碱性介质中表面活性剂对超细锌粉分散性能的影响

首先,用直流电弧等离子体法制备超细锌粉,并通过测定其表面Zeta值,选取了三种表面活性剂。利用硝酸镧作缓蚀剂,借分光光度法,研究了超声分散时间、硝酸镧加入量以及表面活性剂浓度对碱性介质中超细锌粉分散性能的影响。结果表明,最佳分散工艺为:超声功率560W,超声分散时间20min,硝酸镧与十六烷基三甲基溴化铵加入的质量分数分别为10%和6%,从而解决了超细锌粉在碱性电池中的应用问题。     

LED人工天窗瑞利散射材料的稳定性及光学性能研究

以纳米二氧化钛(nano-TiO2)为原料,选取六偏磷酸钠(SHMP)、曲拉通X-100(Tritor-X-100)、聚乙二醇(PEG)400、十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)和十六烷基三甲基溴化铵(CTAB)做分散剂,采用超声手段在去离子水中制备得到nano-TiO2分散液。通过UV-Vis分光光度计测量样品的吸光度,分析了超声时间、分散剂种类与浓度对样品稳定性的影响,并对样品的光学性能进行检测。研究结果表明:加入SHMP,超声处理35min可获得吸光度维持在0.1左右的稳定nano-TiO2分散液,且在LED光源(CCT=10 000K)照射下,可以实现模拟天空光照射环境的瑞利散射效果。     

微波-Fenton法处理垃圾渗滤液的研究

微波法用于消除有机污染物,具有快速、高效、不污染环境的特点。实验采用微波促进Fenton法降解垃圾渗滤液中的有机污染物,研究了Fenton试剂用量、微波功率、微波作用时间和pH值等对化学需氧量(COD)去除率的影响。实验结果表明,微波Fenton法处理垃圾渗滤液能提高反应效率,有效降低垃圾渗滤液中的COD浓度。微波-Fenton法处理20 mL的COD浓度为896 mg/L的垃圾渗滤液的优化条件为:调节pH值小于3,加入6 mmol/L的硫酸亚铁溶液6 mL,加入1 mL的H2O2,在微波功率800 W下加热处理4 min,其出水COD浓度可降至200 mg/L。     

双片二硫化钼纳米薄片的电子衍射分析

本文使用高分辨透射电子显微和电子衍射方法研究二硫化钼二维纳米材料薄片的微观结构。实验记录了样品在不同倾转角度下的衍射图,分析确认了衍射图中的一些衍射斑点随倾转角度加大而出现分裂的现象。本文通过一个空间几何模型来解释衍射图中衍射斑点分裂现象的成因,认为样品中含有两片互相之间有一定夹角的二硫化钼纳米薄片。两个二维纳米薄片分别对应分裂衍射斑点中的一组。经过模拟计算,得出这两片二硫化钼纳米薄片的夹二面角为156.6°(23.4°)。本文中的实验和模拟方法可以推广到对其它二维纳米材料薄片取向和相对空间方位的计算。     

微波诱导铬渣催化氧化降解甲基橙溶液的研究

采用微波-铬渣法、微波-铬渣-H2O2法处理甲基橙溶液。研究了铬渣用量、溶液初始pH值、微波辐照时间、处理后放置时间等因素对溶液TOC去除率的影响。研究表明,对于150 mL的TOC浓度为200 mg/L的甲基橙溶液,铬渣用量为1 g,H2O2(30%)用量为1 mL,溶液初始pH值在4~10范围内,微波功率80 W,微波辐照3 min,TOC去除率可达80%,处理后放置足够长时间,色度去除率可达100%。处理后溶液中残留Cr(Ⅵ)浓度小于0.05 mg/L。     

一种用于湿度监测的LC无线无源传感器的制备与测试

提出了一种采用丝网印刷和亚胺化工艺制备的LC无线无源技术的二硫化钼(MoS2)/聚酰亚胺(PI)湿度传感器。对比了不同超声时间下的二硫化钼/聚酰亚胺复合材料的湿度敏感性能,得出对湿度最灵敏的材料为超声4 h的二硫化钼/聚酰亚胺材料。测试结果表明,制备的器件在量程10%RH～95%RH内具有较好的频率响应,频率变化值为6.205 MHz;在高湿度范围内(60%RH～95%RH),传感器的灵敏度可达153.59 kHz/%RH。此外,该传感器的响应和恢复时间分别为7.2 s和10.4 s,迟滞性误差约为5%RH且具有较好的稳定性。该传感器可广泛应用于化学合成和矿井环境等领域的湿度监测。     

