• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.451-452
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• 2006

According to the demand of high productivity, the interest of manufacturing skills is growing in the industrial society. Especially the long spindle becomes important these days. The rotating accuracy of the spindle concerns the centrifugal force. In detail explaining, it is influenced by the speed of the spindle. In this study, we would show changes of the distance caused by a rotating speed of the spindle using a software, $ADAMS^{(R)}$. And because of the gravity of the spindle's mass, we would find the static droop of the long spindle.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.134-137
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• 2005

Recently, in VLCC, shafting system is stiffer due to large engine power whereas hull structure is more flexible due to scantling optimization, which can be suffered from alignment damage by incompatibility between shafting and hull, In this study, shafting system without stern tube forward bush was adapted for less sensitive system against external factors. Also, shaft alignment analysis was considered with hull deflection at various ship loading conditions and stern tube after bush of long journal bearing was evaluated by static squeezing pressure and dynamic oil film pressure with sloping control. Whirling vibration was also reviewed to avoid resonance with propeller blade order. So, reliable shafting design for VLCC could be achieved through optimized alignment analysis for the system without stern tube forward bush.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.625-630
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• 2007

This paper accounts for derivations and formulations of the finite element dynamic equation of the rotor-bearing system to analyze its whirling speed. It turns out to be a different form from previous researcher's because of different successive sequences of Euler angles. Correspondingly the adoption of other rotation tensor will be needed for a consistent derivation of the dynamic equation. The process of its finite element formulation with consistent mass matrix and gyroscopic matrix involves a general definition of the modal analysis or the Eigen analysis for the damped system in the inertial frame and rotating frame, respectively.

• Bulletin of the Society of Naval Architects of Korea
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• v.22 no.1
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• pp.38-44
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• 1985

A computer program was developed for the analysis of the coupled transverse vibrations of a multi-supported shaft system. The program, based on the theory of Transfer Matrix Method, was written including the system parameters such as the entrained water and gyroscopic effects of the propeller, the rigidity of bearing combined with the oil film effect, and the whirling frequency of the shaft. The program was used to calculate the resonance frequency of the shafting system of the ship Hanbada. The results show good agreement with the measured values. The results are also compared with those of F.E.M. from the comparison, it is found that both results agree well with each other.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.2
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• pp.106-111
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• 2004

Vertigo is a symptom, not a disease. The tenn vertigo refers to the sensation of spinning or whirling that occurs as a result of a disturbance in balance. It's sometimes referred to as a hallucination of motion. The cause of vertigo is very various and generally divided into peripheral and central. A patient presented with severe vertigo, nystagmus and heteophoria. She has taken the BanHaBaekChulChunMa-tang and treated by acupuncture. After 2 days, her symptoms become disappeared and about 1 week, all symptoms except heterophoria were disapperaed. And after 2 weeks, heterophoria was disappeared. In conclusion, we diagnosed her case as vestbular neuronitis by her clinical course, but we also considered her illness as vertebrobasilar insufficiency, TIA etc.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.2
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• pp.146-152
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• 2004

Introduction: Vertigo is one of the common symptoms that we can see often clinically. It is hallucination to motion of oneself or surroundings. Vertigo include not only simple whirling sensation but also leaning or falling down sensation. Particularly in vestibular neuritis, the principal symptoms is dizziness and accompanied by nystagmus, gait imbalance, nausea, vomiting. Cause of vestibular neuritis is inflammatory disease such as common cold. Objective: The aim of this study was to estimate the efficacy of oriental-treatment on vestibular neuritis patient Subjects: We diagnosed one patient who had severe vertigo and gait imbalance as "dizziness retention of phlegm"(담훈) and treat orientally. Conclusion: After oriental-treatment for 15 days, walk balance was improved and no more vertigo was appeared. We could assume that in the vertigo and gait inbalance due to vestibular neuritis, the acupuncture and herbal medicine can be used.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.334-339
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• 2001

The nonlinear vibration characteristics of hydrodynamic journal bearings with a circumferentially groove are analyzed numerically when the external sinusoidal disturbances are given to the rotor-bearing system continuously. Also, the cavitation algorithm implementing the Jakobsson-Floberg-Olsson boundary condition is adopted to predict cavitation regions in the fluid film more accurately than conventional analysis which uses the Reynolds condition. It is found that the difference between linear and nonlinear analysis is much more remarkable as the amplitude of external disturbance increases, and it depends upon the excitation frequency of external disturbance. It is also shown that the cavity region in the fluid film is increased as the amplitude or excitation frequency of external disturbance increases. The whirling center of the steady state orbit moves closer to the bearing center as the amplitude or the excitation frequency of the external disturbance increases because of smaller range of full film region.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.43-49
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• 1997

A rotating rigid disk, attached on a flexible shaft or supported by a torsional spring, experiences precessional whirling due to gyroscopic moment loading. It is well known in rotor dynamics area that, as the rotational speed increases, the precessional mode of the rotating rigid disk starts splitting into two: forward and backward precessional modes. On the other hand, it is also well known in disk vibration area that a rotating flexible disk also shows another kind of mode splitting phenomenon due to the rotation, resulting in forward and backward traveling waves. When rotating multiple flexible disks are coupled in vibration with the supporting Flexible shaft, the associated mode splitting should be compatible with the two seemingly different vibration analysis methods. This paper investigates the possibility of fusing the precessional and traveling wave mode splittings so that the bending coupled disk vibrations in HDD spindle systems can be better understood.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.16 no.1
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• pp.214-219
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• 2003

Vertigo is one of the common symptoms that we can see often clinically. It is hallucination to motion of oneself or surroundings. Vertigo include not only simple whirling sensation but also leaning or falling down sensation. Particularly in benign paroxysmal positional vertigo(BPPV), the principal symptom is dizziness and accompanied by nausea, lightheadness, vomiting. They are induced by positional change which like shake ones head or lay down or turn over in one' s sleep. Cause of BPPV is otoconium fragments which are released from inner ear and stimulate ampulla of semicircular canal. So in treatment BPPV, we often using the Dix-hallpike maneuver that realignment otoconium fragments. A case of vertigo patient suggested BPPV who is diagnosed oriental medically as weakly dizziness showed prominent improvement by medicate Bojungikgi-tang and operate otoconium-realignmentation (improved Dix-hallpike maneuver) maneuver so we reported.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.94-102
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• 2019

Mono pump rotors are widely used in wastewater treatment plants, medicine, cosmetics, paint, paper, and chemical manufacturing, dairy production, public works, agriculture, and so on. A mono pump comprises two main parts: the rotor and stator. Typically, the rotor is machined using an expensive whirling machine. In this study, we developed an algorithm for 4-axis machining of the rotor on machining center (MCT). NC-code was obtained by applying the algorithm and finally the rotor of the mono pump was machined on a 4-axis MCT. Results of four sample experimental works showed close agreement with design geometries.