• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1398-1401
• /
• 2005

The nano/microstructure, the aging response (in T5 heat treatment), and the mechanical/tribological properties of the eutectic regions in squeeze-cast A356 alloy were investigated using nano/micro-indentation and mechanical scratching, combined wit optical microscopy and atomic force microscope(AFM). Most eutectic Si crystals in the A356 alloy showed a modified morphology as fine-fibers. The loading curve for the eutectic region was more irregular than that of the primary Al region due to the presence of various particles of varying strength. In addition, the eutectic region showed lower pile-up and higher elastic recovery than the primary Al region. The aging responses of the eutectic regions in the squeeze-cast A356 alloys aged at $150^{\circ}C$ for different times(0, 2, 4, 8, 10, 16, 24, 36 and 72 h) were investigated. As the aging time increased, acicular Si particles in the eutectic regions gradually came to a fine structure. Both Vickers hardness ($H_V$) and indentation ($H_{IT}$) test results showed almost the same trend of aging curves, and the peak was obtained at the same aging time of 10 h. A remarkable size-dependence of the tests was found. The friction coefficient for the eutectic region was lower than that for the primary Al region.

• YAKHAK HOEJI
• /
• v.44 no.3
• /
• pp.232-236
• /
• 2000

An intravenous pharmacokinetics for a new red cell substitute, PEG-hemoglobin SB1, was studied in SD rats. Total-hemoglobin and its metabolite methemoglobin in the plasma were determined using a spectrophotometer. The limit of quantitation was 0.01g/dL and the C.V for interday assay reproducibility was less than 6%. Upon intravenous administration of anticipated clinical dose, 10 ml(0.7 gHb)/kg, plasma concentration curve of total-hemoglobin was well described by one-compartment model. The $t_{\frac{1}{2}},{\;}CL_{t}$, Vd and $AUC^{0-48hr}$ were $8.23{\pm}0.96{\;}hr,{\;}0.06{\;}{\pm}{\;}0.01 {\;}dL/hr/kg,{\;}0.66{\pm}0.05{\;}dL/lg{\;}and{\;}13.6{\;}{\pm}{\;}1.01g{\cdot}hr/dL$, respectively, in male rats(n=5, $mean{\;}{\pm}{\;}SD$). Those parameters in female rats were $9.21{\;}\pm{\;}2.31{\;}hr,{\;}0.06{\;}{\pm}{\;}0.01{\;}dL/hr/kg,{\;}0.79{\pm}{\;}0.08{\;}dL/kg{\;}and{\;}13.0{\;}{\pm}{\;}2.36{\;}g{\cdot}hr/dL$, respectively. Similar kinetic profiles between males and females were also obtained from other parameters. Small amount of methemoglobin, an oxidative metabolite of SB1, was detected in the plasma of both sexes, where the $AUC^{0-48{\;}hr,m}$ and $t_{{\frac{1}{2}},m}$ were approximately $1.5{\;}g{\cdot}hr/dL$ and 20 hr, respectively. The present work provides a critical kinetic data for the effective clinical applications of PEG-hemoglobin SB1.

• Journal of Pharmaceutical Investigation
• /
• v.37 no.5
• /
• pp.315-321
• /
• 2007

The purpose of the present study was to evaluate the bioequivalence of two lercanidipine hydrochloride tablets, Zanidip tablet (LG Life Sciences Ltd., Korea, reference drug) and Samchundang Lercanidipine tablet 10 mg (Sam Chun Dang Pharm. Co. Ltd., Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). After adding an internal standard (amlodipine maleate) to human serum, serum samples were extracted using hexan-isoamyl alcohol (100:1, v/v). Compounds were analyzed by liquid chromatography/tandem mass spectrometry. This method showed linear response over the concentration range of 0.05-20 ng/mL with correlation coefficient of 0.9999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ng/mL which was sensitive enough for pharmacokinetic studies. Thirty healthy male Korean volunteers received each medicine at the lercanidipine hydrochloride dose of 20 mg in a $2\;{\times}\;2$ crossover study. There was a one-week washout period between the doses. Serum concentrations of lercanidipine were monitored by an LC/MS/MS fer over a period of 24 hr after the administration. $AUC_t$ (the area under the serum concentration-time curve from time 0 to 24 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (the maximum serum drug concentration) and $T_{max}$ (the time to reach $C_{max}$) were compiled from the serum concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters, indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for Samchundang Lercanidipine/Zanidip were log 0.9505-log 1.2258 and log 0.9987-log 1.2013, respectively. These values were within the acceptable bioequivalence intervals of log 0.80-log 1.25. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Samchundang Lercanidipine tablet 10 mg and Zanidip tablet are bioequivalent.

