Higher chromatic rendition with Cr3+-doped yellow Y3Al5O12:Ce3+ for double-layer remote phosphor white-light-emitting diodes

Remote phosphor designs of white-light-emitting diodes (WLEDs) have been recognized for their high thermal stability and excellent luminous efficiency but not for the chromatic rendering. The study presents an approach for the remote phosphor structure to overcome the low-color-rendering issue by enriching its red-light spectral intensity through co-doping Cr3+ and Ce3+ ions into the yellow  Y3Al5O12 (YAG) phosphor compound. This ion co-doping process probably enhances emission spectra in the far-red range because of the energy transfer of the integrated ions: Ce3+ Cr3+. Additionally, the luminescence and color properties of the phosphor layer significantly depend on the doped concentration of the Cr3+ ion. Here, with 0.008% Cr3+ in the phosphor composite, either internal or external quantum performances of the dual-layer WLED light are enhanced, which achieved the number of 58.9% and 46.7%, respectively. The color rendering index (CRI) would also be higher if Cr3+ is added, about 77.9, compared to the CRI of 63.2 when using the original  YAG:Ce3+ phosphor layer

Exploiting Idioms and Proverbs of Vietnamese Regions in Teaching Mathematics in Primary Schools

Mathematics and idioms, as well as proverbs, all reflect the laws of life. At the same time, primary school children may have heard idioms and proverbs before attending school. Therefore, there are many possibilities to exploit and apply idioms and proverbs in teaching mathematics in primary schools. This study aims to identify appropriate situations and apply idioms and proverbs in different regions of Vietnam to teaching mathematics. The researchers selected 1155 expressions related to mathematics from many typical pieces of research on idioms and proverbs in Vietnam. After surveying 1822 teachers three times in many provinces and cities in all 3 regions of Vietnam: the North, the Central and the South, the researchers have classified the data according to the criteria from closed to open-ended questions. The results show a prominent level of interest (level 4/5) of all teachers participating in the survey, and there is no difference in the effectiveness in the three regions, but there is a clear difference in regions in using idioms and proverbs. Particularly, identifying situations to teach geometric and quantitative knowledge, as well as probability and statistics, allows one to apply idioms and proverbs at a high level. It is concluded that if idioms and proverbs from Vietnamese regions are appropriately selected and applied in teaching mathematics in primary schools, they will contribute to improving students' mathematical ability and preserving the national cultural heritage. Doi: 10.28991/ESJ-2022-SIED-015 Full Text: PD

THE INFLUENCE OF CORE - SHELL RATIO ON CHARACTERISTICS OF MICROCAPSULES CONTAINING CINNAMON ESSENTIAL OIL APPLIED TO AROMATHERAPEUTIC TEXTILES

Microencapsulation is one of the techniques to prepare the functional textiles. In this paper the essential cinnamon oil loaded microcapsules were prepared by solvent evaporation method. In the microencapsulation process, the core - shell ratio was changed by altering the cinnamon oil content in four levels of 0.15, 0.25, 0.35 and 0.45 g while the other components remained unchanged. The microcapsule characteristics including shape and morphology, size and size distribution, microencapsulation efficiency in dependence on the core-shell ratio were investigated. The antimicrobial capacity and the fragrance durability of interlock knitted fabric coated with the elaborated microcapsules were evaluated. The results showed that cinnamon oil was microencapsulated successfully in the spherical microcapsules. When the cinnamon oil content increased, the microcapsule size decreased and the size distribution became broader, the microcapsules were more porous and more aggregate, the fragrance intensity of the fabric treated with microcapsules increased while the activity against E. coli bacteria decreased. According to the results, the microcapsules elaborated with 0.15 g of cinnamon oil was recommended for the treatment of interlock cotton knitted fabric to apply in aroma and antimicrobial textiles

A Pilot Observer Program for the Reduction of Sea Turtle and Other By-catch in Vietnamese Longline Fisheries

Five species of marine turtles are found within the territorial waters of Vietnam, and all populations are declining. As part of a broader strategy and Action Plan, the Government of Vietnam and WWF Vietnam have launched a two-year project to: 1) document relative gear impacts, and geographic hotspots , for sea turtle interactions and, 2) design and implement a first-of-its-kind observer program for Vietnamese fisheries. This presentation will describe the major results of the first component, providing data on the characteristics and extent of sea turtle interactions with key Vietnamese fisheries through initial research and community interviews. Comprehensive data pertinent to the fishery hotspots in Vietnam will be provided. Together with data on sea turtle catch, fleet size, trends, seasons, timing, mesh size etc., this information has informed major recommendations on the design and structure of an observer program, which will also be described. While some information gaps still exist, the knowledge base has been significantly expanded and this new information has ensured that by-catch reduction efforts - specifically the planned observer program and subsequent gear experiments for long-line fisheries and a Management Options Paper for gillnet fisheries - can be most strategically targeted and planned. Additionally, the role of community participation, capacity-building for local fisheries agencies, and overall stakeholder perceptions and impressions will be reviewed. Finally, the concept of how the sea turtle driver could result in broader applications for observer programs for fisheries management in Vietnam, and how this aligns WWF and government strategies for sustainable fisheries management, will be discussed

