Simple and universal method in designs of high-efficiency diffractive optical elements for spectrum separation and beam concentration

Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.

INDIRECT THERMO－OPTICAL DETECTION FOR CAPILLARY ELECTROPHORESIS SEPARATION OF AMINO ACIDS

In this letter, we first reported a novel method-indirect thermo-optical detection used in CE separation of native amino acids. By using methylene blue as background aborber,the detecion limit for lysine was 5×10(-5)mol/L.

Optical Separation of Racemic Phenyl-alanine, and Structure of Complex Consisting of R-Phenylalanine and R-Mandelic Acid

The racemic phenylalanine has been separated by (R)-mandelic acid through the formation of diastereomeric molecular complex. The crystal of the title chiral complex (C8H8O3 C9H11NO2, Mr = 317.33) belongs to monoclinic, space group C2 with a = 19.391(3), b = 5.715(4), c = 15.755(3) ? b = 115.23(1), V = 1579(1) 3, Z = 4, Dc = 1.335 g/cm3, F(000) = 672, m = 0.099 mm-1, R = 0.033 and wR = 0.060 for 1278 observed reflections (I > 2s(I)). The complex consists of (R)-mandelic acid and (R)-phenylalanine in 1:1 molar ratio, and the complex molecules form layered crystal structure by self-assembly through intermolecular H-bonding between carboxyl and carboxylate of the neighboring molecules.

Separation of cortical arteries and veins in optical neurovascular imaging

Separation of arteries and veins in the cerebral cortex is of significant importance in the studies of cortical hemodynamics,such as the changes of cerebral blood flow,perfusion or oxygen con-centration in arteries and veins under different pathological and physiological conditions.Yet the cerebral vessel segmentation and vessel-type separation are challenging due to the complexity of cortical vessel characteristics and low spatial signal-to-noise ratio.In this work,we presented an effective full-field method to differentiate arteries and veins in cerebral cortex using dual-modal optical imaging technology including laser speckle imaging(LSI)and optical intrinsic signals(OIS)imaging.The raw contrast images were acquired by LSI and processed with enhanced laser speckle contrast analysis(eLASCA),algorithm.The vascular pattern was extracted and seg-mented using region growing algorithm from the eLASCA-based LSI.Meanwhile,OIS imageswere acquired altermatively with 630 and 870 nm to obtain an oxy hemoglobin concentration mapover cerebral cortex.Then the separation of arteries and veins was accomplished by Otsuthreshold segmentation algorithm based on the OIS information and segmentation of LSI.Finally,the segmentation and separation performances were assessed using area overlap measure(AOM).The segmentation and separation of cerebral vessels in cortical optical imaging have great potential applications in full-field cerebral hemodynamics monitoring and pathological study of cerebral vascular diseases,as well as in clinical intraoperative monitoring.

Investigation of Dispersion Compensation in 2.5 Gbit/s OOK Label and 40 Gbit/s RZ-DPSK Payload Optical Label Switching System Based on Optical Carrier Suppression and Separation

Three dispersion compensation schemes of an optical label switching transmission system were investigated, which employs 40 Gbit/s return zero differential phase-shift keying（RZ-DPSK） payload labeled with 2.5 Gbit/s on-off keying（OOK） signal based on the optical carrier suppression and separation（OCSS） techniq ue, In the system, proposed are the receiver sensi ti vity oS payload and label, achieving -- 32. 4 dBm and --38.5 dBm, respectively. Using the optimal dispersion compensation scheme, after transmitted over 160 km and 320 km SMF respectively, the label can be recovered without power penalty, while the payload can be recovered with less than 2 dB and 5 dB penalty, respectively.

Results of the Main Phase of Ion Separation in the Process of Plasma-Optical Mass Separation

This paper presents separation results of a mixture of nitrogen, argon and krypton ions in the process of plasma-optical mass separation on the POMS-E-3 separator model. We determined the behavior of the separation with a change in the value of magnetic field induction in the azimuthator and in the degree of compensation of the spatial charge in ion flows. An analysis is performed for experimental data by correlation with the results of a theoretical study and numerical experiments. The objectives of future experiments are outlined.

Theoretical study on isotope separation of an ytterbium atomic beam by laser deflection

Isotope separation by laser deflecting an atomic beam is analyzed theoretically. Interacting with a tilted one- dimensional optical molasses, an ytterbium atomic beam is split into multi-beams with different isotopes like 172yb, Jv3yb, and J74yb. By using the numerical calculation, the dependences of the splitting angle on the molasses laser intensity and detuning are studied, and the optimal parameters for the isotope separation are also investigated. Furthermore, the isotope separation efficiency and purity are estimated. Finally a new scheme for the efficient isotope separation is proposed. These findings will give a guideline for simply obtaining pure isotopes of various elements.

