• Explosives and Blasting
• /
• v.37 no.4
• /
• pp.10-16
• /
• 2019

Information on overpressure, positive phase duration, and impulse are required to assess the effects of shock waves or pressure waves on the structure. In this study, the overpressure and positive phase duration were determined by applying the Multi-Energy Method, which is found to be effective in analyzing the explosion of vapor clouds. Based on the total heat of combustion estimated in the cyclohexane vapor cloud explosion in the Nypro Ltd(UK), overpressure and positive phase duration at the distance of 40, 80, 120, 160, 200, 240, 280, 320, 360(m) from the source of explosion were evaluated. Overpressure was shown to decrease exponentially and positive phase duration increased almost linearly with distance. A probit function was used to assess the probability of damages for the structures at each distance using the overpressure and impact obtained at the above mentioned distances. The Analyses of probability of damages have shown that there is a high probability of collapse at distances within 120m, major damage to structures within 240m, and minor damage and breakage of window panes of structures occur over the entire distances.

• The Korean Journal of Pain
• /
• v.22 no.1
• /
• pp.33-38
• /
• 2009

Background: Complex regional pain syndrome (CRPS) is still difficult to diagnose in the field of chronic pain management. CRPS is diagnosed by purely clinical criteria based on the characteristic signs and symptoms, which have to be differentiated from similar pain conditions like posttraumatic neuropathic pain. Until now, there has been a lack of objective diagnostic tools to confirm the diagnosis of CRPS. The aim of this study was to evaluate the usefulness of a three phase bone scan (TBS) for making the diagnosis of CRPS. Methods: A total of 121 patients who had been diagnosed with CRPS were evaluated. All the patients were examined by performing a TBS as a part of the diagnostic work-up. A diffuse increased tracer uptake on the delayed image (phase III) was defined as a positive finding for CRPS. Results: Forty-one patients (33.9%) out of 121 showed the positive results on the TBS. The patients with a duration of pain of less than 24 months had a significantly higher positive result (43.4%) on the TBS than did the patients with duration of pain longer than 24 months (12.1%). Conclusions: A TBS could give a better objective result for diagnosing CRPS for patients with a shorter duration of pain and a TBS gives little information for the diagnosis of CRPS in patients with a duration of pain longer than 24 months.

• Korean Journal of Biological Psychiatry
• /
• v.20 no.4
• /
• pp.179-186
• /
• 2013

Objectives This study is designed to compare the clinical characteristics of patients with early onset schizophrenia to those of adult onset schizophrenia patients in first episode. Methods Authors reviewed medical records of 16 early-onset schizophrenia patients and 22 adult-onset schizophrenia patients who had been admitted in the psychiatric ward and diagnosed as schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders, fourth Edition (DSM-IV) at Eulji University Hospital during 2004-2008. Socio-demographic data and clinical characteristics such as duration between onset and active phase, number of significant positive and negative symptoms, positive and negative symptom scores of Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression-Severity (CGI-S) scores, duration from onset to admission, duration of admission, and equivalent dose of antipsychotics were reviewed. These clinical characteristics of early-onset group were compared to those of adult-onset group. Correlation between age of onset and other clinical characteristics was also analyzed. Results Early-onset group showed more insidious onset pattern and had longer duration of hospitalization than adult-onset group. Early onset group also exhibited more negative symptoms, higher negative symptom scores, and higher CGI-S scores than adult-onset group after treatment. However, there were no significant differences in family history of psychosis, positive symptom frequency at discharge and equivalent dose of antipsychotics between two groups. Conclusions This study revealed that patients with early-onset schizophrenia exhibited more insidious onset, more negative symptoms, and more severe symptoms than those with adult-onset schizophrenia after treatment.

