다차원 공간내에서 움직이는 등방성매질의 R L C

홍창희,문태정,하영철 東亞大學校 附設 情報通信硏究所 1998 情報通信硏究所論文誌 Vol.6 No.1

From the point of vew of the constitutive relations, electromagnetic waves are studied, with attention given to the behavior inside media that are lenear and isotropic. In describing physical laws of nature, equation are form invariant with respect to uniformly moving observers are called Lorentz covariant. Written in tensor notation, both Maxwell equations and constitutive relations are manifestly covariant. The Lorentz covariant description of the constitutive relations is called bianisotropic. The transformation of field quantities and the constitutive relations from one frame to another is derived from Loretz transformation for 4-dimmension space. Isotropic media, when viewed from a moving frame, became bianisotropic. Problems involving one moving medium can usually be solved in the rest frame of teh medium, with results transformed back to the observers rame of reference. As the final result, we have, the conductivity variation rates are r, the permittivity variation rates are determined by (83), and the permeability variation rates are determined by(84).

Parametric study on the performance of solar air heater equipped with louvered fins

Subhash Chand,Prabha Chand 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8

A theoretical model is developed in this study to investigate the performance of solar air collector equipped with louvered fins. Parameters, such as mass flow rate, fin spacing, louvered pitch ratio (w/Lp), and louvered angle, are considered. The governing equations are solved using a computer code that employs an iterative solution procedure, and the obtained results are compared with that using plain solar air heater. The thermal efficiency of the plain solar air heater is enhanced from 43.14 % to 76.79 % by employing louvered fins with fin spacing values of 5 and 1 cm at a constant mass flow rate of 0.020 kg/s. However, the pressure drop effect becomes dominant that decreases the effective efficiency by 9.4 % at a high mass flow rate of 0.083 kg/s.

Detection of protein kinase using an aptamer on a microchip integrated electrolyte-insulator-semiconductor sensor

Chand, Rohit,Han, Dawoon,Neethirajan, Suresh,Kim, Yong-Sang Elsevier 2017 Sensors and actuators. B Chemical Vol.248 No.-

<P><B>Abstract</B></P> <P>Herein, we developed a microchip electrolyte-insulator-semiconductor (EIS) sensor for the capacitive detection of protein kinase A (PKA). EIS sensing is customarily performed in a Teflon cell to define the sensing area. However, in this work, a rapid prototyping technique was followed to integrate polymeric microchip, a reference electrode, and the EIS sensor. The aptameric peptide was used for one-step and label-free detection of PKA enzyme. The thiolated PKA-specific aptamer was immobilized on the gold nanoparticles decorated EIS sensor surface. The detection of PKA in microchip was based on the change in surface charge of EIS sensor. We also analyzed the ability of microchip-EIS sensor to distinguish between buffers at different pH. An average sensitivity of 96mV/pH for a pH range of 5–9 was obtained. The quantitative detection of PKA was performed by analyzing the capacitance-voltage curve after the aptamer-PKA interaction. The EIS sensor showed a detection limit of 2U/mL with a relative linearity from 10U/mL to 80U/mL for the detection of PKA. This study proposes an integrated and point-of-care applicable biosensor for the rapid diagnosis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The EIS sensor integrated with microchip and reference electrode was fabricated. </LI> <LI> The microchip-EIS was used for detection of protein kinase. </LI> <LI> The change in surface charge alters the V<SUB>G</SUB> of EIS sensor. </LI> <LI> PKA was efficiently detected on-chip using aptamer. </LI> <LI> The microchip-EIS was highly specific, selective and stable. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Voltammetric Analysis on a Disposable Microfluidic Electrochemical Cell

Chand, Rohit,Han, Dawoon,Kim, Yong-Sang Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.4

A microfabricated electrochemical cell comprising PDMS-based microchannel and in-channel gold microelectrodes was fabricated as a sensitive and a miniature alternative to the conventional electroanalytical systems. A reproducible fabrication procedure enabled patterning of multiple microelectrodes integrated within a PDMS-based fluidic network. The active area of each electrode was $200{\mu}m{\times}200{\mu}m$ with a gap of $200{\mu}m$ between the electrodes which resulted in a higher signal to noise ratio. Also, the PDMS layer served the purpose of shielding the electrical interferences to the measurements. Analytes such as potassium ferrocyanide; amino acid: cysteine and nucleoside: guanosine were characterized using the fabricated cell. The microchip was comparable to bulk electrochemical systems and its applicability was also demonstrated with flow injection based rapid amperometric detection of DNA samples. The device so developed shall find use as a disposable electrochemical cell for rapid and sensitive analysis of electroactive species in various industrial and research applications.

