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Although friction characteristics of fault gouge are important to understand reactivation of fault, behavior of earthquake, and mechanism of slope failure, analysis results of fault gouge have low accuracy mostly than those of soils or rocks due to its high heterogeneity and low strength. Therefore, to improve the accuracy of analysis results, we conducted simple regression analysis and structural equation model analysis and selected major influential factors of friction characteristics among many factors, and then we deduced advanced regression model with the highest coefficient of determination (R2) via multiple regression analysis. Whereas most coefficients of determination in simple regression analysis are below 0.3–0.4, coefficient of determination in multiple regression analysis is remarkably large as 0.657.

In surface-enhanced Raman scattering (SERS), two complementary SERS enhancement mechanisms are known: electromagnetic enhancement (EME) and chemical enhancement (CE). Herein, we demonstrated, by exciting SERS with a well-suited laser wavelength near the localized surface plasmon resonance (LSPR) of gold nanorods (AuNRs), that the CE contribution to the SERS signal can be selectively tuned and quantified through its correlation with chemical interface damping (CID), one of the LSPR decay processes in AuNRs. We further elucidated probe electrophilicity of a series of para-substituted aromatic thiophenols through a strong gold–sulfur interaction that plays an important role in hot-electron charge transfer from AuNRs to adsorbates, effectively increasing the CE. Therefore, our findings reveal that strong CID must significantly increase the CE for SERS to allow tuning of the CE under resonant conditions.

Determining the mechanical properties of fault-core-zone materials is challenging because of the low strength of such materials, which affects field sampling, specimen preparation, and laboratory testing. We overcame this problem by preparing and testing mechanical properties of 132 artificial fault-core-zone specimens consisting of mixtures of breccia, sand, clay, and water. The unconfined compressive strength (UCS), elastic modulus (E), and penetration resistance value (PRV) of these fault-core-zone materials were measured, and the effects of breccia content and water content on mechanical properties were assessed. Results show that UCS is inversely proportional to breccia content and water content, and that E is inversely proportional to water content. Furthermore, the inverse relationship of UCS with water content varies with breccia content. UCS is proportional to both PRV and E, and the relationship for each varies with breccia content. High coefficients of determination (R2 = 0.62–0.88) between the parameters suggest that breccia content, water content, and PRV are potentially useful parameters for estimating the mechanical properties of fault core zones.

Plasmonic gold nanoparticles can be an efficient source of hot electrons that can transfer to adsorbed molecules for photochemistry, followed by broadening of the homogeneous localized surface plasmon resonance (LSPR) linewidth. Although chemical interface damping (CID) is one of the main decay processes, it is the most poorly understood damping mechanism in gold nanoparticles. Herein, to better understand CID and to find new functional groups that can induce CID as an alternative to thiol groups (-SH, sulfhydryl groups), we carried out scanning electron microscopy (SEM) correlated dark-field (DF) scattering studies of gold nanorods (AuNRs) at the single-particle level. We found that biotin with sulfur can lead to strong plasmon damping in single AuNRs. We chose biotin in this study because it is widely used as a linker that can selectively bind to streptavidin in many biological sensing experiments. We further demonstrated the possibility of real-time detection of biological molecules, specifically biotinylated BSA proteins, by means of CID in single AuNRs. Therefore, this study allows us to gain a deeper insight into how adsorbate molecules with sulfur affect CID, which is an important step toward developing a CID-based LSPR biosensor to detect real biological molecules having sulfur or thiol groups without interference from the medium dielectric constant in single AuNRs.

Chemical interface damping (CID) is one of the plasmon decay processes that occur in gold nanoparticles. With the aim of exploring new functional groups that can induce CID as an alternative to thiol groups, we performed dark-field (DF) scattering studies of gold nanorods (AuNRs) using pyridine as adsorbate. We found that the adsorption of pyridine molecules on single AuNRs though nitrogen-gold interactions leads to an increase of the localized surface plasmon resonance (LSPR) linewidth. However, pyridine molecules were not adsorbed effectively on AuNR surfaces having a capping reagent. This study allows us to gain insight into the effect and role of the capping reagent in pyridine-induced CID. Furthermore, pyridine was revealed to induce a strong CID through the interaction of the nitrogen atom with the Au surface, provided the capping material was previously removed from the AuNRs by oxygen plasma treatment. Finally, we demonstrated that CID could be used to sense pyridine and its derivatives in real-time.

