Firm Characteristics and Cash Holdings Speed of Adjustment: Evidence from Vietnam

Khiem Dieu TRUONG 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.8

The study investigates the existence of an optimal level of cash and the firm characteristics influencing the decision to hold cash, and the adjusting speed of the cash holdings to the target level. It highlights the heterogeneity of cash adjustment speed in the Vietnam market. The research employs the 417 samples of Vietnamese non – financial listed firms in the period of 2010 to 2019. The study uses the Pool OLS model, Fixed effect model (FEM), Random effect model (REM), and GMM model. According to the research findings, there is an optimal amount of cash at which the firm’s value is maximized in Vietnamese listed firms, and the majority of the firms in the sample retain cash over the target level. Furthermore, the study demonstrates that firms actively modify their cash holdings to the optimal level with an adjustment speed of less than one owing to adjustment cost constraints. This speed varies between groupings of enterprises with different characteristics, underlining the heterogeneity of the adjustment speed even more. Small deviation firms adjust more rapidly than large deviation firms. Large free cash flow (FCF) firms adjust more readily than small FCF firms, and fiscal deficit firms modify more rapidly than firms with a financial surplus.

Empirical formula and computer code for the range of charged particles with Z = 2−103 and E = 2.5−500 AMeV in aluminum

Khiem Le Hong,Duy Nguyen Ngoc,Huy Le Duc 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.4

The aim of this work is to update the coefcients of our empirical formula as a tool for quickly and better estimating the stopping range of diferent charged particles ranging in Z = 2−103 at various energies from 2.5 to 500 AMeV in aluminum material. A graphical-user-interface computer code (SRC v1.0) was also programmed to execute the calculation based on the empirical model. The reliability of the common computer codes, SRIM2013 and ATIMA, was examined together with the empirical formula by comparing the computed results to the experimental data evaluated by Hubert et al. (Atom Data Nucl Data Tables 46:1–213, 1990) for the practical use. The ranges based on the empirical model computed using the selfdeveloped SRC code with the updated coefcients are in an excellent agreement with the experimental data and better than those computed using the SRIM2013 and ATIMA codes. The maximum deviation of the empirical model from the evaluated measured database is only 3% while it is about 10% (or 15%) for the SRIM2013 (or ATIMA) code. The results of the present study are useful for radiation shielding and nuclear experiments at radioactive-isotope accelerator facilities.

A Novel Approach for Accessing Semantic Data by Translating RESTful/JSON Commands into SPARQL Messages

Khiem Minh Nguyen,Hai Thanh Nguyen,Hiep Xuan Huynh 대한전자공학회 2016 IEIE Transactions on Smart Processing & Computing Vol.5 No.3

Linked Data is a powerful technology for storing and publishing the structures of data. It is helpful for web applications because of its usefulness through semantic query data. However, using Linked Data is not easy for ordinary users who lack knowledge about the structure of data or the query syntax of Linked Data. For that problem, we propose a translator component that is used for translating RESTful/JSON request messages into SPARQL commands based on ontology – a metadata that describes the structure of data. Clients do not need to worry about the structure of stored data or SPARQL, a kind of query language used for querying linked data that not many people know, when they insert a new instance or query for all instances of any specific class with those complex structure data. In addition, the translator component has the search function that can find a set of data from multiple classes based on finding the shortest paths between the target classes - the original set that user provide, and target classes- the users want to get. This translator component will be applied for any dynamic ontological structure as well as automatically generate a SPARQL command based on users’ request message.

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.

Capacity Maximization for an RF Energy-harvesting Cooperative Cognitive Radio Network

Khac-Khiem Nguyen,Duc-Phuc Vuong,Le Danh Khanh 대한전자공학회 2018 IEIE Transactions on Smart Processing & Computing Vol.7 No.5

This work considers a cooperative cognitive radio network including a primary system with a primary transmitter-receiver pair (PT-PR) and a secondary system with a secondary transmitter-receiver pair (ST-SR). In order to access the licensed band allocated to primary users, the ST plays the role of a decode-and-forward relay in order to forward primary signals to the PR. In particular, after receiving the primary signals, the ST first uses a power-splitting energyharvesting method to harvest energy and decode the primary signals. Then, the ST superimposes its information on the decoded primary signals, and use the harvested power to transmit the superimposed signal to the PR and the SR. We here devote our efforts to formulating and solving an optimization problem aimed at maximizing the capacity obtained by secondary users while also guaranteeing quality of service for the primary users. Simulation results clearly show that our solution significantly improves the achievable capacity of secondary users.

