• Microbiology and Biotechnology Letters
• /
• v.23 no.6
• /
• pp.710-716
• /
• 1995

$\beta $-1, 4-D-arabinogalactanase isolated from alkalophilic Bacillus sp. HJ-12, approximate Mw 42 kDa, was generally stable in the range of pH 6-10 and below 50$\circ$C and its highest activity was observed at 60$\circ$C with pH 7-9. The isolated $\beta $-1, 4-D-arabinogalactanase specifically hydrolyzed $\beta $-1, 4-galactosyl linkage that is the major structure of soybean arabinogalactan (SAG) but not $\beta $-1, 3-galactosyl linkage of the other polysaccharides. K. was estimated as 0.67 mg/ml by the method of Hanes-Woolf plot. No metals and chemical reagents inhibited the enzyme activity but urea did. The active site of this enzyme assumed to be tryptophan residue. The hydrolysis products from SAG, assayed by gel chromatography, TLC and HPLC, were predominantly galactotetraose (Gal$_{4}$) and triose (Gal$_{3}$) with a small portion. $\beta $-1, 4-D-arabinogalactanase hydrolyzed ONPG as well as SAG, and the degree of hydrolysis of SAG was 15% which is lower than that by the other $\beta $-1, 4-galactanases from different sources. SAG treated with this enzyme resulted in the reduction of specific viscosity up to 70%.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.25-27
• /
• 2002

This paper describes a new economical voltage sag and swell generator suitable to the evaluations of high power custom power devices such as DVR (Dynamic Voltage Restorer) and DSTATCOM (Distribution Static Compensator). This system was designed to generate the several power quality disturbances in MVA power ratings - voltage sag and swell, under voltage, over voltage and harmonic distortions. The basic idea for voltage sag and swell is to use the voltage drop across a reactor, while the voltage swell is to use the step-up transformer and the TCR(Thyristor Controlled Reactor). In this paper, two identical 3 phase TCRs and a step-up transformer with tap changer are used. Additional harmonic filters are added to reduce the voltage distortion when TCRs are operated. Simulation results are given for several cases of voltage sag and swell generations.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.156-158
• /
• 2002

In this paper, we analyze about voltage sag effect at load side during fault according to change of power system condition. through the case studies, we find that there is no close connection between substation bus transfer and voltage sag during fault. however, we find that other feeder connecting with the faulted transmission is directly affected by fault type and magnitude, therefore, the main subject can be divided into the utility and customer side countermeasures, utilities concentrate their effort to prevent the faults and to modify the fault clearing practice in power system. however, the faults in power system can never be completely eliminated. therefore, customer side solutions usually involve the power conditioning equipment for sensitive loads aiso, we investigate that the several methods to reduce the number and severity of voltage sag and to dull the sensitivity of equipment for voltage sag have developed. moreover, about SEMI, the industry association for the semiconductor two voltage sag immunity standards.(SEMI F47, SEMI F42) The simulation is accomplished by PSS/E 26.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.2
• /
• pp.159-163
• /
• 2010

The superconducting fault current limiter (SFCL) plays a role in compensating the voltage sag of the sound feeder adjacent to the fault feeder as well as the fault current limiting operation of the fault feeder. Especially, the SFCL using magnetic coupling of two coils with parallel connection has different voltage sag compensating and current limiting characteristics due to the winding direction and the inductance ratio of two coils. In this paper, the current limiting and the voltage sag compensating characteristics of a SFCL using magnetic coupling of parallel connected two coils were analyzed. Through the analysis on the experimental results considering the winding direction of two coils, the SFCL designed with the additive polarity winding was shown to have the higher limited fault current than the SFCL designed with the subtractive polarity winding. In addition, it could be confirmed that the higher fault current limitation of the SFCL could be contributed to the higher load voltage sag compensation.

• Progress in Superconductivity and Cryogenics
• /
• v.12 no.1
• /
• pp.22-27
• /
• 2010

This paper analyzed bus voltage sag caused by recloser-fuse coordination in a power distribution system with SFCL. Generally, the recloser is installed to upstream of fuse to clear against both permanent and temporary faults appropriately, when the fault happened and to block expansion of the fault area. Furthermore, when the fault occurred, bus voltage sag is caused by increased fault currents. However, in a power distribution system with SFCL, the fault current could be decreased by the effect of the impedance value of the SFCL and place to install one as long as it could improve bus voltage sag. Therefore, to analyze the effect of the improvement of bus voltage sag caused by recloser-fuse coordination in a power distribution system with SFCL, we used PSCAD/EMTDC about a permanent fault at the place behind the fuse.

