Influence of Principle Parameters on the Average Stiffness of Optical Tweezer Using Pulsed Gaussian Beams

In this article expresions used to simulate the trap stiffness k of the optical trap are derived. The influence of principle parameters as total energy, beam waist and duration of pulsed laser beam, radius of dielectric particle, and viscosity of surrounding medium on the stiffness  is simulated and discussed

Learning from Pixels with Expert Observations

In reinforcement learning (RL), sparse rewards can present a significant challenge. Fortunately, expert actions can be utilized to overcome this issue. However, acquiring explicit expert actions can be costly, and expert observations are often more readily available. This paper presents a new approach that uses expert observations for learning in robot manipulation tasks with sparse rewards from pixel observations. Specifically, our technique involves using expert observations as intermediate visual goals for a goal-conditioned RL agent, enabling it to complete a task by successively reaching a series of goals. We demonstrate the efficacy of our method in five challenging block construction tasks in simulation and show that when combined with two state-of-the-art agents, our approach can significantly improve their performance while requiring 4-20 times fewer expert actions during training. Moreover, our method is also superior to a hierarchical baseline.Comment: Accepted at IROS-2023 (Detroit, USA), the first two authors contributed equall

The Simulation of the Stabilizing Process of Glass Nanoparticle in Optical Tweezer Using Series of Laser Pulses

In this article the stable region and stabilizing process of dielectric particle in fluid by the optical tweezer using the series of laser pulses are investigated. The influence of the repetition period and number of laser pulses on the radial variance of particle and the ``so-called'' stable space-time pillar is simulated and discussed

Influence of Energy and Duration of Laser Pulses on Stability of Dielectric Nanoparticles in Optical Trap

In this article the gradient force of optical trap using two counter-propagating pulsed Gaussian beam and the Brownian motion in optical force field are investigated. The influence of the energy and duration time of optical pulsed Gaussian beams on satability of nano-particle in trap is simulated and discussed

Morphology and DNA marker for distinguishing Paphiopedilum hangianum and Paphiopedilum emersonii from Vietnam

Genus Paphiopedilum has species having lovely flowers which are incredibly attractive to everyone. Their ornamental and commercial value caused over-collection and illegal poaching and trade. Due to these reasons, nowadays, the Venus slipper orchids are facing to deplete in nature. Therefore, it is important to consider these species conservation. Mainly, it is necessary to prioritize the identification and phylogenetic analysis methods of the genus Paphiopedilum which includes many species with similar morphological characteristics. Consequently, it isn't easy to distinguish the identical species of this genus when the plants are young or not yet fully flowering. Therefore, this study aimed to distinguish two Paphiopedilum species, i.e. P. hangianum and P. emersonii, which have similar morphological characteristics, through comparative morphological analysis and differences in DNA barcoding sequences. To solve the problem associated with species identifications, a morphological comparison table was created with the four DNA sequence markers matK, rbcL, rpoC1 and trnH-psbA. The results of the morphological analysis showed that P. hangianum and P. emersonii are significantly different from each other in the flower's characteristics. While the difference in leaf morphology of both selected species is found very little, it is also distinguishable upon careful comparison. Moreover, the DNA barcoding indicator gave accurate and rapid distinctions between the two species, even when     the plants are young or without flowers. Furthermore, this DNA barcoding can establish an evolutionary relationship between the two selected species and the other species of the genus Paphiopedilum. The results of this study also suggested that the indicator trnH-psbA is a suitable marker for distinguishing these two species and can be applied for the phylogenetic analysis of the genus Paphiopedilum in Vietnam

