회수수에 당류계 안정화제를 처리한 시멘트 모르터의 특성

金虎林,우종완,한민철,류현기,한천구 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

In this paper, fundamental properties of cement mortar using recycled water with stabilizing agent are discussed in order to investigate the applicability of recycled water. Stabilizing agent content, solid contents and open time are varied in this paper. For fresh mortar properties, highest fluidity with 0.15% of stabilizing agent was observed and air content was increased with an increase in stabilizing agent contents. Solid contents and open time of recycled water had nothing to do with fluidity and air content loss. Little difference in setting time was found with the presence of stabilizing agent and without, while it was accelerated with an increase in open time and solid content. For strength properties, the highest strength value was observed at 0.15% of stabilizing agent. An increase in solid contents resulted in an enhancement of strength, while strength decreased with an increase in open time and elapse of age. Drying shrinkage exhibited a reduction with an increase in stabilizing agent contents and open time. From the present paper, the combination of 0.15% of sacharic based stabilizing agent, 3% of solid content and 1day of open time is found to be an optimal condition to perform effectively.

국내 레미콘사의 부순모래 사용실태 조사

김기훈,金虎林,金光華,윤기원,한천구 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

Crushed sand is made by crushing the rock artificially. With the wide shortage of natural fine aggregates at all regions in Korea. crushed sand has been increasingly consumed as a alternative aggreagtes of natural sand. But there is insufficient information related to the actual situation on the produce. quality and manufacturing company of crushed sand. In this paper. survey is performed in order to know actual consumption situation of crushed sand through ready mixed concrete company in domestic. The remicon companies using crushed sand were estimated with 55%. According to the using method of crushed sand. most remicon company used fine aggregates by mixing natural sand and crushed sand. It is found that natural sand is replaced by crushed sand by about 20~50%. For quality problems in using crushed sand. grain shape. grade and fine particles shall be improved to meet the quality requirement of remicon and wide application. Therefore. it is found that quality improvement of crushed sand is required.

회수수에 처리되는 당류계 안정화제의 혼입률 변화가 콘크리트의 품질에 미치는 영향

文學龍,金虎林,우종완,한민철,한천구 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

The objective of present paper is to investigate the engineering properties of concrete using recycling water incorporating saccharic based stabilizing agent in order to improve qualities of concrete in the region of normal strength and high strength. According to test results, fluidity and air content do not exhibit significant difference with an increase in stabilizing agent contents. Bleeding was not observed at 30% of W Ie, regardless of stabilizing agent contents, nonetheless, concrete with stabilizing agent of 0.15% was observed to occur the least bleeding at 40 and 50% of W IC. For setting time, although presence of recycled water accelerates setting time, setting time shows to be retarded gradually with an increase in stabilizing agent content. For compressive strength, use of stabilizing agent enhanced compressive strength of concrete compared with that of concrete without stabilizing agent. In the side of strength enhancement, adequate dosage of stabilizing agent is found to be 0.15%. As dosage of stabilizing agent increased above 0.15%, drying shrinkage exhibited a tendency to decrease.

Influence of Intravenous Contrast Medium on Dose Calculation Using CT in Treatment Planning for Oesophageal Cancer

Li, Hong-Sheng,Chen, Jin-Hu,Zhang, Wei,Shang, Dong-Ping,Li, Bao-Sheng,Sun, Tao,Lin, Xiu-Tong,Yin, Yong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.3

Objective: To evaluate the effect of intravenous contrast on dose calculation in radiation treatment planning for oesophageal cancer. Methods: A total of 22 intravein-contrasted patients with oesophageal cancer were included. The Hounsfield unit (HU) value of the enhanced blood stream in thoracic great vessels and heart was overridden with 45 HU to simulate the non-contrast CT image, and 145 HU, 245 HU, 345 HU, and 445 HU to model the different contrast-enhanced scenarios. 1000 HU and -1000 HU were used to evaluate two non-physiologic extreme scenarios. Variation in dose distribution of the different scenarios was calculated to quantify the effect of contrast enhancement. Results: In the contrast-enhanced scenarios, the mean variation in dose for planning target volume (PTV) was less than 1.0%, and those for the total lung and spinal cord were less than 0.5%. When the HU value of the blood stream exceeded 245 the average variation exceeded 1.0% for the heart V40. In the non-physiologic extreme scenarios, the dose variation of PTV was less than 1.0%, while the dose calculations of the organs at risk were greater than 2.0%. Conclusions: The use of contrast agent does not significantly influence dose calculation of PTV, lung and spinal cord. However, it does have influence on dose accuracy for heart.

