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Alpha-Glucosidase Inhibitory Activity of Saponins Isolated from Vernonia gratiosa Hance
Cong Pham Van,Anh Hoang Le Tuan,Vinh Le Ba,Han Yoo Kyong,Trung Nguyen Quang,Minh Bui Quang,Duc Ngo Viet,Ngoc Tran Minh,Hien Nguyen Thi Thu,Manh Hoang Duc,Lien Le Thi,Lee Ki Yong 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.6
Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 – 3), designated as vernogratiosides A–C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with αglucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.
Second-Order Sliding Mode Control of a 3D Overhead Crane with Uncertain System Parameters
Le Anh Tuan,이순걸,김재준,임태균,Luong Cong Nho 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
This paper proposes a second-order sliding mode controller for a three-dimensional overhead crane in an extremely complicatedoperation with uncertain system parameters. Three actuators composed of trolley-moving, bridge-traveling, and cargo-hoisting forcessimultaneously drive fine outputs comprising bridge motion, trolley translation, cable length, and two payload swing angles. Simulation and experiment are performed to investigate the controller qualities. The proposed controller asymptotically stabilizes andconsistently maintains system response even when some system parameters are extensively varied.
Model Reference Adaptive Sliding Mode Control for Three Dimensional Overhead Cranes
Tuan, Le Anh,Lee, Soon-Geul,Nho, Luong Cong,Kim, Dong Han Korean Society for Precision Engineering 2013 International Journal of Precision Engineering and Vol.14 No.8
An overhead crane transfers the payloads of various volumes and weights depending on the each operation case. The friction factors characterized by damped coefficients can be changed in connection with operating environment. This study develops an adaptive version of sliding mode controller for the overhead cranes without priori information of system parameters composed of cargo mass and damped aspects. The proposed controller simultaneously executes five duties consisted of tracking the trolley and bridge, hoisting the cargo, keeping the payload swings small during the transport process, and absolutely suppressing the cargo vibrations at destination of trolley and bridge. Both simulation and experiment results indicate that the adaptive robust controller asymptotically stabilizes all crane system responses.
Model Reference Adaptive Sliding Mode Control for Three Dimensional Overhead Cranes
Le Anh Tuan,이순걸,Luong Cong Nho,김동한 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
An overhead crane transfers the payloads of various volumes and weights depending on the each operation case. The friction factors characterized by damped coefficients can be changed in connection with operating environment. This study develops an adaptive version of sliding mode controller for the overhead cranes without priori information of system parameters composed of cargo mass and damped aspects. The proposed controller simultaneously executes five duties consisted of tracking the trolley and bridge, hoisting the cargo, keeping the payload swings small during the transport process, and absolutely suppressing the cargo vibrations at destination of trolley and bridge. Both simulation and experiment results indicate that the adaptive robust controller asymptotically stabilizes all crane system responses.
Second-Order Sliding Mode Control of a 3D Overhead Crane with Uncertain System Parameters
Le, Anh Tuan,Kim, Jae-Jun,Lee, Soon-Geul,Lim, Tae-Gyoon,Luong, Cong Nho 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.5
This paper proposes a second-order sliding mode controller for a three-dimensional overhead crane in an extremely complicated operation with uncertain system parameters. Three actuators composed of trolley-moving, bridge-traveling, and cargo-hoisting forces simultaneously drive fine outputs comprising bridge motion, trolley translation, cable length, and two payload swing angles. Simulation and experiment are performed to investigate the controller qualities. The proposed controller asymptotically stabilizes and consistently maintains system response even when some system parameters are extensively varied.
Tran Cong Phong,Le Thi Thu Phuong,Huynh Vinh Phuc,Pham Tuan Vinh 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.2
We investigate the influence of phonon confinement on the optically-detected electrophonon resonance (ODEPR) effect and ODEPR linewidth in rectangular quantum wires (RQW). The ODEPR conditions as functions of the wire’s size and the photon energy are also obtained. The splittings of ODEPR peaks caused by the confined phonon are discussed. The numerical result for a specific RQW shows that in the two cases of confined and bulk phonons, the linewidth decreases with increasing wire size and increases with increasing temperature. Furthermore, in the small range of the wire’s size (<i>L</i> ≤ 40 nm), phonon confinement plays an important role and cannot be neglected in reaching the ODEPR linewidth.