Synthesis of Cr-doped Al₂O₃ by Pechini sol-gel method and its application for reversible thermochromic sensors

Nguyen, Duy Khiem,Bach, Quang-Vu,Kim, Buyoung,Lee, Heesoo,Kang, Choonghyun,Kim, In-Tae Elsevier 2019 Materials chemistry and physics Vol.223 No.-

<P><B>Abstract</B></P> <P>Aluminum oxide doped with a small amount of chromium is known as “ruby” or “ruby solution” and can be used as a thermochromic material. The Pechini sol-gel process is applied to synthesize this advanced material. The crystal structure, chemical composition, and morphology of the synthesized materials are analyzed using X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, and Fourier transform infrared (FT-IR) spectroscopy. The color performance of the synthesized material is analyzed using UV-VIS spectrometry. Finally, the thermochromism exhibited by the pigment powders at high temperatures is investigated. The pigment exhibits exceptional thermochromic properties, transitioning from pink to gray in a temperature range of 25–600 °C. The change in color is reversible and is dependent on the temperature and chromium concentration; however, it is independent of the exposure time. This novel property of Cr-doped Al<SUB>2</SUB>O<SUB>3</SUB> can be potentially employed in reversible thermochromic sensors that could be used not only for warning users of damage due to overheating when the environmental temperature exceeds certain limits, but also for detecting and monitoring the temperature of various devices, such as aeronautical engine components, hotplates, and furnaces.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cr-doped Al<SUB>2</SUB>O<SUB>3</SUB> powders were prepared by Pechini sol-gel method. </LI> <LI> The Cr<SUP>3+</SUP> contents influence slightly the phase transition temperature but control the brightness of the powders. </LI> <LI> The powder exhibits reversible thermochromic properties in a temperature range of 25–600 °C. </LI> <LI> The color change is dependent on the temperature but independent of the exposure time. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Graphene quantum dots produced by exfoliation of intercalated graphite nanoparticles and their application for temperature sensors

Nguyen, Duy Khiem,Kim, TaeYoung Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.427 No.2

<P><B>Abstract</B></P> <P>Graphene quantum dots (GQDs) have received much attention as a new class of fluorescent materials due to their unique transport phenomena and broadband absorption. Here, we present a method to produce pristine blue-luminescent GQDs from graphite nanoparticles by the intercalation of graphite nanoparticles and subsequent exfoliation in liquids. The as-synthesized GQDs are composed of highly crystalline carbon rings and show uniform size distribution ranging from 3 to 4nm with an average thickness of ∼1nm. The GQDs exhibit an excitation-dependent blue photoluminescence with a quantum yield of 22.3%. Furthermore, the GQDs were explored as an active sensing material for temperature measurement. The GQD-based temperature sensors show high responsivity to temperature changes over the range 30–80°C.</P> <P><B>Highlights</B></P> <P> <UL> <LI> GQDs with 3.5nm diameter and consist of 1–3 layers are produced. </LI> <LI> The produced GQDs emit blue-color under UV light (365nm). </LI> <LI> Temperature sensor fabricated from these GQDs shows high sensitivity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

네트워크 기반 프록시 모바일 IPv6에서 글로벌 이동 지원에 관한 연구

풍기아킴(Gia Khiem Phung),노승환(Soonghwan Ro) 한국통신학회 2010 韓國通信學會論文誌 Vol.35 No.7

Hydrogel Encapsulation of Cells in Core-Shell Microcapsules for Cell Delivery

Nguyen, Duy Khiem,Son, Young Min,Lee, Nae-Eung Wiley (John WileySons) 2015 Advanced Healthcare Materials Vol.4 No.10

<P>A newly designed 3D core-shell microcapsule structure composed of a cell-containing liquid core and an alginate hydrogel shell is fabricated using a coaxial dual-nozzle electrospinning system. Spherical alginate microcapsules are successfully generated with a core-shell structure and less than 300 μm in average diameter using this system. The thickness of the core and shell can be easily controlled by manipulating the core and shell flow rates. Cells encapsulated in core-shell microcapsules demonstrate better cell encapsulation and immune protection than those encapsulated in microbeads. The observation of a high percentage of live cells (?80%) after encapsulation demonstrates that the voltage applied for generation of microcapsules does not significantly affect the viability of encapsulated cells. The viability of encapsulated cells does not change even after 3 d in culture, which suggests that the core-shell structure with culture medium in the core can maintain high cell survival by providing nutrients and oxygen to all cells. This newly designed core-shell structure can be extended to use in multifunctional platforms not only for delivery of cells but also for factor delivery, imaging, or diagnosis by loading other components in the core or shell.</P>

Critical Exponents of the Ferromagnetic-paramagnetic Phase Transition of La<SUB>0.7</SUB>Ba<SUB>0.3</SUB>Mn<SUB>0.95</SUB>Ti<SUB>0.05</SUB>O₃

N. V. Khiem,L. V. Bau,L. V. Hong,N. X. Phuc 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-