On the sleeping gregarious behavior of the potter wasp Antepipona biguttata (Fabricius) (Hymenoptera: Vespidae: Eumeninae)

Pham Phong Huy 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.4

Antepipona biguttata, an Asian potter wasp, is distributed in China, India, Korea, Laos, Malaysia, Myanmar, Taiwan, Thailand and Vietnam. Despite a large geographical distribution, not much is known about its biology. Here, I describe the sleeping gregarious behavior of A. biguttata (Fabricius) for the first time. Seventeen in dividuals of the wasp, including 11 males and 6 females, were found gregariously sleeping on a bunch of panicles of the jungle rice Echinochloa colona. The wasps grasped the plants tightly with their mandibles, their fore and mid legs grasping at panicles, their hind legs either resting on the substrate or free backwards, and their head mostly orientating upwards. The wasps held their body parallel to the perch, with their antennae raised forwards and their wings usually extended at an angle of about 45 degrees. Brief comments on the sleeping behavior of A. biguttata are presented.

Improvement in carrier collection at the i/n interface of graded narrow-gap hydrogenated amorphous silicon germanium solar cells

Pham, Duy Phong,Kim, Sangho,Park, Jinjoo,Le, Anh Huy Tuan,Cho, Jaehyun,Yi, Junsin ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.724 No.-

<P><B>Abstract</B></P> <P>We examined different buffer layers at the i/n interface of narrow-gap amorphous silicon germanium alloy (a-SiGe:H)-based thin-film solar cells. These buffers included a conventional hydrogenated amorphous silicon (a-Si:H), an inversely graded hydrogenated amorphous silicon germanium, and a crystalline seed buffer (CSB). The solar cell with the CSB shows the highest performance, of 10%. The better carrier extraction at the rear side of the device is attributed to the role of the CSB layer. The effect of CSB thickness from 50 nm to 100 nm on cell performance was examined. Cell efficiency increased with the buffer thickness up to 80 nm and decreased with buffer thickness of 100 nm. This decrease can be attributed to increased defect densities of the buffer due to less efficient passivation of amorphous phase at the crystalline column boundaries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Carrier extraction at the i/n interface is improved by crystalline seed buffer (CSB) layer. </LI> <LI> Role of crystalline seed buffer layer is discussed in detail. </LI> <LI> High efficiency of 10% of graded a-SiGe:H thin film solar cell is obtained with CSB buffer. </LI> </UL> </P>

Controlling a crystalline seed layer for mirocrystalline silicon oxide window layer in rear emitter silicon heterojunction cells

Pham, Duy Phong,Kim, Sangho,Lee, Sunhwa,Le, Anh Huy Tuan,Cho, Eun-Chel,Park, Jinjoo,Yi, Junsin Elsevier 2019 Infrared physics & technology Vol.102 No.-

<P><B>Abstract</B></P> <P>Remarkable progress has been made in the improvement of rear-emitter silicon heterojunction (RE-SHJ) solar cells with the use of very thin n-type front contact layers. However, further reducing the thickness of the front window layers while maintaining high conductivity for mitigating the parasitic absorption and carrier collection loss has proven challenging. In this study, we implement controlling a seed layer for achieving ultra-thin, high crystalline and conductivity of n-type hydrogenated microcrystalline silicon oxide (n-µc-SiO<SUB>x</SUB>:H) front window layer in RE-SHJ solar cells. By using a seed layer, the crystallinity confirmed by Raman and TEM measurements, and the conductivity of the n-µc-SiO<SUB>x</SUB>:H front layers are significantly enhanced compared with that without using the seed layer. This leads to a remarkable increase in the open-circuit voltage (<I>V</I> <SUB>oc</SUB>) by 6 mV and fill factor (<I>FF</I>) by 4.11% while maintaining a high short-circuit current density (<I>J</I> <SUB>sc</SUB>) in range of 38 mA/cm<SUP>2</SUP>. A high cell performance of 21.1% is obtained with the use of an optimised seed layer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of deposition power densities on seed-growth via TEM measurement was discussed. </LI> <LI> High crystallinity and conductivity of ultra-thin n-µc-SiOx:H front layer for RE-SHJ solar cells. </LI> <LI> V<SUB>oc</SUB> enhancement by 6 mV and fill factor by 4.11% due to optimization of seed layer. </LI> </UL> </P>

Biology and predatory ability of the reduviid Sycanus falleni Stal (Heteroptera: Reduviidae: Harpactorinae) fed on four different preys in laboratory conditions

Truong Xuan Lam,Pham Huy Phong,Thai Thi Ngoc Lam 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4

The reduviid Sycanus falleni Stal (Heteroptera: Reduviidae) is an important predatory insect in biological control pests in vegetable, soybean, corn and rice plants. It is omnivorous species and has a wide range of prey. The influence of fed on four different preys as Pieris rapae (Linnaeus), Spodoptera litura (Fabricius), Plutela xylostella (Linnaeus) and Corcyra cephalonica (Stainton) on biological parameters, ability to eat prey and body weight of the nymph and adult of S. falleni were evaluated in laboratory conditions (26 ± 2 °C, 75 ± 5% RH and light:dark 14:10 h) in Vietnam. The biological parameters of reduviid S. falleni reared on the laboratory were determined by observing the development stage of egg, development stage of nymph, pre-oviposition period, life cycle, longevity of adult, number of eggs laid, sex ratio. The nymph and adults of reduviid S. falleni consumption the number of P. xylostella, P. rapae, S. litura and C. cephalonica larvae were different, and an adult female consumed more than an adult male while the body weight of the I and V nymphal instars, male and female adults of reduviid S. falleni wasn't significantly different (P < 0.01).