• Journal of Korean Medicine Rehabilitation
• /
• v.23 no.4
• /
• pp.159-167
• /
• 2013

Objectives In this study, we wanted to find out the characteristics - gender, SLR test, valsalva test, duration, ESR, CRP and night pain - of lumbar disc herniation being classified as blood stasis and phlegm-retained fluid. Methods We surveyed 42 patients suffering from lumbar disc herniation using the diagnosis blood stasis syndrome, water retention syndrome of the comprehensive diagnosis of QI blood water. Blood stasis and phlegm-retained fluid are identical with blood stasis syndrome, water retention syndrome. Then we analyzed the characteristics - gender, SLR test, valsalva test, duration, ESR, CRP and night pain - of the patients suffering from lumbar disc herniation who were diagnosed as blood stasis and phlegm-retained fluid. Results Patients were sorted into two groups: 18 blood stasis patients and 30 phlegm-retained fluid patients. Gender (Woman), acute phase and night pain are related to blood stasis. Acute phase, positive of SLR test is related to phlegm-retained fluid. There was no correlation between blood stasis and SLR test, valsalva test, duration, ESR, CRP. Also no correlation between phlegm-fluid and gender, valsalva test, duration, ESR, CRP and night pain. Conclusions By Considering the characteristics - gender, SLR test, valsalva test, duration, ESR, CRP and night pain - of lumbar disc herniation patients, it can help to analyze the pattern of its symptoms.

• The Korean Journal of Physiology and Pharmacology
• /
• v.19 no.2
• /
• pp.167-175
• /
• 2015

A retinal prosthesis is being developed for the restoration of vision in patients with retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Determining optimal electrical stimulation parameters for the prosthesis is one of the most important elements for the development of a viable retinal prosthesis. Here, we investigated the effects of different charge-balanced biphasic pulses with regard to their effectiveness in evoking retinal ganglion cell (RGC) responses. Retinal degeneration (rd1) mice were used (n=17). From the ex-vivo retinal preparation, retinal patches were placed ganglion cell layer down onto an $8{\times}8$ multielectrode array (MEA) and RGC responses were recorded while applying electrical stimuli. For asymmetric pulses, 1st phase of the pulse is the same with symmetric pulse but the amplitude of 2nd phase of the pulse is less than $10{\mu}A$ and charge balanced condition is satisfied by lengthening the duration of the pulse. For intensities (or duration) modulation, duration (or amplitude) of the pulse was fixed to $500{\mu}s$($30{\mu}A$), changing the intensities (or duration) from 2 to $60{\mu}A$(60 to $1000{\mu}s$). RGCs were classified as response-positive when PSTH showed multiple (3~4) peaks within 400 ms post stimulus and the number of spikes was at least 30% more than that for the immediate pre-stimulus 400 ms period. RGC responses were well modulated both with anodic and cathodic phase-1st biphasic pulses. Cathodic phase-1st pulses produced significantly better modulation of RGC activity than anodic phase-1st pulses regardless of symmetry of the pulse.

• Journal of the Korean Applied Science and Technology
• /
• v.25 no.2
• /
• pp.211-218
• /
• 2008

The performance of positive plates depends on the structure of the lead dioxide active mass. The positive active materials (PAM) consists of a skeleton, built up of agglomerates and macropores. Agglomerates, in their turn, comprise particles and micropores. This paper described a study conducted to determine the effects of different soaking times between the acid fill and formation stages of the tubular plate production. For the positive plates a lead oxide were filled into tubular bag with a red lead. After filling the positive plates were soaked in $H_2SO_4$ solution. X-ray diffraction(XRD), scanning electron microscopy(SEM) and electrical testing had been used to study the compositional and morphological aspects of the positive active material(PAM) just prior and after formation. Results indicate that PAM compositions were effected by the soaking time and acid density of $H_2SO_4$ solution. It can be seen that as the soaking time duration increases, $\alpha$-PbO, $Pb_3O_4$, and Pb were all gradually sulphating. Composition of 3BS reached a maximum at around 3 h duration and $H_2SO_4$ of sp. gr. 1.10 on soaking. This results would suggest that the most beneficial conditions for soaking were the $H_2SO_4$ of sp. gr. 1.10 and 2 to 6 h of soaking.

