Quantification of six bioactive compounds in Zhenqi Fuzheng preparation by high-performance liquid chromatography coupled with diode array detector and evaporative light scattering detector

A simple and accurate high-performance liquid chromatography（HPLC）coupled with diode array detector（DAD）and evaporative light scattering detector（ELSD）was established for the determination of six bioactive compounds in Zhenqi Fuzheng preparation（ZFP）.The monitoring wavelengths were 254,275 and 328 nm.Under the optimum conditions,good separation was achieved,and the assay was fully validated in respect of precision,repeatability and accuracy.The proposed method was successfully applied to quantify the six ingredients in 31 batches of ZFP samples and evaluate the variation by hierarchical cluster analysis（HCA）,which demonstrated significant variations on the content of these compounds in the samples from different manufacturers with different preparation procedures.The developed HPLC method can be used as a valid analytical method to evaluate the intrinsic quality of this preparation.

An active coronagraph using a liquid crystal array for exoplanet imaging:principle and testing

High-contrast imaging coronagraphs, used for the detection of exoplanets, have always adopted passive coronagraph optical components. It is therefore impossible to actively optimize the coronagraphs to achieve their best performance. To solve this problem, we propose a novel high-contrast imaging coronagraph which combines a liquid crystal array （LCA） for active pupil apodization and a deformable mirror （DM） for phase correction. The LCA we use is an amplitude-only spatial light mod- ulator. The LCA is well calibrated and compensates for its amplitude non-uniformity and nonlinear intensity responsivity. We measured the imaging contrasts of the coron- agraph system with the LCA only and without the DM deployed. Imaging contrasts of 10-4 and 10-5 can be reached at an inner working angular distance of 2.5 and 5A/D, respectively. A simulation shows that the phase errors on the coronagraph pupil limit the contrast performance. The contrast could be further improved if a DM is deployed to correct the phase errors induced by the LCA and coronagraph optics.

Wideband Reconfigurable Millimeter-Wave Linear Array Antenna Using Liquid Crystal for 5G Networks

The advanced design of a 10 × 1 linear antenna array system with the capa-bility of frequency tunability using GT3-23001 liquid crystal (LC) is pro-posed. The design for this reconfigurable wideband antenna array for 5G ap-plications at Ka-band millimeter-wave (mmw) consists of a double layer of stacked patch antenna with aperture coupled feeding. The bias voltage over LC varies from 0 V to 10.6 V to achieve a frequency tunability of 1.18 GHz. The array operates from 25.3 GHz to 33.8 GHz with a peak gain of 19.2 dB and a beamwidth of 5.2° at 30 GHz. The proposed reconfigurable antenna ar-ray represents a real and efficient solution for the recent and future mmw 5G networks. The proposed antenna is suitable for 5G base stations in stadiums, malls and convention centers. It is proper for satellite communications and radars at mmw.

Propagation of liquid surface waves over finite graphene structured arrays of cylinders

Based on the multiple scattering method,this paper investigates a benchmark problem of the propagation of liquid surface waves over finite graphene (or honeycomb) structured arrays of cylinders.Comparing the graphene structured array with the square structured and with triangle structured arrays,it finds that the finite graphene structure can produce more complete band gaps than the other finite structures,and the finite graphene structure has less localized ability than the other finite structures.

Orthogonal array design for the optimization of stripping Sr(Ⅱ) from ionic liquids using supercritical CO2

The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(C_2mimNTf2) with dicyclohexyl-18-crown-6(DCH18C6) was stripped effectively by supercritical CO_2(sc-CO_2).Hexafluoroacetylacetone(HFAA)-acetonitrile was found to be an excellent modifier of sc-CO_2 to enhance the stripping efficiency.In the orthogonal array design(OAD),OA_(25)(5~5)matrix was employed to optimize the stripping of Sr(Ⅱ) from the DCH 18C6-C_2mimNTf_2 system.Effects of five experimental factors:temperature,pressure,concentration of HFAA,static and dynamic extraction times as well as each factor at five-levels on the stripping of Sr(Ⅱ) were optimized.The effects of these parameters were treated by the analysis of variance(ANOVA).The results showed that Sr(II) could be nearly 100%extracted from the IL phase at 308 K,30 MPa,40 min of dynamic extraction and 60 mmol·L^(-1) HFAA in acetonitrile,respectively.Finally,the stripping mechanism was studied by ESI-MS.

