1,655 research outputs found
Description of Geocenamus vietnamensis sp. n. (Nematoda : Merliniidae) from Vietnam
A new species of the genus Geocenamus was isolated from soil and root samples from the rhizosphere of Casuarina equisetifolia (Casuarinaceae) in Quang Nam province, Vietnam. This species is characterized by a round-to-hexagonal labial disc, the presence of a labial region, which is continuous or slightly offset from the body with six sectors, lateral sectors of first labial annulus being smaller than the submedian sectors, the presence of six to seven labial annules; the absence of deirids; stylet length 24 to 28 mu m long, body length 776 to 979 mu m long; lateral field with six to eight lateral lines, without areolation at mid-body and with areolation in outer bands at the tail region and a pointed tail terminus. Geocenamus vietnamensis n. sp. most closely resembles G. boghiae in having a non-sclerotized head framework and lacking a bursa in the males. It can be clearly distinguished from all other species of the genus Geocenamus by these characteristics. The combination of morphology, morphometric features, and phylogenetic trees, based on D2-D3 of 28S and ITS rDNA sequences, showed that this new species can be clearly separated from all other sequenced species. This record is the first for Geocenamus in Vietnam
Morphological and molecular characteristics of Pratylenchus haiduongensis sp. n., a new species of root-lesion nematodes associated with carrot in Vietnam
Pratylenchus haiduongensis sp. n. is described as associated with carrot (Daucus carota subsp. sativus (Hoffm.) Schubl. & G. Martens) in Hai Duong Province, Vietnam. P. haiduongensis sp. n. is characterized by the lip region with three annuli and slightly separated from the body. Stylet knobs are rounded (never indented anteriorly). The lateral field includes four incisures, bearing areolation at the pharynx region and tail region and occasionally appears in the vulval region. Sometimes the appearances of oblique broken striaes divide the lateral field into five or six incisures. The ovary is distinct with one row of oocytes. Spermatheca is oval in shape with round central cavity, without sperm or reduced in some specimens. The postvuval uterine sac is long surpassing the vulva body diameter by 2 to 2.5 times (PUS = 31 to 65 mm). High vulva position with V = 66 to 75%. The tail shape can be subhemispherical with a smooth, slightly indented, broadly smooth, or cleft terminus observed in some specimens. The matrix code of P. haiduongensis sp. n. is: A2, B1, C4, D(1,3), E1, F(5,6), G(1,2), H(1,4); I(1,2,3,4), J1, K(1,2) according to Castillo and Vovlas (2007). The LSU-D2D3 segment and the ITS-rDNA region of this species were amplified and sequenced. The morphological characters and molecular phylogenetic analyses confirmed that this is a new species of the genus Pratylenchus in Vietnam
Factores que afectan el ciclo de vida del producto en las empresas electrónicas: evidencia de un país emergente
Introduction:This paper is the product of the study “Factors affecting product life cycle in electronic enterprises – Evidence from an emerging country” developed at the Electric Power University and National Economics University between 2020 and 2022.
Problem:The electronic manufacturing industry is increasingly developing in emerging markets and integrating into the global economy. The life cycle of electronic products is shorter and requires management.Objective:The paper aims to study factors that affect the product life cycle in Vietnamese electronic enterprises. The study helps managers in cost management.
Methodology:The paper used a survey of non-probability sampling, and applied regression analysis to examine Vietnamese electronic enterprises. The analysis is done by SPSS and Smart PLS software.
Results:The research results indicate that technology, consumer trends, and R&D are factors affecting product life cycle and post-sale service, and disposal has no impact on electronic products’ life cycle. This could be explained by the fact that electronic products are constantly updating and their life cycle is short, that post-sales service does not play a key role, and that waste treatment after sales is not taken seriously by manufacturers, customers, or other related parties.
