Role of localised surface plasmon polaritons coupling in optical transmission through double-layer metal apertures

In this paper, we investigate the optical properties of the double-layer metal films perforated with single apertures by analysing the coupling of localized surface plasmon polaritons （LSPPs）. It is found that the amplitude and the wavelength of transmission peak in such a structure can be adjusted by changing the longitudinal interval D between two films and the lateral displacements dx and dy which are parallel and perpendicular to the polarization direction of incident light, respectively. The variation of longitudinal interval D results in the redshift of transmission peak due to the change of coupling strength of LSPPs near the single apertures. The amplitude of transmission peak decreases with the increase of dy and is less than that in the case of dx, which originates from the difference in coupling manner between LSPPs and the localized natures of LSPPs.

Optimization of Microwave Extraction of Flavonoids from Water Chestnut Skin Dregs with Response Surface Method

[Objective] In order to take full advantage of processing by-product of water chestnut, the microwave extraction method of flavonoids from water chestnut skin dregs was optimized. The extracted flavonoids had a relatively high yield. [Method] The Box-Behnken design-based response surface method was adopted to optimize the microwave extraction of flavonoids from water chestnut skin dregs, a by-product of water chestnut starch. The mathematical relationships between various influencing factors and flavonoids yield were established. [Result] The optimum extraction conditions of flavonoids from water chestnut skin dregs were as follows： ethanol concentration of 55.4%, solid/liquid ratio of 1：30 g/ml, microwave power of 320 W, microwave time of 3 min and microwave time of 2 times. Under the optimum extraction conditions, the theoretical flavonoids yield was 2.376%. However, the actual flavonoids yield under the optimum extraction conditions was 2.365%. The relative error between actual values and theoretically predicted values was 0.461%. [Conclusion] The results showed the optimized extraction method is reliable, and it can provide a reference for the comprehensive and highly efficient utilization of water chestnut processing wastes.

RESEARCH ON NURBS SKINNING SURFACE VIA COMPLEX CURVES

In order to design the production with complex external shapes, a newmethod is put forward using non-uniform rational B-spline(NURBS)curves to unifythe description of complex curves composed of several segments with different degrees,and then these complex curves are used to construct NURBS skinning surface. Somekinds of skills are used to dispose the knot of NURBS curves and surfaces for practicalproblems. Finally, the method is verified by several complex examples.

Skin Sensitive Difference of Human Body Sections under Clothing— Smirnov Test of Skin Surface Temperatures' Dynamic Changing

Skin sensitive difference of human body sections under clothing is the theoretic foundation of thermal insulation clothing design. By a new method of researching on clothing comfort perception, the skin temperature live changing procedure of human body sections affected by the same cold stimulation is inspected. Furthermore with the Smirnov test the skin temperatures dynamic changing patterns of main human body sections are obtained.

Treatment of Aged Skin with a pH 4 Skin Care Product Normalizes Increased Skin Surface pH and Improves Barrier Function: Results of a Pilot Study

The physiological skin surface pH is just below 5. With age the skin surface pH increases up to 6. An increased pH correlates with reduced barrier integrity/cohesion. The present pilot study assesses possible normalization of an increased skin surface pH of the elderly and improvement of barrier function via application of ≈pH 4.0 skin care products. Baseline skin surface pH was determined in elderly (80+ years old;n = 15) compared to middle aged adults (31 - 50 years old;n = 15). The effect of o/w emulsions at pH-values of 3.5, 4.0, 4.5 and 5.5 on the skin surface pH was determined in both groups. Further, the effect of a 4-week treatment with a pH 4.0 skin care product on the skin surface pH, skin hydration and barrier integrity was assessed. Thirteen elderly females were involved in this home-in-use test. Increased baseline skin surface pH of the elderly normalizes to the physiological pH of 4.5 - 5.0 over 7 hours after single application of o/w-emulsions with a given pH of 3.5 or 4.0. A 4 week treatment employing the pH 4.0 skin care product improves the epidermal barrier integrity of the elderly significantly (p = 0.005). Reduction of the increased baseline skin surface pH of the elderly is accompanied by improved epidermal barrier integrity. Skin care products for the elderly have to be adjusted in the pH range of 3.5 to 4.0.