Nguyen Van Hieu,Le Thi Ngoc Loan,Nguyen Duc Khoang,Nguyen Tuan Minh,Do Thanh Viet,Do Cong Minh,Tran Trung,Nguyen Duc Chien 한국물리학회 2010 Current Applied Physics Vol.10 No.2
In this paper, a very simple procedure was presented for the reproducible synthesis of large-area SnO2nanowires (NWs) on a silicon substrate by evaporating Sn powders at temperatures of 700, 750, and 800 ℃. As-obtained SnO2 NWs were characterized by field emission scanning electron microscopy (FESEM),transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. They revealed that the morphology of the NWs is affected by growth temperature and the SnO2 NWs are single-crystalline tetragonal. The band gap of the NWs is in the range of 4.2–4.3 eV as determined from UV/visible absorption. The NWs show stable photoluminescence with an emission peak centered at around 620 nm at room-temperature. The sensors fabricated from the SnO2 NWs synthesized at 700 ℃ exhibited good response to LPG (liquefied petroleum gas) at an operating temperature of 400 ℃.
Removal of Manganese and Copper from Aqueous Solution by Yeast Papiliotrema huenov
( Phu Nguyen Van ),( Hai Thi Hong Truong ),( Tuan Anh Pham ),( Tuan Le Cong ),( Tien Le ),( Kim Cuc Thi Nguyen ) 한국균학회 2021 Mycobiology Vol.49 No.5
Papiliotrema huenov was previously reported to be highly tolerant of a range of extremely toxic heavy metals. This study aimed to identify the potential of P. huenov to remove manganese and copper from aqueous solution. Physical conditions which affect removal of Mn(II) and Cu(II) were determined. Optimal temperature for adsorption of both metal ions was 30 ℃, and optimal pH for maximum uptake of Mn(II) and Cu(II) were 5 and 6, respectively. Under these conditions, living cells of P. huenov accumulated up to 75.58% of 110mg/ L Mn(II) and 70.5% of 128mg/L Cu(II) over 120 h, whereas, the removal efficiency of metal ions by dead cells over 1 h was 60.3% and 56.5%, respectively. These results indicate that living cells are more effective than dead biomass for bioremediation, but that greater time is required. The experimental data extends the potential use of P. huenov in biosorption and bioaccumulation of toxic heavy metals to copper and manganese, two of the most common industrial contaminants.
Yen-Lien T. Nguyen,Anh-Tuan Le,Khanh Nguyen Duc,Vinh Nguyen Duy,Cong Doan Nguyen 서울시립대학교 도시과학연구원 2021 도시과학국제저널 Vol.25 No.4
This study aims to develop the models of emission and fuel consumption during idling of motorcycles (MCs) in Hanoi, including the unsteady and steady idling stages. Five MC models commonly used in Hanoi were selected to measure the instantaneous emission and fuel consumption rates under the controlled conditions at the laboratory conditions. The instantaneous emission and fuel consumption models during idling were developed for the test MCs in the unsteady idling stage. The R2 of obtained models are higher than 0.9. The average emission and fuel consumption rates in the steady idling stages were determined. The average idling emissions of pollutants CO, CO2, HC and NOx were 60.9, 534.3, 10.3 and 1.8 g/h, respectively. The average fuel loss during idling is around 180 g/h. The emission released from the MC fleet in Hanoi during idling was estimated for the year 2018. The total idling emissions from the MC fleet of 3.9 million vehicles in the year 2018 of CO, CO2, HC and NOx were 6.5, 57.1, 1.1 and 0.2 kt, respectively. The total fuel loss during idling of the MC fleet in 2018 was ∼19.3 kt. The air pollutants eliminated in the idle mode as CO, CO2, HC and NOx contributed 2.23%, 3.19%, 1.14% and 1.03%, respectively, of the total emission from the MC fleet in Hanoi.
Copper Tolerance of Novel Rhodotorula sp. Yeast Isolated from Gold Mining Ore in Gia Lai, Vietnam
Kim Cuc Thi Nguyen,Phuc Hung Truong,Cuong Tu Ho,Cong Tuan Le,Khoa Dang Tran,Tien Long Nguyen,Manh Tuan Nguyen,Phu Van Nguyen 한국균학회 2023 Mycobiology Vol.51 No.6
In this study, twenty-five yeast strains were isolated from soil samples collected in the goldmining ore in Gia Lai, Vietnam. Among them, one isolate named GL1T could highly tolerateCu2þ up to 10 mM, and the isolates could also grow in a wide range of pH (3–7), and temperature(10–40 �C). Dried biomass of GL1 was able to remove Cu2þ effectively up to 90.49%with a maximal biosorption capacity of 18.1 mg/g at pH 6, temperature 30 �C, and incubationtime 60 min. Sequence analysis of rDNA indicated this strain was closely related toRhodotorula mucilaginosa but with 1.53 and 3.46% nucleotide differences in the D1/D2domain of the 28S rRNA gene and the ITS1-5.8S rRNA gene-ITS2 region sequence, respectively. Based on phylogenetic tree analysis and the biochemical characteristics, the strainappears to be a novel Rhodotorula species, and the name Rhodotorula aurum sp. nov. is proposed. This study provides us with more information about heavy metal-tolerant yeasts andit may produce a new tool for environmental control and metal recovery operations.