Conclusion:The results give some meaningful insights for electronics or other enterprises in Vietnam to use effective management of product life cycle. Originality:The results of this paper provide practical insights into the management of product life cycle and cost management of product life cycle for researchers and managers.Limitations:The research model should be expanded and the sample size increased to get an overview and greater insight.Introducción: Este artículo es producto del estudio “Factores que afectan el ciclo de vida del producto en empresas electrónicas – Evidencia de un país emergente” desarrollado en la Electric Power University y la National Economics University entre 2020 y 2022.Problema: La industria de fabricación electrónica se está desarrollando cada vez más en los mercados emer-gentes y se está integrando a la economía global. El ciclo de vida de los productos electrónicos es más corto y requiere gestión.
Objetivo: El documento tiene como objetivo estudiar los factores que afectan el ciclo de vida del producto en las empresas electrónicas vietnamitas. El estudio ayuda a los gerentes en la gestión de costos.
Metodología: El documento utilizó una encuesta de muestreo no probabilístico y aplicó un análisis de regresión para examinar las empresas electrónicas vietnamitas. El análisis se realiza mediante el software SPSS y Smart PLS.
Resultados: Los resultados de la investigación indican que la tecnología, las tendencias de consumo y la I+D son factores que afectan el ciclo de vida del producto y el servicio postventa, y que el desecho no tiene impacto en el ciclo de vida de los productos electrónicos. Esto podría explicarse por el hecho de que los productos electrónicos se actualizan constantemente y su ciclo de vida es corto, que el servicio posventa no juega un papel clave y que el tratamiento de residuos posventa no es tomado en serio por los fabricantes, clientes u otras partes relacionadas.
Conclusión: Los resultados brindan algunas ideas significativas para la electrónica u otras empresas en Vietnam para utilizar una gestión eficaz del ciclo de vida del producto.
Originalidad: los resultados de este documento brindan información práctica sobre la gestión del ciclo de vida del producto y la gestión de costos del ciclo de vida del producto para investigadores y gerentes.Limitaciones: el modelo de investigación debe ampliarse y aumentar el tamaño de la muestra para obtener una visión general y una mayor comprensión
Improving color rendering index of WLEDs with convex-dual-layer remote phosphor geometry using red-emitting CaGa2S4:Mn2+ phosphor
The white-light light-emitting diode (LED), a conventional illumination solution, usually consists of one chip and one phosphor layer, which leads to the insufficient color rendering index (CRI) in this configuration. To optimize the efficiency of WLED, a new LED package with 2 chips and one phosphor was proposed, this innovative configuration can yield more lights and achieve high CRI. Thus, this study aims at perfecting the color performance with the two chips and dual phosphor layers package with the proportions and densities of phosphor in the silicone constantly changed to find the best option. The white-light LED module is adjusted using a specialized color design model. The comparison results between the measured and the simulation from the color design model CIE 1931 color coordinates suggest that the highest discrepancy is about 0.0063 and is achieved at around 5600K correlated color temperature (CCT). This study’s results lay a firm path in customizing white-light LED modules that guarantee CRI and lumen output qualities
Enhance the chromatic uniformity and luminous efficiency of WLEDs with triple-layer remote phosphor structures
The angular color uniformity (ACU) with the ability to evaluate chromatic performance of WLED has become an important target to achieve in producing higher-quality WLEDs. This paper studies the ACU enhancing effects of novel triple-phosphor configuration in lighting devices with remote phosphor structure. Moreover, the optical influences of remote phosphor structure with three phosphor layers (TL) on WLEDs properties are calculated and compared to the dual-layer (DL) one for reference. The experiments are applied to devices at 5 distinct correlated color temperature ranging from 5600-8500 K. The results presented that DL structure attains better color rendering index (CRI) than the TL one. Meanwhile, in terms of color quality scales (CQS), TL model shows higher values at all ACCTs, compared to the DL. Moreover, the luminous flux of DL configuration is lower than that of TL structure. In addition, the diversion of color temperature depicts as D-CCT in TL structure is much better than the value in DL structure, especially at high ACCT as 8500 K, which means TL is good for chromatic uniformity of high ACCTs WLEDs. These results proved that the triple-layer structure is superior and more effective to apply for acquiring the enhancement of WLEDs package
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