Earticle

이 연구에서는 안동 봉정사 영산회괘불도에 대한 비파괴성분 분석과 현미경 관찰을 통해 괘불에 채색된 안료의 화학적 성분 및 채색 기법을 해석하였고 이를 바탕으로 괘불의 화기에 명시되어 있는 채색 재료의 명칭에 대한 화학적 특성을 규명하였다. 백색 안료는 연백, 황색 안료는 석황, 유기염료, 적색 안료는 진사/주, 연단, 대자, 적색 염료을 사용하 였으며, 녹색 안료는 석록 또는 녹염동광, 청색 안료는 석청, 쪽, 흑색은 먹을 사용한 것으로 추정된다. 화기에 명시된 안료 이름은 주홍, 중청, 하엽, 황단, 황금 등으로 주홍은 진사(천연) 또는 주(인공), 중청은 석청, 하엽은 석록 또은 녹염동 광, 황단은 석황, 황금은 금박인 것을 확인하였다.

This study interpreted the chemicals of the pigments and the coloring techniques employed on Youngsan Ritual Ceremony Buddhist Painting through a nondestructive analysis method and a microscopic observation. Based on the interpretation, this study closely examined the chemical properties of the names of the coloring materials specified on the ceremonial writing of the Buddhist painting. It is estimated that lead white was used for the white pigments, orpiment and organic pigment for the yellow pigment, cinnabar/vermilion, minium, red ochre, and red dyes for the red pigments, malachite or atacamite for the green pigments, azurite and indigo for the blue pigments, and ink stick for the black pigments. The pigment names specified on the ceremonial writing are juhong, jungcheong, hayeop, whangdan, and whanggeum, and it was verified that juhong is cinnabar or vermilion, jungcheong is azurite, hayeop is malachite or atacamite, whangdan is minium, and whanggeum is a gold foil.

18세기 제작된 유언호 초상화에 대한 비파괴분석 통해 채색에 사용된 안료의 종류와 채색기법을 추정하였으며, 이를 바탕으로 18세기의 초상화 11점과의 채색특성을 비교해보았다. 유언호 초상에 사용된 안료는 백색에 연백, 황색에 염료, 적색에 진사, 연단, 적색염료, 녹색에 석록, 청색에 석청, 갈색에 적색산화철, 갈색염료, 자주색에 청색과 분홍색의 염료 등을 사용하였다. 11점의 초상화와 채색 안료를 비교한 결과 18세기 초상화에 사용된 안료는 시기별로 큰 차이를 보이지 않았으며, 동일 화첩에 수록된 초상화일지라도 안료의 사용은 초상화마다 개별적으로 나타났다. 채색기법에서는 유언호 초상 이후의 초상에서 얼굴에 진사를 사용하지 않고 산화철만 사용하였으며, 의복의 배채에 녹색 안료 대신 염료를 사용하였다. 본 연구를 통해 18세기 전반에 걸쳐 제작된 초상화의 채색 특성을 확인할 수 있었다. 이번 연구 결과가 조선 후기 초상화의 채색기법 연구에 기초자료로 활용되기를 기대해 본다.

We estimated pigments and painting techniques with nondestructive analysis for Yu Eonho’s portrait made in the eighteenth century, then compared with 11 portraits and painting characteristics at that time. The pigments used to Yu Eon-ho's portrait include lead white, yellow dye, cinnabar, minium, and pink dye, malachite, azurite, iron oxide red and brown dye, blue and pink dye for purple. In the result compared with painted pigments of 11 portraits, iron oxide red without cinnabar was used on the face part and organic green dye only was used instead of inorganic pigments on the other side of clothing after Yu Eonho’s portraits portrait. This study is show the painting techniques on the portraits in the late 18th century. We expect to use as useful referencing data for the study on the coloring technique of a portrait in the late Joseon Dynasty.

