Wave propagation control and switching for wireless power transfer using tunable 2-D magnetic metamaterials

Pham, Thanh Son,Bui, Huu Nguyen,Lee, Jong-Wook Elsevier 2019 Journal of magnetism and magnetic materials Vol.485 No.-

<P><B>Abstract</B></P> <P>Magnetic metamaterials operating at low megahertz frequencies provide various important commercial and research applications. In this work, we investigate the control of wave propagation in two-dimensional (2-D) tunable magnetic metamaterials for wireless power transfer (WPT). The propagation control is achieved by using reconfigurable defect cavities formed in the metamaterial, which allows for the dynamic creation of various waveguide configurations with switching control. The physical mechanism for creating the cavity is described using Fano interference, in which the resonant frequency of the cavity falls into the bandgap of the metasurface. And the routing and transmission control of the proposed waveguide is easily achieved by resonant switching. The proposed approach allows highly localized, strong field confinement in the deep subwavelength scale of 2.6λ × 10<SUP>−3</SUP>. The transmission losses and bandwidths of various dynamically tunable metamaterial waveguides are experimentally characterized. This result can find useful applications for integrated surface wave devices and planar WPT.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Investigation of new type of magnetic metamaterial working at low MHz frequency range. </LI> <LI> Active tunable magnetic metamaterial applied for wireless power transfer. </LI> <LI> A defect cavity is introduced for localization of the magnetic field into deep subwavelength scale. </LI> <LI> New type of low loss 2-D waveguide created by novel defect cavity mode. </LI> <LI> Simple and effective transmission switching control on 2-D metasurface for wireless power transfer. </LI> </UL> </P>

Analysis and experiments on Fano interference using a 2D metamaterial cavity for field localized wireless power transfer

Pham, Thanh Son,Ranaweera, Aruna Kumara,Ngo, Duc Viet,Lee, Jong-Wook Institute of Physics Publishing Ltd. 2017 Journal of Physics. D, Applied Physics Vol.50 No.30

<P>To meet both safety and efficiency demands of future wireless power transfer (WPT) systems, field leakage to the nearby environment should be controlled below a certain level. Therefore, field localization is one of the key issues in advanced WPT systems. Recently, metamaterials have shown great potential for enhanced control of electromagnetic propagation in various environments. In this work, we investigate a locally modified metamaterial to create a two-dimensional (2D) cavity for field localization at a sub-wavelength scale. We also show that the field localization in the cavity can be explained using Fano-type interference. We believe that this is one of the first works demonstrating that Fano-type interference can be applied for resonance-coupled mid-range WPT. Using the proposed approach, we achieve a localized WPT in a region that is eight times smaller than that of a transmit coil. At a distance of 0.6 meters, the measured efficiency is 56.5%, which represents a six-fold and two-fold enhancement compared to free space and uniform metamaterial slabs, respectively.</P>

Pancreaticoduodenectomy with superior mesenteric artery first-approach combined total meso-pancreas excision for periampullary malignancies: A high-volume single-center experience with short-term outcomes

Thanh Khiem Nguyen,Ham Hoi Nguyen,Tuan Hiep Luong,Kim Khue Dang,Van Duy Le,Duc Dung Tran,Van Minh Do,Hong Quang Pham,Hoan My Pham,Thi Lan Tran,Cuong Thinh Nguyen,Hong Son Trinh,Yosuke Inoue 한국간담췌외과학회 2024 Annals of hepato-biliary-pancreatic surgery Vol.28 No.1

Backgrounds/Aims: Pancreaticoduodenectomy (PD) is the only radical treatment for periampullary malignancies. Superior mesenteric artery (SMA) first approach combined with total meso-pancreas (MP) excision was conducted to improve the oncological results. There has not been any previous research of a technique that combines the SMA first approach and total MP excision with a detailed description of the MP macroscopical shape. Methods: We prospectively assessed 77 patients with periampullary malignancies between October 2020 and March 2022 (18 months). All patients had undergone PD with SMA first approach combined total MP excision. The perioperative indications, clinical data, intra-operative index, R0 resection rate of postoperative pathological specimens (especially mesopancreatic margin), postoperative complications, and follow-up results were evaluated. Results: The median operative time was 289.6 min (178−540 min), the median intraoperative blood loss was 209 mL (30−1,600 mL). Microscopically, there were 19 (24.7%) cases with metastatic MP, and five cases (6.5%) with R1-resection of the MP. The number of lymph nodes (LNs) harvested and metastatic LNs were 27.2 (maximum was 74) and 1.8 (maximum was 16), respectively. Some (46.8%) patients had pancreatic fistula, but mostly in grade A, with 7 patients (9.1%) who required re-operations. Some 18.2% of cases developed postoperative refractory diarrhea. The rate of in-hospital mortality was 1.3%. Conclusions: The PD with SMA first approach combined TMpE for periampullary malignancies was effective in achieving superior oncological statistics (rate of MP R0-resection and number of total resected LNs) with non-inferior short-term outcomes. It is necessary to evaluate survival outcomes with long-term follow-up.

