Partial Conduction Block as an Early Nerve Conduction Finding in Neurolymphomatosis

박형준,신하영,김세훈,정하늘,최영철,서범천,박기덕,김승민 대한신경과학회 2018 Journal of Clinical Neurology Vol.14 No.1

Background and Purpose Neurolymphomatosis is a rare manifestation of hematological malignancy and is characterized by direct infiltration of the peripheral nervous system. The objective of this study was to identify the clinical and electrophysiological features of neurolymphomatosis. Methods We retrospectively analyzed the medical records of 13 patients with neurolymphomatosis. Seven (54%) of the patients were men, and the median age at symptom onset was 60.0 years. Results The most common type of underlying malignancy was diffuse large B-cell lymphoma (69%). Twelve patients had painful asymmetric neuropathies. The median survival time after diagnosis was 7 months, and 12 patients died during the study period. Thirty-eight motor nerve conduction studies (NCSs) were performed in the affected nerves. Ten and 28 motor nerves were classified into the conduction-block and simple-axon-degeneration groups, respectively. The median time interval between symptom onset and the NCS was significantly shorter in the conduction-block group than in the simple-axon-degeneration group (p=0.032). However, no significant differences in the motor nerve conduction velocities, terminal latencies, and distal compound muscle action potential amplitudes were identified between the conduction- block and simple-axon-degeneration groups. The conduction-block group showed excessive temporal dispersion in only five of the ten NCSs (50%). Follow-up NCSs revealed that partial conduction blocks had changed into axonal degeneration patterns. Conclusions This is the first study to analyze the electrophysiological features of patients with neurolymphomatosis. Our findings showed that a partial conduction block is not rare and is an early nerve conduction abnormality in neurolymphomatosis.

방실차단 및 심실내전도장애에 관한 통계적 고찰

배형준 대한임상병리사협회 1994 대한임상병리사회지 Vol.26 No.1

A statistical study was done on atrioventricular block and intraventricular conduction disturbance in 127 cases taken on 1,761 patients subjected to electrocardiographic examination. The results were as follows 1. Total incidence of conduction disturbance was 7.21%, atrioventricular block was 2.67% and intraventricular block was 4.54% of total patients. Among of these, first degree atrioventricular block was 2.44% which was the most common occurred one, and complete right bundle branch block(2.33%), incomplete right bundle branch block (1.13%), left anterior hemiblock(0.74%), third degree atrioventricular block and left bundle branch block(each 0.17%), bifascicular block(0.11%), second degree atrioventricular block and left posterior hemiblock(erach 0.06%) in the order of frequency. 2. The ratio of male to female was 1.2:1 for atrioventricular block and 1.4:1 for intraventricular block. Atrioventricular block and intraventricular block were both common in over fifth decade. 3. The abnormal ECG findings wjth first degree atrioventricular block were sinus bradycardia(27.3%), left ventricular hypertrophy(21.2%), atrial enlargement(12.2%). In third degree atrioventricular block, the majority(50.0%) showed atrioventricular junctional escape rhythm. In complete right bundle branch block, there were 22.8% of atrial fibrillation and 14.3% of myocardial infarction. In incomplete right bundle branch block, there were 29.4% of both atrial enlargement and atrial fibrillation. In left anterior hemi-block. there was 21.5% of sinus bradycardia.

나노다이아몬드가 첨가된 탄소블록의 열전도도 특성

이준숭 ( Jun Soong Lee ),문지훈 ( Ji Hun Mun ),주성욱 ( Sungwook Joo ),이승욱 ( Seung Uk Lee ),김민일 ( Min Il Kim ) 한국공업화학회 2023 공업화학 Vol.34 No.6