Determinants Influencing Entrepreneurial Intention in Hanoi, Vietnam

This research employed survey data from 204 students between two groups of  economics and technical majors in Hanoi city for assessing the impact levels of determinants on entrepreneurial intention. The results show that a number of determinants including Need for achievement, Self-efficacy, and Instrumental readiness have positive impacts on student’s entrepreneurial intention. Besides, this study is also to create a basis for  comparative students among different economics and technical majors, work exoperience, and gender. These findings are the basis to recommend policies and solutions to promote entrepreneurship movement in Vietnam. Keywords: Entrepreneurial intention, need for achievement, self-efficacy, instrumental readiness. DOI: 10.7176/EJBM/12-15-10 Publication date:May 31st 2020

PATHOGENICITY OF EIMERIA SPECIES ISOLATED FROM CHICKEN IN THUA THIEN HUE PROVINCE

Abstract: The present study clarifies the effect of locally isolated Eimeria species on chickens in central Vietnam. Oocysts of Eimeria species were isolated from feces suspected to be infected with coccidiosis in 3 farms in Huong Thuy district, Thua Thien Hue province. A total of 54 2-week-old chickens were randomly allocated to 2 groups: 3 replicates containing 9 chickens in each replicate. The chicken in group 1 were orally inoculated with 2×104 isolated oocysts of Eimeria species, while the chickens in group 2 were inoculated with PBS as a control. Growth performance, oocyst output, gross lesions, and histopathological lesions were measured at 5, 10 and 28 days after infection. The chicks in group 1 showed general signs of ruffled feathers, anorexia, huddling together with diarrhea and/or bloody dropping from 4–7 days post-infection. Feed intake, growth performance and body weight in group 1 were lower than those of the control chicks. The oocyst was detected in the feces of chicks in group 1 from 6–14 days post-infection, among them, the number of oocysts reach the peak at 8 days post-infection. At day 5 post-infection, the most damaged part of the intestine is the ceca with a large amount of blood in the ceca content. The histopathological lesions were detected clearly by HE staining at day 5 and 10 post-infection. In conclusion, the locally isolated oocysts of Eimeria species have high virulence to the chickens. The present study provides useful information related to the pathogenicity of Eimeria species which may contribute to coccidiosis diagnosis and treatment in poultry production.Keywords: Eimeria, coccidiosis, infection, central Vietna

DETERMINATION THE PRIORITY OF FACTORS INFLUENCING OVERSEAS INVESTMENT DESTINATIONS OF BUSINESSES USING AN ANALYTIC HIERARCHY PROCESS METHOD

Because of the great benefits overseas investment brings, countries and businesses are increasingly concerned with the question of an ideal investment destination. Many studies have shown that, factors of the consumption market, the infrastructure and resources, economic and political environment have a significant impact on the decision to choose an investment location, however the priority order of these factors are different for various research spaces. By studying the specific case of Viettel Group - one of the largest telecommunications groups in Vietnam that is having many international investment activities in recent years, the study has been verified the priority order of factors influencing the decision to choose an overseas investment location of this corporation. The research outcomes show that the group of factors that have the most influence on investment decisions is the group "Consumption market", more specifically, the sub-factor "Market Size" is considered more than the others.    Keywords: Investment Destinations, Foreign Investment Decision, Analytic Hierarchy Process

Direct Observation of Exceptional Points in Photonic Crystal by Cross-Polarization Imaging in Momentum Space

This study explores exceptional points (EPs) in photonic crystals (PhCs) and introduces a novel method for their single-shot observation. Exceptional points are spectral singularities found in non-Hermitian systems, such as leaky PhC slabs. However, directly observing EPs in PhC systems using regular reflectivity spectroscopy is a considerable challenge due to interference between guided resonances and background signals. In this work, we present a simple, nondestructive technique that employs crossed polarizations to directly observe EPs in momentum-resolved resonant scattering. This approach effectively suppresses the background signal, enabling exclusive probing of the guided resonances where EPs manifest. Our results demonstrate the formation of EPs in both energy-momentum mapping and isofrequency imaging. All experimental findings align seamlessly with numerical simulations and analytical models. Our approach holds great potential as a robust tool for studying non-Hermitian physics in PhC platform