Grinding Marks on Ultra-Precision Grinding Spherical and Aspheric Surfaces

Bing Chen,Bing Guo,Shichun Li,Zhaohui Deng,Qingliang Zhao 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.4 No.4

Grinding marks are regard as a great obstacle to manufacture spherical and aspheric surfaces with higher surface quality, lower energy and wastage. The scallop-height was studied for optimizing the grinding parameters firstly to reduce its effect on grinding marks. Secondly, the expression of grinding points distribution was established to characterize the grinding marks caused by the radial run-out of grinding wheel. And then, the aspheric grinding experiments of monocrystalline silicon were carried out to investigate the influence of grinding marks on surface quality. The experiments revealed that the remarkable grinding marks with patterned grinding points distribution would cause more fractures and roughness, deeper grooves, and more inhomogeneous surface quality compared with the weak grinding marks. The discriminating standard of grinding marks was established, and the grinding parameters were optimized for homogenizing the grinding points distribution by this discriminating standard to reduce the grinding marks in actual grinding process. Finally, the large size infrared lens was ground with high surface quality by the optimized grinding parameters, and the results of surface quality demonstrate that the discriminating standard was effective. This research provides references and ideas for grinding aspherical surface with high surface quality and efficiency, low energy and wastage.

Simultaneous quantitation and validation of method for the quality evaluation of Eucommiae cortex by HPLC/UV

( Bing Tian Zhao ),( Su Yang Jeong ),( Tae In Kim ),( Eun Kyoung Seo ),( Byung Sun Min ),( Jong Keun Son ),( Mi Hee Woo ) 영남대학교 약품개발연구소 2016 영남대학교 약품개발연구소 연구업적집 Vol.26 No.-

A new HPLC/UV method has been developed for the simultaneous quantitative determination of four major components in Eucommiae cortex, namely geniposidic acid (1), geniposide (2), pinoresinol di-O-β-D-glucopyranoside (3), and liriodendrin (4). Simultaneous separations of these four components were achieved on a J``sphere ODS CI8 column (250 x 4.6 mm, 4 mm), The elution was done using water with 0.1 % phosphoric acid (A) and acetonitrile with 0.1 % phosphoric acid (B) in a two-step elution of the mobile phase at a flow rate of 1.0 mL/min and a wavelength of 230 nm. The method was validated for linearity, recovery, precision, accuracy, stability and robustness. All calibration curves showed good linear regression (r² > 0.999) within the test ranges. This method showed good recovery and repro-ducibility for the quantification of these four components in 85 species of Eucommiae cortex. The intra-day and inter-day precisions were lower than 0.53 % (as a relative standard deviation, RSD) and accuracies between 93.00 and 106.28 % for all standards. The results indicate that the established HPLC/UV method is suitable for quantitation and quality evaluation of Eucommiae cortex.

Quantitative determination and pattern recognition analyses of bioactive marker compounds from Dipsaci Radix by HPLC

Bing Tian Zhao,Su Yang Jeong,문동철,손건호,손종근,우미희 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.11

In this study, quantitative and pattern recognitionanalyses were developed using HPLC/UV for thequality evaluation of Dipsaci Radix. For quantitativeanalysis, five major bioactive compounds were assessed. The separation conditions employed for HPLC/UV wereoptimized using ODS C18 column (250 9 4.6 mm, 5 lm)with a gradient of acetonitrile and water as the mobilephase at a flow rate of 1.0 mL/min and a detection wavelengthof 212 nm. These methods were fully validated withrespect to linearity, accuracy, precision, recovery, androbustness. The HPLC/UV method was applied successfullyto the quantification of five major compounds in theextract of Dipsaci Radix. The HPLC analytical method forpattern recognition analysis was validated by repeatedanalysis of 17 Dipsaci Radix and four Phlomidis Radixsamples. The results indicate that the established HPLC/UV method is suitable for quantitative analysis.

