Performance Analysis of SACOCDMA-FSO System Using MD Codes

Bhanu Priya 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.5

Performance of SACOCDMA-FSO system using MD codes at 10 Gbps is evaluated. MD code has become an area of interest in optical communication because of its ability to support many users at higher data rates, flexibility to select weight parameters. The proposed system was compared with SACOCDMA-FSO System employing RD codes in different conditions. The simulative results demonstrated that optical system based on MD codes is better than the system employing RD codes.

Differential VCO with Diodes Feedback Using InGaP/GaAs HBT Technology

Bhanu Shrestha,Seong Soo Cho,Jun Gil Kang,Nam Young Kim 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

This paper presents on-chip base collector (BC) diodes feedback voltage controlled (VCO) using InGaP/GaAs HBT technology for interference cancellation system (AF-ICS). The VCO achieved a low phase noise of - 131.04 ㏈c/㎐ at 1 ㎒ offset from the carrier frequency of 1.540 ㎓ with output power of -11.26 ㏈m when supplying the controlled voltage of 1.9 V. A tuning range of 141 ㎒ is achieved with integrated tuning BC diodes.

Role of A-TIG process in joining of martensitic and austenitic steels for ultra-supercritical power plants -a state of the art review

Bhanu Vishwa,Gupta Ankur,Pandey Chandan 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

The need for Dissimilar Welded Joint (DWJ) in the power plant components arises in order to increase the overall efficiency of the plant and to avoid premature failure in the component welds. The ActivatedTungsten Inert Gas (A-TIG) welding process, which is a variant of Tungsten Inert Gas (TIG) welding, is focus of this review work concerning the DWJ of nuclear grade creep-strength enhanced ferritic/ martensitic (CSEF/M) steels and austenitic steels. A-TIG DWJs are compared with Multipass-Tungsten Inert Gas (M-TIG) DWJ based on their mechanical and microstructural properties. The limitations of multipass welding have put A-TIG welding in focus as A-TIG provides a weld with increased depth of penetration (DOP) and enhanced mechanical properties. Hence, this review article covers the A-TIG welding principle and working parameters along with detailed analysis of role played by the flux in welding procedure. Further, weld characteristics of martensitic and austenitic steel DWJ developed with the A-TIG welding process and the M-TIG welding process are compared in this study as there are differences in mechanical, microstructural, creep-related, and residual stress obtained in both TIG variants. The mechanics involved in the welding process is deliberated which is revealed by microstructural changes and behavior of base metals and WFZ

The Tripler Differential MMIC Voltage Controlled Oscillator Using an InGaP/GaAs HBT Process for Ku-band Application

Bhanu Shrestha,Nam-Young Kim,Gary P. Kennedy,Chan-Hyeong Park,Hee-Yong Yoo,Rok-Hee Lee 한국전자파학회JEES 2006 Journal of Electromagnetic Engineering and Science Vol.6 No.2

In this paper, a fully integrated Ku-band tripler differential MMIC voltage controlled oscillator(VCO), which consists of a differential VCO core and two triplers, is developed using high linearity InGaP/GaAs HBT technology. The VCO core generates an oscillation frequency of 3.583 ㎓, an output power of 3.65 ㏈m, and a phase noise of ?96.7 ㏈c/Hz at 100 ㎑ offset with a current consumption of 30 ㎃ at a supply voltage of 2.9 V. The tripler shows excellent side band rejection of 23 dBc at 3 V and 12 ㎃. The tripler differential MMIC VCO produces an oscillation frequency of 10.75 ㎓, an output power of ?13 ㏈m and a phase noise of ?89.35 ㏈c/Hz at 100 ㎑ offset.

Cellular and molecular mechanisms of DEET toxicity and disease-carrying insect vectors: a review

Bhanu Shrestha,Youngseok Lee 한국유전학회 2020 Genes & Genomics Vol.42 No.10

Background Several insects such as mosquitoes, fies, ticks, feas, lice, and mites are known to serve as vectors for a vast number of pathogens. Many such vectors are hematophagous, and therefore introduce pathogens directly into the host’s bloodstream. Importantly, the capacity of these vectors to spread disease can lead to serious global health crises. Furthermore, crop damage can be exacerbated by pathogen infection and increased insect foraging due to recent global warming. Methods Our study categorized insect-associated damage into three groups: animal infection, plant infection, and direct crop damage due to insect foraging. To manage these problems, insect repellents and pesticides have been developed, among which DEET is the most broadly used and studied pest control agent. This review discusses the mode of action and possible mechanisms of DEET action, including olfactory and gustatory mechanisms and central nervous system impairment. Conclusion To protect humans from malaria, yellow fever, dengue fever, zika, and flariasis, as well as to reduce economic losses associated with crop damage, considerably more eforts are needed to characterize the interactions between insects and insect repellents/pesticides to develop more potent pest control agents.

