• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.11
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• pp.923-930
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• 2002

Cooling characteristics of a parallel channel with protruding heat sources using convection and conduction heat transfer are studied numerically. A two-dimensional model has been developed for numerical prediction of transient, compressible, viscous, laminar flow, and conjugate heat transfer between parallel plates with uniform block heat sources. The finite volume method is used to solve the problem. The assembly consists of two channels formed by two covers and one printed circuit board which has three uniform heat source blocks. Six different cooling methods are considered to find out the most efficient cooling method in a given geometry and heat sources. The velocity and temperature fields of cooling medium, the temperature distribution along the block surface, and the maximum temperature in each block are obtained. The results are compared to examine the cooling characteristics of the different cooling methods.

• The Korean Journal of Pain
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• v.2 no.1
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• pp.97-99
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• 1989

Epidural block is used extensively in each of the fields of surgical anesthesia, obstetric anesthesia, and diagnosis and management of acute and chronic pain. New developments in the understanding of pain conduction have extended the use of continuous epidural blockade to the administration of drugs that selectively block pain conduction while leaving sensation and motor power essentially unchanged. The safety and the reliability of spinal epidural catheter techniques have permitted relief of acute and chronic pain. However, one of the important aspects of the management of the epidural catheter is the possibility of epidural infection. We have experienced a case of epidural infection during control of post-herpetic neuralgia and discuss management of the epidural catheter in this article.

• Journal of Chest Surgery
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• v.11 no.3
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• pp.326-332
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• 1978

There appears some conduction defects frequently after total correction of Tetralogy of Fallot. Common defect is right bundle branch block due to surgical intervention. We experienced complete A-V block which occured 3 months later after total correction of Tetralogy of Fallot in a 8 year old boy. The patient was completely free of any A-V block after the operation for 3 months, and sudden onset of A-V block with coupled premature ventricular contractions resulted him in shock state during the attack of severe bronchopneumonia for 4 days prior to the second visit. Emergency implantation of Cordis demand type temporary pacemaker was necessary to control the complete heart block with bradyarrhythmia and frequent ventricular fibrillation. Permanent cardiac pacemaker was implanted two weeks later as indicated with Cordis Stanicor lambda demand pacemaker, and the patient was discharged uneventfully on the 8th post implantation day with the heart rate of 72/min. Another 3 months after the implantation, the patient was transported to this hospital as dead on arrival after an accidental fall from a 2 meter height, and all possible cardiopulmonary resuscitation was performed for 60 minutes at the emergency room in vain. Autopsy was done to find out the cause of sudden death and the etiology of complete heart block. Microscopic focal infarctions with scar formation were noted along the course of conduction system in the interventricular septum, which might be the main cause of complete heart block during the attack of severe bronchopneumonia complicated with acute bacterial endocarditis. The tip of the pacemaker wire was slipped from the granulation scar at the apex of the right ventricular cavity, and this might be the direct cause of pacing failure and death.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.602-605
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• 2009

The heat generation in the high-$T_c$ superconducting (HTS) wire is related with the cost efficiency and safe factor of HTS devices. This paper deals with the thermal quench at the conduction-cooled joint between HTS wire and copper terminals. The 3-D numerical simulation of thermal distributions in part of the copper terminals was implemented and the premature quench at copper block was observed through the test. The results will be helpful to design the conduction-cooled HTS magnets.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.390-395
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• 2001

Cooling characteristics using convection and conduction heat transfer in a parallel channel with extruding heat sources are studied numerically. A two-dimensional model has been developed for numerical prediction of transient, compressible, viscous, laminar flow, and conjugate heat transfer between parallel plates with uniform block heat sources. The finite volume method is used to solve this problem. The considered assembly consists of two channels formed by two covers and one PCB which has three uniform heat source blocks. Five different cooling methods are considered to find efficient cooling method in a given geometry and heat source. The velocity and temperature fields, local temperature distribution along surface of blocks, and the maximum temperature in each block are obtained.

• Annals of Clinical Neurophysiology
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• v.19 no.1
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• pp.3-12
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• 2017

Using threshold tracking, differences have been established between large myelinated sensory and ${\alpha}$ motor axons in humans. Major differences are that sensory axons are relatively depolarised at rest such that they have a greater persistent $Na^+$ current, and have greater activity of hyperpolarisation-activated cyclic nucleotide-gated (HCN) channels. Sensory axons may thereby be protected from hyperpolarising stresses, and are less likely to develop conduction block. However, the corollary is that sensory axons are more excitable and more likely to become ectopically active.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.175-176
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• 1998

The automated ECG diagnostic systems that are used in hospitals have low performance of P wave detection when faced with some diseases such as conduction block. So, the aim of this study is the improvement of detection performance in conduction block which is low in P wave detection. Median QRS-T segments were subtracted from the raw data and residual in the QRS-T regions was zeroed. After band pass filtering, we applied approximated length transformation to detect P wave.

