• Toxicological Research
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• 제34권2호
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• pp.127-132
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• 2018

Alcohol consumption triggers toxic effect to organs and tissues in the human body. The risks are essentially thought to be related to ethanol content in alcoholic beverages. The identification of ethanol in blood samples requires rapid, minimal sample handling, and non-destructive analysis, such as Raman Spectroscopy. This study aims to apply Raman Spectroscopy for identification of ethanol in blood samples. Silver nanoparticles were synthesized to obtain Surface Enhanced Raman Spectroscopy (SERS) spectra of blood samples. The SERS spectra were used for Partial Least Square (PLS) for determining ethanol quantitatively. To apply PLS method, $920{\sim}820cm^{-1}$ band interval was chosen and the spectral changes of the observed concentrations statistically associated with each other. The blood samples were examined according to this model and the quantity of ethanol was determined as that: first a calibration method was established. A strong relationship was observed between known concentration values and the values obtained by PLS method ($R^2=1$). Second instead of then, quantities of ethanol in 40 blood samples were predicted according to the calibration method. Quantitative analysis of the ethanol in the blood was done by analyzing the data obtained by Raman spectroscopy and the PLS method.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.466-470
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• 2004

The crystals of the new melaminium salt, i.e. melaminium acetate acetic acid solvate monohydrate, $C_3H_7N_6^+ {\cdot}CH_3COO^- {\cdot}CH_3COOH{\cdot}H_2O$, were obtained by the slow evaporation of an aqueous solution at room temperature. Powder infrared and Raman spectra were measured and interpreted. The vibrational spectra in the region of internal vibrations of ions corroborate structural data recently published by Perpetuo and Janczak.$^1$ Some spectral features of this new crystal are referred to corresponding one for melamine crystal as well as other melamine complexes in crystalline form. Hydrogen-bonded network present in the crystal gives notable vibrational effect.

• 전자공학회논문지SC
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• 제47권4호
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• pp.40-46
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• 2010

본 논문은 혈소판으로부터 측정한 라만 스펙트럼을 알츠하이머병(AD: Alzheimer's Disease) 진단에 사용하는 연구에 관한 것이다. 실험에 사용한 라만 스펙트럼은 다음과 같은 몇 가지 전처리 과정을 거친 다음 분류기를 이용하여 질병의 유무를 판별하였다. 먼저 스펙트럼은 간단한 smoothing을 거친 다음 스펙트럼의 각 피크 크기를 쉽게 측정할 수 있도록 기준선 (baseline)의 왜곡을 차감하였고, 그 다음 기준 피크를 중심으로 그 위치를 정렬한다. 이와 같은 전처리 과정을 수행한 라만 스펙트럼으로부터 AD과 정상상태(NOR: normal)를 구분할 수 있는 특징을 조사하였는데 그 결과 여러 피크들 중 743과 757 $cm^{-1}$ 영역의 피크 비와 1658 $cm^{-1}$ 영역의 피크 크기가 AD와 NOR 스펙트럼에서 가장 변별력 있는 특징을 나타내는 것을 확인하였다. 이 특징들을 MAP(maximum a posteriori)와 MLP(multi-layer perceptron) 분류기에 사용하여 총 278개의 스펙트럼에 적용한 결과 MLP에서 평균 약 95.5%의 분류율을 보였다. 이 결과는 혈소판 라만 스펙트럼이 알츠하이머병 진단에 매우 효과적으로 사용될 수 있음을 보여준다.

• 한국산학기술학회논문지
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• 제19권3호
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• pp.32-39
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• 2018

라만 스펙트럼은 측정 장비 및 환경 조건에 따라 동일한 물질이라도 스펙트럼의 강도 차이를 보인다. 이는 라만 분광의 패턴 인식적인 접근에 제약을 주기 때문에 장비간의 호환성 및 라만 데이터베이스의 재사용을 위해 반드시 해결해야 하는 문제다. 이를 위해 이전의 주요 연구들에서는 측정 장비 간에 전달 함수를 가정하고 이를 구한 후 직접적인 스펙트럼의 교정을 수행하였다. 하지만 이 방식은 강도 왜곡을 발생시키는 다른 조건들에 대해서는 대처 할 수 없는 방법이다. 따라서 본 논문에서는 다양한 측정 조건에 보다 유연하게 대응 할 수 있는 선형 강도 교정을 이용한 분류 방법을 제안하였다. 제안한 방법의 성능 평가를 위해 실험에서는 14033종의 화학 물질에서 측정된 라만 라이브러리를 실험물질에 대한 판별 지표로 사용하였으며, 3개의 라만 분광기로부터 측정된 10종의 화학 물질 라만 스펙트럼을 실험 데이터로 사용하였다. 실험결과에 따르면 제안한 방법을 사용하였을 때 강도 왜곡된 스펙트럼에 대해 100%의 판별 성능을 보였으며, 판별된 스펙트럼에 대해서도 이전보다 높은 상관점수를 보여 사용자가 화학 물질을 판별하는 데 유용한 도구로 사용될 수 있음을 확인하였다.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.612-620
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• 2015

