低温等离子体辅助聚乳酸表面接枝乳酸链球菌素 及抗菌性

该文主要通过低温等离子体处理聚乳酸薄膜,并研究了不同处理时间(0、15 s、30 s、45 s 和 60 s)后薄膜的表面形貌及亲水性。在此基础上,将低温等离子体处理后的聚乳酸薄膜浸泡到乳酸链球 菌素溶液中,对其抗菌性能进行测定。通过调节等离子体处理时间,可以明显改善聚乳酸薄膜的表面 亲水性及粗糙度。结果表明,随着处理时间的增加,聚乳酸薄膜表面粗糙度先增加后减小,接触角先 降低后增加。经过 60 s 低温等离子体处理的聚乳酸薄膜,浸泡乳酸链球菌素溶液进行接枝,可有效降 低单核增生李斯特菌的菌落总数。因此,低温等离子体处理聚乳酸薄膜,为其在食品抗菌包装领域提 供了一个非常好的思路。     

一种具有广泛适应性的微机械加工方法研究

研究了一种具有广泛适应性的微机械制造方法,该方法可用于制备各种不同的器件,包括硅微陀螺仪、加速度计、剪切应力传感器以及光开关等.利用该方法,制备了硅微陀螺仪,并给出了所制备的硅微陀螺仪的性能测试结果,同时分析了利用该制备方法制备各种不同器件时,工艺流程对器件性能的影响,重点讨论了硅-玻璃阳极键合、减薄工艺以及深刻蚀所形成的侧壁质量,包括侧壁垂直度、侧壁杂质等因素对器件性能的影响.     

低温等离子体降解偏二甲肼废水研究

该文研究了悬浮电极介质阻挡放电装置(FE-DBD)产生的低温等离子体对偏二甲肼废水的降 解效果,并对处理条件进行优化。首先,对比了低温等离子体装置、氙灯和紫外灯降解偏二甲肼废水的效果;然后,考察了低温等离子体装置的放电间隙、初始溶液 pH、工作时间和氢氧化钠加投量对偏 二甲肼降解的影响;最后,探究了低温等离子体对偏二甲肼废水 pH 值的影响。实验结果表明,不加入其他试剂的情况下,低温等离子体装置降解偏二甲肼效果好于氙灯及紫外灯;装置放电间隙从 4 mm缩短至 2 mm,偏二甲肼降解率增加 47.2%。随着等离子体处理时间的增加,偏二甲肼的含量降低,处理 20 min 即可降解 82.1% 偏二甲肼。同时,低温等离子体处理会引起偏二甲肼废水 pH 值下降,处理10 min 后废水 pH 从 10 下降至 6.9。废水初始 pH 在 2～10 时,偏二甲肼降解率随废水 pH 值的升高而增大 ：与 pH＝2 相比,初始 pH＝10 时偏二甲肼降解率增加 65.9%。低温等离子体处理 10 min 后,往废水中加入氢氧化钠溶液至终浓度为 1 mg/mL,再继续处理 10 min,可将偏二甲肼降解率提高至 95%。     

MEMS封装中全Cu3Sn焊点组织演变及剪切性能

对Cu/Sn+Sn/Cu结构进行了低温键合,在不同的键合时间下制备焊点,分析了键合时间对焊点界面组织演变的影响和全Cu₃Sn焊点制备过程中界面反应机理,对焊点的剪切性能进行了分析和研究。结果表明,随着键合时间的增加,Cu₆Sn₅逐渐变成扇贝状并不断长大。键合时间达到90 min时,Sn完全被消耗,继续增加键合时间,Cu₃Sn以Cu₆Sn₅的消耗为代价不断长大,最终全部转变成Cu₃Sn。随着加载速率的增加,全Cu₃Sn焊点的抗剪切强度值逐渐减小,焊点界面两侧Cu₃Sn界面处沿晶断裂占焊点断裂模式的比例越来越大,因为这种沿晶断裂的抗剪切能力较小,所以焊点的抗剪切强度随着加载速率的增加而下降。     