不同分散剂对超细镍粉分散性能的影响

通过测量直流电弧等离子体法制备的超细镍粉的Zeta电位,选取油酸(OA)、十二羟基硬脂酸(12HSA)、十二烷基苯磺酸钠(SDBS)、六偏磷酸钠(SHMP)、甲基丙烯酸甲酯(MMA)及司班-85(Span-85)作为分散剂,系统研究了六种分散剂在不同超声时间和不同分散剂浓度下,对超细镍粉的分散性能的影响。结果表明:随着超声时间和分散剂加入浓度的提高,粉体分散效果呈现先变好后变差趋势;推荐超细镍粉的最佳分散工艺为:添加质量分数3%的六偏磷酸钠进行分散,超声时间为25 min。     

二硫化钼催化析氢电极的构筑及其性能研究

针对目前MoS₂作为析氢催化剂时存在的活性位点数目少且材料导电性能差等问题,文中通过液相超声剥离法以及离心处理制备得到MoS₂/PVP分散液。PVP的辅助剥离作用使得剥离得到的MoS₂纳米片尺寸大幅减小,提高了MoS₂催化析氢活性位点的丰度;MoS₂在PVP辅助剥离过程中发生了2H相到1T相的转变,同样增强了催化析氢活性。文中选用含有导电铜层的PI基片作为电极基底,利用喷墨印刷技术将MoS₂/PVP催化剂固载于导电基底上制得催化析氢电极。该电极在10 mA·cm ^-2处的过电位为77 mV,Tafel斜率为65 mV·dec ^-1,这一结果表明该催化电极具有高催化活性。     

镧掺杂纳米二氧化钛透明光触媒乳液的制备及光催化性能

以四氯化钛、草酸、氨水、硝酸镧、D-山梨醇等为主要的实验药品,采用了常温络合-控制水解法,制备出平均粒径6.9 nm的镧掺杂纳米二氧化钛透明光触媒乳液。在太阳光照射下利用该透明乳液对酸性红3R染料降解,并研究了染料初始浓度、样品加入量、体系pH值、加热回流时间对降解效果的影响。采用XRD、纳米激光粒度分析仪、紫外-可见分光光度计等对样品的物相、粒径、组成、光吸收、光催化等性质进行了表征。结果表明,当镧掺杂量为0.1%、体系pH值为6、回流时间为10 min时,镧掺杂纳米二氧化钛光催化性能最好。太阳光照射60 min后,对浓度为25 mg/L的酸性红3R染料溶液的降解率达到98%以上。     

锐钛纳米TiO_2制备及表面性质测定

以TiCl4为原料,加入硫酸盐作为添加剂,采用沸腾回流强迫水解法成功地制备了粒度小、粒径分布窄的锐钛型纳米TiO2,用粒度分布仪、透射电子显微镜、X射线衍射计检测了产物形貌、粒径及晶型。同时,采用接触角测量仪、Zeta电位仪、分光光度计等对样品表面性能进行测定。结果表明,通过控制浆液和SO24-离子的浓度,加入分散剂六偏磷酸钠,选择适宜的固液比及pH值等因素,可得到粒度分布窄、在水中分散均匀的锐钛纳米TiO2,为纳米TiO2的有机修饰做好必要的前期准备。     

纳米Ag-Cu-In-Sn合金粉体的分散稳定性研究

通过等离子体蒸发凝聚法制备纳米Ag-Cu—In—Sn合金粉，初步研究了聚乙烯吡略烷酮K-30（PVP）和十六烷基三甲基溴化铵（CTAB）及其分散工艺对合金粉体分散性能的影响。研究结果表明：随着超声时间的增加，吸光率增大，分散性能变好；与CTAB相比PVP的分散效果更好，其最佳分散浓度为1．8g／L。     

Structural,surface and mechanical characterization of spray-deposited molybdenum disulfide thin films

Molybdenum disulfide (MoS₂) was deposited with the precursor salt of ammonium molybdate tetrahydrate and thiourea on glass substrate at various precursor solution volume (10–50 mL) using the spray pyrolysis technique. The X-ray diffraction pattern indicates the polycrystalline nature of the film with a hexagonal structure and the occurrence of peak shift due to stacking fault. The field-emission scanning electron micrograph shows the increment in grain growth with increase in the precursor solution volume, leading to the conversion of grains to nanoflakes. Energy dispersive spectrum confirms the presence of molybdenum and sulfur. Vickers microhardness shows increament in microhardness with decrease in the precursor solution volume. The mechanical properties related to microhardness were analyzed. Raman analysis confirms the hexagonal structure of MoS₂ with the presence of vibrational modes.     