• The Korean Journal of Pain
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• v.12 no.2
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• pp.177-182
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• 1999

Background: Clonidine, an ${\alpha}_2$ adrenergic agonist blocks nerve conduction. However, in our previous experiment we found that adrenaline neither blocks nerve conduction by itself nor augment nerve conduction blockade by lidocaine near clinical concentrations. Possible explanations are: 1) there may be antagonism between some of adrenergic receptors, 2) clonidine may block nerve conduction via non-adrenergic mechanism. The purpose of this study is to obtain dose-response curves of several different forms of adrenergic receptor agonist to see the relative potencies of each adrenergic receptors to block nerve conduction. Methods: Recordings of compound action potentials of A-fiber components (A-CAPs) were obtained from isolated sciatic nerves of adult male Sprague-Dawley rats. Nerve sheath of the sciatic nerve was removed and desheathed nerve bundle was mounted on a recording chamber. Single pulse stimuli (0.5 msec, supramaximal stimuli) were repeatedly applied (2Hz) to one end of the nerve and recordings of A-CAPs were made on the other end of the nerve. Dose-response curves of epinephrine, phenylephrine, isoproterenol, clonidine were obtained. Results: $ED_{50}$ of each adrenergic agonist was: $4.51\times10^{-2}$ M for epinephrine; phenylephrine, $7.74\times10^{-2}$ M; isoproterenol, $9.61\times10^{-2}$ M; clonidine, $1.57\times10^{-3}$ M. Conclusion: This study showed that only clonidine, ${\alpha}_2$ adrenergic agonist, showed some nerve blocking action while other adrenergic agonists showed similar poor degree of nerve blockade. This data suggest that non-effectiveness of epinephrine in blocking nerve conduction is not from the antagonism between adrenergic receptors.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.76-80
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• 2003

A contractible heat pipe is designed and tested to improve cooling performance of conduction cooled superconducting magnet. When the heat pipe temperature drops below the triple point temperature, heat pipe working fluid freezes to create low pressure. From this moment the heat pipe does net work any more (OFF state) and it just works as a heat leak path when the temperature of the first stage is higher than that of the second stage. Considering small cooling capacity of the second stage around 4.2 K, the conduction loss is not negligible. Therefore, the contractible heat pipe, made of a metal bellows and copper tubes, was considered to eliminate the conduction loss. Nitrogen and argon are as working fluid of heat pipe. The copper block is cooled down with these heat pipe and the cooling performance for each heat pipe is compared. At off state, the bellows is contracted due to the low pressure of heat pipe and the evaporator section of the heat pipe is detached about 3 mm from the second stage cold head of the cryocooler. In this way, we tan eliminate the conduction loss through the heat pipe wall.

• Annals of Clinical Neurophysiology
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• v.6 no.1
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• pp.14-19
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• 2004

Backgrounds and objectives: POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome is the rare cause of polyneuropathy. Although the polyneuropathy is essential for the diagnosis of the disease, the pattern of electrodiagnostic abnormalities has not been characterized in detail. The purpose of this study was to elucidate the features of nerve conduction abnormalities in POEMS syndrome. Methods: We reviewed the medical records and nerve conduction studies (NCS) of 12 consecutive patients with POEMS. Results: A total of 68 motor and 46 sensory nerves were examined. Compound muscle action potentials (CMAPs) and sensory nerve action potentials were abnormally attenuated or not elicited in majority of motor and sensory nerves (80.88% in motor, and 82.6% in sensory nerves). Frequency of the nerves with no potential was significantly higher in lower limbs than in upper limbs (p<0.01 in both motor and sensory nerves), and CMAP amplitude was more reduced in lower limbs than in upper limbs (p<0.01). Conduction slowing was very frequently observed with 95% and 76% of motor and sensory nerves, respectively, having the abnormally reduced values of conduction velocity. Distal motor latencies were abnormally prolonged in 75% of motor nerves, and terminal latency indices were significantly higher in patients than in normal controls (p < 0.05). Conduction block was observed only in 5% of motor nerves. Conclusions: NCS in POEMS syndrome showed characteristic patterns, in which conduction abnormalities were more frequently and severely affected in the lower limbs, and more predominantly in the intermediate nerve segments than in the distal portions. The recognition of these characteristic patterns may be helpful in early diagnosis of polyneuropathy in POEMS syndrome.