A novel method for vehicle load detection in cable-stayed bridge using graph neural network

Van-Thanh Pham,Hyesook Son,Cheol-Ho Kim,Yun Jang,Seung-Eock Kim 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.6

Vehicle load information is an important role in operating and ensuring the structural health of cable-stayed bridges. In this regard, an efficient and economic method is proposed for vehicle load detection based on the observed cable tension and vehicle position using a graph neural network (GNN). Datasets are first generated using the practical advanced analysis program (PAAP), a robust program for modeling and considering both geometric and material nonlinearities of bridge structures subjected to vehicle load with low computational costs. With the superiority of GNN, the proposed model is demonstrated to precisely capture complex nonlinear correlations between the input features and vehicle load in the output. Four popular machine learning methods including artificial neural network (ANN), decision tree (DT), random forest (RF), and support vector machines (SVM) are refereed in a comparison. A case study of a cable-stayed bridge with the typical truck is considered to evaluate the model's performance. The results demonstrate that the GNN-based model provides high accuracy and efficiency in prediction with satisfactory correlation coefficients, efficient determination values, and very small errors; and is a novel approach for vehicle load detection with the input data of the existing monitoring system.

Fabrication and Characteristics of Fully-sprayed ZnO/CdS/CuInS2 Solar Cells

Tran Thanh Thai,Nguyen Duc Hieu,Luu Thi Lan Anh,Pham Phi Hung,Vo Thach Son,Vu Thi Bich 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.9

This paper reports the successful fabrication of deposited Glass/ZnO/CdS/CuInS₂ solar cells with superstrate structure using Full Spray Pyrolysis Deposition (FSPD). The structure, optical and electrical properties of the constituent layers are investigated. It is observed that the CuInS₂ (CIS) film deposited from starting solution with [Cu]/[In] = 1.1, and Al-doped CuInS₂ (CIAS) film deposited from solution with [Cu]/[In] = 1.0, [Al]/[In] = 0.12, and using sulfurization process exhibited the best crystallites with tetragonal structure. The optical band gap of the CIAS film is obtained as 1.49 eV. Some physical properties of both ZnO, and CdS thin films are also studied. The parameters of the cells obtained are V_OC = 425 mV, J_SC = 14.02 mA/cm², FF = 28.75% and efficiency of 1.71%. The results in our experiment show that FSPD is a potential technique to prepare solar cells based on CIS absorbers in a superstrate structure with low cost and high performance.

Nano-porous Silicon Microcavity Sensors for Determination of Organic Fuel Mixtures

Van Hoi Pham,Huy Bui,Le Ha Hoang,Thuy Van Nguyen,The Anh Nguyen,Thanh Son Pham,Quang Minh Ngo 한국광학회 2013 Current Optics and Photonics Vol.17 No.5

We present the preparation and characteristics of liquid-phase sensors based on nano-porous silicon multilayer structures for determination of organic content in gasoline. The principle of the sensor is a determination of the cavity-resonant wavelength shift caused by refractive index change of the nano-porous silicon multilayer cavity due to the interaction with liquids. We use the transfer matrix method (TMM)for the design and prediction of characteristics of microcavity sensors based on nano-porous silicon multilayer structures. The preparation process of the nano-porous silicon microcavity is based on electrochemical etching of single-crystal silicon substrates, which can exactly control the porosity and thickness of the porous silicon layers. The basic characteristics of sensors obtained by experimental measurements of the different liquids with known refractive indices are in good agreement with simulation calculations. The reversibility of liquid-phase sensors is confirmed by fast complete evaporation of organic solvents using a low vacuum pump. The nano-porous silicon microcavity sensors can be used to determine different kinds of organic fuel mixtures such as bio-fuel (E5), A92 added ethanol and methanol of different concentrations up to 15%.

