Dual-layer remote phosphor structure: a novel technique to enhance the color quality scale and luminous flux of WLEDs

The effects of red light-emitting phosphor CaMgSi2O6:Eu2+,Mn2+ on the optical properties of single-layer remote phosphor structure (SRPS) and dual-layer remote phosphor structure (DRPS) are the focus of this study. The differences in color quality and luminous flux (LF) of white light-emitting diodes (WLEDs) between these two structures are also revealed and demonstrated based on the Mie theory. SRPS consists of one mixed phosphor layer betweenCaMgSi2O6:Eu2+,Mn2+ andYAG:Ce3+particles, while DRPS includes two separated layers: red phosphor layer and yellow phosphor layer. In this work, 5% SiO2 is added into the phosphor layers to increase scattering abilities. Discrepancies in structures greatly affect the optical characteristics of WLEDs. The results showed that the color rendering index (CRI) increased with the concentration in both structures with nearly equal values. Meanwhile, color quality scale (CQS) of DPRS is 74 at ACCTs ranging from 5600K to 8500K, higher than CQS of SRPS which is only 71 at 8500K. In addition, the luminous flux of DRPS is significantly higher than SRPS at 2% -14% of CaMgSi2O6:Eu2+,Mn2+. In summary, DRPS is better for color quality and lumen outputin comparison to SRPS and adding the right amount of red phosphor can enhance CQS and LF

Review of two genera of freshwater crabs, Larnaudia Bott, 1966 and Neolarnaudia Türkay & Naiyanetr, 1987 (Crustacea: Decapoda: Potamidae) with redescription Neolarnaudiaphymatodes (Kemp, 1923) from Southern Vietnam

ABSTRACT: The occurrence of Larnaudia Bott, 1966 in southern Vietnam remains obscure. Although some previous studies described the presence of Larnaudialarnaudii A. Milne-Edwards, 1869 in Vietnam, our analysis of freshwater crab specimens collected at many locations in southern Vietnam revealed that Neolarnaudia Türkay Naiyanetr, 1987, but not Larnaudia Bott, 1966, is present in southern Vietnam. In this study, we recorded two species of Neolarnaudia, N. phymatodes (Kemp, 1923) and N. botti Türkay Naiyanetr, 1987 in southern Vietnam. Neolaurnaudia phymatodes was poorly knownsince the original description, and is, thus, re-described here. This species can be distinguished from all other Neolarnaudia species by a suite of characters; carapace broader, frontal area with many granules, supraorbital margingranulated, suborbital and pterygostomian regions and merus of third maxillipedcovered with many granules, terminal segment of Gonopod 1 strongly curved inwards and covered with many pubescences, lateral margin of telsonstrongly concaved. Citation: Do Van Tu, Dang Van Dong, Le Van Tho, Phan Doan Dang, 2017. Review of two genera of freshwater crabs, Larnaudia Bott, 1966 and Neolarnaudia Türkay Naiyanetr, 1987 (Crustacea: Decapoda: Potamidae) with redescription Neolarnaudiaphymatodes (Kemp, 1923) from Southern Vietnam. Tap chi Sinh hoc, 39(4): 398-405. DOI: 10.15625/0866-7160/v39n4.8464.*Corresponding author: [email protected], [email protected] 19 September 2017, accepted 12 December 201

Investigation of Some Characterizations of Black TiO2_2 Nanotubes Via Spectroscopic Methods

The black TiO$_2$ with substantial Ti$^3+$ and oxygen vacancies exhibit an excellent photoelectrochemical water-splitting performance due to the improved charge transport the extended visible light response. In this study, black TiO$_2$ nanotube arrays synthesized by the anodization method, and then, they have been investigated some characterizations by spectroscopic methods such as UV-visible reflectance (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectrum. The results showed that some highlighted properties of the black TiO2 nanotube arrays and they could apply for water-splitting effect

Phlogacanthus cornutus: chemical profiles and antioxidant effects

Phlogacanthus cornutus is a rare species and the chemical profiles and the bioactivities of this plant are unknown. In present study, the chemical components of the acetone extract as well as the antioxidant activity of acetone extract and its fractions such as n-hexane, chloroform and ethyl acetate of P. cornutus were firstly reported. A total of 33 constituents were identify in the acetone extract of this plant using Gas Chromatography/Mass Spectrometry assay, in which trans-cinnamic acid (21.26%), neophytadiene (6.36%), linolenic acid (5.86%), dihydroagathic acid (5.71%), n-hexadecanoic acid (5.53%), phytol (4.14%) and cis-cinnamic acid (3.23%) were the major compounds. The acetone extract and its fractions such as n-hexane, chloroform and ethyl acetate of P. cornutus showed DPPH radical scavenging activity with IC50 value of 234.31, 185.95, 758.65 and 458.52 µg/mL respectively

