Isolation of L-theanine from Tea Solution by Cation Exchange Resin in Batch and Fixed Bed Column

Jian-Hui Ye,Yi-Wen Luo,Hui-Ling Liang,Jian-Liang Lu,Jing Jin,Yue-Rong Liang,Xin-Qiang Zheng,Xian-Yang Luo 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.2

L-Theanine, a bioactive compound in tea, was isolated from tea solution using cation exchange resin no.732. The adsorption of L-theanine by cation exchange resin no.732 fit the Langmuir isotherm model and was a monolayer molecular interaction process. Thermodynamic studies revealed that the adsorption of L-theanine by resin no.732 was an exothermic and spontaneous physically driven process. The adsorption capacity was influenced by temperature, initial concentration, and pH. The L-theanine adsorption capacity under conditions at room temperature,pH 4.73, and initial L-theanine concentration 18 g/L was 241.731 ± 3.679 mg/g. The Thomas model was fit to describe the column adsorption data at different flow rates and initial concentrations. The L-theanine adsorbed by resin no.732 could be desorbed by 0.134 mol/L Na2HPO4aqueous solution with a recovery rate of 84.96%. These findings indicate that resin no.732 was a promising material for isolating L-theanine from tea solution.

Improvement of DITC SRM with a Novel 4-level Converter

Jianing Liang,이진국(Zhen-Guo Lee),이동희(Dong-Hee Lee),안진우(Jin-Woo Ahn) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7

This paper presents a direct instantaneous torque control (DITC) of Switched Reluctance Motor (SRM) with a novel 4-1evel converter to obtain smooth torque and dynamic performance improvement. The DITC method can reduce the high inherent torque ripple of SRM drive system, but driving efficiency and dynamic performance are somewhat low due to the slow excitation current build-up. Since the 4-level converter can obtain a addition high voltage to get fast excitation current and demagnetization current, so, it can improve dynamic performance easily. As a high performance SRM drive system with low torque ripple and high dynamic performance can be implemented. The validity of proposed method is verified by some computer simulations and comparative experiments.

Single Phase SRM Converter with Boost Negative Bias

Jianing Liang,석승훈(Seung-Hun Seok),이동희(Dong-Hee Lee),안진우(Jin-Woo Ahn) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.7(초록집)

A Novel Direct Instantaneous Pressure Control of Hydraulic Pump System with SR Drive

Jianing-Liang,Tae-Hyoung Kim,Dong-Hee Lee,Jin-Woo Ahn 전력전자학회 2007 전력전자학술대회 논문집 Vol.- No.-

This paper proposes a novel direct instantaneous pressure control(DIPC) of hydraulic pump system with SR drive. And it has very simple control structure, because it doesn’t use any speed and torque control for adjusting pump pressure. The hysteresis band of pressure and proper switching rules can make the actual pump pressure to be constant with fast dynamic response. Therefore, the proposed DIPC method can control of hydraulic pump pressure steadily with fast dynamic response.

Series-Parallel Type Passive Boost Converter for 3-phase SRM

Jianing Liang,Seung-Hun Seok,Dong-Hee Lee,Jin-Woo Ahn 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1

This paper presents a novel series-parallel type passive boost converter for 3-phase SRM. The proposed simple passive circuit added three diodes and one capacitor in the front-end of conventional asymmetric converter in order to obtain high negative bias. Based on this passive power network, the terminal voltage of the converter side is general dc-link voltage level in parallel mode and is u to double dc-link voltage level in series mode. So it can suppress the negative torque generation from the tail current and improve the output power. Combining passive circuit with 3-phase asymmetric converter, without the phase current overlap, the phase winding obtains the dc-link voltage in the demagnetization mode. With the phase current overlap, the dc-link voltage or double dc-link voltage is dependent on the overlap current. The operation modes of the proposed converter are analyzed with a 3-phase SR motor in detail. The compared simulation and experiments for conventional and proposed converter have been executed. And the results verify the performance of proposed converter.

Analysis of Passive Boost Power Converter for Three-Phase SR Drive

Jianing Liang,Dong-Hee Lee,Guoqing Xu,Jin-Woo Ahn IEEE 2010 IEEE transactions on industrial electronics Vol.57 No.9

<P>This paper presents a novel passive boost power converter and its analysis for a three-phase switched reluctance (SR) drive. The proposed simple passive circuit adds three diodes and one capacitor to the front end of a conventional asymmetric converter in order to obtain a high negative bias. Based on this passive power network, the terminal voltage of the converter side is at general dc-link voltage level in parallel mode and is up to a double dc-link voltage level in series mode. As a result, it can suppress the negative torque generation from the tail current and improve the output power. Combining a passive circuit with a three-phase asymmetric converter without phase-current overlap, the phase winding obtains the dc-link voltage in the excitation mode and the negative double dc-link voltage in the demagnetization mode. With the phase-current overlap, the dc-link voltage or the double dc-link voltage is dependent on the overlap current. The operation modes of the proposed converter are analyzed with a three-phase SR motor. The selection of the boost capacitor is considered, and a detailed analysis of current-overlap modes is presented. The compared simulation and experiments are done. The results verify the performance of the proposed converter.</P>

Progress in Extraction of Active Components from Tea

Jian-Liang Lu,Xin-Qiang Zheng,Ci-Jie Hu 한국차학회 2015 한국차학회지 Vol.- No.S

Extraction is the first processing step of ready-to-drink (RTD) beverage, instant tea and tea extracts. The extraction efficiency and extracts quality are significantly influenced by material, solvent and condition. The effect of material and solute characteristics, solvent type and property as well as performance conditions was reviewed, and their mechanism was also discussed.