Rational design of lignin peroxidase H8 from Phanerochaete chrysosporium for degradation of lignin at the strong acidic condition

Hae Won SON,Le Thanh Mai PHAM,Yong Hwan KIM 한국생물공학회 2017 한국생물공학회 학술대회 Vol.2017 No.10

Rational design of acid stable lignin peroxidase H8 of Phanerochaete chrysosporium for depolymerization of lignin

Hae won SON,Le Thanh Mai PHAM,Yong Hwan KIM 한국생물공학회 2018 한국생물공학회 학술대회 Vol.2018 No.4

The role of rapid tissue expansion in separating xipho-omphalopagus conjoined twins in Vietnam

Tran, Thiet Son,Pham, Thi Viet Dung,Ta, Thi Hong Thuy,Vu, Duy Kien,Nguyen, Thanh Liem Korean Society of Plastic and Reconstructive Surge 2021 Archives of Plastic Surgery Vol.48 No.4

Conjoined twins are rare, and each set of conjoined twins has a unique conjoined anatomy. It is necessary to perform separation to increase the chance of patient survival. Tissue expansion is an advanced technique for providing sufficient soft tissue and skin for wound closure. We report the successful application of rapid tissue expansion in 10-month-old xipho-omphalopagus conjoined twins in Vietnam. A tissue expander was placed on the anterior body between the sternum and umbilicus with a baseline of 70 mL sterile saline (0.9% NaCl). The first injection into the tissue expander began on the 6th day after expander insertion, and injections continued every 2 days with approximately 30-70 mL per injection according to the expansion of the skin. The expander reached 335 mL after six injections and within 10 days. In order to prepare for surgical separation, expansion was completed on the 15th day after insertion. The expanded skin area was estimated to be 180 cm², which was sufficient to cover both patients' skin deficiencies. The twins presented for surgical separation 6 days following the completion of tissue expansion. Both babies were discharged in good health 1 month after separation.

Adsorption of pharmaceuticals onto trimethylsilylated mesoporous SBA-15

Bui, Tung Xuan,Pham, Viet Hung,Le, Son Thanh,Choi, Heechul Elsevier 2013 Journal of hazardous materials Vol.254 No.-

<P><B>Abstract</B></P> <P>The adsorption of a complex mixture of 12 selected pharmaceuticals to trimethylsilylated mesoporous SBA-15 (TMS-SBA-15) has been investigated by batch adsorption experiments. The adsorption of pharmaceuticals to TMS-SBA-15 was highly dependent on the solution pH and pharmaceutical properties (i.e., hydrophobicity (log <I>K</I> <SUB>ow</SUB>) and acidity (p<I>K</I> <SUB>a</SUB>)). Good log–log linear relationships between the adsorption (<I>K</I> <SUB>d</SUB>) and pH-dependent octanol–water coefficients ( K ow pH ) were then established among the neutral, anionic, and cationic compounds, suggesting hydrophobic interaction as a primary driving force in the adsorption. In addition, the neutral species of each compound accounted for a major contribution to the overall compound adsorption onto TMS-SBA-15. The adsorption kinetics of pharmaceuticals was evaluated by the nonlinear first-order and pseudo-second-order models. The first-order model gave a better fit for five pharmaceuticals with lower adsorption capacity, whereas the pseudo-second-order model fitted better for seven pharmaceuticals having higher adsorption capacity. In the same group of properties, pharmaceuticals having higher adsorption capacity exhibited faster adsorption rates. The rate-limiting steps for adsorption of pharmaceuticals onto TMS-SBA-15 are boundary layer diffusion and intraparticle diffusion including diffusion in mesopores and micropores. In addition, the adsorption of pharmaceuticals to TMS-SBA-15 was not influenced by the change of initial pharmaceutical concentration (10–100μgL<SUP>−1</SUP>) and the presence of natural organic matter.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Trimethylsilylated SBA-15 for adsorptive removal of a mixture of 12 pharmaceuticals. </LI> <LI> Hydrophobic interaction as a primary driving force in the adsorption. </LI> <LI> The rate-limiting steps were diffusion through boundary layer, mesopores and micropores. </LI> <LI> Adsorption efficiency was not changed as pharmaceutical concentration varied. </LI> <LI> Adsorption efficiency was not influenced by the presence of natural organic matters. </LI> </UL> </P>