• Structural Engineering and Mechanics
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• v.29 no.1
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• pp.37-53
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• 2008

Plane steel portal frames, with pitched roof, exposed to fire, are examined. First, a determinate frame is analysed by hand. For flexible columns and shallow roof, snap-through occurs before plastic hinges mechanism is formed. An indeterminate frame with shorter columns and taller roof is also analysed by hand. Then, the same frame is simulated by a truss and a nonlinear static analysis is performed by use of a short computer program. The results of computer analysis by use of truss model are compared with those of analysis by hand and a satisfactory approximation between them is observed.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.218.2-218.2
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• 2005

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.252-253
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• 2010

• Computational Structural Engineering
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• v.10 no.3
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• pp.167-174
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• 1997

Engineers must be aware of possible sources of chaotic behavior. They may render conventional design predictions untrustworthy and potentially unsafe because of the sensitivity to initial conditions. Dynamic responses of a spherical shell subjected to impulsive loading which act on the center are analyzed using the finite element method. The chaotic responses are identified by the standard methods, such as displacement-time histories, Poincare maps, and phase diagrams. The responses are chaotic, but, not so sensitive to the initial conditions, and the characteristics of responses are not changed with time, in contrast to the case of the responses of beam. The Poincare points scattered in the limited area represent that the responses are chaotic, but do not show the geometric structures. The snap-through phenomena of the shell to the side of the direction of the load or of the opposite direction, is analysed by using the energy diagram.

• Journal of Korean Association for Spatial Structures
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• v.12 no.2
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• pp.89-98
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• 2012

This study investigates the optimum structural design of space truss considering global buckling, and is to obtain the minimal weight of the structure. The mathematical programming method is used for optimization of each member by member force. Besides, dynamic programming method is adapted for consideration in snap-through buckling. The mathematical modeling for optimum design of truss members consists of objective function of total weight and constrain equations of allowable tensile (or compressive) stress and slenderness. The tangential stiffness matrix is examined to find the critical point on equilibrium path, and a ratio of the buckling load to design load is reflected in iteration procedures of dynamic programming method to adjust the stiffness of space truss. The star dome is examined to verify the proposed optimum design processor. The numerical results of the model are conversed well and satisfied all constrains. This processor is a relatively simple method to carry out optimum design with consideration in global buckling, and is viable in practice with respect to structural design.

• Journal of Welding and Joining
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• v.33 no.5
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• pp.41-46
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• 2015

The snap cure NCP(non-conducive paste) adhesive material is essentially required for the high productivity flip chip bonding process. In this study, the accessibility of DEA(dielectric analysis) method for the evaluation of snap cure behavior was investigated with comparison to the isothermal DSC(differential scanning calorimetry) method. NCP adhesive was mainly formulated with epoxy resin and imidazole curing agent. Even though there were some noise in the dielectric loss factor curve measured by DEA, the cure start and completion points could be specified clearly through the data processing of cumulation and deviation method. Degree of cure by DEA method which was measured from the variation of the dielectric loss factor of adhesive material was corresponded to about 80% of the degree of cure by DSC method which was measured from the heat of curing reaction. Because the adhesive joint cured to the degree of 80% in the view point of chemical reaction reveals the sufficient mechanical strength, DEA method is expected to be used effectively in the estimation of the high speed curing behavior of snap cure type NCP adhesive material for flip chip bonding.

• Journal of Veterinary Clinics
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• v.34 no.4
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• pp.229-233
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• 2017

The object of the present study was to compare abnormal serum canine pancreas-specific lipase results and pancreatic ultrasonographic findings in dogs with pancreatitis. Pancreatitis is a common disease in dogs that is difficult to diagnose. The noninvasive diagnostic procedures, including a serum canine pancreatic-specific lipase (cPL) test and ultrasonographic changes in the pancreas, can be considered for the diagnosis of canine pancreatitis in clinical practice. A retrospective study was performed to assess pancreatitis in dogs. Forty client-owned dogs were suspected to have pancreatitis, which was confirmed by abnormal serum SNAP cPL results. Abdominal ultrasound examinations were also performed. The present study investigated the distribution of clinical signs associated with pancreatitis, and the dogs were divided into two groups: group 1 (clinical signs compatible with pancreatitis; n = 30) and group 2 (no clinical signs; n = 10). Based on this study, an abnormal result on the SNAP cPL assay can still present as a normal pancreas through an ultrasonographic examination, and a normal health status can identify the status of pancreatic ultrasonographic abnormal lesions. Therefore, for dogs with suspected pancreatitis, it is important to repeat an ultrasonographic evaluation. There is no significant difference between clinical symptoms and ultrasonographic changes in the pancreas.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.209-216
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• 2018

Reactive oxygen species (ROS) and nitrogen species (RNS) are involved in cellular signaling processes as a cause of oxidative stress. According to recent studies, ROS and RNS are important signaling molecules involved in pain transmission through spinal mechanisms. In this study, a patch clamp recording was used in spinal slices of rats to investigate the action mechanisms of $O_2{^{{\bullet}_-}}$ and NO on the excitability of substantia gelatinosa (SG) neuron. The application of xanthine and xanthine oxidase (X/XO) compound, a ROS donor, induced inward currents and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in slice preparation. The application of S-nitroso-N-acetyl-DL-penicillamine (SNAP), a RNS donor, also induced inward currents and increased the frequency of sEPSC. In a single cell preparation, X/XO and SNAP had no effect on the inward currents, revealing the involvement of presynaptic action. X/XO and SNAP induced a membrane depolarization in current clamp conditions which was significantly decreased by the addition of thapsigargin to an external calcium free solution for blocking synaptic transmission. Furthermore, X/XO and SNAP increased the frequency of action potentials evoked by depolarizing current pulses, suggesting the involvement of postsynaptic action. According to these results, it was estblished that elevated ROS and RNS in the spinal cord can sensitize the dorsal horn neurons via pre- and postsynaptic mechanisms. Therefore, ROS and RNS play similar roles in the regulation of the membrane excitability of SG neurons.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1358-1363
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• 2011

In this study, GEC, VVVF train is mounted in the cab on the Improvement of Brake Controller checks were carried out. Brake Controller in a single-acting snap action switches, double acting snap action switches, and terminals associated with all the parts individually checked, rather than the current trains, and the same conditions, the overall depth review and analysis through the improvements in the meantime, failure to advance found by processing station Minimal and directly related to the safety of disabled passengers, the train station to contribute to safety in this study began.

• 한국컴퓨터산업교육학회:학술대회논문집
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• 2003.11a
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• pp.71-74
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• 2003

A vertical trench electrode type EST has been proposed in this paper. The proposed device considerably improve the snap-back effect which leads to a lot of problem of device applications. In this paper, the vertical dual gate Emitter Switched Thyristor(EST) with trench electrode has been proposed for improving snap-back effect. It is observed that the forward blocking voltage of the proposed device is 800V. The conventional EST of the same size were no more than 633V. Because the proposed device was constructed of trench-type electrode, the electric field moved toward trench-oxide layer, and the punch through breakdown of the proposed EST is occurred at latest.