Fault gouges play an important role in the shear deformation of fault zones, by causing weakness and frictional instability in structures. Previous studies have investigated the evolution of shear deformation of fault zones by observing experiments using remolded and synthetic gouge specimens at a micro-scale. However, how the spatial configuration of the rock constituents accounts for the 3D anisotropy of intact structures of fault gouges, particularly at the core-scale, is not well understood. We obtained 3D μ-CT images of directionally cored gouge specimens and performed statistical analysis to quantify the major orientation of the internal structures. Direct shear tests were conducted to investigate the relationship between the distribution of the internal structures and geomechanical behavior. The results show that the undisturbed fault gouge has a clear anisotropy parallel to the fault plane even at the core-scale. Moreover, the direct shear test results show that the frictional resistance of a fault gouge has anisotropy related to the fault plane. The simple, yet robust method proposed in this study confirms that the core-scale structural anisotropy is correlated to the anisotropic shear resistance.

Plasmon damping in gold nanorods (AuNRs) results in the broadening of the localized surface plasmon resonance (LSPR) linewidth. LSPR broadening of plasmonic nanoparticles is useful to maximize the fraction of light energy in light harvesting and energy conversion transferred to molecules attached on the surface. However, our understanding of plasmon decay channels in AuNRs is still limited, and chemical interface damping (CID) is the most poorly understood damping mechanism. Herein, to better understand plasmon damping including CID, we performed a single particle study of plasmonic anisotropic AuNRs using dark-field (DF) microscopy and spectroscopy. First, we examined the size-dependent broadening of the homogeneous LSPR linewidth of single AuNRs in water with three different aspect ratios (ARs) at a fixed diameter of 25 nm. The LSPR linewidth increased with a decrease in the AR of single AuNRs because of the reduced average distance of hot electrons to the surface. Second, we investigated the effect of refractive index variation of the surrounding medium on the LSPR linewidth in single AuNRs of three different sizes. The LSPR linewidth in single AuNRs remained almost constant regardless of their sizes while increasing the dielectric constant of the medium. Finally, we examined the effect of adsorbate thiol molecules on the homogeneous LSPR linewidth of single AuNRs in ethanol. The LSPR linewidth was broadened upon increasing the carbon chain length of 1-alkanethiol, and 4-nitrothiophenol with a strong electron withdrawing group induced a large broadening of the LSPR linewidth. Furthermore, single AuNRs with smaller ARs showed a larger broadening of the LSPR linewidth in the presence of adsorbate thiol molecules through CID. Therefore, this investigation provides a deeper insight into the size effect on plasmon damping including CID induced by the chemical interface effect in single AuNRs.

Fault core materials (fault breccia and fault gouge) exhibit heterogeneous particle size distributions due to many factors, including the type of cataclasis, the degree of weathering, and the scale and mechanism of the fault system. When studying particle size distributions in fault core materials, there is no clear standard of the sample size that should typically be used for testing and analysis. In this study, we present a method to establish the ideal sample size by statistically assessing a suite of laboratory tests on 451 fault-core samples from 21 locations in South Korea. These samples were divided into five different classes according to grain size. Weight ratios of gravel, sand, and silt/clay were calculated from laboratory tests on each sample, and the means and standard deviations were subsequently assessed via analysis of variance and multiple comparison analysis. The results of the analysis of variance suggested that classes 1–5 are different from each other in at least one factor. Tukey’s HSD tests and Duncan’s LSR tests were also applied to identify groups within the classes that might be statistically similar to each other. In this manner, it was found that classes 1 and 2 could be grouped together (group A), as could classes 3, 4, and 5 (group B). Standard deviation means and distribution ranges within groups were used to deduce that group B, rather than group A, contained the sample sizes that best represented the site. Furthermore, class 3 (which had the smallest weight among the different classes in group B) was determined as being the representative elementary volume (REV). This deduction is consistent with the recommendation for reference sample size used in soil particle size analysis (as defined by the American Society for Testing and Materials).