Portable Laser Doppler Flowmeter for Microcirculation Detection

Chang-Lin Hu,Meng-Lin Li,Zhan-Sheng Lin,Yen-Yu Chen,Yuan-Hsiang Lin 대한의용생체공학회 2013 Biomedical Engineering Letters (BMEL) Vol.3 No.2

Purpose The microcirculatory system of the human body is closely related to its physiological conditions. The laser Doppler flowmeter can detect symptoms through variations in the microcirculation; however, the present commercial Doppler flowmeter is very expensive, heavy, and inconvenient to carry. Therefore, an inexpensive, small, and portable laser Doppler flowmeter is proposed. Methods In this study, we designed a laser Doppler flowmeter transmitting receiving module based on the fundamental principles of laser Doppler, using a common computer for flow calculation. A self-designed correction system was used to validate the portable laser Doppler flowmeter. Results The coefficient of correlation between the mean frequency offset <ω> of the flowmeter and the actual mimicked blood flow rate reached a high value of R = 0.99, and the variations in microcirculation flow could be accurately measured. Conclusions The results proved that the low-cost portable laser Doppler flowmeter can be used extensively in early symptom detection for disease prevention and control.

The impact of oxygen supply flow rates on the distribution of aerosols between the patient and the surgeon during lung intubation

Lin Tee,Zargar Omid Ali,Hu Ming-Hsuan,Wang Chung-Chun,Hu Shih-Cheng,Leggett Graham 대한설비공학회 2022 International Journal of Air-Conditioning and Refr Vol.30 No.1

The outbreak of COVID-19 has caused a worldwide pandemic. The widespread infection of the medical staff has caused great attention from all quarters of society. There is a particular concern when considering intubation treatment in the emergency operating room, where a significant amount of virus droplets are typically spread within the room, exposing the medical staff to a high risk of infection. Hence, there is currently a pressing need to develop an effective protection mechanism for the medical staff to prevent them from being infected during routine work. In order to understand the spread of droplets and aerosols when different oxygen supply devices are used for intubation therapy, this study uses particle image velocimetry (PIV) technology to analyze the airflow distribution between the medical staff and the patient. In the experiment, a simple version of the respirator was established to reproduce the breathing of human lungs. This model used oil to create smoke as a tracer aerosol, then a high-sensitivity camera was used to record the scattering light from this smoke (which is irradiated by the green laser sheet). Ultimately, after applying post-processing techniques, the airflow distribution is analyzed. PAO aerosol is the primary aerosol source in this experiment, and it is used to quantify the patient’s breathing; the concentration of PAO aerosol was measured at three different points: head, trunk, and feet. In addition, flow field visualization can effectively present the flow field distribution of the entire operating room; also, the results can be mutually verified with the PAO concentration measurement results. Aerosol concentrations were measured for six different oxygen supply devices with various tidal volumes of the artificial respirator, and the results were ranked from high to low concentrations for different oxygen supply devices and their operational oxygen supply flowrates: HFNC (70 l/min) > CPAP (40 l/min) > HFNC (30 l/min) > nasal cannula (15 l/min) > NRM (15 l/min) > VAPOX (28 l/min).

STABILITY OF THE MILSTEIN METHOD FOR STOCHASTIC DIFFERENTIAL EQUATIONS WITH JUMPS

Hu, Lin,Gan, Siqing The Korean Society for Computational and Applied M 2011 Journal of applied mathematics & informatics Vol.29 No.5

In this paper the Milstein method is proposed to approximate the solution of a linear stochastic differential equation with Poisson-driven jumps. The strong Milstein method and the weak Milstein method are shown to capture the mean square stability of the system. Furthermore using some technique, our result shows that these two kinds of Milstein methods can well reproduce the stochastically asymptotical stability of the system for all sufficiently small time-steps. Some numerical experiments are given to demonstrate the conclusions.

Effects of dietary energy and crude protein levels on growth performance, blood profiles, and nutrient digestibility in weaning pigs

Lin Hu Fang,Ying Hai Jin,도성호,홍진수,김병옥,한태희,김유용 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.4