• Nuclear Engineering and Technology
• /
• v.53 no.9
• /
• pp.2926-2936
• /
• 2021

Rare-earth (RE) industries generate a massive amount of radioactive residue containing high thorium concentrations. Due to the fact that thorium is considered a non-economic element, large volume of these RE processed residues are commonly disposed of without treatment. It is essential to study an appropriate treatment that could reduce the volume of waste for final disposition. To this end, this research investigates the applicability of carbon-based adsorbent in separating thorium from aqueous phase sulphate is obtained from the cracking and leaching process of solid rare-earth by-product residue. Adsorption of thorium from the aqueous phase sulphate by carbon-based electrodes was investigated through electrosorption experiments conducted at a duration of 180 minutes with a positive potential variable range of +0.2V to +0.6V (vs. Ag/AgCl). Through this research, the specific capacity obtained was equivalent to 1.0 to 5.14 mg-Th/g-Carbon. Furthermore, electrosorption of thorium ions from aqueous phase sulphate is found to be most favorable at a higher positive potential of +0.6V (vs. Ag/AgCl). This study's findings elucidate the removal of thorium from the rare-earth residue by carbon-based electrodes and simultaneously its potential to reduce disposal waste of untreated residue.

• Clinical and Experimental Pediatrics
• /
• v.61 no.5
• /
• pp.160-166
• /
• 2018

Purpose: This study aimed to analyse laboratory values according to fever duration, and evaluate the relationship across these values during the acute phase of Kawasaki disease (KD) to aid in the early diagnosis for early-presenting KD and incomplete KD patients. Methods: Clinical and laboratory data of patients with KD (n=615) were evaluated according to duration of fever at presentation, and were compared between patients with and without coronary artery lesions (CALs). For evaluation of the relationships across laboratory indices, patients with a fever duration of 5 days or 6 days were used (n=204). Results: The mean fever duration was $6.6{\pm}2.3days$, and the proportions of patients with CALs was 19.3% (n=114). C-reactive proteins (CRPs) and neutrophil differential values were highest and hemoglobin, albumin, and lymphocyte differential values were lowest in the 6-day group. Patients with CALs had longer total fever duration, higher CRP and neutrophil differential values and lower hemoglobin and albumin values compared to patients without CALs. CRP, albumin, neutrophil differential, and hemoglobin values at the peak inflammation stage of KD showed positive or negative correlations each other. Conclusion: The severity of systemic inflammation in KD was reflected in the laboratory values including CRP, neutrophil differential, albumin, and hemoglobin. Observing changes in these laboratory parameters by repeated examinations prior to the peak of inflammation in acute KD may aid in diagnosis of early-presenting KD patients.

• Explosives and Blasting
• /
• v.35 no.1
• /
• pp.1-17
• /
• 2017

The understanding of the pressure associated with air blast, which travels through air, and its effect on surface and underground structures is highly important. It is necessary to determine the pressure change with time and distance for a computer simulation of the explosion impact on a structure. From the previous studies, many empirical equations for estimating the parameters related to the pressure change. In this study, the empirical equations for predicting peak overpressure, duration of positive phase, impulse, minimum negative pressure, duration of negative pressure, arrival time, and decay constant were reviewed and analyzed. Also, the pressure changes predicted from the Kingery equation, which is the most commonly used, and from the other empirical equations were compared.

• Korean Journal of Applied Biomechanics
• /
• v.15 no.3
• /
• pp.9-19
• /
• 2005

The purpose of this study was to analyze the effects of three different types of preparatory movement(squat, countermovement and hopping) in sideward responsive propulsion movement. 7 healthy subjects performed left and right side movement task by external output signal. 3D kinematics were analyzed The results were followed First, performance time in the countermovement and hopping conditions was shorter(10-20%) than that in the squat condition. The hopping condition that is more related to pre-stretch showed excellent performance. Second, time difference between after turned on the external signal and until take off was the primary factor in performance results among movement conditions. The preparatory phase before the propulsive phase in the squat condition produced more time than that in other conditions. The hopping condition showed the most short time in both the preparatory and the propulsive phase, therefore it was advantage for performance result Third, significant difference was not found in take-off velocity among movement conditions although there was difference of the time required in the propulsive phase. The maximum acceleration in the propulsive phase was larger in order of the hopping. countermovement, and squat condition. The countermovement and hopping conditions showed high take-off velocity although the propulsive phase in those conditions was shorter than that in squat condition. The pre-stretch by preparatory countermovement was considered as the positive factor of producing power in concentric contraction. Fourth, the hopping condition produced large angular velocity of joints. In hopping condition, large amount of moment for rotation movement was revealed in relatively short time and it was considered to cause powerful joint movements. In conclusion, the hopping movement using countermovement is advantage of responsive propulsion movement. It is resulted from short duration until take off and large amount of joint moment and joint power in concentric contraction by pre-stretch.