• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.103-111
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• 2006

Statement of problem: The previous unilateral bite force recorder has several limitations for taking long time for measuring and causing discomfort to subjects. Because of these reasons, it could not use widely for epidemiological researches. However, 'Dental Prescale System' which is new equipment for measuring bite force, is more convenient for measuring bite force than previous unilateral recorder. Purpose: The purpose of this study was to compare a new technique(Dental Prescale System) using pressure sensitive foils for recording of maximal jaw closing force with conventional measurement using unilateral bite force recorder Material and method: This studies included 22 healthy dental students in college of dentistry Yonsei university in Rep of Korea. Mean age was 23.9 years. All subjects had continuous dental arches and no significant malocclusion or signs from the teeth and craniomandibular system. The Dental Prescale System (Fuji Film, Tokyo, Japan) consists of a horseshoe-shaped pressure sensitive sheet (50H, R type) and a computerized scanning system.(FPD705) We also used unilateral bite force recorder(Denbotics Co. Seoul, Rep.Korea) for comparing with Dental Prescale. Results and conclusion: The total bite force recorded with Dental Prescale System (1423 N) was systematically higher than that recorded by unilateral bite force recorder. (256 N) However, the maximum bite force values measured in the two ways were significantly correlated (r=0.46, p<0.05). The Dental Prescale bite force calculated for first molar (208 N) was lower than that recorded by unilateral bite force recorder. (256 N) The two values were also very significantly correlated. (r=0.66. p<0.001) There were significantly different in bite force between two measurement methods. The reasons were first, unilateral bite force recorder measured only the bite force of a part of teeth, and Dental Prescale measured the total teeth force. Second, in measurement, a difference in muscle contraction appeared by an extent of mouth-opening. Third, unilateral bite force recorder has the reducing effect of the bite force by protective tape. Fourth, Dental Prescale has limitations during the computer scanning procedure. Therefore, Dental Prescale System is considered to be a very promising alternative to be conventional bite force recording methods.

• Applied Microscopy
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• v.44 no.3
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• pp.100-104
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• 2014

As decreasing device size, probing of nanoscale surface properties becomes more significant. In particular, nanoscale probing of surface potential has paid much attention for understanding various surface phenomena. In this article, we review different atomic force microscopy techniques, including electrostatic force microscopy and Kelvin probe force microscopy, for measuring surface potential at the nanoscale. The review could provide fundamental information on the probing method of surface potential using atomic force microscopy.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.773-780
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• 2009

The facility equipments generate dynamic force on building floor and the force can be measured with force transducer. However, this method depends on the measuring capacity or range of sensor, or mounts installation condition of equipments. Because of this restricting condition on force measuring system, this paper suggests a indirect method, the TPA(transfer path analysis) method, that produces a closely approximate dynamic force of equipments. This method calculates the dynamic force by using transfer response function. Firstly, the calculated dynamic force of impact load and continuous load was respectively compared with the sensor-measured value to examine the accuracy of TPA method. After that, the dynamic force and response induced by large facility equipments - a cooling tower, AHU and a large ventilator - were calculated by TPA method and the validity of these value were examined.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1173-1182
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• 2001

Recent noticeable advances of CNC machine tools have considerably improved productivity and precision in manufacturing processes. However, in the respect of productivity some defects still remain because selection of machining conditions entirely depends on the experiences of programmers. Usually, machining conditions such as feed rate and spindle speed have been selected conservatively by considering the worst cases, and it has brought the loss of machining efficiency. Thus, the improvement of cutting force controller has been done to regulate cutting force constantly and to maximize feedrate simultaneously in case that machining conditions change variously. In this study, sliding mode control with boundary layer is applied to milling process for cutting force regulation and in a commercial CNC machining center data transfer between PC and PMC (programmable machine controller) of CNC machine is done using a standard interface method. And in the cutting force measurement, an indirect cutting force measuring system using current signal of AC servo is adopted in order not to use high-priced equipment like tool dynamometer. The purpose of this study is to maximize the productivity in milling process, thus its results can be applied to cases such as rough cutting process.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.715-724
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• 2011