反应溅射镀膜的等离子体发射控制系统设计

介绍了一种基于Allen-Bradley可编程控制器的等离子体发射监控闭环控制系统;在介绍溅射镀膜工作原理的基础上,分析了影响镀膜性能的多个因素,提出了等离子体发射监控反应溅射镀膜的控制方案;进而,具体介绍了等离子体发射监控系统的传感器、执行器的结构与设计,并进行了PLC-PID控制软件的编程,实现了快速、稳定的控制功能,使反应溅射镀膜工作均匀;实际运行证明了本等离子发射监控设计合理性,可制备氮化钛、氧化钛化合物薄膜,具有良好的推广价值。     

基于表面波激励的等离子体单极天线的研究

等离子体天线是一种新型的非金属介质天线,在电控、隐身等方面具有优异性能.在等离子体天线基本工作原理的基础七,利用非磁化冷等离子体理论,为了研究柱型等离子体表面波的产生方式,得出了维持稳定等离子体的能量关系.又采用等离子体表面波的色散关系理论,计算了不同激励功率下表面波波数沿等离子体天线轴向的变化,通过改变激励功率和碰撞频率来控制等离子体天线方向图.结果表明,等离子体天线具有良好的辐射性能,并且通过改变激励源功率可以实现等离子体天线参数的电控.     

面向工程设计过程的劳动计量方法与模型研究

提出工程设计过程的工作转换模型。基于该模型,将工程设计分为功能性和非功能性设计两大过程,进而研究了两设计过程的工作步与操作特性及劳动量影响因素,在此基础上,应用神经网络理论等,建立面向工程设计过程的劳动计量方法与模型。     

4,6-双-(5-氨基-3-硝基-1,2,4-三唑-1-基)-5-硝基嘧啶(DANTNP)性能的量子化学研究

用B3LYP法,在6-31G(d,p)基组水平上计算4,6-双-(5-氨基-3-硝基-1,2,4-三唑-1-基)-5-硝基嘧啶(DANTNP)的性能,得其稳定的几何构型和键级;在振动分析的基础上求得体系的振动频率、IR谱及不同温度的热力学性质及温度对热力学性能影响的关系式。用UHF-PM3法探讨其热解机理,求得热解反应时的过渡态和活化能,发现热解始于N-H键断裂时。     

纳米SnO2材料的晶化及其对气敏特性的影响’

本文对以无水SnCl_4为源、采用低温等离子体法制备的10nm量级的SnO_2粉料的晶化现象进行了多方面的讨论.由DTA得到了这种粉料的晶化温度;结合IR分析了升温过程中粉料的失重原因;从X-射线衍射谱图中分析了制得粉料的热稳定性.在晶化温度前后对粉料进行热处理,得到了不同的电导-温度曲线.比较了两种温度烧结制得的气敏元件的灵敏度.     

低温等离子体灭活核糖核酸酶研究

该文主要探讨了低温等离子体技术在核糖核酸酶灭活方面的应用,分析了作用气体类型和等 离子体发生器结构对酶灭活性能的影响。实验结果表明,低温等离子体能够有效地灭活核糖核酸酶, 混有氧气或水汽的作用气体能够明显提高对酶的灭活能力,且悬浮式电极介质阻挡放电装置的灭活效 果优于表面介质阻挡放电装置。     

Investigating into a Ca-sensitive electrostatic self-assembly films to fabricate reproducible immunobeads for flow immunoassay

A novel strategy has been developed for fabricating reproducible bead-based flow immunoassay system by combining the merits of Ca²⁺-induced cross-linkage of sodium alginate with negative carboxyl groups of alginate. The sodium alginate was applied to modify the polyallyamine beads and render beads negative charge to immobilize antibodies via electrostatic/hydrogen bonding interaction between alginate and antibodies to realize the fabrication of immunobeads in buffer solution of 0.01 mol/l acetic-acetate (pH 7.5). The Ca²⁺-induced cross-linkage of alginate on the immunobeads can easily release antibodies from beads and regenerate a fresh alginate-modified beads for next fabrication of new immunobeads. The electrochemical flow immunoassay system based on the so-made immunobeads has been fabricated and the feasibility of the proposed strategy and qualities of so-fabricated flow immunoassay system was evaluated by applying to a competitive transferrin–transferrin antiserum immunoassay system.     