은 소지 위에 금을 도금한 은제금도금유물을 대상으로 성분분석을 위해 X선 형광 분석기를 이용하여 비파괴분석을 실시하면 소지금속인 Ag에서 전자궤도에 따라 무게백분율(wt.%)의 값이 큰 차이가 나타나는 특이점을 확인할 수 있다. 이러한 특이점을 이용하여 육안으로는 파악하기 쉽지 않은 유물에서도 은제금도금기법이 사용되었는지를 판단할 수 있는 근거를 제시하고자 재현시료를 제작하여 비교분석을 실시하였다. 그 결과 수은아말감도금법과 전기도금법으로 제작된 시료에서는 실제 유물들의 분석결과와 같은 결과를 볼 수 있었다. 하지만 금은합금시료의 경우 도금시료와는 달리 주성분들의 전자궤도에 따른 차이가 미미한 것을 확인할 수 있었다. 도금시료에서 나타나는 이러한 원인으로는 단일재료가 아닌 도금으로 인한 이중구조에 의해 도금층에서 XRF 빔을 흡수하면서 발생하는 것으로 보인다. 따라서 비파괴분석에서 나타나는 이러한 결과를 이용한다면 단면을 관찰하지 않아도 은제금도금 기법의 사용 여부를 판단할 수 있을 것으로 확인하였다.

If the nondestructive analysis is carried out by using an X-ray Fluorescence Analyzer(XRF) for ingredient analysis with the target of gold plated silverware that plates gold on a silver basis, a singular point showing big difference at the value of weight percent(wt.%) according to the electron orbit of the principal ingredient can be confirmed. The present research made reproduced samples and carried out comparative analysis in order to suggest a basis that can judge whether the technique of gold plated silverware was used in case of remains uneasy to understand with eyes by using this singular point. As a result, the same result as analysis results of actual remains could be seen in specimens manufactured by a mercury amalgam plating method. However, in case of gold and silver alloy specimens, it could be confirmed that the difference according to the electron orbit of the principal ingredients is slight unlike plated specimens. The reason appearing at plated specimens seems to be generated while absorbing XRF beam at plated layers by double structure due to plating instead of single material. Accordingly, if this result appearing at nondestructive analysis is used, it was confirmed that the application of the technique of gold plated silverware can be judged without observing its section.

대통사는 삼국시대 사찰 중에서 가장 이른 시기에 창건된 것으로 알려져 있다. 창건주체와 목적 및 사찰명 등은 고문헌과 공주지역에서 출토된 ‘대통’ 명의 유물에서 확인할 수 있으나, 사찰의 위치와 사역에 대해서는 다양한 논의가 진행 중이다. 이 연구에서는 공주 반죽동 일대의 대통사 추정 지에서 출토된 주칠흔(적색안료) 기와에 대해 비파괴 분석으로 제작기법을 검토하였다. 연구대상 기 와의 등면에는 주칠흔이 선명하며, 원료는 정선과정을 거친 것으로 나타났다. 또한 태토를 점토판으로 제작하여 와통에 포목을 둘러 붙이는 방식으로 성형하였으며, 일부 기와는 모골와통을 활용한 것으로 판단된다. 한편 등면에서 나타나는 주칠흔의 산출상태와 조성으로 볼 때 산화철을 주성분으로 하는 석간주 또는 주토를 활용한 단청 안료로 해석된다. 고문헌에 알려진 석간주의 산출지는 공주에서 원거리에 있으나, 산화철은 다수의 암석에서 비교적 쉽게 나타나는 물질로서, 근거리의 원료수급과 관련하여 대통사 추정지를 중심으로 추가적인 검토가 필요하다.

The Daetongsa temple is the earliest temple to be constructed during the era of the Three Kingdoms in ancient Korea. The main architect, purpose, and name of the temple have been confirmed through ancient literature and archeological materials carved in the Chinese letter, Daetong, excavated around Gongju. However, the location and range of the temple have remained elusive and were discussed in various studies. In this study, we examine the roof tiles obtained from the presumed site of the Daetongsa temple. The tiles were found to contain traces of red paint (red pigments) on their surface and analyzed using nondestructive techniques. The results imply that roof tiles were made using clay tablets and wooden cylinders, with latticed cloth in between. Additionally, some wooden cylinders appeared to comprise numerous wooden plates tied together by strings. The clay tablets used to make the roof tiles were produced from the source clay via the sorting process. The traces of red paint on the surface of the roof tiles were verified to be traditional pigments used for painting wooden buildings. These pigments were extracted from red ocher or red clay (Seokganju), mainly consisting of iron oxide. In the literature, the location of provenance sites for Seokganju is estimated to be far from Gongju. However, the materials for extracting the red pigments were relatively easy to source because most rocks comprised iron oxides. Therefore, it is necessary to discuss the provenance of the red pigments around the presumed site of Daetongsa.