Chiral Separation of Spiro-compounds and Determination Configuration

Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synthesizing active enantiomers, or as surface modifiers on silica particles to resolve entantiomers. In this study, five spiro compounds of 3,9-diphenyl-2,4,8,10-tetraoxaspiro[5.5]-undecane（1）, 3,9-（4-methoxyphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（2）, 3,9-（4-methylphenyl）-2,4,8,10-tetraoxaspiro [5.5] -undecane（3）, 4,4＇-（2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl）dibenzoic acid（4） and 3,9-di（4-formyl-phenyl）-2,4,8,10-tetraoxa-spiro[5.5]-undecane（5） were synthesized by grinding pentaerythritol with benzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-carboxybenzaldehyde or terephthalaldehyde monoacetal in the presence of InI3r3 under solvent-free conditions. A normal phase HPLC method was successfully developed to resolve entantiomers of compounds 1--5 on a chiral column. Specific optical rotation of R or S entantiomers（1） was determined and the corresponding configurations were proposed based on Lowe＇s rule.

Automatic separation system for marine meiobenthos based on laser-induced fluorescence technology

An automatic system for marine meiobenthos separation was developed by using laser-induced fluorescence tech- nology. Rose Bengal was used as organism dye and the spectrums of Rose Bengal were measured. Laser-induced fluorescence system was established to detect marine meiobenthos in sediments. Data obtained from experiments were analyzed by using a mathematical model. The results showed that laser-induced fluorescence technology worked well in the system. The system could select the meiobenthos efficiently and precisely.

Optical Measurements of Shock Waves in Critical Nozzles at Low Reynolds Numbers

Two-dimensional critical nozzle flows at low Reynolds numbers are visualized by the rainbow schlieren deflectometry. Experiments have been performed in a region of overexpanded nozzle flow. The variation of the shock structure against the back pressure ratio can be clearly visible with color gradation. Static pressure rises due to the shock-induced flow separation are compared with the previous theories. The unsteady characteristics of overexpanded critical nozzle flows at low Reynolds numbers are quantitatively and qualitatively visualized using laser schlieren and Mach-Zehnder interferometer systems combined with a high-speed digital camera. It was found that an oscillating normal shock wave appears inside the nozzle, and that the shock wave has a specified dominant frequency. Also the time-history of the oscillating shock wave is obtained from both the systems and compared with each other.

Separation and insertion of optical bit-serial label in optical packet switching

The bipolar phase-shift-keying （BPSK） optical orthogonal codes （OOCs） are inserted into the optical packet format of bit-serial label. The ultra-fast separation of the label and payload is performed through the auto-correlation pulses indicating the time position at whicl, the optical switch changes the state. The insertion of the new label can also be realized by detecting the auto-correlatiou pulse at the line rate. Especially, the scheme can be adapted to the asynchronous separation and insertion and realize the variable-length packet switching. The results of simulation verify the fea.sibility of the scheme.

Highly Soluble Polyimides Containing Di-tert-butylbenzene and Dimethyl Groups with Good Gas Separation Properties and Optical Transparency

A rigid aromatic diamine monomer containing di-tert-butylbenzene and dimethyl groups,3,3'-dimethyl-4,4'-diaminophenyl-3",5"-di-tert-butyltoluene,was successfully synthesized by a simple coupling reaction using 3,5-di-tert-butylbenzaldehyde and o-toluidine as starting materials.A series of novel polyimides(PI 3a-3c)with large pendant groups were prepared with the obtained diamine monomer and three different commercial aromatic dianhydrides(3,3',4,4'-biphenyltetracarboxylic dianhydride,4,4'-oxydiphthalic anhydride,and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride)by one-step high temperature polycondensation.The prepared polyimides exhibited high solubility and good membrane forming ability:they could be dissolved not only in some high boiling solvents such as DMF,NMP,DMAc,and m-Cresol at room temperature,but also in some low boiling solvents such as CHCl3,CH2Cl2,and THF.Their solubility in most solvents could exceed 10 wt%,and the flexible membranes could be obtained by casting their solutions.The prepared membranes exhibited good gas separation properties.The permeability coefficients of PI 3c for CO2 and O2 were up to 124.6 and 42.8 barrer,respectively,and the selectivity coefficients for CO2/CH4 and O2/N2 were 14.7 and 3.3,respectively.The membranes had light color and good optical transmission.Their optical transmittance at 450 nm wavelength was in the range of 67%-79%,and the cutoff wavelength was in the range of 310-348 nm.They also had good thermal properties with glass transition temperature(Tg)values in the range of 264-302℃.In addition,these membranes possessed good mechanical properties with tensile strength ranging between 77.8-87.4 MPa,initial modulus ranging between 1.69-1.82 GPa,and elongation at break ranging between 4.8%-6.1%.

