改性剂对旋转法SiO2减反膜均匀性的影响

 分析了采用旋转涂膜法制备溶胶-凝胶SiO₂减反膜过程中条纹缺陷产生的机理,利用含氟醇类试剂对减反膜溶胶进行改性,使溶胶链段柔顺性及流动性得到改善。在光学显微镜下对改性前后的膜层进行了对比和分析,对膜层的表面形貌、表面粗糙度以及透射比等特性进行了表征。结果表明:溶胶改性之后的膜层未出现条纹缺陷,表面粗糙度均方根值从4.55 nm下降到小于1.00 nm,膜层表面质量有了较大提高;改性前后膜层的增透性能相当,在熔石英基片上制备的膜层峰值透射比为99.60%~99.89%,膜层激光损伤阈值为21.0~25.3 J/cm²。     

表面改性多孔二氧化硅减反膜的稳定性研究

以正硅酸乙酯为原料,采用溶胶-凝胶法制备SiO_2溶胶,通过提拉法涂制多孔SiO_2减反膜,并在多孔SiO_2减反膜上涂制一层甲基三乙氧基硅烷(MTES)预聚体。通过疏水的MTES预聚体涂制在多孔SiO_2减反膜上,对多孔SiO_2减反膜的表面进行改性,以提高膜层的环境稳定性。经过表面改性的复合膜层的透过率峰值可达99.67%,折射率为1.231,水接触角达123.6°,在相对湿度为95%的环境中放置475 d后膜层的峰值透过率为99.09%,稳定性提高明显。膜层表面平整,激光损伤阈值约为24.5 J/cm~2。     

溶胶凝胶ZrO2/SiO2宽带减反膜的制备与性能

采用溶胶凝胶法制备得到以正丙醇锆和正硅酸乙酯为前驱体的ZrO₂和SiO₂溶胶,通过TFCalc光学薄膜软件模拟了ZrO₂/SiO₂三层“宽M型”基频二倍频减反膜,并使用提拉法制备得到了该均匀膜层。三层减反膜在527 nm和1053 nm处的透过率约为99.5%,且透过率大于99%的波长范围均超过150 nm。经热处理后的膜层表面均方根粗糙度为1.34 nm,表面平整性良好;并运用1-on-1激光损伤阈值测试方法测得该减反膜的零几率激光损伤阈值达到36.8 J·cm^-2(1064 nm,10.7 ns)。     

活性炭负载对甲苯磺酸催化微波合成环己酮乙二醇缩酮

在微波辐射下,以活性炭负载对甲苯磺酸为非均相催化剂,不用溶剂,用环己酮和乙二醇为原料合成环己酮乙二醇缩酮。重点考察了酮醇物质的量比、催化剂用量、微波功率和辐射时间对产品收率的影响。实验结果表明,活性炭负载对甲苯磺酸有着良好的催化活性,当环己酮的加入量为0.2mol,n（环己酮）：n（乙二醇）=1：1.6,催化剂用量为反应物总质量的0.75%,微波功率450W,辐射时间4min时,缩酮收率可达76.7%,且催化剂重复使用6次仍保持较高活性。     

常压百级洁净度环境中SiO2薄膜稳定性

在常压百级洁净度环境下,采用三种不同折射率的SiO₂溶胶在熔石英基底上涂制四种不同薄膜,利用光学理论计算模拟了三种胶体涂制的膜层稳定性,通过实验考查了膜层光学指标随时间的变化规律。SiO₂薄膜能够显著提升光学元件透射率,但由于膜层表面的大量羟基及其多孔结构,SiO₂薄膜易吸附周围环境中的有机污染物及水分填充膜层孔隙,从而导致膜层折射率发生变化,影响膜层透射率、反射率等光学性能。实验结果发现,三种溶胶凝胶化学膜在常压百级环境中的有效期为80 d(绝对变化率小于0.1%),且三种胶体涂制的膜层稳定性由高到低依次为折射率1.19, 1.15, 1.25的膜层。     

辐射探测芯片吸收膜理论设计及镍磷黑膜制备

对新型条形辐射探测芯片的吸收膜层进行了理论分析,并且在金刚石材质的探测芯片上采用电镀方法制备了镍磷黑吸收膜.辐射探测芯片的膜层吸收分析表明,芯片吸收膜层的吸收率正比于表面粗糙度.通过对辐射吸收膜层设计与制作工艺的研究,制备出一种用于条形辐射探测芯片的镍磷黑吸收膜,通过测量其表面形貌结构,表明该膜层具有50nm—1.5μm范围的微结构;红外吸收测试表明其吸收率在1.4—8μm波段为0.989以上,从而提高了辐射探测芯片的性能.     