Mechanisms of Carboxylic Acid Attraction in Drosophila melanogaster

Bhanu Shrestha,이영석 한국분자세포생물학회 2021 Molecules and cells Vol.44 No.12

Sour is one of the fundamental taste modalities that enable taste perception in animals. Chemoreceptors embedded in taste organs are pivotal to discriminate between different chemicals to ensure survival. Animals generally prefer slightly acidic food and avoid highly acidic alternatives. We recently proposed that all acids are aversive at high concentrations, a response that is mediated by low pH as well as specific anions in Drosophila melanogaster. Particularly, some carboxylic acids such as glycolic acid, citric acid, and lactic acid are highly attractive to Drosophila compared with acetic acid. The present study determined that attractive carboxylic acids were mediated by broadly expressed Ir25a and Ir76b, as demonstrated by a candidate mutant library screen. The mutant deficits were completely recovered via wild-type cDNA expression in sweet-sensing gustatory receptor neurons. Furthermore, sweet gustatory receptors such as Gr5a, Gr61a, and Gr64a-f modulate attractive responses. These genetic defects were confirmed using binary food choice assays as well as electrophysiology in the labellum. Taken together, our findings demonstrate that at least two different kinds of receptors are required to discriminate attractive carboxylic acids from other acids.

Review: Advancement of Integrated Passive Device Technology

Bhanu Shrestha 한국디지털융합학회 2017 IJICTDC Vol.2 No.2

In this paper, an advancement of integrated passive device (IPD) technology will be reviewed and its wide implementation will be investigated. This technology can be implemented to fabricate passive components like resister, inductor and capacitor to design and fabricate filters, combiners, dividers, baluns, and antenna etc. This is a kind of radio frequency (RF) solution in wireless technology and its main features are excellent device performance, higher integration, and higher reliability, and higher repeatability, device packaging and low cost. IPD can be fabricated using especially thin film and photolithography processing. The substrates can be used for this are silicon, GaAs, InGaP, alumina etc. and this technical is more beneficial to internet of things (IoT) which is an emerging technology.

An InGaP/GaAs HBT Based Differential Colpitts VCO with Low Phase Noise

Bhanu Shrestha,Nam-Young Kim 한국전자파학회JEES 2007 Journal of Electromagnetic Engineering and Science Vol.7 No.2

An InGaP/GaAs HBT based differential Colpitts voltage control oscillator(VCO) is presented in this paper. In the VCO core, two switching transistors are introduced to steer the core bias current to save power. An LC tank with an inductor quality factor(Q) of 11.4 is used to generate oscillation frequency. It has a superior phase noise characteristics of ?130.12 ㏈c/㎐ and ?105.3 at 1 ㎒ and 100 kHz frequency offsets respectively from the carrier frequency(1.566 GHz) when supplied with a control voltage of 0 volt. It dissipates output power of ?5.3 ㏈m. Two pairs of on-chip base collector (BC) diodes are used in the tank circuit to increase the VCO tuning range(168 ㎒). This VCO occupies the area of 1.070×0.90 ㎟ including buffer and pads.

Microstrip Bandstop Filter based on Coupled SIR for Communication Systems

Bhanu Shrestha 한국디지털융합학회 2018 IJICTDC Vol.3 No.1

In this paper, a microstrip bandstop filter (BSF) is designed and simulated for X-band wireless communication system. It consists of open stubs (parallel line with T-shaped) coupled with high impedance of stepped impedance resonator (SIR) at 7.5 GHz for X-band system applications. All the stubs are optimized to have the stopband characteristics. The layout pattern is simulated using Sonnet EM tool on Teflon substrate with a dielectric constant of 2.54 and thickness of 0.54 mm. The main features of this work are smaller size, low cost, and controllable bandwidth. The bandwidth can be controlled by adjusting the parallel line open stubs connected with open T-stub. The 3dB bandwidth is achieved as 0.3 GHz at 7.5 GHz with good frequency responses. The overall physical dimension of the designed BSF is 23.62 mm by 8.0 mm excluding reference lines.

Symmetric Microstrip Meanderspurline Bandstop Filter

Bhanu Shrestha,Chae Bong Sohn 한국디지털융합학회 2016 IJICTDC Vol.1 No.1

In this paper, a symmetric microstrip meander spurline bandstop filter (SMMBF) is designed and simulated for X-band applications. The designed bandstop filter has a bandstop characteristic with higher insertion loss. The operating resonance frequencies of the bandstop filter is 9.2 GHz with insertion loss of less than 28 dB and return losses are below 1 dB. The miniaturized resonator filters consist of symmetric meander spurline with inductive and capacitive characteristics. The capacitive loaded spurline resonator filter provides a band rejection frequency response. The quality factor (Q) of the resonators filter is good for implementing in microwave oscillators too. Implementation of such resonator filter in MMIC technology is also possible due to their inherent capability to integrate into small sizes.