Isotope separation of Potassium with a magneto–optical combined method

Due to the similar physical and chemical properties, isotopes are usually hard to separate. On the other hand, the isotope shifts are very well separated in a high-resolution spectrum, making them possible to be addressed individually by lasers, thus separated. Here we report such an isotope separation experiment with Potassium atoms. The isotopes are independently optical pumped to the desired spin states, and then separated with a Stern–Gerlach scheme. A micro-capillary oven is used to collimate the atomic beam, and a Halbach-type magnet array is used to deflect the desired atoms. Finally, the 40K is enriched by two orders of magnitude. This magneto–optical combined method provides an effective way to separate isotopes and can be extended to other elements if the relevant optical pumping scheme is feasible.

Spatial separation of spectrum inside the tapered metamaterial optical waveguide

In this work,the optical metamaterials based on silver dendritic cells are prepared by electrochemical deposition,and its transmission and focusing behaviors are investigated.The experimental results show that the optical metamaterials reveal a multiple pass-band transmission spectrum and a prominent focusing effect at the wavelength corresponding to the maximum transmission coefficient.Two optical metamaterial samples are combined into a tapered optical waveguide,and the spectra of transmitted light at the surface of the tapered optical waveguide is measured by using the fiber spectrometer along the light propagation direction.The results demonstrate that each frequency component of the wave packet is stopped at a different waveguide thickness,leading to the spatial separation of its spectrum.The spatial separation of spectrum can be effectively tuned by adjusting the inclination of the tapered optical waveguide,which can be used for storing photons and slow-light research.

Phaco联合房角分离术治疗急性闭角型青光眼合并白内障患者的疗效及对视盘血流密度的影响

目的:探讨白内障超声乳化吸出(Phaco)联合房角分离术治疗急性闭角型青光眼(APACG)合并白内障患者的疗效及对视盘血流密度的影响。方法:选取100例APACG合并白内障患者为研究对象,依据手术方式不同分为对照组和观察组,每组各50例。对照组患者实施Phaco+小梁切除术治疗;观察组患者实施Phaco+房角分离术治疗,随访2个月。比较两组患者术后2个月临床疗效;术前、术后7 d、术后1及2个月最佳矫正视力(BCVA);术前及术后2个月眼压、散光度、前房深度及前房角度;术前、术后1 d、术后7 d、1个月及2个月视盘及盘周血流密度;治疗及随访期间并发症发生情况。结果:观察组术后2个月临床总有效率高于对照组(96.00%vs.84.00%,P<0.05)。术后随时间推移,两组患者BCVA均上升(P<0.05),且观察组各时间点均高于对照组(P<0.05)。术后2个月,两组患者眼压均下降(P<0.05),但组间差异无统计学意义(P>0.05);散光度均上升(P<0.05),但观察组低于对照组(P<0.05);前房深度均上升,但组间差异无统计学意义(P>0.05);前房角度均上升(P<0.05),且观察组高于对照组(P<0.05)。术后1 d,两组患者视盘整体血流密度均下降(P<0.05),术后7 d开始上升(P<0.05),术后1个月与术前无统计学差异(P>0.05),术后2个月较术前升高(P<0.05),且术后各时间点观察组均高于对照组(P<0.05)。术前及术后各时间点两组盘周血流密度差异无统计学意义(P>0.05)。观察组总并发症发生率低于对照组(8.00%vs.24.00%,P<0.05)。结论:相较于Phaco+小梁切除术,Phaco联合房角分离术能进一步提升APACG合并白内障患者临床疗效,能更好改善患者术眼散光度及前房角度,提升患者视盘血流密度,且并发症较少。

高光纯D-乳酸生产菌株假肠膜明串珠菌HL64-1的分离鉴定及其发酵特性

从自然界中筛选分离产酸菌是获得高光学纯度乳酸生产菌株有效的途径之一。从腐烂果实中分离获得一株产高光学纯度D-乳酸菌株HL64-1,经形态学、16S rDNA序列分析、序列相似性Blast比对分析鉴定为假肠膜明串珠菌(Leuconostoc pseudomesenteroides)。在基础发酵培养基中摇瓶发酵24 h,产D-乳酸的量达到62.18 g/L,产酸速率达2.59 g/(L·h),光学纯度达99.90%(ee);在5 L发酵罐中放大培养,通过补加碳源,发酵72 h,D-乳酸产量达到78.74 g/L,平均产酸速率达1.09 g/(L·h)。该菌株可以有效利用农业副产物花生饼粉和棉籽粉作为替代氮源以降低发酵原料成本。该菌还可利用木糖产生D-乳酸,且葡萄糖能显著提高木糖的利用效率,极具工业应用前景。

