Filters








6,199 Hits in 1.8 sec

Enhanced thermoelectricity at the ultra-thin film limit [article]

Thao T. T. Nguyen, Linh T. Dang, Giang H. Bach, Tung H. Dang, Kien T. Nguyen, Hong T. Pham, Thuat T. Nguyen, Tuyen V. Nguyen, Toan T. Nguyen, Hung Q. Nguyen
2019 arXiv   pre-print
At the ultra-thin film limit, quantum confinement strongly improves thermoelectric figure of merit in materials such as Sb_2Te_3 and Bi_2Te_3. These high quality films have only been realized using well controlled techniques such as molecular beam epitaxy. We report a two fold increase in the Seebeck coefficient for both p-type Sb_2Te_3 and n-type Bi_2Te_3 using thermal co-evaporation, an affordable approach. At the thick film limit greater than 100 nm, their Seebeck coefficients are around 100
more » ... μ V/K, similar to results obtained in other work. When the films are thinner than 50 nm, the Seebeck coefficient increases to about 500 μ V/K. With a total Seebeck coefficient ∼ 1 mV/K and an estimate ZT ∼ 2, this pair of materials is the first step to a practical micro-cooler at room temperature.
arXiv:1912.11274v1 fatcat:i6hxyqbgivbp7m3cr3zptcxr64

HYCEDIS: HYbrid Confidence Engine for Deep Document Intelligence System [article]

Bao-Sinh Nguyen, Quang-Bach Tran, Tuan-Anh Nguyen Dang, Duc Nguyen, Hung Le
2022 arXiv   pre-print
Measuring the confidence of AI models is critical for safely deploying AI in real-world industrial systems. One important application of confidence measurement is information extraction from scanned documents. However, there exists no solution to provide reliable confidence score for current state-of-the-art deep-learning-based information extractors. In this paper, we propose a complete and novel architecture to measure confidence of current deep learning models in document information
more » ... on task. Our architecture consists of a Multi-modal Conformal Predictor and a Variational Cluster-oriented Anomaly Detector, trained to faithfully estimate its confidence on its outputs without the need of host models modification. We evaluate our architecture on real-wold datasets, not only outperforming competing confidence estimators by a huge margin but also demonstrating generalization ability to out-of-distribution data.
arXiv:2206.02628v1 fatcat:kqfwjpjrjjd73ifge4xs5kubqm

Cytotoxic Activity and Phytochemical Constituents of Macrosolen bidoupensis Tangane & V.S. Dang

Kieu Hung Le, Tran Canh Nguyen, The Anh Nguyen, Nu Dan Phuong Nguyen, Thi Hong Tuoi Do, Le Thanh Tuyen Nguyen, Van Son Dang, Trong Duc Tran, Nhat Minh Phan, Trong Dat Bui, Dinh Tri Mai, Nguyen Tan Phat
2020 Records of Natural Products  
Dang, a new species discovered in Viet Nam were conducted and led to the purification of ten compounds, comprising three lupane-type (1-3), three friedelane-type (4-6), and one glutinane-type (7) triterpenoids  ...  ORCID Kieu Hung Le: 0000-0003-0964-7751 Tran Canh Nguyen: 0000-0002-3711-172X Figure 1 . 1 Chemical structures of compounds (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) Table 1 . 1 Cytotoxic activity of  ...  Van Son Dang, Institute of Tropical Biology, Vietnam Academy of Science and Technology.  ... 
doi:10.25135/rnp.197.20.02.1545 fatcat:tjf63xk2bbffpnd5glkyhcdrxy