이 연구에서는 비파괴 기법을 활용하여 관룡사 약사전 벽화에 채색된 안료의 화학적 특성을 규명하고, 손상유형에 따른 정밀진단을 통해 훼손도를 정량적으로 평가하였다. 각 색상에 따른 추정 안료는 기존의 연구와 동일한 것으로 확인되었으나, 청색계통과 화조화의 바탕으로 채색된 녹색계통의 안료에서 검출된 Co는 지금까지 전통 채색 안료에서 확인된 바 없는 특이한 결과이다. 훼손도 진단을 위해 초음파 측정, 적외선 열화상 촬영 등을 실시한 결과, 관룡사 약사전 벽화에 발생한 균열 및 박리 ․ 박락은 수분의 영향으로 판단된다. 따라서 이 벽화의 장기적인 보존을 위해서는 벽화로 유입되는 수분의 침투경로를 정확히 파악하고 효율적인 주변환경 관리를 통해 장기적인 보존대책을 마련해야 할 것이다.

We have investigated chemical properties of the pigments and carried out the deterioration diagnosis using nondestructive techniques of the wall painting in Yaksajeon Hall of Gwanyongsa Temple. As the results of pigments analysis, it was unusual that the cobalt was detected in the blue and green colors used to traditional paint background. According to the deterioration diagnosis, ultrasonic measurement and infrared thermography, dominant cracks and exfoliation caused by high content of moisture. Therefore, it should be devised effective plan to prevent penetration of water for the long term this wall painting.

Semiconductors are crucial components in communication technology, playing important roles in various communication systems. They are essential for signal processing, data transmission, and ensuring the stability of communication networks. In particular, high-performance semiconductor chipsets and processors enable ultra-fast data transmission and ultra-low latency in communication technology. For example, semiconductors are indispensable in smartphones, wireless networks, and satellite communication systems. For semiconductor packaging products, nondestructive internal analysis for defect analysis and process improvement without causing deformation of system packaging is an important part of the product development process. In this study, nondestructive analysis techniques using X-ray equipment are discussed. The results of this study can provide fast and accurate nondestructive analysis of semiconductor packaging products and can play a significant role in supporting the growth of the communication industry.

The aim of this study was to examine whether near infrared spectroscopy (NIRS) is an acceptable tool to determine cholesterol and collagen in human atherosclerotic plaque without destruction of the analyzed areas and without danger the endothelial cells - three preconditions for the development of a NIR-heart-catheter. The questions were: Can the cholesterol and collagen content of the arterial intima be estimated with acceptable precision in vitro by NIRS despite the matrix inhomogeneity of the plaques and their anatomic variability\ulcorner How deep can such NIR radiation penetrate into arterial tissue without danger for endothelial cells\ulcorner Is this penetration sufficient for information on the lipid and collagen accumulation\ulcorner Using NIRS, cholesterol and collagen can be determined with acceptable precision in model mixtures and human aortic specimens (r=0,896 to 0,957). The chemical reference method was HPLC. The energy dose was 71 mW/$cm^{-2}$ using a fiber optic strand with a length of 1.5m and an optical window of d=4mm. This dose appears to be not dangerous for endothelial cells, It will be attenuated to 50% by a arterial tissue of about 170-$200\mu\textrm{m}$ thickness. The results are also acceptable using a thin coronary catheter-like fiber optic strand (d=1mm).

Nondestructive nanostructural analysis is indispensable in the development of nano-materials and nano-fabrication processes for use in nanotechnology applications. In this paper, we demonstrate for the first time a quantitative, nondestructive analysis of nanostructured thin films supported on substrates and their templated nanopores by using grazing incidence X-ray scattering and data analysis with a derived scattering theory. Our analysis disclosed that vertically oriented nanodomain cylinders had formed in 20-100 nm thick films supported on substrates consisting of a mixture of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and PMMA homopolymer, and that the PMMA nanodomains were selectively etched out by ultraviolet light exposure and a subsequent rinse with acetic acid, resulting in a structure consisting of hexagonally packed cylindrical nanopores.

We studied the nondestructive evaluation of the elastic wave signal of SiC ceramics and SiC/SiC composite ceramics under monotonic tensile loading. The elastic wave signal of cross and unidirectional SiC/SiC composite ceramics were obtained by the pencil lead method and a bending test. This was applied for the time-frequency method which used the discrete wavelet analysis algorithm. The time-frequency analysis provides the time variation of each frequency component involved in a waveform, which makes it possible to evaluate the contribution of the SiC fiber frequency. The results were compared with the characteristic of the frequency group from SiC slurry and fibers. Based on the results, if it is possible to shift up and design a higher frequency group, we can then make a superior material better than those of exiting SiC/SiC composites.