离子源工艺参数对BCB胶刻蚀速率和表面粗糙度的影响

为了研究离子束刻蚀抛光过程中离子源工艺参数对刻蚀速率及表面粗糙度的影响,采用微波离子源为刻蚀离子源,以BCB胶为主要研究对象,研究了离子束能量、离子束电流、氩气流量、氧气流量对BCB胶刻蚀速率及表面粗糙度的影响,获得了离子源工艺参数与刻蚀速率及表面粗糙度演变的关系。研究结果表明,离子束能量在从400 eV增大到800 eV的过程中,刻蚀速率不断增大,从3.2 nm/min增大到16.6 nm/min;离子束流密度在从15 mA增大到35 mA的过程中,刻蚀速率不断增大,从1.1 nm/min增大到2.2 nm/min;工作气体中氧气流量从2 mL/min增大到10 mL/min的过程中,刻蚀速率会整体增大,在8 mL/min处略有下降。表面粗糙度变化不大,可以控制在1.8 nm以下。     

用于超薄反射镜热成形的Pt、Pt/Cr分离膜

针对热弯玻璃成形法制备高精度超薄反射镜时Pt分离膜造成的镜片污染问题,研究了Pt/Cr分离膜中不同Cr层厚度对热成形超薄反射镜玻璃基底表面粗糙度的影响.采用厚度为0.3 mm的Schott D263玻璃作为超薄反射镜基底材料,选取Pt、Pt/Cr作为模具和D263镜片之间的分离层材料进行实验.Pt薄膜的厚度为50nm,Cr层厚度分别为5nm、3.5nm、2.5nm、1.5nm,热成形实验采用"直接"复制方式.实验结果表明:Cr层厚度为1.5nm时,成形后模具表面分离膜未发生脱落,镜片表面粗糙度约为0.5nm,与D263镜片初始值接近,能够满足高能X射线望远镜对反射镜基底表面粗糙度的要求.     

富勒烯作为过渡层生长金刚石薄膜研究

采用微波等离子体化学气相淀积法，以Ｃ６０膜过渡层，在光滑的单晶Ｓｉ衬底（１００）表面的研磨的石英衬底表面等光学衬底上，首次在无衬底负偏压条件下生长出多晶金刚石薄膜，通过扫描电镜观察到生长膜晶粒呈莱花状，生长表面为金刚石（１００）界面。     

基于传输矩阵法的多层介质膜反射特性研究

薄膜干涉是大学物理波动光学教学的重要内容,也是薄膜光学的理论基础.薄膜干涉的一个重要应用是用于设计减反膜和高反膜.本文基于传输矩阵法,定量计算了多层介质膜的反射率.以BK7玻璃为例,无镀膜时在可见光范围内,其反射率约为4%.利用薄膜的相消干涉可以减少表面的反射率.镀一层减反膜时,对设计波长550 nm其反射率下降为1.3%,一旦偏离设计波长减反效果变差;镀两层减反膜时,在470 nm～670 nm范围内,减反效果明显改善,反射率均低于1.3%.利用薄膜的相长干涉可以增加表面的反射率.以熔石英为例,镀一层薄膜时,对设计波长1500 nm其反射率可由未镀膜时的3.3%提高到30%;镀七组薄膜时在1360 nm～1660 nm范围内其反射率均可达99%以上.通过这些定量计算,让学生更加深刻地理解所学理论知识在实际中的应用,培养工程意识,提高学习兴趣.     

Development of high performance nano-porous polyethersulfone ultrafiltration membranes with hydrophilic surface and superior antifouling properties

Hydrophilic nano-porous polyethersulfone ultrafiltration membranes were developed for milk concentration. The membranes were prepared from new dope solution containing polyethersulfone (PES)/polyvinylpirrolidone (PVP)/polyethyleneglycole (PEG)/cellulose acetate phthalate (CAP)/acrylic acid/Triton X-100 using phase inversion induced by immersion precipitation technique. This casting solution leads to formation of new hydrophilic membranes. The morphological studies were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the hydrophilicity and performance of membranes were examined by contact angel measurements and cross-flow filtration (pure water flux, milk water permeation, protein rejection and antifouling measurements). The contact angle measurements indicate that a surface with superior hydrophilicity was obtained for PES membranes. Two concentrations of PES (16 and 14.4 wt.%) and two different non-solvents (pure water and mixtures of water and IPA) were used for preparation of membranes. The morphological studies showed that the higher concentration of PES and the presence of IPA in the gelation media results in formation of a membrane with a dense top and sub-layer with small pores on the surface. The pure water flux of membranes was decreased when higher polymer concentration and mixtures of water and IPA were employed for membrane formation. On the other hand, the milk water permeation and protein rejection were increased using mixtures of water and IPA as non-solvent. Furthermore, the fouling analysis of the membranes demonstrated that the membrane surface with fewer tendencies for fouling was obtained.     

