• Korean Journal of Oriental Medicine
• /
• v.1 no.1
• /
• pp.441-459
• /
• 1995

To study stability of distilled herbal medicine, we chose changes in UV spectrum, pH, conductivity, and HPLC chromatogram. Aconiti Lateralis preparata Radix and Scutellariae Radix were selected and studied. There ws no consistancy in UV spectrums of preparatons and in duration. The changes in pH and conductivity were not correlated to those in UV spectrums. HPLC chromatograms were also compared each other depending on the preparations. One interesting peak of distilled Aconiti solution was appeared at 40 min retention time which was not identified yet. Ingeneral, UV spectrum, pH, conductivity measurements are pretty poor tool to study stability of herbal medicine although HPLC analysis should be studied further.

• Korean Journal of Materials Research
• /
• v.14 no.4
• /
• pp.260-264
• /
• 2004

The problem of polyaniline (PANi) sensor has been poor mechanical and chemical stability under atmosphere condition. In order to overcome these problems, the PANi sensor coated with polyvinylidenefluoride ($PVF_2$) was employed. The morphology of $PVF_2$ coated-PANi layer was showed smooth and transparent properties at 15% concentration of coating solution. The resistance of $PVF_2$ coated-PANi was kept at constant value and had a good stability at long-term periods in presence of humidity.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1670-1672
• /
• 2000

The stability of ZnO-$Pr_{6}O_{11}$-CoO-$Cr_{2}O_{3}-Dy_{2}O_3$ based varistors with d.c. stress were investigated. ZnO varistor doped with 4.0 mol% $Dy_{2}O_3$ exhibited the highest nonlinear exponet, but stability was very poor because of low density. In particular, the varistor containing 0.5 mol% $Dy_{2}O_3$ showed very excellent V-I characteristic, which the nonlinear exponent was 67.39 and leakage current was 1.18 ${\mu}A$, and high stability.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.49 no.2
• /
• pp.136-140
• /
• 2004

Twenty-one lowland rice genotypes were evaluated for their stability parameters with respect to grain yield in a multi locational trial at five different sites of Eastern India viz. CRRI, Cuttack (Orissa); OUAT, Bhubaneswar (Orissa); CRS, Masodha (UP); RAU, Pusa (Bihar) and RARS, North Lakhimpur (Assam). Pooled analysis of variance reflects existence of genotype x environment interactions and contribution of both linear and nonlinear components to genotype (G) x environment (E) interactions. Through stability parameter analysis it was found that Rayda $\textrm{B}_3$, CR 778-95 and CR 661-236 were suitable for over all environments where as Sabita, OR 1334-16 and OR 1358-RGA-4 were suitable for rich environments. PSR 1209-2-3-2, CR 780-1937, Ambika, OR 877-ST-4-2 and CR 662-2211 were identified for poor environments.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.6
• /
• pp.45-51
• /
• 2003

This paper presents a method to improve lateral stability of a four-seat canard aircraft, Velocity-173. Longitudinal stability of Velocity-173 is rather good, but lateral stability is relatively poor. A small panel which increases the area of vertical tail is designed and manufactured. In a design process, AAA(Advanced Aircraft Analysis) is used to predict the change in stability. Flight test is performed to validate the effect of a small panel attached under the vertical panel. Maximum likelihood estimation method is used to extract lateral controllability / stability derivatives from flight test data. This work validates the effect of a small panel attached under the vertical tail.

• Human Ecology Research
• /
• v.56 no.2
• /
• pp.157-165
• /
• 2018

Using data from the Panel Study on Korean Children, this study investigated whether children with high levels of problem behaviors adjusted more poorly on the $1^{st}-grade$ than children with low levels of problem behaviors, and whether there was evidence of intra-individual stability in behavior problems over time. Data were analyzed by use of the Latent Growth Model and group differences analyses. Three findings were noteworthy. First, there was evidence of intra-individual and inter-individual variability in behavior problems between poor- and non-poor household children. Second, children with higher initial levels of internalizing and externalizing behaviors at 4 years had lower school readiness scores at 6 years. Finally, children with lower levels of school readiness at 6 years had lower school adjustment scores in $1^{st}$ grade. The results discuss implications for future research and policies for preschool children. With mediating effect of school readiness, developmental trajectories of child's problem behavior have been found to be predictors of delayed achievements in school. The results show that intervention programs are necessary for children with high levels of problem behavior. This study also showed that children who experienced poverty at home could have more difficulties in school readiness and school adjustment.