A Novel Self-organizing Fuzzy Cerebellar Model Articulation Controller Based Overlapping Gaussian Membership Function for Controlling Robotic System

This paper introduces an effective intelligent controller for robotic systems with uncertainties. The proposed method is a novel self-organizing fuzzy cerebellar model articulation controller (NSOFC) which is a combination of a cerebellar model articulation controller (CMAC) and sliding mode control (SMC). We also present a new Gaussian membership function (GMF) that is designed by the combination of the prior and current GMF for each layer of CMAC. In addition, the relevant data of the prior GMF is used to check tracking errors more accurately. The inputs of the proposed controller can be mixed simultaneously between the prior and current states according to the corresponding errors. Moreover, the controller uses a self-organizing approach which can increase or decrease the number of layers, therefore the structures of NSOFC can be adjusted automatically. The proposed method consists of a NSOFC controller and a compensation controller. The NSOFC controller is used to estimate the ideal controller, and the compensation controller is used to eliminate the approximated error. The online parameters tuning law of NSOFC is designed based on Lyapunov’s theory to ensure stability of the system. Finally, the experimental results of a 2 DOF robot arm are used to demonstrate the efficiency of the proposed controller

Phytoplankton diversity and its relation to the physicochemical parameters in main water bodies of Vinh Long province, Vietnam

Phytoplankton samples were collected in 2016 during the dry and rainy seasons at nine sampling sites in Vinh Long province, Vietnam. Some basic environment parameters such as temperature, pH, dissolved oxygen, nitrate and phosphate were measured and a total of 209 phytoplankton species (six phyla, 96 genera) were identified. The phylum that had the greatest number of species was Bacillariophyta (82 species), followed by Chlorophyta (61 species), Cyanophyta (39 species), Euglenophyta (21 species), Chrysophyta (three species) and Dinophyta (three3 species). The phytoplankton density ranged from 4,128 to 123,029 cells/liter. The dominant algae recorded in the study area include Microcystis aeruginosa, Merismopedia glauca, Oscillatoria perornata, Jaaginema sp., Planktothrix agardhii, Coscinodiscus subtilis, Melosira granulata. In particular, Microcystis aeruginosa was the most density dominant species in the total number of sampling sites during the dry season survey, and this species was classified as a group producing toxins harmful to the environment. Surface water quality, according to QCVN 08: 2015/BTNMT was classified into Column A1 for pH, nitrate and Column B1 for dissolved oxygen, and Column B2 for phosphate. Phytoplankton community structure and environmental factors changed substantially between dry and rainy seasons. A Pearson (r) correlation coefficient was used for the relative analysis. The results indicated that the number of phytoplankton species were a significantly positive correlation with pH, dissolved oxygen and nitrate in the rainy season. The phytoplankton abundance was uncorrelated with environmental factors in both seasons.Các mẫu thực vật phù du được thu thập trong năm 2016 (mùa khô và mùa mưa) tại 9 vị trí ở tỉnh Vĩnh Long, Việt Nam. Một số thông số môi trường như nhiệt độ, pH, oxy hòa tan, nitrat và phốt phát được đo ngay tại hiện trường. Tổng cộng 209 loài thực vật phù du được ghi nhận (6 ngành, 96 chi). Số lượng loài cao nhất là tảo Silic (82 loài), kế đến là tảo Lục (61 loài), tảo Lam (39 loài), tảo Mắt (21 loài), tảo Vàng ánh (3 loài) và tảo Giáp (3 loài). Mật độ thực vật phù du dao động từ 4.128 đến 123.029 tế bào/ lít. Các loài ưu thế ghi nhận được ở khu vực nghiên cứu gồm có: Microcystis aeruginosa, Merismopedia glauca, Oscillatoria perornata, Jaaginema sp., Planktothrix agardhii; Coscinodiscus subtilis, Melosira granulata. Trong đó, loài Microcystis aeruginosa chiếm ưu thế nhiều nhất trên tổng số điểm thu mẫu trong đợt khảo sát mùa khô, đồng thời loài này được xếp vào nhóm sản sinh độc tố gây hại cho môi trường. Chất lượng nước mặt theo QCVN 08:2015/BTNMT được xếp vào loại A1 đối với thông số pH, nitrat và loại B1 đối với thông số oxy hòa tan, và loại B2 đối với phốt phát. Cấu trúc quần xã thực vât nổi và các yếu tố môi trường thay đổi đáng kể giữa mùa mưa và mừa khô. Hệ số tương quan Pearson (r) được dùng để phân tích. Kết quả cho thấy số lượng thực vật phù du có tương quan thuận với pH, oxy hòa tan và nitrat trong mùa mưa và có ý nghĩa về mặt thống kê. Mật độ của thực vật phù du không tương quan với các yếu tố môi trường trong cả hai mùa