Comparative performance study of four nanofiltration membranes in the separation of mercury and chromium

In this paper, four nanofiltration membranes, viz., (1) coating of N,O-carboxymethyl chitosan (NOCC) on polyethersulfone ultrafiltration (PES UF) substrate membrane; (2) chitosan and acrylonitrile butadiene styrene (ABS) in the blend ratio of 0:100 (ABS); (3) diethylenetriamine pentaacetic acid coating via casting method on PES UF substrate membrane (DC50); and (4) NOCC and cellulose acetate (CA) polymer blend solution (0.4?wt%) coated on a glass plate (NOCC?CCA), were selected from our previous work. By using these membranes, separation behaviour of mercury and chromium ions was studied at different operating conditions from their salt solutions. From the experimental data, it is evident that ABS membrane gave highest observed solute rejection (92.88 and 88.67?% for 10?ppm feed concentration of mercury sulphate?Cwater system and chromium sulphate?Cwater system, respectively) and NOCC?CCA membrane gave highest permeate volume flux. But from the rejection as well as permeate volume flux point of view, NOCC?CPES membrane is considered to be the best choice among all the membranes.     

The influence of sulfonated polyethersulfone (SPES) on surface nano-morphology and performance of polyethersulfone (PES) membrane

In this research, firstly sulfonation of polyethersulfone (PES) was carried out and then polyethersulfone (PES)/sulfonated polyethersulfone (SPES) blend membranes were prepared with phase inversion induced by immersion precipitation technique. polyvinylpyrrolidone (PVP, 2 wt% concentration) was added in the casting solution as pore former. SPES was characterized by FT-IR and UV-visible spectra, ion exchange capacity and swelling ratio. The characterization of SPES polymer indicates that the sulfonic acid groups were produced on PES polymer. Also, the prepared PES/SPES blend membranes were characterized by contact angle, AFM, SEM and cross-flow filtration for milk concentration. The contact angle measurements indicate that the hydrophilicity of PES membrane is enhanced by increasing the SPES content in the casting solution. The SEM and AFM images show that the addition of SPES in the casting solution results in a membrane with larger surface pore size and higher sub-layer porosity. The mean pore size of the membrane increased from 98 nm for PES membrane to 240 and 910 nm for 50/50 and 0/100 PES/SPES blend membranes, respectively. The pure water flux and milk water permeation through the prepared membranes are increased by blending PES with SPES. Moreover, the protein rejection of PES/SPES blend membranes was lower than PES membrane.     

The effect of non-contact heating (microwave irradiation) and contact heating (annealing process) on properties and performance of polyethersulfone nanofiltration membranes

In this work the effect of microwave irradiation on morphology and performance of polyethersulfone (PES) membranes was investigated. The membranes were prepared with 20 wt.% of PES by phase inversion method. N,N-dimethylformamide (DMF) and mixture of water and ethyl alcohol (90/10 vol.%) were employed as solvent and coagulant respectively. Polyvinylpirrolidone (PVP) with the concentration of 2 wt.% was selected as pore former. The effects of irradiation time (10, 30, 60, 90, 120 s) and microwave power (180, 360, 720 and 900 W) on structure and performance of membranes were studied. Increasing the irradiation time and power caused variation in permeate flux and ion rejection. Moreover, the effects of annealing processes (60, 70, 80 °C) were studied. Transmembrane pressure was selected around 1.5 MPa for all experiments. Scanning electron microscope (SEM) and atomic force microscope (AFM) were employed to describe the surface morphology of the prepared membranes. The effect of microwave irradiation time in different power revealed alterations in membrane surface morphology and AFM images represented that surface parameters (such as surface roughness) have been changed. The membrane exhibited moderate rejection (47%) and low permeate flux (4.5 kg/m² h) at 80 °C for NaCl solution. The SEM images indicate that the dense skin layer is formed at 80 °C annealing.     

