• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.206-209
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• 2000

A wavelength stabilized high power CW DFB LD module was designed and fabricated for use in externally modulated, Dense Wavelength Division Multiplex (DWDM) systems. A simple, compact wavelength monitoring technology using a thin solid Etalon and PD array assembly was developed for a low cost wavelength stabilized DFB LD module. Also, the excellent module have high power characteristic of 13.5 mW in CW 100 mA current injection with high optical coupling coefficient over 43%. r 43%.

• Korean Journal of Radiology
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• v.22 no.3
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• pp.366-375
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• 2021

Objective: To evaluate the radiological tumor response patterns and compare the response assessments based on immune-based therapeutics Response Evaluation Criteria in Solid Tumors (iRECIST) and RECIST 1.1 in metastatic clear-cell renal cell carcinoma (mccRCC) patients treated with programmed cell death-1 (PD-1) inhibitors. Materials and Methods: All mccRCC patients treated with PD-1 inhibitors at Henan Cancer Hospital, China, between January 2018 and April 2019, were retrospectively studied. A total of 30 mccRCC patients (20 males and 10 females; mean age, 55.6 years; age range, 37-79 years) were analyzed. The target lesions were quantified on consecutive CT scans during therapy using iRECIST and RECIST 1.1. The tumor growth rate was calculated before and after therapy initiation. The response patterns were analyzed, and the differences in tumor response assessments of the two criteria were compared. The intra- and inter-observer variabilities of iRECIST and RECIST 1.1 were also analyzed. Results: The objective response rate throughout therapy was 50% (95% confidence interval [CI]: 32.1-67.9) based on iRECIST and 30% (95% CI: 13.6-46.4) based on RECIST 1.1. The time-to-progression (TTP) based on iRECIST was longer than that based on RECIST 1.1 (median TTP: not reached vs. 170 days, p = 0.04). iRECIST and RECIST 1.1 were discordant in 8 cases, which were evaluated as immune-unconfirmed PD based on iRECIST and PD based on RECIST 1.1. Six patients (20%, 6/30) had pseudoprogression based on iRECIST, of which four demonstrated early pseudoprogression and two had delayed pseudoprogression. Significant differences in the tumor response assessments based on the two criteria were observed (p < 0.001). No patients demonstrated hyperprogression during the study period. Conclusion: Our study confirmed that the iRECIST criteria are more capable of capturing immune-related atypical responses during immunotherapy, whereas conventional RECIST 1.1 may underestimate the benefit of PD-1 inhibitors. Pseudoprogression is not rare in mccRCC patients during PD-1 inhibitor therapy, and it may last for more than the recommended maximum of 8 weeks, indicating a limitation of the current strategy for immune response monitoring.

• Transactions on Electrical and Electronic Materials
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• v.7 no.6
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• pp.313-318
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• 2006

This paper introduces a partial discharge (PD) severity metric, S, based on the evaluation of time-sequence PD data capture and resulting Time-Sequence-Analysis Discharge (TSAD) level distributions. Basically based on an IEC60270 measurement technique, each PD event is time stamped and the discharge level noted. By evaluating the time differences between a previous and subsequent discharge, a 3D plot of time-sequence activity and discharge levels can be produced. From these parameters a measurement of severity, which takes into account dynamic or instantaneous variations in both the time of occurrence and the level of discharge, rather than using standard repetition rate techniques, can be formulated. The idea is to provide a measure of the severity of PD activity for potentially measuring the state of insulation within an item of plant. This severity measure is evaluated for a simple point-plane geometry in $SF_{6}$ as a function of gap distance and applied high voltage. The results show that as the partial discharge activity increases, the severity measure also increases. The importance of future investigations, quantifications and evaluations of the robustness, sensitivity and importance of such a severity measurement, as well as comparing it with typical repetition rate assessment techniques, and other monitoring techniques, are also very briefly discussed.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.22-30
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• 2019

Background: Piton du Milieu (PdM) impounding reservoir is suspected to be eutrophic based on the elevated level of orthophosphate and nitrate. Water supplies from three adjacent rivers are primarily thought to contribute to the nutrient enrichment of the reservoir. It is also suspected that there is leaching of orthophosphate, nitrate and organic matter into the rivers during rainfall events and also as a result of anthropogenic activities within the catchment area. The aim of this study was to ascertain the impact of nutrient loading on the water quality of PdM water and on the population of freshwater microalgae in the reservoir. The enumeration and identification of algae from PdM were performed by differential interference contrast microscopy. Dissolved oxygen (DO) and pH were determined by electrometric methods, whereas nutrient levels, silica and total organic carbon (TOC) were determined by instrumentation techniques. Results: Annual mean orthophosphate, nitrate and total organic carbon input from the three feeders within the catchment area of PdM reached levels as high as 0.09 mg/L, 0.4 mg/L and 2.62 ppm respectively. Over a 12-month period, mean TOC concentration in the reservoir was 2.32 ppm while the mean algal cell count was 4601 cells/mL. The dominant algal species identified were Oscillatoria, Cyclotella, Navicula and Cosmarium. Conclusion: This study highlights the trophic state of the reservoir water and clearly points to the need for constant monitoring in order to avoid the occurrence of an impending harmful algal bloom.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.203-209
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• 2017