A Review of Wet Chemical Etching of Glasses in Hydrofluoric Acid based Solution for Thin Film Silicon Solar Cell Application

Hyeongsik Park,Jae Hyun Cho,Jun Hee Jung,Pham Phong Duy,Anh Huy Tuan Le,Junsin Yi 한국태양광발전학회 2017 Current Photovoltaic Research Vol.5 No.3

High efficiency thin film solar cells require an absorber layer with high absorption and low defect, a transparent conductive oxide (TCO) film with high transmittance of over 80% and a high conductivity. Furthermore, light can be captured through the glass substrate and sent to the light absorbing layer to improve the efficiency. In this paper, morphology formation on the surface of glass substrate was investigated by using HF, mainly classified as random etching and periodic etching. We discussed about the etch mechanism, etch rate and hard mask materials, and periodic light trapping structure.

Investigation of 3-dimensional structural morphology for enhancing light trapping with control of surface haze

Park, Hyeongsik,Shin, Myunghun,Kim, Hyeongseok,Kim, Sunbo,Le, Anh Huy Tuan,Kang, Junyoung,Kim, Yongjun,Pham, Duy Phong,Jung, Junhee,Yi, Junsin Elsevier 2017 Optical materials Vol.66 No.-

<P><B>Abstract</B></P> <P>A comparative study of 3-dimensional textured glass morphologies with variable haze value and chemical texturing of the glass substrates was conducted to enhance light trapping in silicon (Si) thin film solar cells (TFSCs). The light trapping characteristics of periodic honeycomb structures show enhanced transmittance and haze ratio in numerical and experimental approaches. The periodic honeycomb structure of notched textures is better than a random or periodic carved structure. It has high transmittance of ∼95%, and haze ratio of ∼52.8%, and the haze property of the angular distribution function of transmittance shows wide scattering angles in the long wavelength region because of the wide spacing and aspect ratio of the texture. The numerical and experimental approaches of the 3-D texture structures in this work will be useful in developing high-performance Si TFSCs with light trapping.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3-D Light trapping structures are investigated for Si thin film solar cells. </LI> <LI> A glass texturing method is developed using chemical solutions of diluted HF. </LI> <LI> FDTD simulation shows a notched periodic honeycomb texture will be effective one. </LI> <LI> Periodic texturing shows better light scattering performance than random structures. </LI> <LI> Fabricated periodic honeycomb structure shows high transmittance and haze values. </LI> </UL> </P>

A Review of Wet Chemical Etching of Glasses in Hydrofluoric Acid based Solution for Thin Film Silicon Solar Cell Application

Park, Hyeongsik,Cho, Jae Hyun,Jung, Jun Hee,Duy, Pham Phong,Le, Anh Huy Tuan,Yi, Junsin Korea Photovoltaic Society 2017 Current Photovoltaic Research Vol.5 No.3

High efficiency thin film solar cells require an absorber layer with high absorption and low defect, a transparent conductive oxide (TCO) film with high transmittance of over 80% and a high conductivity. Furthermore, light can be captured through the glass substrate and sent to the light absorbing layer to improve the efficiency. In this paper, morphology formation on the surface of glass substrate was investigated by using HF, mainly classified as random etching and periodic etching. We discussed about the etch mechanism, etch rate and hard mask materials, and periodic light trapping structure.

Baseline susceptibility of Asian corn borer (Ostrinia furnacalis (Guenée)) populations in Vietnam to Cry1Ab insecticidal protein

Duc Khanh Le,Quang Khai Le,Thi Thuy Hang Tran,Duc Viet Nguyen,Thi Hang Dao,Thi Thuy Nguyen,Xuan Lam Truong,Quang Cuong Nguyen,Huy Phong Pham,Thi Thu Thuy Phan,Gajendra Babu Baktavachalam 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.2

Susceptibility of Asian corn borer (ACB), Ostrinia furnacalis (Guenée) to Bacillus thuringiensis (Bt) Cry1Ab protein was studied between 2015 and 2016 with 11 ACB populations, collected from various geographical regions in Vietnam. A concentration range of Cry1Ab from 0.20 to 26.10 ng/cm 2 of diet was evaluated against F 1 ACB neonates using diet surface-overlay bioassays. Mortality data was recorded daily until seven days after infestation. Growth inhibition was recorded at the end of seven days. The median lethal concentration (LC 50 ) varied ≈3-fold among the different populations, ranging from 0.58 to 1.83 ng/cm 2 of diet with an overall mean of 0.86 ng/cm 2 of diet. Even the lowest concentration of 0.20 ng/cm 2 caused 73.53% growth inhibition. > 90% growth inhibition was achieved at 0.82 ng/cm 2 or higher concentrations. The results reflect natural variation in Bt susceptibility among ACB populations rather than variation caused by prior exposure to selection pressures. LC 99 value (17.26 ng/cm 2 ) was generated by pooling mortality data across different populations. The upper fiducial limit of LC 99 (24.38 ng/cm 2 ) could be a potential diagnostic dose for future resistance monitoring programs. The findings from this study suggest that ACB populations in Vietnam are highly susceptible to Cry1Ab protein. This is the first report of Cry1Ab susceptibility of different ACB populations in Vietnam and will serve as a baseline for future resistance monitoring work.