동함유 제올라이트상에서 일산화탄소의 산화반응

이창용,서곤,하백현,최고열 한국화학공학회 1989 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.27 No.2

이온 교환 및 담지에 의해 제조한 동함유 제올라이트 촉매상에서 일산화탄소의 산화반응을 실시하였다. 수소형 모더나이트(HM)과 이를 열처리 및 염화암모늄 용액으로 이온 교환을 반복 실시하여 부분적으로 탈알루미늄된 모더나이트(HM#), 그리고 HY를 질산구리 용액으로 이온 교환하여 동의 함량을 달리하는 이온 교환 촉매를 얻었다. 또한 HY, HM# 및 HZSM-5에 1 wt%의 동 및 백금을 담지시켜 이들과 이온 교환 촉매의 활성을 비교하였다. 일산화탄소의 산화반응에 대한 이온 교환 촉매의 활성은 동의 함량에 따라 증가하였으며 또 동의 원자가 상태가 Cu(II)<Cu(I)<Cu(0)의 순으로 증가하였다. 또한 이온 교환 촉매의 활성은 제올라이트 구조내의 실리카-알루미나 비에 의해서도 영향을 받는 것으로 생각된다. 즉, 부분적인 탈알루미늄에 의해 실리카-알루미나 비가 커진 CuHM#가 가장 큰 활성을 보였다. 동이 담지된 촉매는 같은 양의 동이 이온 교환된 촉매보다 더 큰 활성을 보였다. 또한 담지 촉매에서도 이온 교환 촉매와 마찬가지로 구조내의 실리카-알루미나의 비가 증가함에 따라 활성은 증가하였다. 또한 Cu(0)의 경우 환원으로 인해 생성된 금속 동이 제올라이트 결정 표면에 편재하게 되어 활성을 증가시키기 때문으로 생각된다. The oxidation of carbon monoxide was carried out on the copper zeolites prepared by ion exchange and impregnation. Hydrogen mordenite(HM), partially dealuminated mordenite(HM#) obtained by repeating thermal treatment as well as ammonium ion-exchange and HY were ion-exchanged in cupric nitrate solution to get the copper zeolites having various level of copper content. HY, HM#, and HZSM-5 were impregnated with copper or platinum in 1 wt% and the activities of these impregnated catalysts were compared with those of ion-exchanged ones. The activities of ion-exchanged catalysts for the oxidation of carbon monoxide increased with an increase in the copper containing level of the catalysts, but decreased with an increase in the valence state of the copper [i.e., Cu(0)>Cu(I)>Cu(II)]. It is considered that the activity of ion-exchanged catalysts is affected by the silica-alumina ratio of the zeolite structure. Partially dealuminated copper mordenite showed highest activity among the catalysts. The impregnated catalyst was more active than the ion-exchanged one at the same level of copper content. The activity of impregnated catalysts also increased as their silica-alumina ratio of the structure increased as the same as the ion-exchanged catalysts. The higher activity for Cu(0) could be also explained by the increase of copper concentration on the surface of zeolite.

Design of Interface IP for Automotive I/O Control on SoC FPGA

이창용,이용환 한국정보기술학회 2024 한국정보기술학회논문지 Vol.22 No.1

In order to control various input/output devices of automobiles, we simultaneously design interface IP H/W and driving S/W on Zynq SoC FPGA, which combines MCU and FPGA, to be advantageous in terms of noise, heat generation, and speed. To control analog and digital input/output data for automobile control at high speed, each of ADC, DAC, and DI/O is made into IP, and the user controls it using ARM programming through AXI bus. For verification, the chips mounted on the control board were modeled and the designed IP was connected and simulated. After connecting the control board and the Zynq board together, the desired operation was ensured by checking the register map of the PS area and measuring the actual waveform using an oscilloscope. It was confirmed that the maximum error rate between the input ADC data and the calculated data was 0 to 0.65 percent depending on the voltage level. The DAC's output data showed that most signals met the standard level of output, and at high voltage levels, an error rate of up to 1.67% was observed.

