• Computers and Concrete
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• 제25권6호
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• pp.485-495
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• 2020

This paper, presents the dynamic and stability analysis of the simply supported single walled Carbon Nanotubes (SWCNT) reinforced concrete beam on elastic-foundation using an integral first-order shear deformation beam theory. The condition of the zero shear-stress on the free surfaces of the beam is ensured by the introduction of the shear correction factors. The SWCNT reinforcement is considered to be uniform and variable according to the X, O and V forms through the thickness of the concrete beam. The effective properties of the reinforced concrete beam are calculated by employing the rule of mixture. The analytical solutions of the buckling and free vibrational behaviors are derived via Hamilton's principle and Navier method. The analytical results of the critical buckling loads and frequency parameters of the SWCNT-RC beam are presented in the form of explicit tables and graphs. Also the diverse parameters influencing the dynamic and stability behaviors of the reinforced concrete beam are discussed in detail.

• 한국군사과학기술학회지
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• 제23권5호
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• pp.502-515
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• 2020

To identify the dynamic characteristics of the Auto-leveling system applied to the Tractor-Trailer type Transporter for mounting a large scale precision equipment, Dynamics Modeling & Simulation were performed using general Dynamics Analysis Program - RecurDyn(V9R2). The axial load data, transverse load data and pad trace data of leveling actuators were obtained from M&S. And they were analyzed and compared with each other by parameters, i.e. friction coefficients on the ground, landing ram speed of actuators, and direction & quantity of ground slope. It was observed that ground contact friction coefficients affected to transverse load and pad trace; the landing ram speed of actuators to both amplitude of axial & transverse load, and this phenomena was able to explain from the frequency analysis of the axial load data; the direction of ground slope to driving sequence of landing ram of actuators. But the dynamic behaviors on the two-directional slope were very different from them on the one-directional slope and more complex.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.190.1-190.1
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• 2016

One of the most serious problems faced by billions of people today is the availability of fresh water. According to statistics, 15% of the world's total output of dye products is discharged into the environment as dye wastewater, which seriously pollutes groundwater resources. For the treatment of chemically and biologically contaminated water the advanced oxidation processes (AOPs) shows the promising action. The main advantage with AOPs is the ability to degrade the organic pollutants to $CO_2$ and $H_2O$. For this degradation process the AOPs generation of powerful and non-selective radicals that may oxidize majority of the organic pollutants present in the water body. To generate the various reactive chemical species such as radicals (${\bullet}OH$, ${\bullet}H$, ${\bullet}O$, ${\bullet}HO_2$) and molecular species ($H_2O_2$, $H_2$, $O_2$) in large amount in water, we have used the atmospheric pressure plasma. Among the reactive and non-reactive species, the hydroxyl radical (${\bullet}OH$) plays important role due to its higher oxidation potential (E0: 2.8 V). Therefore, in this work we have checked the degradation of various dyes such as methyl orange, methylene blue and congo red using different type of atmospheric pressure plasma sources (Indirect jet and direct jet). To check the degradation we have used the UV-visible spectroscopy, HPLC and LC-MS spectroscopy. Further, to estimate role of ${\bullet}OH$ on the degradation of dyes we have studied the molecular dynamic simulation.

• 한국재료학회지
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• 제19권11호
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• pp.601-606
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• 2009

$BiFeO_3$ (BFO) thin films were prepared on $Pt/TiO_2/Si$ substrate by r.f. magnetron sputtering. The effects of deposition pressure on electrical properties were investigated using measurement of dielectric properties, leakage current and polarization. When BFO targets were prepared, Fe atoms were substituted with Mn 0.05% to increase electrical resistivity of films. (Fe+Mn)/Bi ratio of BFO thin films increases with increasing partial pressure of $O_2$ gas. The deposited films showed the only BFO phase at 10 mTorr, the coexistence of BFO and $Bi_2O_3$ phase at 30-50 mTorr, and the only $Bi_2O_3$ phase at 70 mTorr. The crystallinity of BFO films was reduced due to the higher Bi contents and the decrease of surface mobility of atoms at high temperature. The porosity and surface roughness of films increased with the increase of the deposition pressure. The films deposited at high pressure showed low dielectric constant and high leakage current. The dielectric constant of films deposited at various deposition pressures was 84${\sim}$153 at 1 kHz. The leakage current density of the films deposited at 10${\sim}$70 mTorr was about $7{\times}10.6{\sim}1.5{\times}10.2A/cm^2$ at 100 kV/cm. The leakage current was found to be closely related to the morphology and composition of the BFO films. BFO films showed poor P-E hysteresis loops due to high leakage current.

