• Title/Summary/Keyword: 반다공성

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A study on Enhancement Effectiveness of Cyanoacrylate Fumed Fingermark by the Solvent of Rhodamine 6G (Rhodamine 6G 용매에 따른 CA 훈증 지문 증강 효과에 관한 연구)

  • Shim, Yea-Ra;Yu, Je-Seol
    • The Journal of the Korea Contents Association
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    • v.17 no.7
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    • pp.294-302
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    • 2017
  • In this study, latent fingermarks deposited in porous or non-porous surface was developed by cyanoacrylate fuming, and then the developed fingermark is enhanced by using Rhodamine 6G. Between water-based R6G and organic solvent-based R6G, author studied about which material have higher effectiveness in enhancing fingermark. In all seven types of surfaces depositing fingermark, water-based R6G have higher effectiveness in enhancing fingermark and lower surface coloring than organic solvent-based R6G. But because the surfaces found in crime scene have multicolor background and various quality, the additional study about various surfaces is needed.

Enhancement of cyanoacrylate-developed marks using p-dimethylaminobenzaldehyde (DMAB) on semi-porous surfaces and analysis of the influence factors on fluorescence intensity (반다공성 재질에 유류된 지문의 CA 훈증 후 p-dimethylaminobenzealdehyde(DMAB) 형광시약 적용 시 표면적과 주변 온도, 기압이 형광착색에 미치는 효과에 관한 연구)

  • Yu, Je-Sul;Kim, Ju-Hah
    • Analytical Science and Technology
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    • v.27 no.4
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    • pp.187-195
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    • 2014
  • It is very important to minimize the damage of latent fingerprints at enhancing the contrast. This study proves the enhancement effects of cyanoacrylate-fumed latent fingerprints using p-dimethylaminobenzealdehyde (DMAB) on semi-porous surfaces and the influence factors. The latent fingerprints in experiment were developed for cyanoacrylate treatment in a vacuum chamber and used after drying at room temperature for 24 hours. For fluorescence staining, the cyanoacrylate-developed marks using DMAB were sublimated during 48 hours under the different conditions of surface area, temperature, atmospheric pressure. First experiment showed how surface area effects on the sublimation rate and fluorescence intensity by DMAB of particle size and container size. In addition, the fluorescence staining using DMAB with solvent-free contact method had the greatest fluorescence intensity after 36 hours and a low fluorescence intensity over a certain size of surface area. Second experiment showed that the evaporation of DMAB solid crystals got a satisfying result in a temperature of $20^{\circ}C$ and reduced time to get the greatest fluorescence intensity. It took a long time to get a optimum level of fluorescence intensity at $30^{\circ}C$ or more and it was less effective in fluorescence intensity. Third experiment on the pressure indicated that the fluorescence intensity of vacuum was weaker than nonvacuum but it was inapplicable to very high variations in pressure.

Comparison of vacuum metal deposition (VMD) and powder method for developing latent fingerprint on plastic envelope surface (플라스틱 봉투 표면에서 지문을 현출하기 위한 Vacuum Metal Deposition (VMD)과 분말법의 비교)

  • Kim, Chaewon;Lee, Narae;Kim, Taewon;Yu, Jeseol
    • Analytical Science and Technology
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    • v.33 no.3
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    • pp.159-166
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    • 2020
  • Vacuum metal deposition (VMD) is effective to develop latent fingerprints on non-porous and semi-porous surfaces. VMD can be used in cases when fingerprints that can not be developed by generalized techniques or deposited on difficult surfaces. The recommended surfaces for VMD techniques include vinyl, polymer bills, magnetic coated tickets, etc. In this study, the minimum amount of gold input was explored for developing fingerprints from at least 12 hours to up to 28 days after deposit fingerprint on the pink high density polyethylene envelope (HDPE) and low density polyethylene envelope (LDPE), which are mainly used as delivery envelopes. And the results were compared with the effects of black powder and fluorescent powder. In addition, delivery envelopes used for delivery were collected, then classified as HDPE and LDPE and pseudo-operation test was performed. As a result, VMD method developed good quality of fingerprints.