탄소블록의 열전도도를 증가시키기 위하여 탄소블록 제조 공정 중 nano-diamond (ND)를 첨가하였다. 첨가된 ND는 탄화 과정에서 바인더 피치의 휘발로 인하여 생성된 탄소블록의 기공을 제어하였다. ND의 첨가는 코크스 및 바인더 피치의 혼련 공정에 추가하였으며, 성형, 탄화를 거쳐 탄소블록을 제조하였다. 첨가된 ND의 양이 증가할수록 탄소블록의 ND 비율이 증가하였다. 첨가된 ND는 탄화 과정에서 바인더 피치의 휘발로 인하여 발생하는 가스의 이동 통로역할을 하여 탄소블록의 밀도를 높이고, 기공률을 감소시켰다. ND의 첨가를 통하여 높아진 밀도, 낮아진 기공률, ND의 높은 열전도도를 통하여 탄소블록의 열전도도를 향상시킬 수 있었다. Nano-diamond (ND) was added during the carbon block preparation process to increase the thermal conductivity of the carbon block. Added ND controlled the generated pore of carbon block due to the volatilization of the binder pitch during the carbonization process. The ND was added to the kneading process of coke and binder pitch, and carbon blocks were prepared by pressing and carbonization. As the amount of added ND increased, the ND ratio of the carbon block increased. The added ND made a pass-way for generated gas by volatilizing the binder pitch during the carbonization process, increasing the density of the carbon block and reducing the porosity. The thermal conductivity of the carbon block was improved by increased density, lowered porosity, and the high thermal conductivity of added ND.

Development of effective thermal conductivity models for Reserve Shutdown Control fuel block of prismatic HTGR for hydrogen production

Shin, Dong-Ho,Yoon, Su-Jong,Cho, Hyoung Kyu,Park, Goon-Cherl,Kim, Taewan Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.29

<P><B>Abstract</B></P> <P>A hydrogen production system coupled to High Temperature Gas-cooled nuclear Reactor (HTGR) is considered to be one of the most promising ways for massive hydrogen production. For the reliability of the coupled system, the safety analysis on the HTGR is to be conducted by a system-scale analysis code. The system-scale analysis code adopts an effective thermal conductivity (ETC) model for a fuel block due to its complex geometry containing large number of coolant holes and nuclear fuel rods. The ETC of the fuel block is crucial to calculate the heat transfer inside the reactor core and prediction of thermal distribution over the reactor core is the most significant for the safety analysis of HTGR. Therefore, the verification of the ETC model that contributes to the prediction is essential. This ETC model based on Maxwell's theory shows an inaccurate prediction when the configuration of the composite materials is not homogeneous. Since the geometry of Reserve Shutdown Control (RSC) fuel block of HTGR is not homogeneous due to a large RSC hole, the ETC model for RSC fuel block should be developed to improve the accuracy and reliability of the reactor system analysis code. In this study, the two ETC models for the RSC fuel block have been developed by the thermal network modeling. Computational fluid dynamic simulations with a real geometry were performed to evaluate the accuracy of the ETC models for the RSC fuel block. The comparative result between CFD analysis and the ETC model shows that the newly developed model predicts the effective thermal conductivity of RSC fuel block more accurately than the previous model.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Study on the analyzing method on thermal distribution of High Temperature Gas-cooled nuclear Reactor (HTGR) is presented. </LI> <LI> Effective thermal conductivity model for Reserved Shutdown Control (RSC) fuel block was developed. </LI> <LI> The developed ETC model was evaluated over wide range of temperature and neutron fluence by CFD analysis. </LI> </UL> </P>