Casting of microstructured shark skin surfaces and possible applications on aluminum casting parts

Within the project "Functional Surfaces via Micro-and Nanoscaled Structures" which is part of the Cluster of Excellence "Integrative Production Technology" established and financed by the German Research Foundation (DFG),an investment casting process to produce 3-dimensional functional surfaces down to a structural size of 1μm on near-net-shape-casting parts has been developed.The common way to realize functional microstructures on metallic surfaces is to use laser ablation,electro discharge machining or micro milling.The handicap of these processes is their limited productivity.The approach of this project to raise the efficiency is to use the investment casting process to replicate microstructured surfaces by moulding from a laser-microstructured grand master pattern.The main research objective deals with the investigation of the single process steps of the investment casting process with regard to the moulding accuracy.Actual results concerning making of the wax pattern,suitability of ceramic mould and core materials for casting of an AlSi7Mg0.3 alloy as well as the knock-out behavior of the shells are presented.By using of the example of an intake manifold of a gasoline race car engine,a technical shark skin surface has been realized to reduce the drag of the intake air.The intake manifold consists of an air-restrictor with a defined inner diameter which is microstructured with technical shark skin riblets.For this reason the inner diameter cannot be drilled after casting and demands a very high accuracy of the casting part.A technology for the fabrication and demoulding of accurate microstructured castings are shown.Shrinkage factors of different moulding steps of the macroscopic casting part as well as the microscopic riblet structure have been examined as well.

Study on manufacturing freeform surface parts in micro EDM based on skin effect theory

Micro fabrication of freeform surface parts made of hard and brittle materials is always a tough job in micro machining field. This paper tries to fabricate freeform surface feature by using smooth surface of tool electrode after tool wear in micro EDM. According to the skin effect theory, the tool end shape in the stage of uniform wear can be changed by adjusting the frequency of discharge pulse. The electrical energy distributing rule of tool electrode section in RC circuit has been investigated under the influence of skin effect, and the law of spark location change has been summarized. The experimental studies demonstrate that different shapes of tool ends can be achieved by varying the pulse frequencies of discharge power supply. Additionally, a micro part of freeform surface feature with high precision and good surface quality has been successfully obtained by micro EDM through adopting the smooth surface after tool wear.

Skin Sensitive Difference of Human Body Sections under Clothing - Multiple Analysis of Skin Surface Temperature Changes

A new researching method on clothing comfort perception is developed.By it the skin surface temperature changes and subjective psychological perception of human body sections stimulated by the same cold stimulation are studied.With the multiple comparison analysis method the changing laws of skin temperature of main human body sections is obtained.

Influence of Surface Topography on the Tactile Friction of Medical Compression Textiles against a Mechanical Skin Model

Influence of surface topography on the tactile friction of medical compression textiles was studied in this paper. The friction behavior was investigated for three kinds of medical textiles with various structures and compositions by using a textile friction analyzer under dry condition. In order to simulate the contacts of textiles/human finger, a mechanical skin model with similar texture to the skin and applied normal load oflN were selected. Meanwhile, the 3D surface topography of textiles was measured using a digital microscope. The topographical data were analyzed concerning height distribution and material ratio, and the real contact area was estimated as a function of penetration depth. Results showed that the investigated textiles revealed a significant variation on the friction coefficients, which were （ 0.41 ± 0.01 ） （ polyamide, jersey 2 × 2 ）, （0.56 ± 0. 01） （cotton, jersey 2×2） and （0. 47 ± 0. 01） （polyamide, jersey 1 × 1 ）, respectively. The textile with higher friction coefficient was found to own a relative compact and homogenous surface and larger contact area, vice versa.

New Algorithm for Local Shape Preservation T-Spline Surface Skinning

Surface skinning is a widely used algorithm in CAD modeling which permits designer to pass surface through several section curves, thus providing modeling process with powerful ability to describe complex shapes and transform the 2D design intention into 3D space. This paper contributes in the combination of T-Spline technology and surface skinning modeling by introducing a new algorithm for local shape preservation T-Spline surface skinning. The examples given in the paper show that this algorithm is effective.