CRYPTANALYSIS AND IMPROVEMENT OF A PROXY SIGNATURE WITH MESSAGE RECOVERY USING SELF-CERTIFIED PUBLIC KEY

Chande, Manoj Kumar,Lee, Cheng-Chi Korean Mathematical Society 2016 대한수학회보 Vol.53 No.4

Combining the concept of self-certified public key and message recovery, Li-Zhang-Zhu (LZZ) gives the proxy signature scheme with message recovery using self-certified public key. The security of the proposed scheme is based on the discrete logarithm problem (DLP) and one-way hash function (OWHF). Their scheme accomplishes the tasks of public key verification, proxy signature verification, and message recovery in a logically single step. In addition, their scheme satisfies all properties of strong proxy signature and does not use secure channel in the communication between the original signer and the proxy signer. In this paper, it is shown that in their signature scheme a malicious signer can cheat the system authority (SA), by obtaining a proxy signature key without the permission of the original signer. At the same time malicious original signer can also cheat the SA, he can also obtain a proxy signature key without the permission of the proxy signer. An improved signature scheme is being proposed, which involves the remedial measures to get rid of security flaws of the LZZ et al.'s. The security and performance analysis shows that the proposed signature scheme is maintaining higher level of security, with little bit of computational complexity.

Protective Effects of Milk Thistle (Silybum marianum) against Aflatoxin B1 in Broiler Chicks

Chand, N.,Muhammad, Din,Durrani, F.R.,Qureshi, M. Subhan,Ullah, Sahibzada S. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.7

Aflatoxin-contaminated feed cause mortality, suppression of the immune system, reduced growth rates and losses in feed efficiency. This research study was planned to investigate the immunomodulatory and growth promoting effect of milk thistle as feed additive against aflatoxin $B_1$ in broiler chicks at NWFP Agricultural University Peshawar, Pakistan. Two hundred and forty (240) day old broilers chicks were randomly assigned into four major groups AfF, aflatoxin free feed; Aflatoxin $B_1$ was present in the feed at the levels of 80-520 ${\mu}g/kg$ of the feed in the remaining three groups. Aflatoxin contaminated feed was provided for 5 weeks. Group AfB was supplemented with toxin binder "Mycoad" at 3 g/kg of feed and group AfT was supplemented with milk thistle at10 g/kg of feed. Each group was further sub divided into two sub-groups, vaccinated against ND (Newcastle disease), IB (Infectious bronchitis) and IBD (Infectious bursal diseases) according to recommended schedule of vaccination or non vaccinated. Each sub group carried three replicates with 10 chicks per replicate. Chicks were reared in pens in an open sided house. Supplementary heat was provided to all the chicks during brooding period. Mean body weight gain and dressing percentage were significantly (p<0.05) higher in group AfF, followed by AfT, AfB and Af. Weight gain and dressing percentage was the same in group AfB and AfT, while it was significantly lower in group Af. Feed intake, breast, thigh and leg weight were found significantly (p<0.05) higher in group AfF, followed by AfB, AfT and Af. Significantly lower (better) FCR value was recorded in group AfT. Water intake was significantly (p<0.05) higher in group AfT and AfF as compared to other groups. Mortality was significantly (p<0.05) higher in group Af. Mean bursa and thymus weights were found significantly (p<0.05) higher in group AfF, AfB and AfT followed by Af, while higher spleen weight was recorded in group AfT. Mean antibody titer against ND, IB and IBD was significantly (p<0.05) higher in group AfT, as compared to other groups. It is concluded that milk thistle at 10 g/kg of feed could effectively be utilized as immunostimulant and growth promotant in the presence of immunosuppressant aflatoxin $B_1$ in the feed.