• The Korean Journal of Physiology
• /
• v.27 no.1
• /
• pp.37-49
• /
• 1993

Ventilatory responses to inhaled $CO_2$ were measured during continuous negative pressure breathing (CNPB) in awake dogs. End expiratory lung volume (EELV) decreased linearly with pressure level during CNPB (correlation coefficient= 0.81, p<0.005) during air breathing. When CNPB was applied during 5% $CO_2$ inhalation, the decrease in EELV was not significantly different (p<0.5) from that during air breathing. As a result of a lowered EELV, tidal volume ($V_T$) significantly decreased by 22% and breathing frequency ($f_B$) increased by 68% in the steady state during air breathing (p<0.0001). These responses were similar during 5% $CO_2$ inhalation, thus the $CO_2$ response curve measured during CNPB shifted upward without a change in sensitivity (p>0.05). These results indicate additive effects of CNPB and $CO_2$ inhalation. The degree of hyperventilation during CNPB at eupnea was estimated to be 63% of that during control ventilation and was significantly greater than zero (p<0.0001), which suggests an alveolar hyperventilation due to CNPB. These results suggest that the mechanical alterations associated with n decrease in lung volume could play an important role in ventilatory control independently of chemical regulation of breathing. Thus, exercise hyperpnea, which is associated with a lowered functional residual capacity (FRC), may in part be explained by this mechanical stimulation of breathing.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1132-1136
• /
• 2004

In this paper, we intend to make FFS mode cell with LC alignment used non-rubbing method, ion beam alignment method on the a-C:H thin film, to analyze electro-optical characteristics in this cell. We studied on the suitable inorganic thin film for FFS-LCD and the aligning capabilities of nematic liquid crystal (NLC) using the new alignment material of a-C:H thin film as working gas at rf bias condition. A high pretilt angle of about 5$^{\circ}$ by ion beam(IB) exposure on the a-C:H thin film surface was measured. An excellent voltage-transmittance (V-T) and response time curve of the ion-beam-aligned FFS-LCD was observed with oblique ion beam exposure on the DLC thin films.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.2
• /
• pp.446-454
• /
• 2016

In this paper, we present experimental results of the soil discharge characteristics as a function of moisture content when a 1.2/50-㎲ lightning impulse voltage is applied. For this study, laboratory experiments were carried out based on factors affecting the transient behavior in soils. The electrical breakdown voltages in soils were measured for a 0-6% range of moisture content for sand and a 0 - 4% range of moisture content for gravel. A test cell with semi-spherical electrodes buried face-to-face in the middle of a cylindrical container was used. The distance separating the electrodes is 100 mm. As a result, the time-lag to breakdown in soils decreases as the amplitude of applied voltage increases. The time-lag to initiation of ionization streamer is decreased, with an increase in the moisture content. However, the formative time-lag is rarely changed. The behavior of soil discharges depend not only on the type of soil and its moisture content but also on the amplitude of the impulse voltage. When the test voltage is applied repeatedly, electrical breakdown occurs along different discrete paths, leading radially away from the injected electrode. i.e., the fact that the ionization streamers propagate in different paths from shot to shot was observed.