Objective: This experiment was conducted to investigate the effect of reducing dietary metabolic energy (ME) and crude protein (CP) levels on growth performance, blood profiles, and nutrient digestibility in weaning pigs. Methods: A total of 240 crossbred pigs (Duroc×[Landrace×Yorkshire]) with an average body weight of 8.67±1.13 kg were used for a 6-week feeding trial. Experimental pigs were allotted to a 2×3 factorial arrangement using a randomized complete block design. The first factor was two levels of dietary ME density (low ME level, 13.40 MJ/kg or high ME level, 13.82 MJ/kg) and the second factor was three dietary CP levels based on subdivision of early and late weaning phases (low CP level, 19.7%/16.9%; middle CP level, 21.7%/18.9%; or high CP level, 23.7%/20.9%). Results: Over the entire experimental period, there were no significant difference in body weight among groups, but a decrease in diet energy level was associated with an increase in average daily feed intake (p = 0.02) and decrease in gain-feed ratio (G:F) ratio (p<0.01). Decreased CP levels in the diet were associated with a linear increase in average daily gain (p< 0.05) and quadratic increase in G:F ratio (p<0.05). In the early weaning period, blood urea nitrogen concentration tended to increase when ME in the diet decreased and decrease when CP level in the diet decreased (p = 0.09, p<0.01, respectively). Total protein concentration tended to increase when CP level was reduced (p = 0.08). In the late weaning period, blood urea nitrogen concentration decreased linearly as CP level decreased (p<0.01). The CP and crude fat digestibility decreased when ME was decreased by 0.42 MJ/kg (p = 0.05, p = 0.01, respectively). The CP digestibility increased linearly as CP level decreased (p = 0.01). Conclusion: A weaning pig diet containing high ME level (13.82 MJ/kg) and low CP level (19.7%/16.9%) can improve pig growth performance and nutrient digestibility.

A Voronoi path planning extracted from improved skeleton for dynamic environments

Lin Jiang,Jun Li,Yuxin Hu,Feng Pan,Jianyang Zhu,Bin Lei,Rui Lin 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

Aiming at the problems that the robot being in the process of navigation cannot meet the requirements of real-time and accuracy at the same time, moreover is too close to obstacles and lacks the initiative to avoid obstacles, a Voronoi diagram algorithm for improved skeleton extraction suitable for dynamic environment is proposed. On the one hand, firstly the grid map is preprocessed by binarization, corrosion and expansion, so the reduced skeleton map suitable for navigation is obtained, then the reduced skeleton map is extracted for searching the global path, finally the improved cubic spline smoothing algorithm is used to optimize the global path each planned, thus overcoming the defects of bloated and tortuous in the path obtaining by original Voronoi diagram algorithm. On the other hand, the position information of all obstacles is obtained by a single scan lidar. Firstly, segmenting and linearly fitting all laser point clouds to remove the known obstacles in the map. Then to mark new possible dynamic obstacles with circles of appropriate size. Secondly detecting dynamic obstacles by the alteration of their center coordinates, moreover, solving their motion equations. Finally expanding the cost map along the speed direction of dynamic obstacles and combining DWA dynamic window method to realize dynamic obstacle avoidance. Compared with the original DWA algorithm, it can predict the motion state of dynamic obstacles in advance, which improves the safety of the robot in the dynamic environment. Moreover, the effectiveness of the algorithm is verified by many simulation experiments and real environment experiments.

Synthesis of Some Biologically Active Halogenopurines

Hu, Yu Lin,Liu, Xiang,Lu, Ming,Ge, Qiang,Liu, Xiao Bin Korean Chemical Society 2010 대한화학회지 Vol.54 No.4

A series of some biologically active halogenopurines were synthesized from commercially available guanine (1). The reaction of guanine with acetic anhydride yielded 2,9-diacetylguanine (2-1) by acetylation reaction. Further treatment of 2-1 with $POCl_3$ by PEG-2000 phase transfer catalysis furnished the important compound 3a, then 2-amino-6-halogenopurines (3b-d) were obtained through chlorine-exchange halogenations between KX and 3a by TPPB phase transfer catalyst. Further, 2-halogenopurines (2-2a-d, 4-2a-d, 5a-d) were efficiently prepared from 2-amino-6-substituted purines (1, 3a, 4-1) via a diazotization catalyzed by their corresponding CuX, and some new compounds 2-2a, 2-2c, 2-2d, 4-2c, 4-2d, 5b, 5c and 5d have been discovered. The structures of synthesized compounds were mainly established on the basis of their elemental analysis, $^1H$ NMR, as well as their mass spectral data. All the title compounds were screened for their antifungal activities, and some of the compounds showed promising activity. Guanine (1)으로부터 생물활성이 있는 halogenopurines계 화합물을 합성하였다. Guanine을 acetic anhydride와 반응시켜서 2,9-diacetylguanine (2-1)을 합성하여 얻어진 화합물을 $POCl_3$와 반응시켜서 화합물 3a를 합성하고, 다음 단계에서 2-amino-6-halogenopurines (3b-d)를 합성하였다. 2-Halogenopurines (2-2a-d, 4-2a-d, 5a-d)을 2-amino-6-substituted purines (1, 3a, 4-1)로부터 효율적으로 합성한 후에, 새로운 화합물인 2-2a, 2-2c, 2-2d, 4-2c, 4-2d, 5b, 5c 및 5d를 합성하였다. 합성한 화합물의 구조를 원소분석, $^1H$ NMR, mass spectral data로 확인하였으며, 합성한 화합물에 대한 항균 활성을 시험하였다.