ĐIỀU TRA TÌNH HÌNH CỎ LỒNG VỰC PHÁT SINH TRỞ LẠI TRÊN RUỘNG LÚA GIEO SẠ SAU KHI SỬ DỤNG THUỐC TRỪ CỎ Ở THỪA THIÊN HUẾ

Studying herbicide resistance in Vietnam is limited, and there are very few reports on the regrowth of weed after applying herbicides. A survey to investigate the cultivating habit and the barnyard grass regrowing in the direct-seeded rice fields after applying herbicides in Thua Thien Hue shows that the main labourers of rice cultivation are male with a low educational level to understand scientific and technical knowledge. The most common grass regrowing in direct-seeded rice fields after applying herbicides includes Barnyard grass (Echinochloa crus-galli), Grass-like fimbry (Fimbristylis miliacea), Bermuda grass (Cynodon dactylon), and Sprangletop (Leptochloa chinensis). The yield decreases from 12.1 to 14.0% because of regrowing of barnyard grass. The herbicides commonly used in Thua Thien Hue are Sofic 300EC (Pretilachlor) and Sunrice 15WDG (Ethoxysulfuron), but their effectiveness has decreased in recent time owing to farmers’ inappropriate spraying skills and the decrease in the effectiveness of herbicides. A more thorough assessment of the factors that cause grass regrowing after spraying herbicides is required for better weed management.Nghiên cứu sự kháng thuốc trừ cỏ ở Việt Nam còn hạn chế và có rất ít báo cáo về sự phát sinh của cỏ dại sau khi sử dụng thuốc trừ cỏ. Kết quả điều tra về tập quán canh tác và tình hình cỏ lồng vực phát sinh trở lại trên ruộng lúa sau khi sử dụng thuốc trừ cỏ ở Thừa Thiên Huế cho thấy lực lượng lao động chính canh tác lúa là nam giới, trình độ dân trí không cao nên khả năng tiếp thu kiến thức khoa học – kỹ thuật hạn chế. Các loại cỏ gây hại phổ biến trên ruộng lúa gieo sạ là cỏ lồng vực (Echinochloa crus-galli), cỏ chác (Fimbristylis miliacea), cỏ chỉ (Cynodon dactylon), cỏ đuôi phụng (Leptochloa chinensis) là các loại cỏ xuất hiện trở lại sau khi đã sử dụng thuốc trừ cỏ. Cỏ lồng vực mọc trở lại có thể gây giảm năng suất cây lúa 12,1–14,0%. Các loại thuốc trừ cỏ được sử dụng phổ biến là Sofic 300EC (Pretilachlor) và Sunrice 15WDG (Ethoxysulfuron). Hiệu quả thuốc trừ cỏ lúa có xu hướng giảm trong thời gian gần đây do kỹ thuật sử dụng và sự giảm hiệu quả của các sản phẩm thuốc trừ cỏ. Chúng tôi kiến nghị cần đánh giá đầy đủ hơn về các yếu tố gây nên tình trạng cỏ dại mọc trở lại sau khi phun thuốc để có định hướng quản lý cỏ dại tốt hơn

A multi locus sequence analysis scheme for phylogeny of the Bacillus subtilis species complex and its advantages over 16S rRNA genes

A multi locus sequence analysis (MLSA approach) was studied on the Bacillus genus, or the Bacillus subtilis species complex for specific, including 08 strains from four species (B. subtilis, B. pumilus, B. licheniformis and B. amyloliquefaciens) were provided by Biotechnology Center of Ho Chi Minh City. The research was based on sequences of 16S rRNA genes, the concatenation of five protein-coding housekeeping genes: glpF, pta, purH, pycA, and rpoD. After PCR amplification and sequencing the phylogenetic tree of 16S rRNA sequences, concatenate sequences (as well as the phylogenetic tree of each housekeeping gene) are constructed for comparison and discussion. The aim of this study is reach for better resolution and differentiation of strains and species within the B. subtilis species and to determine whether MLSA scheme show advantages in 16S rRNA gene-based studies