This study was conducted to develop neural networks of predicting the sugar content of fruits based on the optical densities obtained from a spectrophotometer. Pear, apple and peach were used in investigating the feasbility of the developed neural networks as a nondestructive measurement. A spectrophotometer was used to measure the optical densities of test fruits. The neural networks suggested in this study consisted of multi-layers having one hidden layer and one output layer. The correlation coefficients between the predicted and the measured sugar content for most fruits were high. The neural networks using 2nd derivatives of optical density spectrum produced a better results in predicting the sugar content of fruits. This study contributed to develop a method for nondestructively predicting the sugar content of fruits.

The spin valve tunneling magnetoresistance (SV-TMR) sensor performance is analyzed using Stoner-Wohlfarth model for the detection of eddy current signals in nondestructive testing applications. The SV-TMR response in terms of the applied AC magnetic field dominantly generates the second harmonic amplitude in hard axis direction. The second harmonic eddy current signal detection using SV-TMR sensor shows higher performance than that of the coil sensor at lower frequencies. The SV-TMR sensor with high sensitivity gives a good solution to improve the low frequency performance in comparison with the inductive coil sensors. Therefore, the low frequency eddy current techniques based on SV-TMR sensors are specially useful in the detection of hidden defects, and it can be applied to detect the deeply embedded flaws or discontinuities in the conductive materials.

In this studies, joint time-frequency analysis techniques were applied to analyze ultrasonic signals in the degraded austenitic 316 stainless steels, to study the evolution of damage in these materials. It was demonstrated that the nonstationary characteristics of ultrasonic signals could be analyzed effectively by these methods. The WVD was more effective for analyzing the attenuation and frequency characteristics of the degraded materials through ultrasonic. It is indicated that the joint time-frequency analysis, WVD method, should also be useful in evaluating various damages and defects in structural members.

The 3-dimensional measuring machine by using an ultrasonic sensor is used one of the NDE(Nondestructive Examination). It is applied to the inspection of pipelines, boreholes, pressure vessel and tank, and so on. In particular when a harsh environment prohibits the use of moving mechanical parts. The 3-dimensional measuring machine by using an ultrasonic sensor, which measure 1-dimensional information and 2-dimensional information simultaneously from a target of inspection, and then reembody 3-dimensional information. So we can find the situation in progress and predict remaining life and corrosion without destructive examination. It's a point of excellence that the 3-dimensional measuring machine is portable.

A large variety of mineral pigments has been used for Korean paintings and it has known that organic pigments have been used together on the Buddhist painting and the portrait. Haehakbando-do, which is from Honolulu Academy Museum in the United States, 12-fold screen was commissioned by Court of the late Joseon Dynasty in order to pray for the King's longevity. Therefore, it seems that all material used including pigments were selected very carefully and a great deal of technical effort was gone into its process. The purposes of this research were to estimate the pigments and the contributory elements of each color used on Haehakbando-do, in accordance with the conservation treatment carried out by Gochang Conservation Institute throughout last year. Without extracting sample, property of pigment was measured by nondestructive method, X-ray spectral analysis, and by comparing with the data about ancient pigments. In spite of the limited range of pigment analysis by nondestructive method, it should be noted that this method would not cause damage to the cultural properites. White pigment was found in all colored parts except the background, so it can be suggested that white color was used as a grounding of other color pigments. This would be flake white[$2PbCO_3{\cdot}Pb(OH)_2$] as Pb was found. Pb was the only element could be found in yellow, however, it can be organic pigment like Gamboge as same as background. Red would be Cinnabar (HgS) as hydrargyrum (Hg) was detected. For the light purple in cloud, organic pigments were probably used since any element is not detected except for Pb, which is used for background. It is possible that green color is the mixture of Malachite[$CuCO_3{\cdot}Cu(OH)_2$] and Azurite [$2CuCO_3{\cdot}Cu(OH)_2$], which share Cu as their main element. Azurite[$2CuCO_3{\cdot}Cu(OH)_2$] was used for bluish pigments. Black is carbon compound. For gold, solid gold (Au) was detected. It shows that gold was gilded on the flake white background. Red painted on the frame of screen was identified as Cinnabar (HgS) and the gold pattern was solid gold (Au). The supporting leg of folding screen was made of brass because both copper and zinc were detected. In conclusion, white pigment was used as grounding of all colors of Haehakbando-do, and specific pigments were used for each color. Additionally, result from the analysis of several pigments shows that mineral pigment and organic pigment, or different mineral pigments were mixed to make various colors.