DÂY CHẰNG NHÂN TẠO TRONG SỬA VAN HAI LÁ Ở TRẺ EM

Đoàn Quốc Hưng, Lê Quang Thiện, Nguyễn Đăng Hùng, Nguyễn Sinh Hiền, Nguyễn Hoàng Hà
2021 Y học Việt Nam  
Tuy nhiên, độ bền lâu dài và sự thích ứng sinh học của chỉ khâu PTFE khi bệnh nhi tăng trưởng đang còn bàn cãi[1],[2].  ...  Trong nhóm mổ lại, có nhóm nguyên nhân tiến triển hẹp van do mô van dày và dây chằng tự nhiên co rút như tổn thương thấp thứ phát; các nhóm nguyên nhân gây hở van mổ lại thường do tiến triển bênh lý ở  ...  Tuy nhiên, nó không phải là kĩ thuật được lựa chọn cho trẻ em đang trong giai đoạn tăng trưởng hình thể.  ... 
doi:10.51298/vmj.v504i1.838 fatcat:zads2r4tnjh7jl3vbypgzn4oeu

Effect of Silica Nanoparticles on Properties of Coatings Based on Acrylic Emulsion Resin

Vuong Thien Nguyen, Hung Dao Phi, Hung Dao Phi, Thanh Van Trinh, Thanh Van Trinh, Phuc Van Mac, Phuc Van Mac, Hiep Anh Nguyen, Hiep Anh Nguyen, Hieu Manh Dang, Hieu Manh Dang, Linh Thi Nguyen (+3 others)
2018 Vietnam Journal of Science and Technology  
Effect of nanosilica size on physic-mechanical properties, thermal stability and weathering durability of coating based on acrylic emulsion. Nanocomposite coating formulas were filled by 2 wt.% nanosilica particles which were used in this study, namely: nanosilica from Sigma (15-20nm), nansilica from rice husk (~70-200 nm) and nanosilica from Arosil – Belgium (7-12 nm). Obtained results showed that viscosity flow of coating formula containing nanosilica from Arosil saw the highest flow-time
more » ... e coating formulas filled other nanosilica and unfilled nanosilica experienced similar flow-time. In presence of nanosilica, coating properties were improved in comparison with neat coating. However, coating filled by nanosilica from rice husk indicated the best properties in studied coating formula. It may explained that size of nanosilica from rice husk was the largest in studied nanosilica particles and thus easily dispersing into coating formula.
doi:10.15625/2525-2518/56/3b/12731 fatcat:lasba6aeurefnlozmitk7tymva

Fabricating Ultra-thin Silicon Nitride Membranes Suspended on Silicon Wafer

Pham Thi Hong, Dang Huu Tung, Nguyen Hai Anh, Dang Tuan Linh, Nguyen Thi Thu Thao, Dinh Thuy Hien, Nguyen Minh Hieu, Nguyen Minh Hue, Nguyen Tran Thuat, Nguyen Viet Tuyen, Nguyen Quoc Hung
2021 VNU Journal of Science Mathematics - Physics  
Ultrathin silicon nitride SiNx membrane suspended on a silicon wafer is a popular two-dimensional platform in MEMS applications. The unsupported membrane has a low thermal conductivity, is electrically insulated, and very robust against mechanical impact. Remarkably thin, it is difficult to fabricate and manipulate. Recently equipped with a dual chamber system for plasma enhanced chemical vapor deposition (PECVD) and reactive ion etching, we calibrate it to deposit silicon nitride Si3N4,
more » ... dioxide SiO2, and to dry etch these materials. Based on the superb quality of Si3N4, we perform a through-wafer etch that creates suspended Si3N4 membranes. The recipe is reliable and reproducible. We analyze the membrane's chemical composition and optical properties. Although created by PECVD, the membrane is so robust that it survives multiple lithography steps. It extends our capability to study thermal transport at the submicron scale as well as to fabricate micron size devices for MEMS applicati
doi:10.25073/2588-1124/vnumap.4518 fatcat:fb63dmpmcnfxrcrgmtva6gjxqm

Improve Market Share of International Freight of Vietnamese Fleets

Manh Hung Nguyen, Thi Cam Huyen Nguyen, Thanh Nam Dang
2020 Zenodo  
Manh Hung Nguyen, Thi Cam Huyen Nguyen, and Thanh Nam Dang, "Improve market share of international freight of Vietnamese fleets," International Journal of Multidisciplinary Research and Publications (IJMRAP  ...  Manh Hung Nguyen, Thi Cam Huyen Nguyen, and Thanh Nam Dang, "Improve market share of international freight of Vietnamese fleets," International Journal of Multidisciplinary Research and Publications (IJMRAP  ... 
doi:10.5281/zenodo.3668954 fatcat:w3runwgpezbyfga6yzdx4hrge4

