• 한국분무공학회지
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• 제5권3호
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• pp.9-16
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• 2000

In a SI engine, three-way catalyst converter has the best efficiency when A/F ratio is near the stoichiometry. The feedback control using oxygen sensors in the commercial engine has limits caused by the system delays. So it is necessary to control fuel quantity in accordance with intake air amount in order to reduce exhaust emission and improve the specific fuel consumption. Precise A/F ratio control requires measurement of air amount with respect to the cylinder and injection fuel according to the air amount In this paper, we applied nonlinear fuel injection model and developed the algorithm of A/F ratio control. This algorithm includes the methods of measurement of transient air mass flowing into each cylinder, of calculation of injection pulse width for measured air mass, and the method of feedback and engine control by using lambda sensor. Also we developed control program for IBM-PC by using C++ Builder, and tested it in the commercial engine.

• 전력전자학회논문지
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• 제18권3호
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• pp.225-231
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• 2013

This paper presents an improved signal processing technique in the square-wave-type voltage injection method for IPMSM sensorless drives. Since the sensorless method based on the square-wave voltage injection does not use low-pass filters to get an error signal for estimating rotor position and allows the frequency of the injected voltage signal to be high, the sensorless drive system may achieve an enhanced control bandwidth and reduced acoustic noise. However, this sensorless method still requires low-pass and band-pass filters to extract the fundamental component current and the injected frequency component current from the motor current, respectively. In this paper, these filters are replaced by simple arithmetic operations so that the time delay for estimating the rotor position can be effectively reduced to only one current sampling. Hence, the proposed technique can simplify its whole signal process for the IPMSM sensorless control using the square-wave-type voltage injection. The proposed technique is verified by the experiment on the 800W IPMSM drive system.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.52-57
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• 2003

Common rail injection system is flexible in injection timing, injection duration and pressure in engine. Many researches have reported on the merits in the application of common rail systems. This research investigated on characteristics and performance for single cylinder diesel engine with a common .ail injection system by varying major parameters such as injection timing, injection duration and common rail pressure. The injection timing and injection duration were controlled by electronic pulse generated. and common rail pressure were controlled by PCV driver. The 498cc single cylinder diesel engine was used in this experiment. All data for combustion pressure, injection timing and injection duration were recorded by Labview. Furthermore, this test was focused on how to optimize injection conditions.

• 한국환경보건학회지
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• 제8권1호
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• pp.55-60
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• 1982

This study was carried out in order to clarify the combined effect of cadmium and lead on rat bones when exposed to single metal (1 mg cd/kg body weight) and cambined metals (1 mg cd + 4 mg pb/kg body weight). Seventy five mature rats of Sprague-Dawley species were divided into a control group and a treatment group that were administered by daily peritoneum injection for 7 to 9 weeds, and their body weights were measured every week. The results were summarized as follows 1. Body weight gains of the combined injection group and the single injection groups were lower than that of the control group. 2. In case of the combined injection group, the amount of cadmium accumulated in femur was more than that of the cadmium group. These amounts of cadmium accumulated showed an increasing trend. 3. The lead amount in bone tissue of the combined injection group presented also an increasing trend. In this case, the additive action of cadmium to the lead accumulation in bone tissue was conspicuous. 4. The amounts of calcium and phosphorus in femur showed clear a decreasing trend in the cadmium group and combined administration group. The ratio of calcium and phosphorus (ca/p) in the cadmium group was not different from that of the control group, but in the combined injection group the ratio was a little lower.

• 한국자동차공학회논문집
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• 제22권4호
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• pp.98-104
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• 2014

The technologies employing spray-guided type combustion system for ultra-lean combustion direct injection engine is focused as a promising technology for satisfying emission regulations and improving fuel economy. In the present study, control and design optimization of lean-burn LPG direct injection engine was carried out with control strategy and injection position changes. Inter-injection spark ignition strategy was applied and the effect of the strategy was assessed at relatively higher load operation condition than previous researches. In order to create richer mixture in the vicinity of spark plug electrode, relative distance between the dead-end of injector and the electrode of spark plug was changed.