Evaluation of Three Adolescent Sexual Health Programs in Ha Noi and Khanh Hoa Province, Vietnam

With an increase in sexual activity among young adults in Vietnam and associated risks, there is a need for evidence-based sexual health interventions. This evaluation of three sexual health programs based on the Protection Motivation Theory (PMT) was conducted in 12 communes in Ha Noi, Nha Trang City, and Ninh Hoa District. Inclusion criteria included unmarried youth 15–20 years residing in selected communes. Communes were randomly allocated to an intervention, and participants were randomly selected within each commune. The intervention programs included Vietnamese Focus on Kids (VFOK), the gender-based program Exploring the World of Adolescents (EWA), and EWA plus parental and health provider education (EWA+). Programs were delivered over a ten-week period in the communities by locally trained facilitators. The gender-based EWA program with parental involvement (EWA+) compared to VFOK showed significantly greater increase in knowledge. EWA+ in comparison to VFOK also showed significant decrease at immediate postintervention for intention to have sex. Sustained changes are observed in all three interventions for self-efficacy condom use, self-efficacy abstinence, response efficacy for condoms, extrinsic rewards, and perceived vulnerability for HIV. These findings suggest that theory-based community programs contribute to sustained changes in knowledge and attitudes regarding sexual risk among Vietnamese adolescents

Chemical profiles and biological activities of acetone extracts of nine Annonaceae plants

This study investigated the chemical components and bioactivities of acetone leaf extracts of nine Annonaceae plants collected in the Binh Chau-Phuoc Buu Nature Reserve, Vietnam. A total of 182 constituents were identified, with linolenic acid, diaeudesmin, germacrene D, 1-octadecenoic acid, 8-(3-octyl-2-oxiranyl)-1-octanol, oleic acid, and phenylmethyl ester being the major compounds. The antimicrobial activity of the extracts was evaluated using a disc diffusion assay. Eight of the nine extracts, except for the Mitrephora thorelii extract, showed an inhibition effect against Bacillus cereus and Staphylococcus aureus. The antioxidant activity of the extracts was determined using DPPH assay, and the cytotoxic activity was deter mined using SRB assay. The results showed that the acetone extracts of Artabotrys hexapetalus, Uvularia grandiflora, Polyalthia luensis, Xylopia pierrei, Sphaerocoryne affinis, Desmos cochinchinensis, Uvaria littoralis, Mitrephora thorelii, and Goniothalamus touranensis had significant activity with IC50 for the DPPH radical scavenging activity ranging from 18.56 to 702.33 μg/mL, and the IC50 for the cytotoxic effects ranged from 5.39 to 251.77 μg/mL. Overall, the results obtained provide experimental evidence for the potential use of these plants in medicine and other related fields

Impacts of Economic Development on the Awareness of Cultural Preservation of Ethnic Minority People in the Border Region of Northern Vietnam

Purpose: The aim of this study is to examine how the Vietnamese government's economic development strategies affect ethnic minority people's knowledge of cultural preservation in the border area of Northern Vietnam.   Theoretical framework: The study focuses on three main driven factors of the awareness of cultural preservation that are economic changes, societal changes, and environmental changes from three economic fields: agriculture, industry, and trade and services.   Design/methodology/approach: The research sample was taken from ethnic minorities in Northern Vietnam's border area. For questionnaire administration, interviewees are selected at random from the population. Face-to-face, drop-off, and phone-calling approaches were used to disseminate the questionnaire. We received 544 completed returns out of 725 surveys sent out. The data was then cleaned and analyzed with SPSS 20 software using Partial Least Squares Structural Equation Modelling (PLS-SEM).   Findings: The results of a study of ethnic minority communities in seven provinces in Northern Vietnam's border region show that the development of agriculture, industry, trade and service significantly impacts ethnic minority people's awareness of cultural preservation issues due to environmental changes. In contrast, economic and sociological developments appear to have little influence on ethnic minority people's attention to cultural preservation. This phenomenon may be due to the long-term effects of economic and sociological changes, which mostly affect intangible cultural heritages. In contrast, environmental impats are felt swiftly and primarily on physical cultural heritages that can be seen.   Research, Practical & Social implications: The findings of the research provide policymakers with valuable insights on the effects of economic development on cultural preservation. The study's recommendations can inform policies that promote sustainable economic development while preserving the cultural heritage of ethnic minority communities.   Originality/value: The research focuses on the border region of Northern Vietnam, which is an area of strategic importance for economic development and cultural preservation. The study's unique focus on this region provides insights into the cultural and economic dynamics of a specific area that has not been extensively studied