基于5 μm厚向列相液晶的高效圆极化相控阵系统的设计、校准和实验验证

This paper presents a systematic investigation and demonstration of a K-band circularly polarized liquidcrystal-based phased array(LCPA),including the design,over-the-air(OTA)in-array calibration,and experimental validation.The LCPA contains 16 phase-shifting radiating channels,each consisting of a circularly polarized stacked patch antenna and a liquid-crystal-based phase shifter(LCPS)based on a loaded differential line structure.Thanks to its slow-wave properties,the LCPS exhibits a maximum phase-shifting range of more than 360°with a figure of merit of 78.3(°)·dB^(-1)based on a liquid crystal layer with a thickness of only 5μm.Furthermore,an automatic OTA calibration based on a state ergodic method is proposed,which enables the extraction of the phase-voltage curve of every individual LCPA channel.The proposed LCPA is manufactured and characterized with a total profile of only 1.76 mm,experimentally demonstrating a scanned circularly polarized beam from-40°to+40°with a measured peak gain of 12.5 dBic and a scanning loss of less than 2.5 dB.The bandwidth of the LCPA,which satisfies the require-ments of port reflection(|S_(11)|)<-15 dB,an axial ratio(AR)<3 dB,beam squinting<3°,and a gain variation<2.2 dB,spans from 25.5 to 26.0 GHz.The total efficiency is about 34%,which represents a new state of the art.The use of the demonstrated low-profile LCPA to support circularly polarized scanning beams,along with the systematic design and calibration methodology,holds potential promise for a variety of millimeter-wave applications.

Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

Simultaneous Determination of Saponins in Radix Glycyrrhizae, Notoginseng and Ginseng by High Performance Liquid Chromatography

To establish a method for determining five saponins(notoginsenoside R1, ginsenoside Rg1, ginsenoside Re, ginsenoside Rb1 and ammonium glycyrrhizinate) in Glycyrrhizae, Notoginseng and Ginseng, the high performance liquid chromatography with diode array detector(HPLC-DAD) method was applied to an Inertsil ODS-SP column(4.6 mm×250 mm, 5 μm) with a mobile phase consisting of acetonitrile-0.05% phosphoric acid in a gradient elution manner. The flow rate was 1.0 mL/min. The column temperature was 30 ℃ and the detection wavelengths were 203 nm and 237 nm, respectively. The linear ranges were 0.700,0—7.000,0 μg for R1(r=1.000,0), 0.751,1— 7.511,4 μg for Rg1(r=1.000,0), 0.677,2—6.771,6 μg for Re(r=1.000,0), 0.733,9—7.339,1 μg for Rb1(r= 1.000,0), and 0.540,0—5.399,8 μg for ammonium glycyrrhizinate(r=0.999,9), respectively. In addition, their average recoveries were 100.28%, 105.83%, 104.09%, 99.36% and 98.54%, respectively. The relative standard deviations(RSDs) of precision, reproducibility and recovery were all less than 1.5%. The results indicate that the method is simple, accurate and reproducible so that it can be used for the simultaneous determination of the five saponins in Chinese patent medicines containing the three kinds of herbs.

Extraction and Determination of Three Chlorophenols by Hollow Fiber Liquid Phase Microextraction - Spectrophotometric Analysis, and Evaluation Procedures Using Mean Centering of Ratio Spectra Method

A method termed hollow fiber liquid phase microextraction (HF-LPME) was utilized to extract three chlo- rophenols, 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6- trichlorophenol (2,4,6-TCP), separately from water. The extracted chlorophenols were then separated, identified, and quantified by UV-Vis spectrophotometry with photodiode array detection (UV-Vis/DAD). In the study, experimental con-ditions such as organic phase identity, acceptor phase volume, sample agitation, extraction time, acceptor phase NaOH concentration, donor phase HCl concentration, salt addition, and UV absorption wavelength were optimized. The statistical parameters of the proposed method were investigated under the selected con-ditions. The analytical characteristics of the method such as detection limit, accuracy, precision, relative standard deviation (R.S.D.) and relative standard error (R.S.E.) was calculated. The results showed that the proposed method is simple, rapid, accurate and precise for the analysis of ternary mixtures.

Liquid crystal Fresnel lens display

A novel see-through display with a liquid crystal lens array was proposed.A liquid crystal Fresnel lens display（LCFLD） with a holographic screen was demonstrated.The proposed display system has high efficiency,simple fabrication,and low manufacturing cost due to the absence of a polarizer and color filter.