• Applied Microscopy
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• 제18권2호
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• pp.177-186
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• 1988

Degeneration of the axon terminals of mamillo-thalamic tract following the electrical coagulation of mamillary body is well known. In this study, the author investigated the ultrastructural alterations of neuropil components, initiated by terminal degenerations. Rats weighing approximately 250 gm were fixed on the stereotaxic instrument(David Kopf Inc., Heavy duty model), and NE 300 active electrode(Rhodes Med. Instr. Inc.) was introduced to the mamillary position of anterior 3.8 mm, lateral 0.5 mm, height 3.8 mm and lateral angle of $23^{\circ}$ according to De Groot's Atlas. Electric current of 20 mA was applied during 1 minute between active and inactive electrodes with Radio Frequency Lesion Generator(RFG 4, Radionics Inc.). Two hours, 2 days, 1 week and 2 weeks following the electrical coagulation of mamillary body, ipsilateral anterior thalamic nucleus was fixed in 1% glutaraldehyde-l% paraformaldehyde and 2% osmium tetroxide, embedded in Araldite mixture, cutted with LKB ultra tome V, stained with uranyl acetate-lead citrate and observed with JEOL 100 CX electron microscope. Observed results were as follows; 1. Degenerated mamillo-thalamic synapses were observed to form asymmetric axospinous or axo-dendritic types. 2. Terminal degeneration was not easily discernible at 2 hours interval after mamillary lesion, but following 2 days the terminal degeneration was apparent. 3. Postsynaptic spines, dendrites and even their cell bodies show edematic changes caused by the degeneration of postsynaptic counterpart. 4. Astrocytic territories, including perivascular processes forming glial limitans of blood-brain barrier, exhibit remarkable expansion. 5. Oligoglia and astroglia are actively engaged in the removal of degenerated elements. 6. Active forms of microglia were increased. 7. The observed results may represent typical ultrastructural alteration pattern within neuropil following the degeneration of certain input axon terminals.

• 전력전자학회논문지
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• 제4권5호
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• pp.462-473
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• 1999

디지털 제어 방식으로 구동되는 모든 교류 전동기 벡터제어시스템의 근간을 이루는 전류 측정에 관한 문제를 다룬다. 일반적인 펄스폭 변조 방식 교류 전동기 구동 시스템에서 전동기 전류에 포함된 인버터 스위칭 노이즈를 없애기 위하여 저역 통과 필터를 사용하는데 이러한 필터는 필연적으로 측정된 신호의 시간 지연을 유발하게 된다. 따라서 샘플링한 전류값에는 기본파 성분 뿐만아니라 고조파 리플 성분이 포함된다. 본 논문에서는 3상 대칭 펄스폭 변조시 기준 전압 벡터의 위치에 다른 전류 샘플링 오차를 해석적으로 구하고 이러한 샘플링 오차를 최소화하기 위한 기법을 제안한다. 제안된 지연 보상 샘플링 기법을 사용하면 정상 상태 전류 측정 오차를 최소화할 수 있고 보다 정확한 토오크 제어가 가능하게 됨을 시뮬레이션과 실험을 통해 보였다.

• Journal of Acupuncture Research
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• 제18권3호
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• pp.114-122
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• 2001

Objective : The present study was carried out to determine if Juglandis Semen Aquacupuncture(JSA) exerts beneficial effect against the urine concentrating defect induced by glycerol injection in rabbits. Methods : In order to test the effect of JSA, rabbits were acupunctured with $0.5m{\ell}$ of 1%JSA for 7days at both sides of $Sh{\grave{e}}ns{\bar{u}}$(BL23) before the glycerol injection. The other animals were pretreated with an equal volume of saline instead of JSA. Results : The urine flow was reduced, but the urine osmolality was significantly lower than the basal period in glycerol-injected animals, indicating that glycerol causes the urine concentrating defect. The fractional excretion of Na and K was increased in glycerol-treated animals. The Free-water clearance and fractional water excretion(V/GFR) were increased in animals treated with glycerol. Conclusion : These results indicate that glycerol injection resulted an impairment in the urine concentrating ability in rabbits. Such changes were prevented by JSA. JSA may be used as a method to treat and prevent glycerol-induced acute renal failure.