• Tribology and Lubricants
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• 제13권3호
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• pp.63-72
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• 1997

The stability of a rotor-bearing system supported by swirl-controlled hybrid journal bearing with pair-type angled injection orifices is investigated for improvement of the whirl frequency ratio by allowing effective control of the tangential flow inside the bearing clearance, i.e., by achieving more freedom in controlling strength and direction of the supply tangential flow inside the bearing clearance. It is suggested that the system instability can be improved through the change of bearing dynamic characteristic parameters with the swirl control. The orifice diameter $d_0$ and recess injection angle $\alpha$ along with combinations of swirl/anti-swirl supply pressures and directions (3.0~3.0 MPa, 4.0~2.0 MPa, 2.0~4.0 MPa) are selected for design parameters for swirl-controlled effective factors dependent on journal speeds (3000, 9000, 15000, 21000 rpm). It has been found that the orifice diameter $d_0$ shows strong effects on effective maneuverability of direct-stiffness and direct damping values, while recess injection angle $\alpha$ results in substantial effects on the magnitude and direction of cross-stiffness. Specifically, recess injection parameters which are functions of angle of orifice feeding flow and recess dimensions showed very feasible effect on the stability control of swirl-controlled rotor-bearing system.

• 대한약침학회지
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• 제12권3호
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• pp.31-40
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• 2009

Objective : This study was to investigate the effects of distilled Cervi Pantotrichum Cornu Pharmacopuncture and Zizyphi Spinosi Semen Pharmacopuncture on autonomic nervous system with Heart Rate Variability(HRV). Purpose of the trial was to observe what influence distilled Cervi Pantotrichum Cornu Pharmacopuncture and Zizyphi Spinosi Semen Pharmacopuncture have on the autonomic nervous system. Methods : 60 healthy male volunteers were divided into three groups which consist of two experimental groups such as Cervi Pantotrichum Cornu Pharmacopuncture and Zizyphi Spinosi Semen Pharmacopuncture, and a control group. Study design was a randomized, placebo-controlled, double-blind clinical trial. 20 subjects in experimental group were injected distilled Cervi Pantotrichum Cornu Pharmacopuncture at $GB_{21}$(Kyonjong), 20 subjects in other experimental group were injected distilled Zizyphi Spinosi Semen Pharmacopuncture and 20 subjects in control group were injected Normal Saline at $GB_{21}$(Kyonjong). One volunteer of each groups were excluded from analysis because of error during measuring HRV. At the end of the study 57 volunteers completed HRV analysis. HRV was measured by QECG-3:LXC3203(LAXTHA Inc. Korea) at P0, P1, P2, P3, P4, P5 and P6 and its time-course dependent change in each group was analyzed using paired t-test, and the difference of HRV fluctuation among two experimental group and a control was evaluated by one way ANOVA(p<0.05). Results : A. Time Domain Analysis 1. Analysis of Mean HRV, SDNN and Complexity After injection of distilled Cervi Pantotrichum Cornu Pharmacopuncture, Mean HRV was significantly decreased only at 20 minutes after injection. SDNN was significantly increased from 15 minute after injection. Complexity was significantly decreased only at 15 minute after injection. After injection of distilled Zizyphi Spinosi Semen Pharmacopuncture, Complexity was significantly decreased at 10, 15 and 30 minutes after injection. 2. Analysis of HRV index, pNN50 After injection of distilled Cervi Pantotrichum Cornu Pharmacopuncture, pNN50 was significantly decreased at 15, 20 and 25 minutes after injection. Compared with Normal Saline injection, distilled Cervi Pantotrichum Cornu Pharmacopuncture and Zizyphi Spinosi Semen Pharmacopuncture showed significant difference on HRV index and pNN50 at 5 minutes after injection. B. Frequency Domain Analysis 1. Analysis of Ln(TP), Ln(VLF) After injection of distilled Cervi Pantotrichum Cornu Pharmacopuncture, Ln(TP) was significantly increased at 15 and 30 minutes after injection. Ln(VLF) was significantly increased at 10, 15 and 30 minutes after injection. After injection of distilled Zizyphi Spinosi Semen Pharmacopuncture, Ln(VLF) was significantly increased only at 30 minutes after injection. Compared with Normal Saline injection, distilled Cervi Pantotrichum Cornu Pharmacopuncture showed significant difference on Ln(TP) after 5 minutes of injection. Conclusions : Our results suggest that Cervi Pantotrichum Cornu Pharmacopuncture and Zizyphi Spinosi Semen Pharmacopuncture in healthy adult man tend to activate the autonomic nervous system and sympathetic nervous system compared to Normal Saline within normal range.