Ferroelectric Liquid Crystal Gates and Optical Computing

The surface stabilized ferroelectric liquid crystal device configuration and ferroelectric liquid crystal gates are described.The liquid crystal electrooptical gates have numerous applications,including optical computation,optodigital circuits,and optical communication networks.

HPLC-DAD法同时测定银黄含片中黄芩苷和绿原酸的含量

目的：建立同时测定银黄含片制剂中黄芩苷和绿原酸含量的方法，及测定不同厂家银黄含片中黄芩苷和绿原酸的含量。方法：采用HPLC法，用DAD检测器，岛津VP-ODS C18（250 mm ＆#215;4．6 mm，5（m）色谱柱，流动相：乙腈-0.4％磷酸溶液，梯度洗脱，流速1.0 ml＆#183;min-1，检测波长为绿原酸327 nm、黄芩苷280 nm。结果：绿原酸和黄芩苷分别在0.17～3.40μg和0.33～6.60μg范围内线性关系良好（r＝0.9999），平均加样回收率分别为100.59％（RSD＝0.94％）和98.91％（RSD＝1.14％）。结论：本文建立的方法可以同时准确地测定银黄含片中绿原酸和黄芩苷的含量，方法快速、准确、重复性好，可用于银黄含片的质量控制。

Simultaneous determination of 20 food additives by high performance liquid chromatography with photo-diode array detector

An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives, including three sweeteners,seven food colorants,nine synthetic preservatives and caffeine,by high performance liquid chromatography （HPLC） with photodiode array detector（PDA）.This method permits the detection of food additives at very low concentrations（0.005-0.150μg/mL）.The applicability was verified by the determination of food additives present in various foodstuffs.

A Hierarchical Conical Array with Controlled Adhesion and Drop Bounce Ability for Reducing Residual Non-Newtonian Liquids

As a result of frequent food waste and environmental pollution,there has been an increasing demand for the development of packaging materials that intrinsically inhibit and reduce likelihood of non-Newtonian liquids adherence.In this work,inspired from ciliary structures on the leg of water strider,the hierarchical conical array was formed by magnetic field control and laser etching without any mask.Due to the tapered geometry of the cones and the multiscale surface roughness of the array,the droplets would bounce many times after impacting with the superhydrophobic surface(SHS)and roll off.By changing the spaces and apex angles of conical microcolumns the SHS has controlled adhesion,superior self-cleaning property and droplets bounce performance for a variety of non-Newtonian viscous liquids.After suffering from various types of damage including repeated tape tearing,finger touch and folding test,the SHS still maintained excellent superhydrophobic property,which may have potential application as all kinds of packaging interface materials.We demonstrate that the excellent droplets bounce behavior of the hierarchical array enables the efficient and robust prevention of food liquids adhesion.

Orthogonal array optimization of ionic liquid based dispersive liquid-liquid microextraction for toxic anilines in foods

A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction （DLLME） combining with high performance liquid chromatography （HPLC） was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design （OAD） with OA25（54） matrix. Analysis of variance （ANOVA） and percent contribution （PC） were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity （r2 〉 0.99） over the studied range （50-1000 ng g-l） for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections （LODs） and limit of quantitations （LOQs） ranged be- tween 10-15 ng g-1 and 30--45 ng g-1.

Identification and determination of the major constituents in traditional Chinese medicine Longdan Xiegan Pill by HPLC-DAD-ESI-MS

A novel and sensitive HPLC-UV method has been developed for the simultaneous determination of twelve major compounds in Longdan Xiegan Pill.The chemical profile of the twelve compounds,including geniposidic acid（1）,geniposide（2）,gentiopicroside（3）,liquiritin（4）,crocin（5）,baicalin（6）,wogonoside（7）,baicalein（8）,glycyrrhizic acid（9）,wogonin（10）,oroxylin A（11）and aristolochic acid A（12）,was acquired using high-performance liquid chromatography-diode array detector coupled with an electrospray tandem mass spectrometer（HPLC-DAD-ESI-MS）.The analysis was performed on a Dikma Platisil ODS C18 column（250 mm×4.6 mm,5 μm）with a gradient solvent system of acetonitrile-0.1% aqueous formic acid.The validation was carried out and the linearities（r〉0.9996）,repeatability（RSD〈1.8%）,intra-and inter-day precision（RSD〈1.3%）,and recoveries（ranging from 96.6% to 103.4%）were acceptable.The limits of detection（LOD）of these compounds ranged from 0.29 to 4.17 ng.Aristolochic acid A,which is the toxic ingredient,was not detected in all the batches of Longdan Xiegan Pill.Furthermore,hierarchical cluster analysis was used to evaluate the variation of the herbal prescription.The proposed method is simple,effective and suitable for the quality control of this traditional Chinese medicine（TCM）.