본 연구는 참깨에 함유된 세사민 및 세사몰린의 함량을 비파괴적으로 신속하게 평가하기 위하여 NIRS 분석을 이용해 검량식을 작성하고 검량식의 적용가능성을 검증하였다. 검량식 작성에 사용된 482점 참깨의 HPLC 분석 결과를 NIRS 스펙트럼에 적용시킨 후 검량식을 작성하였다. 세사민 및 세사몰린의 R² 값은 각각 0.936, 0.875로 조사되었으며 이를 cross validation 한 결과에서도 각각 0.899, 0.781로 조사되어 리그난 함량 분석에 적용 가능할 것으로 판단되었다. 작성된 검량식의 적용가능성을 확인하기 위해 2020년에 생산된 참깨 유전자원 90종의 종자를 NIRS를 통해 분석한 결과 세사민 및 세사몰린의 R²값이 각각 0.653, 0.596으로 크게 낮아졌으나 리그난 함량이 높은 상위 30%의 자원을 선발하는데 무리가 없었다. 따라서 본 연구에서 작성된 NIRS 검량식은 육종 초기에 고리그난 함량을 선발하는데 적용 가능할 것으로 판단된다.

Sesamin and sesamolin are major lignan components with a wide range of potential biological activities of sesame seeds. Near infrared reflectance spectroscopy (NIRS) is a rapid and non-destructive analysis method widely used for the quantitative determination of major components in many agricultural products. This study was conducted to develop a screening method to determine the lignan contents for sesame breeding. Sesamin and sesamolin contents of 482 sesame samples ranged from 0.03-14.40 mg/g and 0.10-3.79 mg/g with an average of 4.93 mg/g and 1.74 mg/g, respectively. Each sample was scanned using NIRS and calculated for the calibration and validation equations. The optimal performance calibration model was obtained from the original spectra using partial least squares (PLS). The coefficient of determination in calibration (R²) and standard error of calibration (SEC) were 0.963 and 0.861 for sesamin and 0.875 and 0.292 for sesamolin, respectively. Cross-validation results of the NIRS equation showed an R² of 0.889 in the prediction for sesamin and 0.781 for sesamolin and a standard error of cross-validation (SECV) of 1.163 for sesamin and 0.417 for sesamolin. The results showed that the NIRS equation for sesamin and sesamolin could be effective in selecting high lignan sesame lines in early generations of sesame breeding.

In this study, the pressure vessel piping with corrosion used during long term were investigated from the time-frequency analysis method. The damage of piping could be evaluated the attenuation factor by ultrasonic parameters such as center frequency and echo waveform. Based on NDE analysis by time-frequency analysis method, it should also be possible to evaluate from various damages and defects in piping members.

지금까지 퓨리에 변환이 신호처리법으로 가장 널리 사용되고 있다. 그러나, 이 방법은 신호의 주파수성분이 시간에 대하여 어떻게 변화하는지를 표현하지 못한다. 따라서, 최근 이와 같이 비정상신호를 표현하지 못하는 퓨리에 변환의 단점을 보완하여, 신호의 시간과 주파수에 대한 정보를 동시에 표현할 수 있는 시간-주파수 해석법들이 개발되기 시작하였다. 본 연구에서는 인공열화된 SUS 316강의 초음파신호를 시간-주파수 해석법으로 분석하였다. 특히, 단시간 퓨리에 변화법과 위그너 빌 분포법을 이용하여 초음파 신호의 주파수 성분과 특성을 분석하였다.

Fourier transform has been one of the most commonly used tools in study of frequency characteristics of signal. However, based on the Fourier transform. it is hard to tell whether a signal's frequency contents evolve in time or not. Recently, to overcome Fourier transform fault. not to represent non-stationary signal, time-frequency analysis methods are developed and those can represent informations of signal's time and frequency at the same time. In this study we analysed ultrasonic signal for degraded SUS 316 with time-frequency analysis method. In particular the methods such as short time Fourier(STFT) and Wigner-Ville distribution(WVD) were used to extract frequency contents and characteristics from ultrasonic signals.