• International Journal of Highway Engineering
• /
• v.13 no.1
• /
• pp.1-11
• /
• 2011

This study is aimed at suggesting a plan for creating a landscape environment by grasping a landscape preference according to the change of middle span and sag ratio which is a consideration factor when designing the suspension bridge representing long-span bridges and image property of the bridge while applying SD method to a relation between landscape preference and image factor, and a connection of design element with image factor. An analysis on landscape preference about the bridge landscape showed from what the longer the length of middle span, the extent of sag ratio of preference decreased, the longer the middle span low sag ratio was preferred and the higher the landscape preference became. In landscape preference and image factor, the attribute of sag ratio with high landscape preference was all positively correlated with "stability", "plasticity", and "aesthetic" but an influence of "plasticity" was insignificant. In the relation between design element and image factor, the factor of middle span and sag ratio was more related to the factor of "stability" and the lower the sag ratio and the longer the middle span, the higher the "stability" was rated. This result showed the image property of "plasticity" was insignificant among the one of preference in landscape and to highlight the one of "plasticity" a complementary experiment was done with a change in balance and symmetry elements not in proportional element of middle span and sag ratio. The result showed the image property of "plasticity" was more highlighted in the suspension bridge of 3-tower and different bilateral symmetry at sag, and when designing the landscape of suspension bridge later on, the elements of balance and symmetry as well as the proportional element should be considered and reflected in the design.

• Progress in Medical Physics
• /
• v.26 no.2
• /
• pp.106-111
• /
• 2015

In Tomotherapy the couch sags during the treatment due to the weight of the patient. In this study, we developed a simple method to obtain the amount of the sag and the pitch angle of the couch using the image processing technique of MVCT images in Tomotherapy. Using the method we evaluated the sag and pitch of couch for 22 head and neck patients and one craniospinal irradiation (CSI) patient. The sag and the average pitch angle of couch were 0.40~1.54 mm and $0.7^{\circ}$ for head and neck patients, respectively. For head and neck patients, the sag increased as the longitudinal length of the irradiation volume increased and the pitch angle showed no relationship with the longitudinal length. For the CSI patient the sag was 4.97 mm. Using the method the amount of the couch sag could be measured easily and the measured data could be useful in determination of margins considering the table sag error.

• Molecules and Cells
• /
• v.37 no.3
• /
• pp.226-233
• /
• 2014

Excessive reactive oxygen species (ROS) generated from abnormal cellular process lead to various human diseases such as inflammation, ischemia, and Parkinson's disease (PD). Sensitive to apoptosis gene (SAG), a RING-FINGER protein, has anti-apoptotic activity and anti-oxidant activity. In this study, we investigate whether Tat-SAG, fused with a Tat domain, could protect SH-SY5Y neuroblastoma cells against 1-methyl-4-phenylpyridinium ($MPP^+$) and dopaminergic (DA) neurons in the substantia nigra (SN) against 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine (MPTP) toxicity. Western blot and immunohistochemical analysis showed that, unlike SAG, Tat-SAG transduced efficiently into SH-SY5Y cells and into the brain, respectively. Tat-SAG remarkably suppressed ROS generation, DNA damage, and the progression of apoptosis, caused by $MPP^+$ in SH-SY5Y cells. Also, immunohistochemical data using a tyrosine hydroxylase antibody and cresyl violet staining demonstrated that Tat-SAG obviously protected DA neurons in the SN against MPTP toxicity in a PD mouse model. Tat-SAG-treated mice showed significant enhanced motor activities, compared to SAG- or Tat-treated mice. Therefore, our results suggest that Tat-SAG has potential as a therapeutic agent against ROS-related diseases such as PD.

• Journal of Korean Association for Spatial Structures
• /
• v.16 no.3
• /
• pp.47-58
• /
• 2016

Cable network system is a flexible lightweight structure which curved cables can transmit only tensile forces. The weight of cable roof dramatically can reduce when the length becomes large. The cable network system is too flexible, most cable systems are stabilized by pretension forces. The tensile force of cable system is greatly influenced by the sag ratio and pretension forces. Determining initial sag ratio of cable roof system is essential in a design process of cable structures. Final sag ratio and pretension depends on initial installed sag and on proper handling during installation. The design shape of cable system has an affect on the sag and pretension, and must be determined using well-defined design philosophy. This paper is carried out the comparative data of the deflection and tensile forces on the geometric non-linear analysis of cable network systems according to sag ratio. The study of cable network system is provided to technical informations for the design of a large span cable roof, analytical results are compared with the results of other researchers. Structural nonlinear analysis of systems having cable elements is relatively complex than other rigid structural systems because displacements are large as a reason of flexibility, initial prestress is applied to cables in order to increase the rigidity, and then divergence of nonlinear analysis occurs rather frequently. Therefore, cable network systems do not exhibit a typical nonlinear behavior, iterative method that can handle geometric nonlinearities are necessary.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.5A
• /
• pp.657-664
• /
• 2008

Rain-wind induced cable vibration can cause the damages in the cable-stayed bridge due to very little inherent damping characteristics and low fundamental frequency. External Dampers attached to stay cables near anchorages have been shown to be effective means at short stay-cables. However, installation locations of external dampers are limited to a particular range due to aesthetic and practical reasons for very long stay-cables. A recent study by the authors showed that the stay-cable vibration system can perform better than the optimal passive viscous damper, thereby demonstrating its applicability in large cable-stayed bridges. This paper extends the previous study on the taut string representation of the cable by adding cable sag and inclination. The response of the proposed system compared to those of the cable with and without an external damper, and the movable anchorage system provides very effective mitigation of cable vibration. Cable damping ratio is seen to be remarkably reduced by movable anchorage system for a wide range of cable sag. This result shows that the sag effects of the proposed system should be considered.