High Performance Liquid Chromatography used for Quality Control of Achyranthis Radix

Bing Tian Zhao,우미희,Su Yang Jeong,문동철,손건호,손종근 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.8

To establish a standard of quality control and to identify reliable Achyranthis Radix, three phytoecdysones including ecdysterone (1), 25R-inokosterone (2) and 25S-inokosterone (3) were determined by quantitative HPLC/UV analysis. Three phytoecdysones were separated with an YMC J’sphere ODS C18 column (250 mm × 4.6 mm, 4 μm) by isocratic elution using 0.1% formic acid in water and acetonitrile (85:15, v/v%) as the mobile phase. The flow rate was 1.0 mL/min and the UV detector wavelength was set at 245 nm. The standards were quantified by HPLC/UV from Achyranthes bidentata Blume and Achyranthes japonica Nakai, as well as Cyathula capitata Moq. and Cyathula officinalis Kuan, which are of a different genus but are comparative herbs. The method was successfully used in the analysis of Achyranthis Radix of different geographical origin or genera with relatively simple conditions and procedures, and the assay results were satisfactory for linearity, recovery, precision, accuracy, stability and robustness. The HPLC analytical method for pattern recognition analysis was validated by repeated analysis of eighteen A. bidentata Blume samples and ten A. japonica Nakai samples. The results indicate that the established HPLC/UV method is suitable for quantitation and pattern recognition analyses for quality evaluation of Achyranthis Radix.

Surface Micro-Structuring of Coarse-Grained Diamond Wheels by Nanosecond Pulsed Laser for Improving Grinding Performance

Bing Guo,Qingliang Zhao,Xinyu Zhao 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

The conditioned coarse-grained diamond wheels are able to achieve the identical surface roughness, higher form accuracy and largergrinding rate when compared to the traditional fine-grained diamond wheels. However, deeper subsurface damage could be inevitablyintroduced due to the flat tops of the coarse diamond grains. This work presents a micro-structuring method for coarse-graineddiamond wheels by means of nanosecond pulsed laser, which allows the generation of micro grooves arrays on the coarse diamondgrains distributed on the whole grinding wheel cylindrical surface. The influence of laser parameters such as focal point shift, laserpower, scanning speed and scanning passes on micro-structured surface was investigated, and then the laser machining process wasoptimized in fabricating uniform and continuous micro-structures. The grinding experiments indicate that, when compared to the nonmicro-structured grinding wheels, the subsurface cracks depth of ground optical glass was reduced effectually by using the microstructuredcoarse-grained diamond wheels.

Protein tyrosine phosphatase 1B inhibitors from natural sources

Bing Tian Zhao,Duc Hung Nguyen,Duc Dat Le,최재수,민병선,우미희 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.2

Since PTP1B enzyme was discovered in 1988, ithas captured the research community’s attention. Thislandmark discovery has stimulated numerous researchstudies on a variety of human diseases, including cancer,inflammation, and diabetes. Tremendous progress has beenmade in finding PTP1B inhibitors and exploring PTP1Bregulatory mechanisms. This review investigates for thenatural PTP1B inhibitors, and focuses on the commoncharacteristics of the discovered structures and structure–activity relationships. To facilitate understanding, all thenatural compounds are here divided into five differentclasses (fatty acids, phenolics, terpenoids, steroids, andalkaloids), according to their skeletons. These PTP1Binhibitors of scaffold structures could serve as a theoreticalbasis for new concept drug discovery and design.

Discrimination between steam processed and unprocessed Tubers of Gastrodia elata Blume by HPLC

Zhao, Bing Tian,Song, Si Whan,Le, Duc Dat,Ma, Eun Sook,Son, Jong Keun,Woo, Mi Hee The Korean Society of Analytical Science 2019 분석과학 Vol.32 No.6

In this study, to evaluate the effectiveness and safety of oral therapy using Gastrodiae Rhizoma, a new HPLC-PDA analysis method was developed for the simultaneous quantitation of the three major components: (1) gastrodin, (2) gastrodigenin, and (3) p-hydroxybenzaldehyde, in steam processed and unprocessed tubers of Gastrodia elata Blume. The clear separation of the three components was achieved on a C18 column (250 × 4.6 mm, 5 ㎛) by gradient elution using water (including 0.1 % formic acid) and acetonitrile as the mobile phase. The flow rate was 1.0 mL/min, and the UV detector wavelength was set at 270 nm. The results demonstrate satisfactory linearity, recovery, precision, accuracy, stability, and robustness. The established HPLC-PDA method was applied to quantify three major compounds in 59 samples of G. elata Blume tubers. Finally, the steam processed and unprocessed tubers of G. elata Blume were successfully distinguished by pattern recognition analysis.