Flat-Panel Laser Displays Based on Liquid Crystal Microlaser Arrays

Laser displays,benefiting from the characteristic merits of lasers,have led to the revolution of next-generation display technologies owing to their superior color expression.However,the acquisition of pixelated laser arrays as self-emissive panels for flat-panel laser displays remains challenging.Liquid crystal(LC)materials with excellent processability and optoelectronic properties offer considerable potential for the construction of highly ordered multicolor laser arrays.Here,we demonstrate flat-panel laser displays on LC microlaser pixel arrays through a microtemplate-assisted inkjet printing method.Individual organic red-green-blue(RGB)microlaser pixel arrays were obtained by doping dyes into LCs with photonic band edges to obtain single-mode RGB lasing,leading to a much broader color gamut,compared with the standard RGB color space.Then we acquired periodically patterned RGB pixel matrices by positioning LC microlasers precisely into highly ordered arrays,according to the well-organized geometry of the microtemplates.Subsequently,we demonstrated full-color flat-panel laser displays using the LC microlaser pixel matrices as self-emissive panels.These results provide valuable enlightenment for the construction of next-generation flat-panel laser display devices.

A high-contrast coronagraph for direct imaging of Earth-like exoplanets: design and test

A high-contrast coronagraph for direct imaging of an Earth-like exoplanet at the visible band needs a contrast of 10^-10 at a small angular separation of 4λ/D or less. Here we report our recent laboratory experiment that approaches these lim- its. Our test of a high-contrast imaging coronagraph is based on our step-transmission apodized filter. To achieve this goal, we use a liquid crystal array as a phase correc- tor to create a dark hole based on our dedicated algorithm. We have suppressed the diffraction and speckle noise near the point image of a star to a level of 1.68 × 10^-9 at 4λ/D, which can be used for direct imaging of Jupiter-like exoplanets. This demon- strates that a telescope incorporating a high-contrast coronagraph in space has the potential to detect and characterize Earth-like planets.

Study on chromatographic fingerprint of sarcandra glabra (Thunb.) by microwave-assisted extraction coupled to HPLC/DAD

Microwave-assisted extraction(MAE)was used for extraction of effective components of sarcandra glabra(Thunb.),and then chromatographic fingerprint of sarcandra glabra(Thunb.)was studied by high performance liquid chromatography/diode array detector(HPLC/DAD).The conditions of MAE were optimized by an orthogonal experiment,and then the authentication and validation of the chromatographic fingerprint were conducted.Nine peaks were identified as common peaks in the fingerprint chromatograms,and isofraxidin was considered as a reference compound and quantified.Relative standard deviations of retention time and peak area of each component were less than 3% and 8%,respectively.Similarity and difference analysis were conducted by use of PCA and relation coefficient.Twenty batches of sarcandra glabra(Thunb.)samples from two different producing areas could be classified into two different groups in the PCA model.The results showed that MAE-HPLC/DAD method was simple,efficient and stable for the study of complex chromatographic fingerprint of sarcandra glabra(Thunb.),which could provide more reliable and precise information for quality evaluation.

Extraction optimization of coumarins from radix angelicae pubescentis by HPLC-DAD coupled with uniform design

Uniform design was used to optimize extraction condition of direct refluence extraction of coumarins from the Chinese traditional medicine of radix angelicae pubescentis(Duhuo); the sum peak area of coumarins separated with high performance liquid chromatography(HPLC) at detection wavelength of 320nm was considered as detection index, two factors of solvent concentration and extraction time were mainly studied at extraction temperature of 85℃ and a volume ratio of solvent to sample of 10∶1. Optimal subclass, quadric polynomial step by step aggression and neural network method were applied to process the experimental results. The results show that the first and second methods give the same factors combination (concentration of ethanol: 95%, extraction time: 3.6 h) and the second method is much better than the first one. The extraction model is consequently developed.