Research on condition monitoring and diagnosis of power facilities has been conducted to improve the safety and reliability of electric power supply. Although insulation diagnostic techniques for unit equipment such as gas-insulated switchgears and transformers have been developed rapidly, studies on monitoring of cables have only included aspects such as whether defects exist and partial discharge (PD) detection; other characteristics and features have not been discussed. Therefore, this paper dealt with PD characteristics against void sizes and positions, and with defect localization in XLPE cable. Four types of defects with different sizes and positions were simulated and PD pulses were detected using a high frequency current transformer (HFCT) with a frequency range of 150kHz~30MHz. The results showed that the apparent charge increased when the defect was adjacent to the conductor; the pulse count in the negative half of the applied voltage was about 20% higher than that in the positive half. In addition, the defect location was calculated by time-domain reflectometry (TDR) method, it was revealed that the defect could be localized with an error of less than1m in a 50m cable.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2066-2068
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• 2005

We developed an on-line Ultra-high frequency partial discharge monitoring system to prevent a catastrophic failure of gas- insulated switchgears. The system has been tested in the laboratory for detection of various UHF PD signals. We also performed detection sensitivity verification tests and compared them with conventional IEC60270 method.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1894-1896
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• 2003

In this paper, a novel monitoring system, data acquisition & diagnosis unit (DADU), for high-voltage rotating machines is proposed. This system monitors the insulation condition, current, voltage, vibration, and temperature of the stator winding by on-line measurements of partial discharge (PD), flux, etc. This helps more efficient operation and maintenance of the rotating machines.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.112-116
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• 2004

On-line monitoring of fault discharge is an important approach for indicating the condition of electrical insulation of stator winding in high voltage motor. In this paper, several key aspects of on-line monitoring system are discussed, involving the characteristics of fault discharge of stator winding in high voltage motor, spectrum analysis of four simulation fault signals, feature extraction of internal fault discharge from apply voltage to breakdown. The study of the partial discharge activities allows to highlight the ageing stage in the winding fault under test. During the life of the winding insulation fault, the shape of PD signal change relating to the ageing stage. The ageing of stator winding insulation fault of high voltage motor is investigated based on the characteristics of partial discharge pulse distribution and statistical parameters, such as maximum, skewness and kurtosis using discrete wavelet transform coefficients.

• Journal of the Korean Magnetic Resonance Society
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• v.7 no.1
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• pp.1-15
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• 2003

PURPOSE - To investigate neurometabolism from the brain destructive lesions and striatal putamen-pallidus regions to the clinically worst side in patients with Parkinson's disease after stereotactic functional neurosurgery. METHODS - Using proton magnetic resonance spectroscopy ($^1$H MRS), fifteen patients (7 males and 8 females; mean age 56.5 years; age range 43-67 years) with Parkinson's disease (PD) were studied to measure N-acetylaspartate (NAA), creatine (Cr), choline-containing compounds (Cho) and lactate (Lac) levels on the neurosurgical lesions of thalamus, globus pallidus and striatal putamen-pallidus regions in a brain. RESULTS - Brain destructive lesion and striatal putamen-pallidus region in PD compared with controls were highly and significantly related to NAA/Cho ratios reduction, respectively (P =0.002, P =0.04), but showed no difference from the same regions of PD prior to neurosergery (P =0.06, P =0.77). Increased lactate peaks at 1.3 ppm were present in all the cerebral lesions, and these resonances were confirmed at a long TE =136 ms, indicating that these signals distinguished from lipids. CONCLUSIONS - Our results suggest that NAA/Cho ratios may provide as a neurometabolite marker for neurochemical changes in brain surgical lesion, and the ratios might be related to functional change of neuropathophysiological status in the striatal putamen-pallidus region of PD. Increase of lactate signals, being remarkable in surgical lesions, could be consistent with a common consequence of surgical necrosis. Therefore, MR spectroscopy could be a sensitive diagnostic tool in monitoring neurometabolic changes in PD with neurosurgical treatment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.1056-1060
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• 2012

Online monitoring system is becoming an essential element of railway traction system for utilized to condition based malignance management and various techniques currently employed in railway traction system. Among the various techniques, it is efficient to detect partial discharge signals by electromagnetic wave detection in order to detect insulation fault of rectifier. Although VHF (Very High Frequency), UHF (Ultra High Frequency) sensors were adopted to detect partial discharge of power facilities, due to characteristics of urban railway, excessive noise occurs from 500 MHz to 1.5 GHz on UHF bandwidth. In this paper a new measurement system able to monitoring the conditions of power facilities on DC substation in metro was studied and set up. The system uses UHF sensors to measure the partial discharge of the rectifier due to electric faulting and dielectric breakdown. Comparison and estimation for performance of SHF sensor which had devised to detect partial discharge signal of urban railway rectifier has conducted. In order to estimate performance of SHF sensor, we have compared the sensor with existing UHF sensor on sensitivity upon frequency bandwidth generated by pulse generator, and also we have verified performance of the SHF sensor by detection results of partial discharge signal from urban railway rectifier.