Stochastic graph partitioning: quadratic versus SOCP formulations

Dang Phuong Nguyen, Michel Minoux, Viet Hung Nguyen, Thanh Hai Nguyen, Renaud Sirdey
2015 Optimization Letters  
We consider a variant of the graph partitioning problem involving knapsack constraints with Gaussian random coefficients. In this new variant, under this assumption of probability distribution, the problem can be traditionally formulated as a binary SOCP for which the continuous relaxation is convex. In this paper, we reformulate the problem as a binary quadratic constrained program for which the continuous relaxation is not necessarily convex. We propose several linearization techniques for
more » ... ter: the classical linearization proposed by Fortet (Trabajos de Estadistica, 1960, Vol. 11) and the linearization proposed by Sherali and Smith (Optimization Letters, 2007, Vol. 1). In addition to the basic implementation of the latter, we propose an improvement which includes, in the computation, constraints coming from the SOCP formulation. Numerical results show that an improvement of Sherali-Smith's linearization outperforms largely the binary SOCP program and the classical linearization when investigated in a branch-and-bound approach.
doi:10.1007/s11590-015-0953-9 fatcat:6hpx7eh4kbavlnc5d2m2uutyd4

Study on the effects of led light on physiological and morphological characteristics of dang shen (Codonopsis sp.) growth in in vitro condition

Nguyen Khac Hung, Pham Bich Ngoc, Nguyen Thi Thu Hien, Nguyen Thi Thuy Huong, Do Thi Gam, Le Duy Hung, Chu Hoang Ha
2016 TAP CHI SINH HOC  
Với những dược tính quý hiếm, sâm dây đang bị khai thác cạn kiệt ngoài tự nhiên.  ...  Công nghệ chiếu sáng LED đã và đang được sử dụng như nguồn sáng nhân tạo trong các phòng nuôi cấy mô thực vật với nhiều ưu điểm như kích thước nhỏ, tuổi thọ cao, dễ tự động hóa, tiết kiệm năng lượng.  ...  nghệ phục vụ phát triển kinh tế-xã hội vùng Tây Nguyên"-TN3/C09.  ... 
doi:10.15625/0866-7160/v38n2.7106 fatcat:svntuzx5nzgipcukslrshl6rcm

Facile Hydrothermal Synthesis of Two-Dimensional Porous ZnO Nanosheets for Highly Sensitive Ethanol Sensor

Lai Van Duy, Nguyen Hong Hanh, Dang Ngoc Son, Pham Tien Hung, Chu Manh Hung, Nguyen Van Duy, Nguyen Duc Hoa, Nguyen Van Hieu
2019 Journal of Nanomaterials  
Two-dimensional porous ZnO nanosheets were synthesized by a facile hydrothermal method for ethanol gas-sensing application. The morphology, composition, and structure of the synthesized materials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and high-resolution transmission electron microcopy. Results showed that the synthesized ZnO materials were porous nanosheets with a smooth surface and a thickness of 100 nm and a large
more » ... re size of approximately 80 nm. The as-prepared nanosheets, which had high purity, high crystallinity, and good dispersion, were used to fabricate a gas sensor for ethanol gas detection at different operating temperatures. The porous ZnO nanosheet gas sensor exhibited a high response value of 21 toward 500 ppm ethanol at a working temperature of 400°C with a reversible and fast response to ethanol gas (12 s/231 s), indicating its potential application. We also discussed the plausible sensing mechanism of the porous ZnO nanosheets on the basis of the adopted ethanol sensor.
doi:10.1155/2019/4867909 fatcat:ntcr6sz5x5bjxkgltj2ivi3ij4

