Key Laboratory of Impression Evidence Examination and Identification Technology

Shenyang, China

Key Laboratory of Impression Evidence Examination and Identification Technology

Shenyang, China

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Wang M.,Liaoning University | Wang M.,Key Laboratory of Impression Evidence Examination and Identification Technology | Li M.,Liaoning University | Li M.,Key Laboratory of Impression Evidence Examination and Identification Technology | And 6 more authors.
Advanced Functional Materials | Year: 2017

This review presents an overview on the application of latent fingerprint development techniques in forensic sciences. At present, traditional developing methods such as powder dusting, cyanoacrylate fuming, chemical method, and small particle reagent method, have all been gradually compromised given their emerging drawbacks such as low contrast, sensitivity, and selectivity, as well as high toxicity. Recently, much attention has been paid to the use of fluorescent nanomaterials including quantum dots (QDs) and rare earth upconversion fluorescent nanomaterials (UCNMs) due to their unique optical and chemical properties. Thus, this review lays emphasis on latent fingerprint development based on QDs and UCNMs. Compared to latent fingerprint development by traditional methods, the new methods using fluorescent nanomaterials can achieve high contrast, sensitivity, and selectivity while showing reduced toxicity. Overall, this review provides a systematic overview on such methods. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Wang M.,Shenyang University | Wang M.,Key Laboratory of Impression Evidence Examination and Identification Technology | Li M.,Shenyang University | Li M.,Key Laboratory of Impression Evidence Examination and Identification Technology | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2015

The most commonly found fingerprints at crime scenes are latent and, thus, an efficient method for detecting latent fingerprints is very important. However, traditional developing techniques have drawbacks such as low developing sensitivity, high background interference, complicated operation, and high toxicity. To tackle this challenge, we have synthesized two kinds of rare earth fluorescent nanomaterials, including the fluoresce red-emitting YVO4:Eu nanocrystals and green-emitting LaPO4:Ce,Tb nanobelts, and then used them as fluorescent labels for the development of latent fingerprints with high sensitivity, high contrast, high selectivity, high efficiency, and low background interference, on various substrates including noninfiltrating materials, semi-infiltrating materials, and infiltrating materials. © 2015 American Chemical Society.


Wang M.,Shenyang University | Wang M.,Key Laboratory of Impression Evidence Examination and Identification Technology | Zhu Y.,University of Oklahoma | Mao C.,University of Oklahoma
Langmuir | Year: 2015

Fingerprints at crime scenes are usually latent. The powder-dusting method is the most commonly used procedure for developing latent fingerprints in forensic science. However, the traditional powder-dusting method has characteristics of low sensitivity, low contrast, high background noise, and high autofluorescence interference. To overcome the drawbacks faced by the traditional method, we first optimized an oleic acid-based solvothermal approach for the synthesis of NaYF4:Yb,Er fluorescent upconversion nanoparticles (UCNPs) with the highest possible fluorescence intensity under near-infrared (NIR) irradiation. To optimize the synthesis, we studied the effects of the reaction time, reaction temperature, and volume of oleic acid on the size, phase composition, and UC fluorescence intensity of the UCNPs. We then used the resultant UCNPs to fluorescently label the fingerprints on various smooth substrates to improve the development of latent fingerprints because the UCNPs could undergo excitation under 980 nm NIR light to emit visible light. Latent fingerprints on three major types of smooth substrates were studied, including those with a single background color (transparent glass, white ceramic tiles, and black marbles), with multiple background colors (marbles with different complex surface patterns) and with strong background autofluorescence (note papers, Chinese paper money, and plastic plates). Compared with fingerprint development using traditional powders such as bronze powder, magnetic powder, and green fluorescent powder, our development procedure using UCNPs is facile and exhibits very high sensitivity, high contrast, low background interference, and low autofluorescence interference. This work shows that UCNPs synthesized under optimized conditions are a versatile fluorescent label for the facile development of fingerprints and can find their practical applications in forensic sciences. (Figure Presented). © 2015 American Chemical Society.


Wang M.,Shenyang University | Wang M.,Key Laboratory of Impression Evidence Examination and Identification Technology | Li M.,Shenyang University | Li M.,Key Laboratory of Impression Evidence Examination and Identification Technology | And 8 more authors.
Nano Research | Year: 2015

The most commonly found fingermarks at crime scenes are latent and, thus, an efficient method for detecting latent fingermarks is very important. However, traditional developing techniques have drawbacks such as low detection sensitivity, high background interference, complicated operation, and high toxicity. To tackle this challenge, we employed fluorescent NaYF4:Yb,Er upconversion nanoparticles (UCNPs), which can fluoresce visible light when excited by 980 nm human-safe near-infrared light, to stain the latent fingermarks on various substrate surfaces. The UCNPs were successfully used as a novel fluorescent label for the detection of latent fingermarks with high sensitivity, low background, high efficiency, and low toxicity on various substrates including non-infiltrating materials (glass, marble, aluminum alloy sheets, stainless steel sheets, aluminum foils, and plastic cards), semi-infiltrating materials (floor leathers, ceramic tiles, wood floor, and painted wood), and infiltrating materials such as various types of papers. This work shows that UCNPs are a versatile fluorescent label for the facile detection of fingermarks on virtually any material, enabling their practical applications in forensic sciences. [Figure not available: see fulltext.] © 2014, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.


Wang M.,Shenyang University | Wang M.,Key Laboratory of Impression Evidence Examination and Identification Technology
RSC Advances | Year: 2016

NaYF4:Yb,Er and NaYbF4:Er/Tm/Ho NIR-responsive upconversion fluorescent nanocrystals were used to develop latent fingermarks on the surfaces of various substrates. Development exhibited high developing contrast, high developing sensitivity, and high developing selectivity. In particular, one-year-old fingermarks, fingermarks on wet substrates, and fingermarks on surfaces with multicolored background and strong fluorescent properties could be clearly observed through our method. This journal is © The Royal Society of Chemistry 2016.


Chang W.,Key Laboratory of Impression Evidence Examination and Identification Technology | Chang W.,Northeastern University China | Wang H.,Key Laboratory of Impression Evidence Examination and Identification Technology | Wang H.,Northeastern University China
IEEE 7th International Conference on Awareness Science and Technology, iCAST 2015 - Proceedings | Year: 2015

Traffic accident of coach bus occurred frequently in recent years. One important reason of the accident is the fatigue driving of the bus driver. Thus it is very important to monitor and research the state of the driver during the driving process, which can give an evaluation to driver's driving condition and provide a valuable reference to the coach driving. Because there have some different features of human electroencephalogram (EEG) between the fatigue state and the natural state, we used the portable EEG acquisition device, Emotive, to get the EEG of the driver in the natural state (before driving) and the fatigue state (after driving three hours) in the real driving environment. And through the wavelet packet analysis, the EEG was decomposed to four sub frequency band: theta, alpha, beta and delta band, for each band, the nonlinear correlation of different electrode was calculated and functional brain network was constructed. Then the network was converted to binary network by choose an appropriate threshold and some network feature parameters were calculated and compared between the natural state and the fatigue state. The result shows that the differences of the functional brain network between the two states are very clear and this method can be used to monitor and evaluation the driver's fatigue state. © 2015 IEEE.

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