Transparent conductive PVP/AgNWs films for flexible organic light emitting diodes by spraying method

In this study, a simple spraying method is used to prepare the transparent conductive films (TCFs) based on Ag nanowires (AgNWs). Polyvinylpyrrolidone (PVP) is introduced to modify the interface of substrate. The transmittance and bending performance are improved by optimizing the number of spraying times and the solution concentration and controlling the annealing time. The spraying times of 20, the concentration of 2 mg/mL and the annealing time of 10 min are chosen to fabricate the PVP/AgNWs films. The transmittance of PVP/AgNWs films is 53.4%—67.9% at 380—780 nm, and the sheet resistance is 30 Ω/□ which is equivalent to that of commercial indium tin oxide (ITO). During cyclic bending tests to 500 cycles with bending radius of 5 mm, the changes of resistivity are negligible. The performance of PVP/AgNW transparent electrodes has little change after being exposed to the normal environment for 1 000 h. The adhesion to polymeric substrate and the ability to endure bending stress in AgNWs network films are both significantly improved by introducing PVP. Spraying method makes AgNWs form a stratified structure on large-area polymer substrates, and the vacuum annealing method is used to weld the AgNWs together at junctions and substrates, which can improve the electrical conductivity. The experimental results indicate that PVP/AgNW transparent electrodes can be used as transparent conductive electrodes in flexible organic light emitting diodes (OLEDs).     

毛细管区带电泳法测定霍香正气胶囊中和厚朴酚的含量

目的:建立霍香正气胶囊中和厚朴酚含量测定的毛细管区带电泳(CZE)法.方法:采用甲醇溶解样品超声制备供试液;运行缓冲液为40mmol/L硼砂溶液,检测波长254nm.结果:和厚朴酚线性范围0.013-0.20mg/mL,r=0.9917(n=5),厚霍香正气胶囊中和厚朴酚的含量为0.1479mg/粒.结论:此方法快速简便,可用于评价霍香正气胶囊的质量.     

High‐Concentration Aqueous Dispersions of MoS2

Molybdenum disulfide (MoS₂) nanosheets have been attracting increasing research interests due to their unique material properties. However, the lack of a reliable large‐scale production method impedes their practical applications. Here a facile, efficient, and scalable method for the fabrication of high‐concentration aqueous dispersion of MoS₂ nanosheets using combined grinding and sonication is reported. The 26.7 ± 0.7 mg/mL concentration achieved is the highest concentration in an aqueous solution reported up to now. Grinding generates pure shear forces to detach the MoS₂ layers from the bulk materials. Subsequent sonication further breaks larger crystallites into smaller crystallites, which promotes the dispersion of MoS₂ nanosheets in ethanol/water solutions. The exfoliation process establishes a new paradigm in the top‐down fabrication of 2D nanosheets in aqueous solution. In the meantime, MoS₂‐based sensing film produced using this approach has successfully demonstrated the feasibility of a low‐cost and efficient NH₃ gas sensor using inkjet printing as a viable method.     

基于Minitab DOE的铝丝楔焊键合工艺参数优化

为提高国产陶瓷外壳用于铝丝楔焊键合的可靠性和产品质量,利用Minitab统计软件对一种封装形式为CQFP84的国产陶瓷外壳用于铝丝楔焊键合的工艺参数进行试验设计,并对试验结果进行直观分析和方差分析。讨论过键合功率、键合压力、键合时间及超声功率缓慢上升时间(Ramp)对键合拉力的影响及其显著程度。试验研究表明第2段参数的键合压力、第2段参数的键合功率及第1段参数的Ramp对键合拉力值有显著影响,以键合拉力为参考指标,得到了较优的键合工艺参数,通过验证试验键合拉力相比工艺参数优化前有明显提高,分散度也有明显改善,达到了提高产品可靠性的目标。     

Electrochemically Induced High Capacity Displacement Reaction of PEO/MoS2/Graphene Nanocomposites with Lithium

Nanocomposites comprised of poly(ethylene oxide), molybdenum disulfide, and graphene were prepared by the hydrolysis of lithiated molybdenum disulfide in an aqueous solution of PEO and graphene. Structural analysis by XRD shows the nanocomposites are disordered with an expansion of ～6 Å in the interlayer spacing. During the first discharge, the nanocomposites electrochemically dissociates irreversibly into Li₂S and Mo and are able to continously cycle as Li₂S +Mo/Li_x ? S + Mo + Li_x+2 as shown by XRD of the discharged electrodes at different depth of discharge (DOD), cyclic voltammetry (CV), and high resolution TEM. A significant increase of the reversible capacity is found in as‐prepared MoS₂/PEO/graphene composite. The results suggest a new electro‐interaction between lithium and molybdenum metal that only occurs in the nanoregime and is enhanced by PEO. The addition of 2 wt% of graphene to the nanocomposites greatly increases the rate capability with rates as high as 10000mA g^?1 yielding > 250mAh g^?1 and recovering to > 600 mAhr g^?1 at 50mA g^?1.