• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.163-165
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• 2000

We investigated visible light radiated from Plasma Focus device by time-integrated analyzed method. Plasma focus is a device that translated from electric energy into visible light by electric discharge. Spectral analysis is using Monochromator(focal length = 0.5 m). Time-integrated spectrum is analyzed with densitometer the film which developed a constant range of wavelength. The condition of visible emission was that the discharging voltage was 13 kV and the working gas were Argon and Helium.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.07a
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• pp.25-37
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• 2002

The most important industrial application of gamma radiation in characterizing green compacts is the determination of the density. Examples are given where this method is applied in manufacturing technical components in powder metallurgy. The requirements imposed by modern quality management systems and operation by the workforce in industrial production are described. The accuracy of measurement achieved with this method is demonstrated and a comparison is given with other test methods to measure the density. The advantages and limitations of gamma ray densitometry are outlined. The gamma ray densitometer measures the attenuation of gamma radiation penetrating the test parts (Fig. 1). As the capability of compacts to absorb this type of radiation depends on their density, the attenuation of gamma radiation can serve as a measure of the density. The volume of the part being tested is defined by the size of the aperture screeniing out the radiation. It is a channel with the cross section of the aperture whose length is the height of the test part. The intensity of the radiation identified by the detector is the quantity used to determine the material density. Gamma ray densitometry can equally be performed on green compacts as well as on sintered components. Neither special preparation of test parts nor skilled personnel is required to perform the measurement; neither liquids nor other harmful substances are involved. When parts are exhibiting local density variations, which is normally the case in powder compaction, sectional densities can be determined in different parts of the sample without cutting it into pieces. The test is non-destructive, i.e. the parts can still be used after the measurement and do not have to be scrapped. The measurement is controlled by a special PC based software. All results are available for further processing by in-house quality documentation and supervision of measurements. Tool setting for multi-level components can be much improved by using this test method. When a densitometer is installed on the press shop floor, it can be operated by the tool setter himself. Then he can return to the press and immediately implement the corrections. Transfer of sample parts to the lab for density testing can be eliminated and results for the correction of tool settings are more readily available. This helps to reduce the time required for tool setting and clearly improves the productivity of powder presses. The range of materials where this method can be successfully applied covers almost the entire periodic system of the elements. It reaches from the light elements such as graphite via light metals (AI, Mg, Li, Ti) and their alloys, ceramics ($AI_20_3$, SiC, Si_3N_4, $Zr0_2$, ...), magnetic materials (hard and soft ferrites, AlNiCo, Nd-Fe-B, ...), metals including iron and alloy steels, Cu, Ni and Co based alloys to refractory and heavy metals (W, Mo, ...) as well as hardmetals. The gamma radiation required for the measurement is generated by radioactive sources which are produced by nuclear technology. These nuclear materials are safely encapsulated in stainless steel capsules so that no radioactive material can escape from the protective shielding container. The gamma ray densitometer is subject to the strict regulations for the use of radioactive materials. The radiation shield is so effective that there is no elevation of the natural radiation level outside the instrument. Personal dosimetry by the operating personnel is not required. Even in case of malfunction, loss of power and incorrect operation, the escape of gamma radiation from the instrument is positively prevented.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.317-326
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• 1991

The purpose of this study was to establish the principle and the clinical application of dynamic tomogram of a human head by using the dental machine. For this study, a block of wax with details lying at three parallel planes and a human dry skull were used. This experiment was reexamined the dynamic tomogram with specialized radiographic device and view box, and the radiograms taken by the change of exposure time according to the numbers of film used in x-ray taking and taken according to the change of kVp and the types of film were analyzed density with the densitometer. From this study, the obtained results were as follows: 1. When the underexposed radiograms taken by angulation of clockwise and counter-clockwise direction of the film and skull. were superimposed and moved laterally, it was possible to focus on right and left jaws and teeth. 2. The superimposition of the two underexposed radiograms according to each condition of x-ray taking showed some differencies in density visually, and the measurement of density with the densitometer was 1.23 to 1.57 in 75kVp and 1.34 to 1.70 in 90kVp. 3. The superimposition of the two underexposed radiograms according to the kinds of x-ray film showed almost equal density visually, and the measurement of density with the densiometer was 1.34 to 1.37. 4. When seven radiograms taken by each condition of x-ray taking were superimposed on the view box, a intense rear light of view box didn't transilluminate film density regardless of the conditions of x-ray taking. Even though seven radiograms taken according to types of film were superimposed on the view box, a more intense rear light of view box was required to transilluminate total density of films. 6. Long film-object distance resulted in the enlargement and blurring of radiographic images.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.4 s.117
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• pp.47-52
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• 2006

This study is about the effect from properties of coated paper and ink dispersion to the printed mottle. Ink receptivity would be expected that it is mainly effected by roughness of coated paper Because the transfer of ink can not be uniform with rough surface, it will cause the optical appearance such like printed mottle. And also it may be able to cause the printed mottle from uneven transfer of ink due to absorption property of based paper, depend on size degree, by using dampening in Off-set printing. Each different specific of surface and ink dispersion could cause printed mottle. Therefore this study was carried out by using densitometer and image analysis to show the interaction between properties of domestic coated paper and ink dispersion.

• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.249-255
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• 1990

The conditions for separation and identification of anionic and nonionic surfactants by thin layer chromatography were investigated. Polyoxy alkylene-type nonionic surfactants were identified by the distribution of alkyl chain and alkylene oxide. Various polyoxyethylenated nonyl phenols were easily distinguished by densitometer. Some anionic surfactants were identified by $R_f$ and color, and the mixtures of anionic and nonionic surfactants were separated. Polyoxyethylenated fatty acid was separated into three parts of diester, monoester and polyethylene glycol, respectively, and the mixed ratio was determined by densitomer. All the experiments were carried out in 13-20 minutes, and the length of run was 80mm.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.2 s.120
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• pp.31-37
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• 2007

Lithography like off-set printing is processed using the repellent properties between water and oil, so all inks for off-printing must work with dampening solution(water). The dampening water may cause the emulsification of ink by the printing pressure in the printing nip. This study aimed to investigate the effect of emulsified inks on print mottle. The cyan ink was emulsified artificially with the different IPA(isopropyl alcohol) content in this study. We evaluated the print mottle by densitometer and image analysis method. The print mottle phenomenon was directly affected by IPA content. The emulsification of inks also had an influence on flow properties of inks and it increased ink transfer rate. It, however, caused low ink density. Moreover the emulsified inks were spreaded to around dots and cause the thinning density on the non-printing area like print mottle. The trial printing showed that the emulsified inks also cause scumming on the printing result with little mistake of adjusting dampening solution and mostly decreasing dot reproduction. We could, therefore, find out the obvious effect of emulsified inks on print mottle.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.299-308
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• 1999

Purpose: The purpose of this study was to compare the qualities of the four different processing chemicals (solutions). Materials and Methods: With EP 21 films(Ektaspeed plus film, Kodak Co., USA), nine unexposed and nine exposed films of a step wedge were processed utilizing automatic film processor(XR 24, Durr Co., Germany) for 5 days. During 5 days, the total number of processed films including out-patient' s intraoral films were about 400-500 for each brand. Base plus fog density, film density, contrast of processed films were measured with densitometer(model 07-443 digital densitometer, Victoreen Co., USA). These measurements were analyzed for comparison. Results: The results were as follows, 1. For the base plus fog density. there was significant difference among the four chemicals (p<0.05). The sequence of the base plus fog densities was in ascending order by Kodak, X-dol 90. Agfa and Konica. 2. For the film density. all chemicals showed useful range of photographic densities(0.25-2.5). The sequence of the film densities was in ascending order by Kodak, X-dol 90, Konica and Agfa. But there was no statistically significant difference of film density between X-dol and Kodak (p<0.05). 3. The sequence of the contrasts was in ascending order by Konica, X-dol 90, Kodak and Agfa. But there was no statistically significant difference of contrast between X-dol and Konica (p<0.05). Conclusion: These results indicated that the four processing chemicals had clinically useful film density and contrast. but only Kodak processing chemical had useful base plus fog density.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.77-84
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• 2012

The lithographic process depends on a satisfactory ink-in-water emulsion being formed during printing and the speed of wet presses makes the choice of fountain solution vitally important as the ink and fount must react quickly to form a stable emulsion. Ink and water come into contact with each other on the rolls of the press and are forced together in the roll nips. The water is not soluble in the ink since it is slightly fat. Instead, an emulsion is formed, a heterogeneous mass consisting of small water drops mixed into the ink, if the water feed is too great. This emulsification can affect the properties of an off-set ink and negatively affect the printability. So we investigated the effects of the emulsification of phenol free heat-set ink and existing heat-set ink on printed quality, such as amount of ink transfer, printed density, print-through and uniformity. We used Duke emulsification tester for the emulsification of inks, and used IGT printability tester for printed quality. The printed quality were measured by densitometer and were evaluated by the image analysis system. Compared to conventional printing ink, phenol-free ink showed better results of the printability at the emulsification.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.1
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• pp.128-136
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• 1992

This study was undertakened to investigate the change of image characteristics on dental films according to the process of using time of processing solution in automatic processor. Base + fog density, film density and subject contrast were measured with the digital densitometer, the pH of developing and fixing solution were measured with Digital pH / ION Meter. The following results were obtained: 1. Base + fog density was increased with the process of using time of the processing solution and was over the maximum permissible base + fog density 0.25 from the 3rd day. 2. Film density was increased with the process of using time of the processing solution. 3. Subject contrast was decreased with the process of using time of the processing solution. 4. The pH of the developing solution was decreased with the process of using time, the pH of the fixing solution was increased.

• Journal of the Korean Graphic Arts Communication Society
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• v.23 no.1
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• pp.13-25
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• 2005

In order to technical analysis of the Newspaper printing press, the printability such as, dot gain, contrast and printing density change according to the amount of ink and damping water feeding were experimented. t도 Printability assurance in printing aims at a correct and constant color reproduction throughout the whole print-run. And the checked values were checked from densitometer and colorimeter instead of conventional subjective method. In this research, we could propose the range of driving in printing of domestic Newspaper printing press as well as the limits of ink feed speed and damping water feed speed.