Short-range detection of chemical agents deposited on ground surface using a standoff Raman system employing a pulsed laser at 248 nm is described. Mounted in a vehicle such as an NBC reconnaissance vehicle, the system is protected against toxic chemicals. As most chemicals including chemical warfare agents have unique Raman spectra, the spectra can be used for detecting toxic chemicals contaminated on the ground. This article describes the design of the Raman spectroscopic system and its performance on several chemicals contaminated on asphalt, concrete, sand, etc.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.999-1003
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• 2010

Raman spectra of a single layer graphene sheet placed in different gold substrates were obtained and are discussed in the context of surface enhanced Raman scattering (SERS). The gold substrates were composed of a combination of a thermally deposited gold film and a close-packed gold nanosphere layer. The SERS effects were negligible when the excitation wavelength was 514 nm, while the Raman signals were enhanced 3-to 50-fold when the excitation wavelength was 633 nm. The large SERS enhancement accompanied a spectral distortion with appearance of several unidentifiable peaks, as well as enhancement of a broadened D peak. These phenomena are interpreted as the local field enhancement in the nanostructure of the gold substrates. The difference in the enhancement factors among the various gold substrates is explained with a model in which the spatial distribution and polarization of the local field and the orientation of the inserted graphene sheet are considered important.

• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.208-215
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• 2023

Deep learning techniques provide powerful solutions to several pattern-recognition problems, including Raman spectral classification. However, these networks require large amounts of labeled data to perform well. Labeled data, which are typically obtained in a laboratory, can potentially be alleviated by data augmentation. This study investigated various data augmentation techniques and applied multiple deep learning methods to Raman spectral classification. Raman spectra yield fingerprint-like information about chemical compositions, but are prone to noise when the particles of the material are small. Five augmentation models were investigated to build robust deep learning classifiers: weighted sums of spectral signals, imitated chemical backgrounds, extended multiplicative signal augmentation, and generated Gaussian and Poisson-distributed noise. We compared the performance of nine state-of-the-art convolutional neural networks with all the augmentation techniques. The LeNet5 models with background noise augmentation yielded the highest accuracy when tested on real-world Raman spectral classification at 88.33% accuracy. A class activation map of the model was generated to provide a qualitative observation of the results.

• 한국초전도ㆍ저온공학회논문지
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• 제9권4호
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• pp.24-27
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• 2007

The purpose of this work is to develop, integrate, and implement an optical characterization method to evaluate physical properties in coated conductors and investigate the local distribution of the causes of degraded performance. The method that we selected at this moment is Raman scattering spectroscopy, which is accompanied with measurements of local supercurrent transport, phase composition, microstructure, and epitaxy quality for coated conductors that range in size up to multi-meter-length tapes and that embrace the entire tape embodiment (substrate through cap layer). The establishment of Raman spectroscopy as an on-line process monitoring tool is our eventual goal of research, but it requires very robust and cost-effective equipments. We analyzed $YBa_2Cu_3O_7(YBCO)$ thin films grown at various substrate temperatures by using Raman spectroscopy. YBCO films were grown by a high-rate electron-beam co-evaporation method. Raman spectra of YBCO films with lower-transport properties exhibit additional phonon modes at ${\sim}300cm^{-1}$, ${\sim}600cm^{-1}$ and ${\sim}630cm^{-1}$, which are related to second-phases such as $Ba_2Cu_3O_{5.9}$ and $BaCuO_2$. We propose a new method to characterize Raman spectra of coated conductors for an in-line quality control.

• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.130-134
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• 1995

Surface-enhanced Raman (SER) scattering of 2-cyanonaphthalene (2-CN) has been investigated in silver sol. Addition of halide ions was needed to obtain authentic SER spectra of the molecule. The SER spectra thus obtained exhibited a slight but noticeable dependence on the kind of halide ions used. This halide-dependent spectral variation was attributed to the orientational change of molecule on silver sol surface. A possible mechanism for such an orientational change is proposed in terms of the competitive adsorption of 2-CN with halide ions on the so-called halide-specific sites.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.59-64
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• 1989

Raman vibrational Q0branch spectra of pure CO are measured by using the technique of quasicw inverse Raman spectroscopy utilizing a pulsed single-frequency laser source. This approach gives enhanced sensitivity compared to earlier work which employed CW lasers, allowing extension of that work to higher accuracy, higher J states, and higher pressure. Fitting laws with pertubation theory and modified energy gap(MEG) theory are described, and the line broadening and shifting coefficients of J=0 to 24 are determined with both fitting laws.