한국의 외환위기 : 외환위기의 발생 및 발생 과정

이창용 국제무역경영연구원 1997 텔코경영연구원 연구총서 Vol.64 No.-

Characteristics of urinary retention in female inpatients managed with medical treatments

이창용,김철성,조원진 대한비뇨의학회 2015 Investigative and Clinical Urology Vol.56 No.12

Purpose: We aimed to analyze the characteristics of urinary retention (UR) in female inpatients managed with medical treatments. Materials and Methods: We retrospectively analyzed the medical records of female inpatients referred to the department of urology for UR at our institution from January 2009, to December 2014. UR was defined as a difficulty in self-voiding despite a sufficient urine volume or >300-mL postvoid residual. The data included patients' age, body mass index (BMI), ambulatory status, medical and surgical history, classes of taking drugs, and urinary tract infection. Results: A total of 182 women were included as retention group, mean age of 72.64±12.94 years and BMI of 22.94±3.10 kg/m2. In the chi-square analysis, cardiovascular disorders (p=0.000), diabetes mellitus (p=0.008), metastatic malignancy (p=0.008), chronic renal disorders (p=0.028) were found significantly. In the multiple logistic regression analysis, cardiovascular disorders (p=0.002; odds ratio [OR], 0.491), metastatic malignancy (p=0.013; OR, 2.616) were found to increase the risk of UR. The most common surgical history was anti-incontinence surgery (7.2%). In term of medication use, the most prescribed agents were nonsteroidal anti-inflammatory drugs (NSAIDs) (53.8%). The patients taking multiple drugs with antimuscarinic effects except of NSAIDs, narcotics and diuretics were 48 (26.4%). Urinary tract infection was identified in 43 patients (23.6%). Conclusions: UR in females managed with medical treatments could be occurred occasionally. We think that thorough attentions are needed for UR to patients with cardiovascular disorders including diabetes mellitus, metastatic malignancy, chronic renal disorders urinary tract infection, and more careful interests when managing with drugs with antimuscarinic effects.

Statistical self-similar properties of complex networks

이창용 AMER PHYSICAL SOC 2006 PHYSICAL REVIEW E - Vol.73 No.6

Networks of interactions in the secondary and tertiary structure of ribosomal RNA

이창용 ELSEVIER SCIENCE BV 2007 PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIO Vol.386 No.1

Inverse Statistics of the Korea Composite Stock Price Index

이창용,황인극,김진호 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.2

We empirically investigate the inverse statistics of the Korea Composite Stock Price Index (KOSPI) from March of 1992 to February of 2007. We, in particular, study the probability distribution of the first passage time in the KOSPI. We find that the first passage time approximately follows either a power-law distribution or a distribution having an optimal value, depending on the return level. Using the wavelet transformation, we further analyze the KOSPI by decomposing it into the trend and the detrend, i.e., fluctuation around the trend. In the case of the detrend time series, we find that, for all return levels, the first passage time follows a power-law distribution with an exponent α~3/2, which suggests that the result can be partially understood as a consequence of an unbiased random Brownian motion. In the case of the trend, there exists an optimal value of the first passage time; furthermore, the optimal value is correlated with the return level in a power-law fashion. Some results of the inverse statistics of the KOSPI are different from those of other well-known financial index, such as the DJIA and the S&P500.

Development and Application of Technology Intelligence Methods Using Patent Information

이창용 대한산업공학회 2011 대한산업공학회 추계학술대회논문집 Vol.2011 No.11

Characteristics of Volatility in Data Network Traffic

이창용 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.6

We investigated the characteristics of data network traffic obtained from a wide-area computer network. We, in particular, adopted the volatility, a well-established concept in financial market analysis, to the time series of the RTT (round trip time), and empirically analyzed the volatility from the perspective of statistical physics. We found that the volatility followed a log-normal distribution regardless of the window size. We further found that the volatility exhibited a multi-fractal property,which implied that different values of the volatility had different scaling strengths. Based on the log-normal distribution and the multi-fractal nature of the volatility, we showed that the volatility in the data traffic of a wide-area network could be described by a random multiplicative process.

Characteristics of Traded Volume in the Korean Composite Stock Price Index

이창용 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.2

We quantitatively investigate the characteristic of the time series of the traded volume in the Korean Composite Stock Price Index from November 1997 to September 2010. We find that the probability distribution of the traded volume approximately displays a log-normal distribution with a power law in the tail region. Motivated by the long tail of the distribution, we show that the traded volume exhibits a multi-fractal property. We further confirm, by a random shuffling of the time series data, that the multifractality of the traded volume is ascribed to the probability distribution of traded volumes and has little to do with the time correlation among them. This enables a description at least partly, if not entirely, of the multifractality by using a random multiplicative process. We also show that the time series of the traded volume displays a long-range persistence. By analyzing the time series of the absolute differences of the traded volume with various window sizes, we find that the time series shows different characteristics depending on the window size.