聚醚砜/微纳纤维素复合膜材料的光谱表征与性能研究

采用FTIR表征了聚醚砜/微纳纤维素复合膜材料的官能团特征,利用XRD分析了复合膜材料的结晶度变化情况。研究了微纳纤维素质量分数的变化对膜亲水性能的影响。通过SEM观察了复合膜支撑层的膜结构。结果表明, 复合膜材料同时具有聚醚砜、微纳纤维素红外特征峰,且没有新峰出现,说明复合膜中微纳纤维素与聚醚砜为氢键缔合作用,无新官能团的产生,达到分子水平的相容。微纳纤维素的存在使得复合膜结晶性能增强,结晶度从37.7%增大至47.9%。随着微纳纤维素质量分数的增加,复合膜对水的范德华力和氢键力增强,亲水角从55.8°下降至45.8°,表面能从113.7 mN·m-2增加到123.5 mN·m-2,从而提高了复合膜材料的亲水性。复合膜多孔支撑层表面孔数较多,孔径有所增大,膜孔分布较为均匀。     

微观结构对膜换湿能力影响研究

对多孔膜换湿过程进行了理论分析,得到了透湿量和湿阻的计算式.同时对三种膜包括PVDF,PES和纤维素膜进行了湿阻的测量实验,通过对实验数据的回归处理,得到了多孔膜的结构参数.结果表明,膜厚、孔径分布、孔隙率及曲折因子对膜的换湿特性都有较大影响,在平均孔径相同的情况下,其它因素仍然导致了不同膜换湿能力的较大差距。在所获得的结构参数基础上,通过数值模拟的方法研究了平均孔径对膜换湿能力的影响。结果表明湿阻随平均孔径的增大而减小,减小趋势逐渐平缓最后趋向一定值。     

Soft X-ray ARPES and Fermiology of strongly correlated electron systems and PES by hard X-ray and extremely low energy photons

Bulk sensitivity is inevitable for photoelectron spectroscopy (PES) when one studies bulk electronic structures of strongly correlated electron systems, which are often much different from surface electronic structures. Combination of soft and hard X-ray PES (SXPES and HAXPES) is a promising approach for this purpose by quantitatively evaluating the contribution of the surface in the observed angle integrated PES spectra. Even in the angle resolved PES studies (ARPES), the bulk sensitivity of the SX-ARPES is required to get the real bulk band dispersions and Fermi surface topology, which may be noticeably modified in the surface region as seen in several materials studied in this paper.Although hard X-ray ARPES is feasible, deep attention is required for the discussion of the possible recoil effects for the valence band. Besides, extremely low energy PES (ELEPES) by use of microwave excited Xe, Kr and Ar lamps will be as useful as those by synchrotron radiation and laser to realize a very high resolution of better than 5 meV with bulk sensitivity under certain conditions.     

陈皮中黄酮类化合物的微波辅助提取

黄酮类化合物对人体具有多种生理活性,对黄酮的提取研究具有重要的实用意义。实验通过改装微波炉,采用微波法提取陈皮中的黄酮类化合物,研究了乙醇浓度、微波温度、微波时间、微波反应器的火力点对黄酮提取率的影响。通过正交试验,确定了最佳提取工艺条件。     

人为扰动的模型势函数及其动力学特征

目前,结合高精度从头算方法和全维量子动力学计算,对四原子气相反应,理论计算可以获得与实验结果完全一致的结果。一般情况下,一个精确的量子动力学模拟需要一个精确的势能面,但是在实际的计算当中,势能面的拟合误差是不可避免的。在本文中,我们考察了在模型势能面外加各种扰动时的动力学反应行为,在2维的势能面上进行了量子动力学计算。反应速率常数对近反应能垒区域或最小能量反应路径上的干预是较为敏感的,但是在势能面上的其它地方加入的外加干扰对反应速率影响不大。本文给出一个比较重要的和比较简单的结论,在量子动力学模拟中,在精确的势能面上增加相关的扰动,会帮助我们更深入地理解给定类型的反应,对于一个特定体系,其精确势能面上可以作为一个模型体系研究。     

Hydrophilic modification of polyethersulfone porous membranes via a thermal-induced surface crosslinking approach

A thermal-induced surface crosslinking process was employed to perform a hydrophilic surface modification of PES porous membranes. Difunctional poly(ethylene glycol) diacrylate (PEGDA) was used as the main crosslinking modifier. The addition of trifunctional trimethylolpropane trimethylacrylate (TMPTMA) into the reaction solutions accelerated the crosslinking progress of PEGDA on PES membranes. The membrane surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and FTIR-ATR spectroscopy. The mass gains (MG) of the modified membranes could be conveniently modulated by varying the PEGDA concentration and crosslinking time. The measurements of water contact angle showed that the hydrophilicity of PES membranes was remarkably enhanced by the coating of crosslinked PEGDA layer. When a moderate mass gain of about 150 μg/cm² was reached, both the permeability and anti-fouling ability of PES membranes could be significantly improved. Excessive mass gain not only contributed little to the anti-fouling ability, but also brought a deteriorated permeability to PES membranes.