Smoothed finite element method for two-dimensional elasto-plasticity

Stéphane Pierre Alain Bordascorres, Hung Nguyen-Dang, Quyen Phan-Phuong, Hung Nguyen-Xuan, Sundararajan Natarajan, Marc Duflot
2009 Vietnam Journal of Mechanics  
This communication shows how the smoothed finite element method (SFEM) very recently proposed by G. R. Liu [14] can be extended to elasto-plasticity. The SFEM results are in excellent agreement with the finite element (FEM) and analytical results. For the examples treated, the method is quite insensitive to mesh distortion and volumetric locking. Moreover, the SFEM yields more compliant load-displacement curves compared to the standard, displacement based FE method, as expected from the
more » ... cal developments recently published in [4], [3] and [6].
doi:10.15625/0866-7136/31/3-4/5655 fatcat:dvhh2jwczvgezhjcpx6gac43oi

Zika preparedness and response in Viet Nam

Dong Nguyen, Hung Do, Huy Le, Nghia Le, Mai Vien, Trieu Nguyen, Lan Phan, Thuong Nguyen, Quang Luong, Hung Phan, Hai Diep, Quang Pham (+13 others)
2018 Western Pacific Surveillance and Response  
Luong, b Hung C Phan, b Hai T Diep, b Quang D Pham, b Thinh V Nguyen, b Loan KT Huynh, b Dung CT Nguyen, b Hang TT Pham, b Khanh KH Ly, b Huong NLT Tran, b Phu D Tran, c Tan Q Dang, c Hung Pham, c Long  ... 
doi:10.5365/wpsar.2018.9.1.002 pmid:30057851 pmcid:PMC6053107 fatcat:jh4lizmd7nhejad2po7xfh544q

Factors Influencing the Dividend Policy of Vietnamese Enterprises

Hung Ngoc Dang, Nguyen Viet Ha, Dang Thai Binh
2018 Asian Journal of Finance & Accounting  
The article explores the factors affecting company's dividend policy such as profitability, firm size, financial leverage and growth rate. Data is collected from enterprises listed on the Vietnam securities market in the period of 2006 - 2017 with 2,150 observations. Using the Generalized Least Squares (GLS), the authors have identified two factors that have a positive and significant effect: (i) return on total assets and (ii) firm size. At the same time, research results also show a negative
more » ... mpact of enterprise's revenue growth rate on the dividend payment ratio. In addition, financial leverage has no impact on company's dividend policy.
doi:10.5296/ajfa.v10i2.13651 fatcat:a5cusf2kjjgwbg4c7tmaxudwam

Ung thư biểu mô tế bào gan dạng Sarcom: Báo cáo ca lâm sàng

Nguyễn Duy Hùng, Nguyễn Minh Thuý, Vương Kim Ngân
2021 Tap chi nghien cuu y hoc  
Chẩn đoán trên mô bệnh học là ung thư biểu mô tế bào gan dạng sarcom.  ...  Đây là loại u hiếm gặp ở người lớn và hiện có dưới 50 ca lâm sàng đã được báo cáo với biểu hiện đa dạng về mặt lâm sàng và các dấu hiệu chẩn đoán hình ảnh.  ...  KẾT LUẬN Ung thư biểu mô tế bào gan dạng sarcom nguyên phát là một loại u hiếm gặp ở người lớn với nguyên nhân và cơ chế bệnh học chưa rõ ràng.  ... 
doi:10.52852/tcncyh.v143i7.249 fatcat:bripmi3ye5gvpkrag4wjd66s5e

Methanol extract from Vietnamese Caesalpinia sappan induces apoptosis in HeLa cells

Tran Hung, Nguyen Dang, Nguyen Dat
2014 Biological Research  
Nguyen et al. reported that a methanol extract and the active compounds from C. sappan heartwood collected in Vietnam exhibited significant xanthine oxidase (XO) inhibitory activity [16, 17] .  ... 
doi:10.1186/0717-6287-47-20 pmid:25028057 pmcid:PMC4101718 fatcat:mtbf2ljzxbcwzkujbtwrmcldnq
« Previous Showing results 1 — 15 out of 6,199 results