Herein, under the quasi-static regime, we used localized surface plasmon resonance (LSPR) inflection points (IFs) of single gold nanorods (AuNRs) to get insightful view in their fundamental role in revealing the dispersivity and tunability of the complex refractive index (RI) of AuNRs. AuNRs exhibited broad-band RIs in the visible range with maxima near the resonance energies, and these broad-bands are even stable at long wavelengths with RIs below 1 RI unit. Furthermore, the low energy IFs with low sensitivities are associated with the highest RI (n) values, whereas the high energy IFs exhibit the highest optical extinction (k).

0.69으로 높게 나타났다. 향후 단층 물질의 전단강도 산정에 대한 유용한 정보를 제공할 수 있을 것으로 판단된다. 주요어 : 단층 비지대, 단층 파쇄대 , 무게비 , 전단강도, 다중회귀분석 The appearance of faults during tunnel construction is often difficult to predict in terms of strike, dip, scale, and strength, even though this information is essential in determining the strength of the surrounding rock mass. However, the strength and rock mass classification of fault zones are generally determined empirically on the construction site. In this study, 109 specimens were collected from fault of nine area throughout Korea, and direct shear tests were conducted and the particle distribution was analyzed to better characterize the fault zones. Six multiple regression models were established, using 97 of the specimens, to analyze the correlation between the shear strengths and weight rations of these fault materials. A verification of the six models, using the remaining 12 specimens, shows that in all of the models the coefficient of determination yielded R 2 ≥ 0.60, with two models yielding R 2 ≥ 0.69. These results provide useful information for determining the shear strength of fault materials in future

In this paper, we deal with an assembly line production system in which an automated guided vehicle (AGV) delivers parts to each workstation of assembly lines from a miniload automated storage/retrieval system (AS/RS). Each assembly production line is characterized by a sequence of workstations linked together for the production of a given type of product. We consider simultaneously the design problem of miniload AS/RS and the problem of determining a unit load size of the AGV. First, a non-linear mathematical model is formulated under a proposed AGV dispatching policy. And then, we determine an appropriate sequence of lines of the vehicle visits. Finally, based on the characteristics of the objective function and feasible region of the decision variables, a heuristic solution procedure is developed to find a near optimal solution. To examine the validity of the model, an example problem is solved.

The objective of this paper is the development of a design model for refrigerated automated storage and retrieval systems (R-AS/RS). Compared with ordinary unit-load AS/RS, the R-AS/RS under this study has several different design and operating characteristics: (I) greater emphasis is placed on the storage function and so it has a double-depth lane in the storage rack; (2) cooling units are required to maintain a cold temperature environment in the system; (3) the maximum number of storage orders handled per unit time is limited by the system capacity. Considering the above characteristics, the design problem is formulated as a non-linear mixed integer programming problem in which the cost of the system is minimized. The decision variables are the storage volume, the number of storage and retrieval (S/R) machines, the type and number of cooling units, and the physical configuration of the building. A case problem is solved to illustrate the model.

This study deals with the problem of determining unit load sizes of automated guided vehicles (AGVs) in multi-product and multi-line assembly production systems. It is assumed that an AGV delivers assembly parts to each workstation of assembly lines from a miniload automated storage/retrieval system (AS/RS), and conveyor lines transport subassemblies between workstations. In this system, determination of the unit load sizes of parts carried by the AGV becomes an important decision factor due to its effects on the work-in-process inventory level and the operating cost of the system. Under a proposed AGV dispatching policy, a nonlinear mathematical model which allows unequal unit load sizes among assembly lines is formulated. Based on the characteristics of the objective function and feasible regions, a heuristic solution algorithm is developed. To illustrate the model, problems are chosen and solved.