马铃薯淀粉羧甲基化过程的优化

羧甲基马铃薯淀粉被广泛应用于工业部门。本文将水分、温度、反应时间、理论取代度（DSt）、淀粉负荷以及氢氧化钠对一氯乙酸钠的摩尔比（nNaOH／nSMCA）作为马铃薯淀粉羧甲基化过程的影响因素,利用响应曲面法中的Box—Behnken设计法对过程进行了优化,并用Matlab中的二次响应曲面函数对结果进行了分析,最终得到了马铃薯羧甲基化过程的最佳反应条件,制备所得羧甲基马铃薯淀粉产物取代度高达DS=1．0602。     

茂金属化合物Cp2ZrCl2与硅胶表面相互作用分子模拟

利用分子力学、分子动力学和基于密度泛函理论的量子力学从头计算方法对茂金属化合物Cp_2ZrCl_2与含有不同基团的硅胶表面之间的相互作用进行了研究,发现茂金属化合物Cp_2ZrCl_2在双羟基表面的物理吸附最强,在单羟基表面的吸附强度次之,在硅氧烷基表面的吸附最弱。Cp_2ZrCl_2在双羟基作用下,中心金属原子与茂环之间的距离增加,导致茂环脱落,这是茂金属化合物直接负载到硅胶表面后活性较低的主要原因。     

On-chip fabrication of magnetic alginate hydrogel microfibers by multilayered pneumatic microvalves

Alginate hydrogel has widespread applications in tissue engineering, cancer therapy, wound management and drug/cell/growth factor delivery due to its biocompatibility, hydrated environment and desirable viscoelastic properties. However, the lack of controllability is still an obstacle for utilizing it in the fabrication of 3D tissue constructs and accurate targeting in mass delivery. Here, we proposed a new method for achieving magnetic alginate hydrogel microfibers by dispersing magnetic nanoparticles in alginate solution and solidifying the magnetic alginate into hydrogel fiber inside microfluidic devices. The microfluidic devices have multilayered pneumatic microvalves with hemicylindrical channels to fully stop the fluids. In the experiments, the magnetic nanoparticles and the alginate solution were mixed and formed a uniform suspension. No aggregation of magnetic nanoparticles was found, which is crucial for flow control inside microfluidic devices. By regulating the flow rates of different solutions with the microvalves inside the microfluidic device, magnetic hydrogel fibers and nonmagnetic hydrogel fibers were fabricated with controlled sizes. The proposed method for fabricating magnetic hydrogel fiber holds great potential for engineering 3D tissue constructs with complex architectures and active drug release.     

Surface interactions of oxidized cellulose with fibrin(ogen) and blood platelets

Hemostatic effects of oxidized cellulose are well known but the mechanism of its action is far from being well understood. Hemostatic (hemostyptic) biomaterials with their ability to initiate or accelerate thrombus formation belong to surgical sealants. Thrombus formation is a surface phenomenon. The exploitation of surface plasmon resonance sensing principle for the examination of interactions of oxidized cellulose with fibrinogen, fibrin and blood platelets is reported. Cellulose decreased and slowed down the interaction of immobilized fibrin monomer with fibrinogen as observed by surface plasmon resonance. Only weak interactions of cellulose with plasma proteins albumin and fibrinogen were observed. Delayed gelation and slower increase in turbidity occurred in fibrinogen–thrombin solutions in the presence of the cellulose. Platelets in plasma but not washed platelets in a buffer were activated in the presence of cellulose. We suppose that activation of the coagulation contact system of blood plasma initiated very likely by the negatively charged surface of the oxidized cellulose leads to the fibrin formation and activation and adhesion of blood platelets. The direct interactions of platelets and fibrinogen with the cellulose seem to play a secondary role.     

