大值的最佳MgCl_2浓度;Mg(OH)_2质量随沉积时间增加呈线性增长,生长速率基本维持恒定.     

湍流中微小冰晶融化时间的理论研究

为了消除过冷水连续制冰系统中的微小冰晶，通过建立模型，分析了湍流中微小冰晶的融化过程，提出了计算融化时间的方法，分析了融化时间与最小旋涡尺度和水温的关系。指出通过增大湍流程度，使最小旋涡尺度小于某一数值(与水温有关，可通过计算确定)，从而可以在较低的水温、较短的时间内融化水中的微小冰晶。     

晶核在高性能混凝土中作用机理的试验研究

本文在高性能混凝土中加入晶胚进行试验。通过调整晶胚的细胞和掺量。研究了晶胚对高性能混凝土的强度和耐久性影响的作用机理。结果表明，加入比表面积大干3000cm^2／g的晶胚。最佳掺量为10％时。影响了晶体的大小及分布形态，因而影响了混凝土的强度和耐久性，有力地促进了混凝土后期强度的增长。提高混凝土的抗折，抗压强度。     

集中供暖室内温度控制系统的硬件设计

介绍了室内温度控制系统的功能及整体结构,分析了主、从控制器的硬件结构。主控制器采用液晶显示模块及键盘模块进行温度、时间的设定与各个房间温度、电磁阀工作状态的监测。从控制器采用数字温度传感器作为温度采集元件,通过驱动双稳态电磁阀的开闭实现温度控制。     

河南九槽沟矿区晶质石墨矿地质特征及成矿条件分析

河南九槽沟矿区位于华北板块构造带与扬子板块构造带结合部河南淅川-陕西商南石墨成矿带上,通过地质工程、测试、资料收集、综合研究等认为主要含矿层赋存于古元古界陡岭群大沟岩组片岩、片麻岩地层中,矿体规模中-大型,不同期次、不同性质的岩浆岩十分发育,物理特征明显,显示出良好的找矿空间。预测在该区域成矿带上有大型晶质石墨矿床存在。