Role of Berberis lycium in Reducing Serum Cholesterol in Broilers

Chand, N.,Durrani, F.R.,Qureshi, M.S.,Durrani, Z. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.4

This study was planned to investigate the role of Berberis lycium in reducing serum cholesterol in broilers. Six experimental rations designated as A, B, C, D, E and F having 0, 0.5, 1.0, 1.5, 2.0 and 2.5% Berberis lycium were fed to 240 broiler chicks, randomly distributed into 24 replicates, so as to have 4 replicates per group and 10 chicks per replicate. The experiment lasted for 35 days. Average serum total cholesterol, triglyceride, high density lipoprotein (HDL) and low density lipoprotein (LDL) were used as criteria of response. Average total serum cholesterol per chick was 129.33, 120.50, 116.50, 113.00, 101.67 and 114.00 mg/dl for group A, B, C, D, E and F respectively. Total serum cholesterol showed decreasing trend with the increasing level of Berberis lycium unto 2% (p<0.05). Mean serum triglyceride level per chick was 60.00, 58.17, 58.00, 55.33, 50.17 and 48.50 mg/dl for group A, B, C, D, E and F respectively. Mean serum triglyceride showed decreasing trend with the increasing level of Berberis lycium (p<0.05). Serum triglyceride was significantly lower in group F than other groups. Mean HDL per chick for the six experimental groups A, B, C, D, E and F was 52.08, 53.42, 60.42, 62.25, 62.92 and 54.50 mg/dl respectively. HDL showed increasing trend with the increase in the level of Berberis lycium unto 2%. The average serum LDL per chick was 65.25, 55.45, 44.48, 39.68, 28.72 and 49.80 mg/dl for group A, B, C, D, E and F respectively. LDL also showed decreasing trend with the increase in the level of Berberis lycium unto 2% (p<0.05). It was concluded that Berberis lycium added to feed at the rate of 2.0% can be used in broiler feed for reducing serum total cholesterol, triglyceride and LDL and increasing HDL.

추운 겨울밤

Chand, Prem,이은구 한국외국어대학교 학생통역협회 1983 외대통역협회지 Vol.1 No.1

Prospective role of insecticides of fungal origin: Review

Chand Narayan SRIVASTAVA,Prejwltta MAURYA,Preeti SHARMA,Lalit MOHAN 한국곤충학회 2009 Entomological Research Vol.39 No.6

Advances in the application of microbial-based technology in insect pest management assist us to counter problems created by the application of chemical pesticides. These are mainly strong environmental effects, resistance development and high costs. Among the microbial pesticides, fungal pesticides are now preferred as they are target specific, ecofriendly, lacking in toxic residue and are economical. Being numerous with great diversification, entomopathogenic fungi therefore have great potential to control a large variety of insect pests. Fungi are applied directly in form of spores, mycelia or blastospores or by their metabolites (mycotoxins). Both approaches have very promising roles in insect pest management. However, there are three main obstacles in the development of fungal pesticides: (i) scant production of mycotoxins; (ii) carcinogenic mycotoxicosis in non-target organisms; and (iii) slow effectiveness. Therefore, to eliminate these problems, attention has recently been paid to a synergistic approach to combating insecticide resistance. Next to synergism, genetic manipulation is also used to enhance the pathogenicity and virulence of fungal insecticides. However, the key risk associated with the release of recombinant microorganisms into the environment is that the novel organism may have unforeseen undesirable characteristics. Therefore, the introduction of synergists in pest control could have great benefit both economically and ecologically. An ideal synergistic approach is the mixing of more than two accelerating components together, i.e. tripartite or multiple synergism to enhance effectiveness. Thus, synergistic approaches have a bright future and require further research and financial support.

Electroimmobilization of DNA for ultrafast detection on a microchannel integrated pentacene TFT

Chand, Rohit,Jeun, Jun-Ho,Park, Min-Ho,Kim, Jung-Min,Shin, Ik-Soo,Kim, Yong-Sang Elsevier 2015 Journal of industrial and engineering chemistry Vol.21 No.-

<P><B>Abstract</B></P> <P>We report a pentacene thin-film transistor integrated with microfluidic channel as an ultrafast DNA sensor. The microchannel assisted in easy transport of sample onto the pentacene active layer. The DNA immobilization time on active layer was drastically shortened by applying low positive electric field at the gate electrode. This helps by attracting the negatively charged DNA toward the pentacene layer. This device was evaluated for the label-free detection of single stranded DNA. The electrical property of the device fiercely changed due to the adsorption of DNA. Furthermore, the electrical characteristics were studied as a function of immobilization voltage and time.</P>