• 한국분무공학회지
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• 제12권3호
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• pp.166-171
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• 2007

Recently, many studies on HSDI diesel engines have been performed to reduce the fuel consumption and $CO_2$ emission. One of the prominent technique to reduce emission is a high pressure multiple injection. For this technique, the injection rate is a critical parameter in order to determine precise injection duration and timing for combustion control. Thus the purpose of this study was to investigate relationship between the injection rate and the time-signature of chamber pressure at different injection pressure conditions in a common rail direct injection type injector using the Zeuch method. Using the measured correlation constants, estimated fuel injection rates are presented at many different injection conditions.

• 대한약침학회지
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• 제3권2호
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• pp.99-130
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• 2000

This study was carried out to investigate the effects of Liriopis Tuber Herbal-Acupuncture on Diabetes Mellitus induced by streptozotocin in rat. Body weight, serum insulin, glucose, triglyceride, HDL cholesterol, free cholesterol and total protein were measured in streptozotocin induced diabetic rat injected with Liriopis Tuber Herbal-Acupuncture solution at Pisu(BL20) respectively for 30 days. In order to study the effects of Liriopis Tuber Herbal-Acupuncture at Pisu(BL20) on Diabetes Mellitus induced by Streptozotocin in rat, The groups were divided into five groups; Normal group(non treated group), N.-Saline group(administration of injection with normal saline at BL20 in 30 days after streptozotocin injection), Control group(non treated group after streptozotocin injection), H. Acup. group (administration of Liriopis Tuber Herbal-Acupuncture at BL20 in 30 days after streptozotocin injection), and Acup. group (administration of acupuncture at BL20 in 30 days after streptozotocin injection). The results obtained were summarized as follows; 1. As compared with Control group, there wae no significant tendency to diminish the rate of weight loss in H. - Acup. group. 2. As compared with Control group, there wae signiticant increase of serum insulin level in H. -Acup. group. 3. As compared with Control group, there was decrease of glucose level in H.- Acup. group. 4. As compared with Control group, there was decrease of triglyceride level in H. - Acup. group. 5. As compared with Control group, trere wae increase of HDL cholesterol level in H. - Acup. group. 6. As compared with Control group, there was significant increase of free cholesterol level in H. - Acup. group. 7. As compared with Control group, there was Increase of total protein level in H. - Acup. group. According to above mentioned results, Liriopis Tuber Herbal-Acupuncture was expected to be effective in treatment of Diabetes Mellitus and its complications.

• Advances in aircraft and spacecraft science
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• 제9권5호
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• pp.433-447
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• 2022

This work deals with an explicit guidance and control architecture for autonomous lunar ascent and orbit injection, i.e., the locally-flat near-optimal guidance, accompanied by nonlinear reduced-attitude control. This is a new explicit guidance scheme, based on the local projection of the position and velocity variables, in conjunction with the real-time solution of the associated minimum-time problem. A recently-introduced quaternion-based reduced-attitude control algorithm, which enjoys quasi-global stability properties, is employed to drive the longitudinal axis of the ascent vehicle toward the desired direction. Actuation, based on thrust vectoring, is modeled as well. Extensive Monte Carlo simulations prove the effectiveness of the guidance, control, and actuation architecture proposed in this study for precise lunar orbit insertion, in the presence of nonnominal flight conditions.