클래드 판재를 사용한 3D 프린터 히팅 블록 개발

원대희 한국융합학회 2017 한국융합학회논문지 Vol.8 No.4

이 연구에서는 3D 프린터 히팅 블록의 발열로 인해 가이드로 열이 전달되어 필라멘트가 녹는 문제점을 개선하기 위해 설계 해석과 폭발압접을 융합한 방법으로 클래드 판재를 만들었다. 클래드 판재에 대한 전단 강도 시험을 하였으며, 히팅 블록으로 가공한 다음 열 해석, 열전도도, 열화상 측정 결과 다음과 같은 결론을 얻었다. 구리와 타이타늄 클래드 판재로 만든 히팅 블록에 대하여 3D 모델링 열 해석 한 결과 필라멘트 가이드 부위의 표면온도가 히팅 블록 표면온도 보다 낮은 온도가 예측되었다. 구리와 타이타늄 클래드 판재로 만든 다음 전단 강도를 측정한 결과 평균 195.6MPa 값을 얻었다. 구리와 타이타늄 클래드 판재로 만든 히팅 블록에 대하여 열전도도를 3회 측정한 결과 평균 62.52 W/m⋅K값을 나타내었다. 구리와 타이타늄 클래드 판재로 만든 히팅 블록에 대하여 열화상 카메라로 표면 온도를 측정한 결과 최대 107.3℃ 측정되었으며, 필라멘트 가이드 부근에서는 183.2℃ 측정되었다. 기존 필라멘트의 부위의 온도 보다 89℃ 낮은 온도 분포를 보였다. In this study, the design analysis and the explosion welding were made into a clad sheet by the convergence method in order to solve the problem of heat transfer to the guide due to the heating of the 3D printer heating block. The shear strength of the clad plate material was tested and the results were analyzed by thermal analysis, thermal conductivity and thermal imaging. The following conclusions were obtained. 3D modeling of the heating block made of copper and titanium clad plate material The thermal analysis showed that the surface temperature of the filament guide area was lower than the heating block surface temperature. The average shear strength of copper and titanium clad plate material was measured and the average value of 195.6MPa was obtained. The thermal conductivity of the heating block made of copper and titanium clad plate material was measured three times and the average value was 62.52 W / m⋅K. The surface temperature of the heating block made of copper and titanium clad plate material was measured by a thermal imaging camera at a maximum of 107.3℃ and 183.2℃ at the filament guide. The temperature distribution was 89℃ lower than that of the existing filament.

시각장애인용 점자블록의 동절기 성능개선에 관한 기초적 연구

성기태,이승용 한국교통대학교 2015 한국교통대학교 논문집 Vol.50 No.-

The preexisting type of braille blocks for the blind loses its performance in winter. Introducing the snow melting system for the preexisting raised blocks for the blind, an experiment study was conducted in order to develop raised blocks for the blind which don't lose its performance in winter. In this article, flexural strength, water absorption ratio, and thermal conductivity of blocks were tested in order to identify the basic performances depending on the materials and properties of insulators and heating cables which are components of raised blocks for the blind. As a result of an experiment, the flexural strength of the concrete blocks was found to be maximum 7.40MPa, which is 1.15 times the flexural strength of the preexisting concrete raised blocks, 6.41MPa, and 1.48 times the KS standard, 5.0MPa. The water absorption ratio of the concrete blocks was found to be maximum 5.09%, which is 1.38 times the water absorption ratio of the preexisting concrete raised blocks and the KSS standard, 7.01% and 7.0%, respectively. The average thermal conductivity of the upper plastic raised blocks was outstanding at 2.45 W/m·k. As a result of an indoor snow melting experiment, they were found to have enough snow melting performances in most domestic regions. However, further outdoor snow melting experiments based on the preexisting study results are considered to be necessary so as to secure enough experimental data.

스티렌-이소프렌-스티렌 블록 공중합체/그래핀 나노복합재료의 혼화성과 물성

이기석(Ki Suk Lee),정한모(Han Mo Jeong) 한국고분자학회 2016 폴리머 Vol.40 No.5

그래핀과 스티렌-이소프렌-스티렌 블록공중합체(SIS)와의 혼화성을 평가하였다. 그래핀은 이소프렌 블록보다는 스티렌 블록과의 혼화성이 좋아, 고분자 중 스티렌 블록의 함량이 많을수록 그래핀의 분산이 양호해지면서, 전기전도성 그래핀에 의해 복합재료의 전기전도도가 효과적으로 향상되었다. 그래핀이 스티렌 블록의 영역에 우선적으로 분포함을 시차주사열량계, 그리고 동적기계적 분석기로 분석한 유리전이온도의 변화로부터 확인할 수 있었다. 그래핀의 투입으로 복합재료의 모듈러스는 크게 향상되었으나, 고분자의 이동성(mobility)이 감소하여 신도, 강인성 등은 크게 감소하였다. The compatibility of graphene with styrene-isoprene-styrene block copolymer (SIS) was examined. The morphology of the SIS/graphene composite observed by optical microscopy and the electrical conductivity of the composite showed that the compatibility of graphene with polystyrene (PS) block is better than that with polyisoprene (PI) block. Thermal analysis showed that the graphene is distributed preferentially at PS block domain rather than at PI block domain. The graphene enhanced the modulus of matrix polymer drastically, however, elongation at break and toughness were reduced evidently.