压力敏感涂料测量技术在掠型叶栅表面测压中的应用

为了获得某掠型叶片吸力面压力分布,对一稠度为1.53,掠角为10.7°的掠叶栅进行了光路布局以及压力敏感涂料(PSP)压力测量,利用图像处理和三维重构算法得到了可读性高、便于数据提取的三维叶片吸力面压力分布,并和测压孔测量结果进行了对比。结果表明:利用自主发展的光路布局方法,有效解决了叶片表面光照辐照度不均匀、拍摄视角受限的问题;得到了高信噪比的原始压敏图像以及宽范围多工况的掠叶栅吸力面全域压力分布。与测压孔测量相比,PSP测量误差在5%以内,并且PSP测量结果还捕捉到了峰值等熵马赫数位置沿弦向的迁移以及叶片尾缘的气流分离现象。对不同攻角和来流马赫数下的掠型叶片吸力面压力分布进行分析:掠型叶片在零攻角和正攻角下存在明显的径向压力梯度,促使后掠型叶片气流向前掠迁移,增加了前掠下流低能流体的能量,使得前掠更有利于延迟角区分离,后掠则更容易发生角区分离;掠型叶片在低来流马赫数下展向压力对称性良好,掠设计的影响不显著,高来流马赫数则放大了前后掠对角区分离控制效果的不同。相比传统测压孔有限的压力分辨率,PSP测量可为掠型叶片设计和流动机理分析提供丰富可靠的压力实验数据。

混合煤矸放落态势特征研究

传统的基于图像检测技术的放顶煤过程中煤流动态特性研究多侧重于某一特定阶段的图像分析,未结合全阶段的动态特性进行综合分析;现有研究较少将放顶煤过程中上覆岩层的松散区变化与放煤过程中的煤矸分离和煤流特性相结合,缺乏对放煤过程的全局性系统分析。针对上述问题,对放顶煤过程中的煤流动态特性、煤矸分离效果及上覆岩层松散区凹陷变化进行了系统研究。首先,提出了一种基于双光流网络的放顶煤过程动态分析方法。实验结果表明:不同放煤方案下,放煤速度不随放煤形式和规律的变化而改变,平均检测准确率随着放煤口数量的增多而提高,尤其在不同放煤步距阶段呈明显线性增长;顶煤放出率与平均检测准确率呈正相关关系,验证了该方法在放顶煤过程监测中的有效性。其次,利用OpenCV技术对上覆岩层松散区凹陷面积进行实验分析。结果表明,初始放煤阶段松散区凹陷面积急剧增长,随后随时间推移逐渐趋于稳定;通过凹陷面积的动态变化趋势,可有效判断顶煤的放出过程,实现透明化放煤监测。最后,结合称重实验数据,分析了放煤量、放出率与含矸率之间的关系。结果表明,初始放煤阶段纯煤放出量最大,周期放煤阶段纯煤放出量趋于稳定,含矸率则随着放煤口数量的增多而减少。该结果进一步揭示了放煤方式对煤矸分离和顶煤放出率的影响。

红外与可见光双模导引头光学系统设计

为了提升导弹在复杂环境下的寻的制导能力,设计了一种红外与可见光双模式导引头光学系统。该方案中采用分光镜透射红外光反射可见光,使结构布局更加紧凑,实现红外与可见光共口径,同时配合红外材料选取,实现光学被动消热差设计。中红外模式视场角3°×2.3°,可见光模式视场角5°×4°,工作温度20℃条件下,双模式在截止频率处,MTF(Modulation Transfer Function)值均大于0.4。红外与可见光双模式光学系统适合应用于复杂环境的导弹制导,对温度有良好的适应性,具有较好的成像质量,满足系统的性能要求。

卷烟制造过程梗签分离工艺及装备研究进展

针对卷烟中过多梗签会损害其物理属性并影响吸食体验的问题,对卷烟制造过程主要梗签分离工艺和装备进行了综述,认为:卷烟制造过程中梗签分离集中在制丝和卷包两个关键工段,分离工艺主要有风选、振筛及复合工艺,其中风选为梗签分离的主流工艺。通过装备改进和参数优化能提高梗签风选分离效率,但烟丝损耗与纯净度间的平衡关系仍面临挑战;振筛易受筛网阻塞和清洁等问题影响,但将其与风选等工艺进行结合的复合工艺逐渐受到重视;光选识别与风选相结合的复合工艺为卷烟工业带来更为精准和智能的梗签分离解决方案,但目前尚未在实际生产线得到广泛应用。未来,可加强风选技术的研发,并将其与振筛、光选识别等技术进行深入、系统的融合,以提高梗签分离效率和烟丝回收利用率,并实现卷烟产品品质与物料消耗的平衡发展。