Monitoring the penetration and accumulation of gold nanoparticles in rat skin ex vivo using surface-enhanced Raman scattering spectroscopy

Contamination by accidental cutaneous contact with the commercial products and the air pol-hutants raised a considerable health and safety issue.This study aimed to trace the dynamics of the 20 nm gold nanopartide(GNP)penetration and accumulation in rat skin tissues using a surface-enhanced Raman scattering(SERS)techmique.After the topical application of GNPs on rat skin surface,the SERS spectra were recorded for every 15 pum to an overall depth of 75 pum from skin surface for 150 min.The processes of GNP penetration in rat skin were accompanied by aggregation of GNPs,which affected SERS spectra.The results revealed that 20 nm GNPs can penetrate through stratum corneum layer,viable epidermis layer,and then into dermis layer.This study demonstrated for the first time the potential of SERS spectroscopy to monitor the penetration and accumulation of GNPs in rat skin.

Large area planar plasma sustained by surface microwave

In this paper, we show theoretically and experimentally that the large-area planar plasma with high density and good uniformity can be sustained by a surface microwave when the electron density is over-dense. From the experimental results we find that the nonuniformities in azimuthal plasma density and electron temperature have been greatly improved and in particular the nonuniformity is less than 10% when the gas pressure is 30 Pa. By improving the antenna shape, enhancing the microwave power and choosing the appropriate gas pressure, the large area planar plasma with high density can be produced.

Theoretical demonstration of surface plasmon polaritons in plasma/vacuum interface in GHz frequency

Negative permittivity of the material may lead to the enhanced radiation of an antenna embedded in a finite plasma,which suggests a potential way to solve blackout problem in space technology.However,the enhanced radiation phenomenon is still lack of strict theoretical investigations of surface plasmon polaritons(SPPs) in plasma in GHz frequency.In this paper,we demonstrate the SPPs excited at a plasma/vacuum interface in GHz frequency by the consistency of the simulated and theoretical results.With SPPs,plasma layer thicker than skin depth can be penetrated with w <w,pwhich is a complement of wave propagation theory in plasma.We also discuss the influences of thickness d,collision frequency Γ,and different plasma frequencies on SPPs.For plasma frequencies with large difference,common numerical methods have difficulties in result comparison under the same mesh size because of the computer capacity and memory.The analytical multilayer method used in the paper does not need to generate mesh,so the studies of plasma frequencies with large difference can be carried out.The simulation shows that the SPPs can be excited for an arbitrary plasma frequency.We believe the study will be beneficial for the problem of wave propagation in plasma science and technology.

Numerical Modeling of Non-Similar Mixed Convection Heat Transfer over a Stretching Surface with Slip Conditions

In this paper, the heat transfer effect on the steady boundary layer flow of a Casson fluid past a stretching surface in the presence of slip conditions was analyzed. The stretching surface is maintained at a constant temperature. The boundary layer conservation equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, stable Keller-box finite difference scheme. The resulting equations are solved numerically by using the Kellerbox finite-difference method, and the expressions for velocity and temperature are obtained. They satisfy all imposed initial and boundary conditions and reduce to some well-known solutions for non-Newtonian fluids. Numerical results for velocity, temperature, skin friction and Nusselt number are shown in various graphs and discussed for embedded flow parameters. It is found that both velocity and temperature decrease with an increase of the Casson fluid parameter.

Predict Aerodynamic Drag of Spacecraft in Very Low Earth Orbit Using Different Gas-Surface Interaction Models

The accurate prediction for aerodynamic drag of spacecraft in very low Earth orbit(VLEO) is a fundamental prerequisite for aerospace missions in VLEO. The present work calculates aerodynamic drag of the Gravity Field and Steady-State Ocean Circulation Explorer(GOCE) satellite using the test particle Monte Carlo(TPMC) method. The primary goal is to obtain a comprehensive understanding of surface pressure and skin friction on the spacecraft surface and assess the sensitivity of aerodynamic drag to the gas-surface interaction(GSI) models. Results indicate that surface pressure is mainly distributed on the front of the satellite body and panels while skin friction is primarily distributed on the sides. In addition, as the GSI model changes from diffuse to specular reflection, the total drag coefficient is reduced at operation altitudes above 170 km. Therefore, the satellite surface should be processed so carefully that the GSI remains far from diffuse reflection from the view point of the drag-reduce design.