• Management & Information Systems Review
• /
• v.8
• /
• pp.25-43
• /
• 2002

Performance evaluation continues to receive attention today as it has for the past few decades. The problem addressed in this paper concerns the relationship between supervisor's causal attributions and their subsequent responses behavior. Previous study in personnel and other disciplines has indicated the importance of causal attributions in the interpretation of poor performance. However, most study has focused on antecedents of attributions than supervisor's responses to the subordinate's poor performance. The objective of this study was to investigate the effects of supervisor's causal attributions and subordinate's responses to a subordinate's poor performance. Specifically, using in the public sector context, the study examined the effects to two dimensions of causal attributions: locus of causality and stability, as well as on the punitiveness of supervisors's responses. The result supported that when the subordinate is internal causes for the performance failure, supervisor's responses were more punitive. Consistent with previous studies, internal attributions were found to result in more punitive behavior than external attribution. In addition, attributions to effort and luck were found to result in more punitive behavior than attributions to ability and task difficulty. Thus, the first hypothesis and second hypothesis supported. These result suggest the importance of appropriately for performance evaluation.

• The Journal of Korean Physical Therapy
• /
• v.24 no.6
• /
• pp.419-422
• /
• 2012

Purpose: Malalignment of the lower limbs may increases the difficulty of maintaining equilibrium. The purpose of this study was to study the effects of genu varum and poor posture in the sagittal plane on postural stability. Methods: We had 27 subjects with varus and 27 normal subjects participate in this study. Subjects for whom the distance between the medial epicondyles in the knee joint was more than 3 cm were classified as varus group, and subjects for whom the distance was less than 3 cm were classified as normal group. The measurements of static and dynamic stability were used overall stability index (OSI), anterioposterior stability index (APSI), and mediolateral stability index (MLSI) using a Biodex balance system. Results: When measuring the static stability index, there were significant differences in the mediolateral stability index between the varus and control groups. When measuring the dynamic stability index, there were significant differences in the overall, anteriorposterior, and mediolateral stability index between the varus and control groups. These results demonstrated that genu varum affects mediolateral movement in static stability, and overall, anterioposterior and mediolateral movements in dynamic stability. Conclusion: As genu varum affects static and dynamic stability in young adults, it increases the risk of injuries or falls. Exercise and surgery are required for realigning the genu varum. Future studies about postural stability in young children and elderly people who have a risk of falls due to lower postural control ability, are needed, as well as in young adults.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.215.2-215.2
• /
• 2015

We fabricated dual active layer (DAL) thin film transistors (TFTs) with indium tin zinc oxide (ITZO) and indium gallium zinc oxide (IGZO) thin film layers using solution process. The ITZO and IGZO layer were used as the front and back channel, respectively. In order to investigate the bias stress stability of ITZO SAL (single active layer) and ITZO/IGZO DAL TFT, a gate bias stress of 10 V was applied for 1500 s under the dark condition. The SAL TFT composed of ITZO layer shows a poor positive bias stability of ${\delta}VTH$ of 13.7 V, whereas ${\delta}VTH$ of ITZO/IGZO DAL TFT was very small as 2.6 V. In order to find out the evidence of improved bias stress stability, we calculated the total trap density NT near the channel/gate insulator interface. The calculated NT of DAL and SAL TFT were $4.59{\times}10^{11}$ and $2.03{\times}10^{11}cm^{-2}$, respectively. The reason for improved bias stress stability is due to the reduction of defect sites such as pin-hole and pores in the active layer.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.2
• /
• pp.320-328
• /
• 2016

The introduction of renewable energy sources into the AC grid can change and weaken the strength of the grid, which will in turn affect the stability and robustness of the doubly-fed induction generator (DFIG) wind farm. When integrated with weak grids, the DFIG wind turbine with vector power control often suffers from poor performance and robustness, while the DFIG wind turbine with synchronized control provides better stability. This paper investigates the critical short circuit ratios of DFIG wind turbine with vector power control and synchronized control, to analyze the stability boundary of the DFIG wind turbine. Frequency domain methods based on sensitivity and complementary sensitivity of transfer matrix are used to investigate the stability boundary conditions. The critical capacity of DFIG wind farm with conventional vector power control at a certain point of common coupling (PCC) is obtained and is further increased by employing synchronized control properly. The stability boundary is validated by electromagnetic transient simulation of an offshore wind farm connected to a real regional grid.