• Asian-Australasian Journal of Animal Sciences
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• 제24권7호
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• pp.952-956
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• 2011

The objective of the study was to evaluate the effect of passive transfer status, determined by measuring serum immunoglobulin (Ig) concentration 24 hours after parturition, on growth performance in buffalo calves allowed to nurse the dam during the first month of life. Serum Ig concentration 24 hours after birth ranged from 28.1 to 35.9 mg/ml, birth weight ranged from 29 to 41 kg, body weight 30 days after birth ranged from 48.5 to 62.9 kg. The Average Daily Gain (ADG) from birth to day 30 ranged from 448 to 1,089 g/d. Significant linear associations were detected between serum Ig concentration 24 hours after birth and day-30 weight (p< 0.05; $R^2$ = 0.31) and between serum Ig concentration 24 hours after birth and ADG from birth to day 30 (p<0.001; $R^2$ = 0.72). Results indicated that passive transfer status was a significant source of variation in growth performance when buffalo calves nursed the dam. Maximizing passive transfer of immunity by allowing calves to nurse the dam can increase growth performance during the first month of life.

• Asian-Australasian Journal of Animal Sciences
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• 제24권7호
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• pp.1019-1025
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• 2011

Toll-like receptors (TLRs) play an important role in the recognition of invading pathogens and the modulation of innate immune responses in mammals. The TLR4 and TLR7 are well known to recognize the bacterial lipopolysaccharide (LPS) and single stranded (ssRNA) ligands, respectively and play important role in host defense against Gram-negative bacteria and ssRNA viruses. In the present study, coding exon fragments of these two TLRs were identified, cloned, sequenced and analyzed in terms of insertion-deletion polymorphism, within bovine TLRs 4 and 7, thereby facilitating future TLR signaling and association studies relevant to bovine innate immunity. Comparative sequence analysis of TLR 4 exons revealed that this gene is more variable, particularly the coding frame (E3P1), while other parts showed percent identity of 95.7% to 100% at nucleotide and amino acid level, respectivley with other Bos indicus and Bos taurus breeds from different parts of the world. In comparison to TLR4, sequence analysis of TLR7 showed more conservation among different B. indicus and B. taurus breeds, except single point mutation at 324 nucleotide position (AAA to AAM) altering a single amino acid at 108 position (K to X). Percent identity of TLR7 sequences (all 3 exons) was between 99.2% to 100% at nucleotide and amino acid level, when compared with available sequence database of B. indicus and B. taurus. Simple Modular Architecture Research Tool (SMART) analysis showed variations in the exon fragments located in the Leucine Rich Repeat (LRR) region, which is responsible for binding with the microbial associated molecular patterns and further, downstream signaling to initiate anti-microbial response. Considering importance of TLR polymorphism in terms of innate immunity, further research is warranted.

• 환경생물
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• 제30권1호
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• pp.71-76
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• 2012

Spills of $M/V$ Hebei Spirit on $7^{th}$ December 2007 caused a seriously damage to the ecosystem of Korean coast. Of these, microbial communities (i.e., attached benthic micro-algae) were reported to be sentive to the environmental change so it can be used for ecological risk assessment. Our experiment was designed to examine the ecological risk assessments for oil pollutant using benthic attached algal community on the artificial substrates of acrylic plates. Field monitoring in the culture system was conducted in Jangmok Bay. The abundances of attached micro-algae on artificial substrates gradually increased with increasing of sampling times. Among them, diatoms were the most important colonizer of coastal water, with the genera $Cylindrotheca$ and $Navicular$ most abundant. In particular, developed the culture system has correctly measured qualitative and quantitative abundance of attached micro-algae because same acrylic plates as artificial substrates were used. Thus, this culture system may be directly applied to the ecological risk experiments of microbial community structure from oil pollutants.