板式家具表面肤感装饰技术研究进展

随着科技的提升和人民生活水平的提高,消费者对木质家居产品的品质要求从“视觉”向“触觉”发展,“肤感”家具产品近年来发展迅速。本文对板式家具表面肤感装饰技术的研究进展进行概述,总结板式家具肤感表面形成机制,肤感产品的生产技术、肤感性能评价方法等,并分析存在的问题与发展建议,为板式家具表面肤感性能的进一步提升提供参考。

针迹类型对表面肌电用刺绣型织物电极性能影响

为设计与开发高性能的表面肌电用刺绣型织物电极,优化其工艺参数,采用镀银纱线作为导电刺绣线,以弹性针织面料作为刺绣基底织物,制备了4种不同针迹类型的刺绣电极,测试了其皮肤-电极阻抗,并在行走和慢跑2种状态下使用刺绣电极与Ag/AgCl凝胶电极同步采集了小腿腓肠肌表面肌电信号,采用时域、频域及相关函数分析了刺绣电极与凝胶电极采集的肌电信号拟合性能。结果表明:针迹类型对刺绣电极的皮肤-电极阻抗有显著影响,其中放射状刺绣电极的皮肤-电极阻抗相对最小,而圆环状刺绣电极的阻抗最大;4种不同针迹类型的刺绣电极与Ag/AgCl凝胶电极的表面肌电信号采集效果较为相似,验证了刺绣电极的可行性;放射状刺绣电极的表面肌电信号拟合性能较优,更适合用于肌电信号监测。

基于遗传算法-反向传播神经网络优化高压-超声-酶解法提取羊皮胶原蛋白工艺

采用高压-超声-酶解法提取羊皮胶原蛋白,对比遗传算法-反向传播(genetic algorithm-back propagation,GA-BP)神经网络模型和响应面模型的优化效果,确定最佳工艺参数。结果表明:GA-BP神经网络在模型拟合和预测方面表现优于响应面模型;最佳提取参数为高压时间23 min、超声时间22 min、酶添加量3.2%、酶解时间222 min,羊皮胶原蛋白提取率达到(80.5±1.6)%,较传统的木瓜蛋白酶法提高40%;紫外-可见吸收光谱和傅里叶变换红外光谱结果显示,此条件下提取的羊皮胶原蛋白结构完整,高压-超声-酶解法对胶原蛋白的破坏较小。

响应面优化酸法提取猪皮胶原蛋白工艺

本实验采用酸法提取猪皮中胶原蛋白,通过单因素和响应面分析实验,研究了柠檬酸浓度、加热时间、液料比和提取温度对胶原蛋白提取率的影响,以提取率为响应值进行响应面优化。结果表明:柠檬酸的胶原蛋白提取率高于盐酸和醋酸,对提取效果的影响大小为提取温度>柠檬酸浓度>加热时间>液料比。胶原蛋白优化最佳工艺为:柠檬酸浓度0.5 mol/L、加热时间29 min、液料比20.6 mL/g、提取温度72℃,该工艺条件下胶原蛋白提取率可达82.7%。

杏仁皮缩合单宁酶法提取工艺优化

在单因素基础上,利用响应面法优化杏仁皮缩合单宁的酶法提取工艺。以杏仁皮缩合单宁提取量为指标,考察了酶的用量、溶液pH值、提取温度、提取时间对杏仁皮缩合单宁提取量的影响。结果显示,所建立的杏仁皮缩合单宁提取工艺模型极显著,且在酶用量为26 U/g、溶液pH值为4.2、提取温度为52℃、提取时间为4 h的条件下,杏仁皮缩合单宁的提取量最高,预测值为38.71 mg/g,实际值为38.73 mg/g,结果表明优化的最佳提取工艺与预测方法相符。