Hyper-miniaturization of monodisperse alginate–TiO2 composite particles with densely packed TiO2 nanoparticles

We report a novel technique to fabricate alginate–TiO₂ composite particles with densely packed TiO₂ nanoparticles. Using a microfluidic device, monodisperse sodium alginate droplets containing low-density TiO₂ nanoparticles (1 or 5 w/v%) were formed in the oil phase. The sodium alginate droplets formed in the oil phase were subsequently placed on a Ca²⁺-loaded agarose-gel plate to induce shrinkage by water removal (from the droplets to the Ca²⁺-loaded agarose-gel plate) and gelation by Ca²⁺ transport (from the Ca²⁺-loaded agarose-gel plate to the droplets). Thus, the produced alginate–TiO₂ composite particles containing densely packed TiO₂ nanoparticles were significantly smaller than the microchannel. We also investigated the optimal conditions to successfully produce spherical composite particles by varying the oil phases, surfactants, calcium concentrations and gel strength of the agarose-gel plate. Moreover, our method could decrease the probability of channel clogging that often occurs when a colloidal suspension (e.g., nanoparticles) is used as the dispersed phase. This method facilitates the stable production of monodisperse alginate–inorganic composite particles for a wide range of applications.     

多溴苊烯化合物的分子结构和热力学性质

多溴苊烯是潜在的一类有机污染物,本文采用密度泛函理论在B3LYP/6-311G**水平上,优化这类化合物的分子几何结构135个,获得它们在理想气态的一些热力学性质的数值,研究这些性质与取代的溴原子数目和位置的关系,根据各异构体的标准生成Gibbs自由能的相对大小,求出它们热力学稳定性的顺序。结果表明:大部分多溴苊烯分子具有平面的几何构型。最稳定及最不稳定异构体的△_fH~θ及△_fG~θ,都随Br原子数目增加而逐渐增加。溴原子数目相同的△_fH~θ和△_fG~θ与溴原子的取代位置有很大的关系,其相对稳定性由分子内Br…Br核排斥作用的强弱而决定。     

Hydrophobic patterning of functional porous pigment coatings by inkjet printing

Paper-based analytical devices provide novel platforms for functional sensing applications, such as medical diagnostics and environmental monitoring. They are based on porous hydrophilic material, which transports the sample liquid by capillary action. The directional flow of aqueous liquids can be controlled by selective hydrophobising of pores. Earlier research in this field has concentrated on highly porous cellulose papers as base substrates, with no significant interest shown for pigment coatings. Such coatings can produce significantly thinner porous layers, thus requiring smaller sample volumes. This study investigates the hydrophobic patterning of custom-designed porous pigment coatings by functional inkjet printing. Tested coatings consisted of reference ground calcium carbonate and porous functionalised calcium carbonate (FCC) pigments combined with various binders, including microfibrillated cellulose. The hydrophobising custom-made inks contain polystyrene or alkyl ketene dimer (AKD) in p-xylene. The patterning is demonstrated by reaction arrays and simple channels. With polystyrene ink, successful hydrophobic barriers could be generated on all tested pigment/binder coatings, although generally requiring printing of multiple layers of barrier material. With AKD ink, hydrophobic patterns could be created successfully on coatings containing an organic binder, but not on coatings with inorganic sodium silicate as binder. The AKD ink generated hydrophobic barriers using fewer ink layers compared with polystyrene ink. Interestingly, AKD ink could hydrophobise the FCC pigment alone without binder, presumably due to hydroxyl groups on the pigment surface. Hydrophobic patterning of the pigment coatings is seen to require large amounts of hydrophobising agent, likely related to the high specific surface area.