• Proceedings of the KIEE Conference
• /
• 1998.07d
• /
• pp.1367-1369
• /
• 1998

To achieve the ULSI goals of higher density, greater performance and operation speed have been scaled down. However, the reduction of channel length cause undesirable problems such as drop of punchthrough voltage, hot-carrier degradation and high leakage current, etc.. It is shown that the device characteristics depend on process parameters. In this Paper, we catched hold of trends of hot-carrier effects and punchthrough voltages due to variation of some process parameters such as LDD doses(P), spacer lengths, channel doses($BF_2$) and $V_T$ adjusting channel implantation energies using design trend curve (DTC). As the LDD and channel doses increased, hot-carrier phenomena became more severe, and punchthrough voltage was decreased. It were represented that punchthrough and hot carrier effects were critically depend on LDD and channel doses.

• Journal of Advanced Marine Engineering and Technology
• /
• v.7 no.2
• /
• pp.15-21
• /
• 1983

Preparing for treatment and management of the emulsified fuel oil which will be generalized henceforth, this paper is an attempt to examine the viscosity-temperature characteristics of emulsified heavy fuel oil which is mixed with water and emulsifier in various mixture ratio by mechanical mixer. The experimental results are summarized as follows: 1. The viscosity-temperature characteristics of the emulsified C & B grade heavy fuel oil mixed with water of same or less weight, is changed according to log.log(v+0.6)=b-3.8log T. 2. The emulsifier has to be added to the emulsified A grade heavy fuel oil mixed with water of same or less weight, because it is instable. Especially if the emulsifier is sodium stearate, it is added more than 0.3% of the weight of oil and water. 3. In the emulsified A grade heavy fuel oil mixed with water and emulsifier, the higher the ratio of water addition becomes, the higher the viscosity is and the more the viscosity-temperature slope decreases. But the higher the ratio of emulsifier addition is, the more the viscosity-temperature slope increases. In this case, the linearity of viscosity-temperature characteristic curve is poorer than that of B and C grade heavy fuel oil. 4. In the emulsified A grade heavy fuel oil mixed with emulsifier of 0.3% or less, the emulsion type is O/W type when water addition ratio is 40%, but it is W/O type when it is 10%, 20%, 30% and 50%.

• International Journal of Reliability and Applications
• /
• v.10 no.2
• /
• pp.89-99
• /
• 2009

Oriented Strand Board (OSB) is an important engineered wood product used in housing construction which has a lower environmental impact or "carbon footprint." In this paper, reliability and statistical tools are applied to gain insights on the strand thickness of OSB panels. An OSB panel consists of several hundred wood strands that are resinated and pressed. The variability of OSB strand thickness for six manufacturers in the Eastern United States is examined as a whole, as well as individually. Little research exists on OSB strand thickness across mills even though strand thickness variability has been documented in laboratory experiments to greatly influence the dimensional stability of OSB panels. Our aims are to quantify and characterize strand thickness, plus apply reliability techniques, such as Kaplan-Meier curves, to characterize the probability of strand thickness. We further explore graphically and statistically the thickness of the strands.

• Korean Journal of Veterinary Research
• /
• v.40 no.1
• /
• pp.35-41
• /
• 2000

We established a new method to analyze abamectin using HPTLC (high performance thin layer chromatography) in order to obtain its pharmacokinetic profiles in pigs. Recovery of abamectin in pig serum after fluorescence derivatization was $80.01{\pm}3.82%$ at 0.1ppm and $83.67{\pm}3.63%$ at 10ppm, respectively. Detection reproducibility in terms of coefficient variation (c.v.) was 3.09% and 2.74% (intra-day), and 3.71% and 51.7%(inter-day), for 0.1 and 10ppm, respectively. Pharmacokinetics of abamectin was studied in five Yorkshire-Landrace mixed bred male pigs ($35.0{\pm}2.7kg$) administered intramuscularly 0.3mg/kg b.w. Pharmacokinetic profiles of abamectin in pigs were described by the 1-compartment open model with first-order absorption and first-order elimination. AUC (area under the curve) was $262.65{\pm}16.44ng{\cdot}day/ml$ and the biological elimination half-life ($t_{1/2},\;k_e$) was $5.28{\pm}0.84$ days, indicating somewhat high bioavailability and long half-life by the intramuscular route. We suggest intramucular injection of abamectin could be also used in place of the recommended route of its subcutaneous administration so far.