Effect of Heat Treatment on the Lipophillic Pigments of Fresh Green Tea Liquor

Jian-Liang Lu,Zhan-Bo Dong,Shun-Shun Pan,Chen Lin,Xin-Qiang Zheng,Borthakur Devajit,Yue-Rong Liang 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3

Changes in lipophillic pigments concentration and its relation to color of fresh green tea liquor during heat treatment were studied. The results showed liquor greenness decreased markedly with extension of incubation time at 55℃, while the brightness and yellowness changed a little. Significant increase in ‘a’ and ‘b’ values of tea liquor was observed at 95℃. Color change of liquor at 55℃ was accompanied by a decrease in the level of chlorophylls, lutein and neoxanthin, and an increase in the pheophytins and β-carotene levels. However, all pigments except β-carotene decreased with time extension at 95℃. Significant correlation was found between pigments and color difference index. The browning of fresh green tea liquor was attributed to vicissitudes of lipophillic pigments during heat treatment, especially to the change of chlorophylls/pheophytins ratio. Result also showed addition of Zn²? at 1.6 μ㏖/ℓ could partially alleviate the decrease in greenness during heat treatment.

Compound glycyrrhizin injection for improving liver function in children with acute icteric hepatitis: A systematic review and meta-analysis

Liang Shi-Bing,Hou Wen-Bin,Zheng Ruo-Xiang,Liang Chang-Hao,Yan Li-Jiao,Wang Hao-Nan,Cao Hui-Juan,Han Mei,Robinson Nicola,Liu Jian-Ping 한국한의학연구원 2022 Integrative Medicine Research Vol.11 No.1

Background: Compound glycyrrhizin injection (CGI) is a preparation with glycyrrhizin as the main active ingredient extracted from licorice. As clinical trials suggest that CGI is effective in improving liver function for acute icteric hepatitis in children (AIHC), this systematic review aimed to evaluate and verify its therapeutic effects and safety. Methods: Six electronic databases were searched from their inception to 15 May 2021. Randomized controlled trials (RCTs) assessing therapeutic effects and safety of CGI for AIHC were included. The risk of bias for each trial was assessed using the Cochrane Risk of Bias Tool 2.0. Primary outcomes were indexes related to liver function, including total bilirubin (TBiL), alanine aminotransferase (ALT) and aspartate transaminase (AST). RevMan 5.4 software was used for data analyses. The certainty of the evidence was assessed using the online GRADEpro tool. Results: Six RCTs involving 608 children were included. The overall bias was assessed as having “high risk of bias” in all trials. All trials compared the combination of CGI and conventional western medicine (CWM) with CWM alone. Regarding the effects of CGI for AIHC, results showed that CGI plus CWM was superior to CWM alone in reducing the levels of TBiL (mean difference (MD) = -8.19 mmol/L, 95% CI -9.86 to -6.53), ALT (MD = -24.09 U/L, 95% CI -30.83 to -17.34) and AST (MD = -18.67 U/L, 95% CI -21.88 to -15.45). No trial reported adverse events. The certainty of the evidence for outcomes were all evaluated as low or very low. Conclusion: CGI may have adjuvant therapeutic effects on improving the liver function of children with AIHC. There is no evidence to determine the safety of CGI for AIHC. As current evidence is weak, further well-designed RCTs are required for verification of the therapeutic effects of CGI. Background: Compound glycyrrhizin injection (CGI) is a preparation with glycyrrhizin as the main active ingredient extracted from licorice. As clinical trials suggest that CGI is effective in improving liver function for acute icteric hepatitis in children (AIHC), this systematic review aimed to evaluate and verify its therapeutic effects and safety. Methods: Six electronic databases were searched from their inception to 15 May 2021. Randomized controlled trials (RCTs) assessing therapeutic effects and safety of CGI for AIHC were included. The risk of bias for each trial was assessed using the Cochrane Risk of Bias Tool 2.0. Primary outcomes were indexes related to liver function, including total bilirubin (TBiL), alanine aminotransferase (ALT) and aspartate transaminase (AST). RevMan 5.4 software was used for data analyses. The certainty of the evidence was assessed using the online GRADEpro tool. Results: Six RCTs involving 608 children were included. The overall bias was assessed as having “high risk of bias” in all trials. All trials compared the combination of CGI and conventional western medicine (CWM) with CWM alone. Regarding the effects of CGI for AIHC, results showed that CGI plus CWM was superior to CWM alone in reducing the levels of TBiL (mean difference (MD) = -8.19 mmol/L, 95% CI -9.86 to -6.53), ALT (MD = -24.09 U/L, 95% CI -30.83 to -17.34) and AST (MD = -18.67 U/L, 95% CI -21.88 to -15.45). No trial reported adverse events. The certainty of the evidence for outcomes were all evaluated as low or very low. Conclusion: CGI may have adjuvant therapeutic effects on improving the liver function of children with AIHC. There is no evidence to determine the safety of CGI for AIHC. As current evidence is weak, further well-designed RCTs are required for verification of the therapeutic effects of CGI.

송풍기용 고속 SRM의 설계 및 구동특성

Jianing Liang,김태형(Tae-Hyoung Kim),안진우(Jin-Woo Ahn),안영주(Young-Joo An) 전력전자학회 2005 전력전자학술대회 논문집 Vol.- No.-

This paper presents dynamic characteristics of super high speed SRM and it's drive. The nonlinear model of super high speed SRM is implement by Matlab/simulink and the simulation results show that the prototypeSRM can operate up 20,000[rpm]with stable performance.