Synthesis and characterization of multi-block poly(arylene ether sulfone) membranes with highly sulfonated blocks for use in polymer electrolyte membrane fuel cells

Yuk, J.,Lee, S.,Nugraha, A.F.,Lee, H.,Park, S.H.,Yim, S.D.,Bae, B. Elsevier Scientific Pub. Co 2016 Journal of membrane science Vol.518 No.-

We synthesized novel sulfonated poly(arylene ether sulfone)s (SPAESs) multi-block copolymer membranes containing highly sulfonated hydrophilic blocks. Two different kinds of multi-block SPAESs sharing the same structure of hydrophobic blocks were proposed to investigate the membrane properties based on the effects of the hydrophilic blocks bearing sulfonic acids. The higher local concentration and acidity of the sulfonic acid groups in the hydrophilic block induced higher proton conductivity. The block SPAESs showed comparable proton conductivities to those of the state-of-the-art perfluorinated sulfonic acid (PFSA) membranes, and their transmission electron microscopy (TEM) images revealed a well-developed phase separation. In particular, the SPAES 4 X10Y10 membrane showed excellent proton conductivity, which was higher than that of the PFSA over the entire relative humidity (RH) range at 80<SUP>o</SUP>C. Moreover, the multi-block SPAES membranes showed a comparable fuel cell performance to the Nafion membranes, even at 50% and 30% RH.

Comparison of alkaline fuel cell membranes of random & block poly(arylene ether sulfone) copolymers containing tetra quaternary ammonium hydroxides

Hossain, Md.A.,Lim, Y.,Lee, S.,Jang, H.,Choi, S.,Jeon, Y.,Lim, J.,Kim, W.G. Pergamon Press ; Elsevier Science Ltd 2014 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.39 No.6

A series of modified anion conductive block poly(arylene ether sulfone) copolymer membranes containing a selective substituted unit, 15%, 20% and 25% 4,4'-(2,2-diphenylethenylidene) diphenol, were prepared for use in alkaline fuel cells. The anion exchange membranes were synthesized by first introducing chloromethyl groups. Quaternary ammonium groups could then be added to the tetra-phenyl ethylene units, followed by subsequent ion exchange. The tetra quaternary ammonium hydroxide polymers showed high molecular weights and exhibited high solubility in polar aprotic solvents. The block copolymer membrane showed higher ionic conductivity (21.37 mS cm<SUP>-1</SUP>) than the random polymer membrane of similar composition (17.91 mS cm<SUP>-1</SUP>). The membranes showed good chemical stability in 1.0 M KOH solution at 60 <SUP>o</SUP>C. They were characterized by <SUP>1</SUP>H NMR, FT-IR, TGA and measurements of ion exchange capacity, water uptake and ionic conductivity.

Synthesis of poly(3-hexylthiophene)-b-poly (ethyleneglycolmethacrylate) for lithium-ion battery applications

김나경,정다운,이종찬 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Poly(3-hexylthiophene)-b-poly(ethylene glycol) methacrylate was synthesized to obtain the polymer system having both ionic and electronic conductivity. The molecular weight of poly(3-hexylthiophene)(P3HT) and poly(ethyleneglycolmethacrylate) (PEGMA) was controlled by Grignard metathesis and ATRP, respectively. Then, block copolymer containing P3HT and PEGMA was synthesized via click reaction. The structure of the block copolymer was systematically investigated by NMR, GPC and FT-IR. It was found that the ionic conductivity of the block copolymer is 1.5×10^-6 S/cm. We believe that this block copolymer could be a promising cathode material for lithium ion-battery.