Research on Narrowband Interference Suppression and Diversity Characteristics in Fast Frequency-Hopping Communication Systems

Bing Zhao,Lei Xin,Jingyu Liu,Qun Ding 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.4

Frequency-hopping communication has the capability to resist narrowband interference, which is in direct proportion to the hopping rate. In frequency-hopping system, interference signals exist in partial de-hopping frequency-hopping signals, equivalent to time-varying interference signals existed in the frequency-hopping signals. Through integrating the diversity combining techniques of fast frequency-hopping communication with singular value decomposition method, this paper detects the frequency-hopping points, masks them, and then combines with undisturbed frequency-hopping signals. MATLAB simulation shows that narrowband interference is well restrained and the system BER is obviously improved.

Quantitative analysis of betaine in Lycii Fructus by HILIC-ELSD

Bing Tian Zhao,Su Yang Jeong,Kyoung Hwangbo,문동철,서은경,이동호,이제현,민병선,마은숙,손종근,우미희 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.10

A rapid and simple high-performance liquidchromatography (HPLC) method with evaporative lightscattering detection (ELSD) was developed for the determinationof betaine from Lycii Fructus. Betaine was separatedwith an Atlantis hydrophilic interaction liquidchromatography silica column (4.6 9 150 mm, 5 lm,100 A ° ) by isocratic elution using 30 mM ammonium acetatebuffer and acetonitrile (20:80, v/v %) as the mobilephase. The flow rate was 1.0 mL/min, and the temperaturefor the spray chamber and drift tube was set at 30 and50 C, respectively. The method was fully validated withrespect to linearity, precision, accuracy, stability androbustness. The HPLC/ELSD method was applied successfullyto the quantification of betaine in the extract ofLycii Fructus. The HPLC analytical method for patternrecognition analysis was validated by repeated analysis oftwenty-six L. barbarum L. from China (BC01–BC26), 3 L. barbarum L. (BJ27–BJ29) from Japan, 12 L. chinenseMiller from China (CC30–CC41) and 51 L. chinense Millersamples (CK42–CK92) from Korea. The results indicatethat the established HPLC/ELSD method is suitable forquality evaluation of Lycii Fructus.

Quality evaluation of Perillae Folium by HPLC/PDA

Bing Tian Zhao,이강노,이제현,민병선,손종근,우미희 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.8

To establish a standard of quality control for Perillae Folium (Lamiaceae Family), four standard compounds including rosmarinic acid, elemicin, perillaldehyde, and dillapiole were evaluated by high-performance liquid chromatography (HPLC)/photodiode array (PDA). The four standards were analyzed with a Phenomenex Kinetex C18 (250 9 4.6 mm, 5 lm) column by gradient elution using 0.1 % formic acid in water and methanol as the mobile phase. The standards were quantified by HPLC/ PDA from Perillae Folium, which included the leaf and twig of Perilla frutescens L. Britton var. acuta (Thunb.) Kudo or Perilla frutescens Britton var. crispa Decne. The method was successfully used in the analysis of Perillae Folium, and the linearity, recovery, precision, accuracy, stability, and robustness were satisfactory according to the validation results. In Perillae Folium samples, the average contents (wt%) of rosmarinic acid, elemicin, perillaldehyde, and dillapiole were 0.540, 0.059, 0.050, and 0.056 %, respectively. The results indicate that the establishedHPLC/PDA method is suitable for the quantitation and quality evaluation of Perillae Folium.