A turn buckle inserted between tension members that sustain the structural loads in a suspension structure system is a device that is capable of adjusting the tensile force. The tension member is an important element of a tension structure, but no simple and economical method of measuring a tensile force applied to members has been proposed yet. Thus, a turn buckle for measuring the tensile force in a tension member was developed in this study. The turn buckles of the measurement limit loads of 100kN, 200kN, and 300kN were tested through a theoretical analysis and a finite element analysis. There was no significant difference in the results of the theoretical analysis, FEA, and the test. In addition, the ultimate strength of the turn buckle using FEA showed that a new turn buckle is sufficiently safe to use even when there is a five-times overload in the measurement limit load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.181-192
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• 2007

In domestic case, there are no results of corresponding researches for measuring external tendon force. The purpose of the present paper is therefore to measure external tendon force by using deriving ultrasonic method. For this purpose, we designed and manufactured wedges and test system, and measured ultrasonic pulse velocity and pulse amplitude. By using measured data, we tried to analyze the characteristics of tendon force, and to derive the relationship between tendon force and ultrasonic pulse velocity, finally to develop the technic of measuring system using ultrasonic pulse velocity. So tendon force-velocity relationship was proposed by equations, and those equations of which errors were 3.92~8.77% will be possible to adapt in-site.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.91-92
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• 2002

Most studies of elsatohydrodynamic lubrication are oriented only to the measurement of film thickness itself with optical interferometer. In order to exactly investigate the characteristics of a certain lubricant under the condition of additives. especially for traction performance. it is also important to get the information of traction force as well. In this work. we developed the device for measuring friction force of EHL contact condition, which can trace the film thickness over the contact area with optical interferometer. To verify the validity of the measuring system, the friction force and film thickness under EHL condition are measured with the variation of additive ratios of viscosity Index improvers.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.134-140
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• 2003

The film sensor is used for measuring pressure distribution at planar area, especially at a small space or gap. The present paper deals with the development of film type sensors and system for pressure distribution measuring. The developed system is consist of (1)film sensor with 40/sup */40 array, (2)PCI interface card with maximum sampling rate of 100㎐, and (3)software for data processing and real-time display. The contact pressure test of wiper blade and front glass of vehicle was performed with wiper blade by 40cm. Generally spring force of wiper arm is designed at 0.7∼1kN. Test results of total force was 9.4N and 7.1N in each driver and passenger toward. The paper suggested possibility for base definition in wiper design. A windshield wiper blade experiment revealed that the system successfully measured the contact force distribution during static state, showing the usefulness of the developed system.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.75-81
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• 1998

It is very important to evaluate the friction force of valve train system in the aspect of reducing friction loss of engine. To this end, we have developed measuring system of friction force of engine valve train system. There were two major factors in the process of development of it. One was it had to accurately measure the friction force up to 3500 Crpm without any problems such as mechanical vibration, electrical noise and so on. The other was it also had to simulate real engine conditions such as Crpm, oil temperature, oil pressure and oil aeration including effect of belt drive system. In this paper we have introduced the process of development of it based on test results, and also analysis process of measured data.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.180-184
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• 2009

A novel set of experimental test tooling for measuring pulling and holding forces for drawbeads on binders inclined at a wide range of angles is introduced. A mechanical design featuring a single load cell, a male-female draw bead set, translation and rotation degrees of freedom, and a screw-driven clamping system has been incorporated into a standard tensile test machine. On a real time basis, restraining and holding force data with respect to draw-in displacement may be directly downloaded into a PC for data processing. The proposed experimental system represents a significant breakthrough in drawbead simulation technology due to its relatively low cost, clever design, and versatility. The system is shown to yield excellent experimental data suitable for verifying theory and numerical model predictions.