차량용 반도체 수요의 증가로 자율 주행 및 전장제품에 시스템 반도체 수요가 증가하고 있다. 차량용 반도체는 기존 AP 같은 칩보다 더 높은 내구성과 신뢰성이 요구되기 때문에 불량 분석이 중요하다. 이러한 환경에서 반도체의 안정적인 생산과 품질 보장을 위해서는 불량 검출과 불량 원인 분석이 중요하다. 본 논문은 기본적인 비파괴 불량 분석 방법에 대하여 조사하고 장단점을 탐구한다. 이를 통해 반도체의 안정적인 양산을 위한 기반 지식을 제공한다.

숏크리트는 터널에서 적용되는 요요한 주지보재이다. 숏크리트의 품질평가는 터널의 안전한 시공과 효과적인 운영을 위한 핵심 요소이다. 숏크리트가 암반에 적절히 타설되었다 하더라도, 막장 및 벤치부에서의 발파, 수축, 지반의 변형 등으로 인해 숏크리트 균열발생 및 배면공동 등의 문제를 야기한다. 본 논문에서는 비파괴 시험인 충격 반항 기법(Impact-Echo) 및 지하레이다 탐사(GPR)를 이용하여 경임에 타설된 숏크리트 배면의 접착상태를 평가하고자 하였다. 기존의 수치해석 연구에 대한 검증과 더불어 현장 적용성에 대한 검토를 위해 실험적 연구를 수행하였다. 숏크리트의 접착상태는 완전 접착, 접착력 상실 및 공동 조건으로 구분할 수 있다. 실내 실대형 시험체에 이 세 가지 숏크리트 접착상태를 조사하였다. 충격반향시험으로부터 획득된 신호는 시간영역, 주파수 영역, 및 시간-주파수 영역에서 각각 분석되었다. 능동적 신호 처리 기법인 Short-Time Fourier Transform(STFT)을 이용하여 숏크리트 배면의 접착상태를 효과적으로 예측할 수 있었으며, 그 결과는 기존의 수치해석 연구로부터 획득한 신호특성과 잘 부합하였다. 숏크리트 배면의 접착상태가 불량할수록 다음과 같은 특징들을 나타낸다. 즉, 주파수 영역에서 자기스펙트럼밀도가 커지며, 기하학적 감쇠비는 감소하고, 시간-주파수 영역에서 윤곽선은 시간축에 평행한 형상을 나타내며, 숏크리트 두께가 얇을수록 그 공진시간이 길어진다. 또한 본 연구에서 제시한 상관계수를 이용하여 숏크리트의 접착상태를 정량적으로 평가할 수 있다. 본 연구 결과를 바탕으로 숏크리트의 접착상태를 평가할 수 있는 평가 기법 및 평가 기준을 제안하였다.

Shotcrete is an important primary support for tunnelling in rock. The quality control of shotcrete is a core issue in the safe construction and maintenance of tunnels. Although shotcrete may be applied well initially onto excavated rock surfaces, it is affected by blasting, rock deformation and shrinkage and can debond from the excavated surface, causing problems such as corrosion, buckling, fracturing and the creation of internal voids. This study suggests an effective non-destructive evaluation method of the tunnel shotcrete bonding state applied onto hard rocks using the impact-echo (IE) method and ground penetration radar (GPR). To verify previous numerical simulation results, experimental study carried out. Generally, the bonding state of shotcrete can be classified into void, debonded, and fully bonded. In the laboratory, three different bonding conditions were modeled. The signals obtained from the experimental IE tests were analyzed at the time domain, frequency domain, and time-frequency domain (i.e., the Short- Time Fourier transform). For all cases in the analyses, the experimental test results were in good agreement with the previous numerical simulation results, verifying this approach. Both the numerical and experimental results suggest that the bonding state of shotcrete can be evaluated through changes in the resonance frequency and geometric damping ratio in a frequency domain analysis, and through changes in the contour shape and correlation coefficient in a time-frequency analysis: as the bonding state worsens in hard rock condition, the autospectral density increases, the geometric damping ratio decreases, and the contour shape in the time-frequency domain has a long tail parallel to the time axis. The correlation coefficient can be effectively applied for a quantitative evaluation of bonding state of tunnel shotcrete. Finally, the bonding state of shotcrete can be successfully evaluated based on the process suggested in this study.