塑料光学元件的清洗、镀膜和胶合

各种塑料光学元件在光学系统中的应用越来越广泛。作为光学元件,必然涉及清洗、镀膜和胶合等工艺技术问题。本文就塑料光学元件的这三个技术作一介绍。     

Characterization of strongly interacted multiple cracks in an infinite plate

Based on the Kachanov method and the alternating iteration technique, a new method is proposed to deal with the problem of the strongly interacted multiple cracks in an infinite plate. Unlike the Kachanov method which neglects the interaction of the tractions of the non-uniform components, the tractions of the non-uniform components on the surfaces of cracks are considered through the alternating technique. The accuracy and efficiency of present method are validated by comparing the results of two collinear and two parallel overlapped open the cracks obtained by the present method with those of the exact solutions, the results of the Kachanov method and the alternating iteration technique. Applications of present method in solving sliding close crack problems and evaluating the plastic zones demonstrate the versatility of present method.     

可用于激光核聚变的闪烁中子探测器

在当前激光核聚变实验中,中子集中在短时间内出现、且产额低。为适应这种特点,要求探测器的效率高,分辨时间短。利用闪烁中子探测器探测激光核聚变所产生的中子,能测定中子产额,记录中子能量,而且探测效率高,分辨时间短。缺点是易受γ射线、X射线的干扰。     

塑料成型工艺实习CAI课件的开发

针对当前学生实习面临的困难，以Authorware为开发工具，编制了塑料成型工艺实习CAI课件，整个软件图文并茂，图像，动画，解说，音乐相结合，形象地介绍了塑料各种成型工艺的主要原理，生产设备，工艺流程和相关产品，应用本软件学生可以进行模拟实习，该软件激发了学生学习的兴趣，提高了实习质量。     

Sensitive Voltammetric Sensing of the 2,3‐Dimethyl‐2,3‐dinitrobutane (Dmnb) Explosive Taggant

The highly sensitive voltammetric detection of the 2,3‐dimethyl‐2,3‐dinitrobutane (DMNB), a required additive to commercial plastic explosives, is described. The protocol relies on a fast square‐wave voltammetric measurement of the DMNB explosive taggant at an unmodified carbon fiber electrode using a phosphate buffer (pH 7.0) solution. Different solutions and working electrodes were evaluated. Under the optimal conditions, a linear response is observed over the 300–3000 μg/L DMNB concentration range examined, with a detection limit of 60 μg/L. A highly stable response, with a relative standard deviation (RSD) of 2.6%, is observed for 30 repetitive measurements. Such electrochemical approach offers great promise for a simple, rapid, sensitive and inexpensive field screening of plastic explosives. Preliminary data illustrate the utility of electrochemical detection for electrophoretic microchips for the simultaneous measurements of DMNB, cyclotrimethylenetrinitramine (RDX) and pentaerythritoltetranitrate (PETN).     

Preparation and characterization of a codeine responsive electrode

Summary The behaviour of codeine reineckate and codeine tetraphenylborate membrane electrodes has been observed with a respectiveNernstian response of 58 and 56 mV/decade for 9.3×10^–5–1.3×10^–3 M codeine sulfate solutions. The workingpH ranges were 5–8 and 4–8, respectively. The selectivity towards sugars, amines, amino acids, cations, and some pharmaceutical compounds was found to be satisfactory. The isothermal temperature coefficient was 0.0014 V/°C. The electrodes were applied successfully for the determination of codeine in some pharmaceutical dosage forms with a relative standard deviation range of 0.16–0.30% and an average recovery of 98.6±0.6%.

---

Herstellung und Charakterisierung einer codeinselektiven Elektrode

Zusammenfassung Das Verhalten von Codeinreineckat- und Codeintetraphenylboratmembranelektroden in 9.3×10^–5–1.3×10^–3 M Codeinsulfatlösungen wurde untersucht (Nernstscher Response: 58 bzw. 56 mV/Dekade). Der verwendetepH-Bereich für die beiden Elektroden war 5–8 bzw. 4–8. Ihre Selektivität gegenüber Zuckern, Aminen, Aminosäuren, Kationen und einigen pharmazeutisch aktiven Verbindungen ist zufriedenstellend. Der isotherme Temperaturkoeffizient beträgt 0.0014V/°C. Die Elektroden wurden erfolgreich zur Bestimmung von Codein in einigen pharmazeutischen Präparaten eingesetzt (relative Standardabweichung: 0.16–0.30%).

     

Purification, cloning and expression of an Aspergillus niger lipase for degradation of poly(lactic acid) and poly(ε-caprolactone)

A lipase from Aspergillus niger MTCC 2594 was purified 53.8-fold to homogeneity by hydrophobic interaction chromatography using octyl sepharose and the enzyme showed two protein bands with apparent molecular mass of 35 and 37 kDa respectively. The lipase exhibited maximum activity at pH 7.0 and 37 °C and was stable between pH 4.0 and 10.0 and temperatures up to 50 °C. The values of K_m and V_max were 3.83 mM and 32.21 μmol/min/mg respectively, using olive oil as substrate. Lipase encoding gene, lipA, coded for 297 amino acid residues with conserved pentapeptide sequence, G-H-S-L-G, was cloned and expressed in Pichia pastoris. Although lipA showed high homology with the known Aspergillus lipases, it exhibited differences in putative lid domain. Both native and recombinant lipases have potential for degradation of poly(lactic acid) and poly(ε-caprolactone), and the present study will serve as a baseline of initial studies for its exploitation in polymer degradation.     

An integrated plastic microchip for enhancing electrophoretic separation using tunable pressure-driven backflows

Microfluidic CE (MCE) is an effective solution for rapid and sensitive determination of multiple analytes. Herein, a dynamic coated cyclic olefin copolymer microchip was developed having an on-chip micropump for fluid velocity adjusting in electrophoretic separations. This micropump was fabricated by constructing a polyacrylamide gel membrane at one channel terminal. Once applying electric field across the membrane, a pressure-driven flow generated automatically to balance the electroosmotic flow (EOF) mismatch at the channel-membrane interface. The influence of gel precursor concentration and operating voltages on the fluid velocity was carefully evaluated. Moreover, the highly integration of injection, separation, and pumping units of the MCE system minimized the dead volume and provides satisfied column efficiency. Experiments showed that by adjusting of pumping voltage reduced the fluid velocity by a factor of 6, resulting six- and threefold resolving power enhancements of rhodamine dye mixture and amino acid mixture, respectively. Furthermore, the developed MCE method was applied for rhodamines and amino acids quantitation in food and cosmetics, with standard addition recoveries of 87.3–106.9% and 89.9–117.4%, respectively. These results were also confirmed by standard HPLC method, revealing the application potential in fast and onsite analysis of complex samples.     

Estimation on the optic loss for acrylic polymers by theoretical modification

Various fluorinated/chlorinated polymers were synthesized and characterized by FT-IR and NMR. Also, theoretical optic loss of the POF were investigated and proposed for the purpose of finding a definite rule of the optic loss.From the computation of the results, the modified equation was theoretically deduced, and the optic loss of each prepared polymer was measured and compared with the calculated optical loss of polymers. Also, it was found that the optic loss from the modified equation fitted well with the experimental data.