• Structural Engineering and Mechanics
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• v.51 no.2
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• pp.315-331
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• 2014

The present study investigated the effect of the correlation of the measured road roughness profiles corresponding to the left and right wheels of a vehicle on the vibration of a vehicle-bridge coupling system. Four sets of road roughness profiles were measured by a laser road-testing vehicle. A correlation analysis was carried out on the four roughness samples, and two samples with the strongest correlation and weakest correlation were selected for the power spectral density, autocorrelation and cross-correlation analyses. The scenario of a three-axle truck moving across a rigid-frame arch bridge was used as an example. The two selected road roughness profiles were used as inputs to the vehicle-bridge coupling system. Three different input modes were adopted in the numerical analysis: (1) using the measured road roughness profile of the left wheel for the input of both wheels in the numerical simulation; (2) using the measured road roughness profile of the right wheel for both wheels; and (3) using the measured road roughness profiles corresponding to left and right wheels for the input corresponding to the vehicle's left and right wheels, respectively. The influence of the three input modes on the vibration of the vehicle-bridge system was analyzed and compared in detail. The results show that the correlation of the road roughness profiles corresponding to left and right wheels and the selected roughness input mode both have a significant influence on the vibration of the vehicle-bridge coupling system.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.963-968
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• 2008

For the [$Cr_2(H_2tmp)_2Cl_4$] compound, simplified models with two bridging methoxo ligands have been studied. The influence of the bridging Cr-O-Cr bond angles on the exchange coupling between metal atoms in the model compound has been analyzed by means of density functional calculations with the broken-symmetry approach. Coupling constant calculated for the full structure is in good agreement with the experimentally reported value, confirming the validity of the computational strategy used in this work to predict the exchange coupling in a family of related dinuclear Cr(III) compounds. The calculations indicate a good correlation between the calculated coupling constant and the sum of the squared energy gap of three pairs of metal $t_{2g}$ OMSOs with a limited variation of the Cr-O-Cr angle. The spin density distribution and the mechanism of magnetic coupling interactions are discussed.

• Journal of Navigation and Port Research
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• v.48 no.2
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• pp.78-87
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• 2024

To quantitatively assess the correlation between subsystems within a port cluster and the overall coordinated development of the port group, the current paper evaluates the coordinated development of port clusters. First, we construct an evaluation index system for the coupling and coordination of port clusters. Next, we introduce the contribution index of port subsystems, coupling degree, and coupling coordination degree functions to formulate a coupling coordination evaluation model for the port cluster. Finally, we use the Yangtze River Delta port cluster as a case study for validation, specifically using empirical data from 2012 to 2021. The findings reveal distinct phased characteristics in the coupling and coordination of port clusters in the Yangtze River Delta, marked by a notable transition from "maladjustment" to "coordination." Further, sustained high coupling values over a decade indicate a significant level of competition and cooperation among ports within the Yangtze River Delta port cluster. Over time, this competitive and collaborative dynamic has progressively evolved toward a more positive and structured direction. Lastly, it is expected that the evaluation model proposed in this paper can be extrapolated to other port clusters to gauge the extent of coordinated development, thereby facilitating horizontal comparisons and vertical analyses.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.3
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• pp.112-115
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• 2021

Herein, a correlation between B-site cation order and spin-phonon coupling in La₂NiMnO₆ double perovskite has been investigated. Raman spectra of La₂NiMnO₆ double perovskite annealed at 950 and 1400℃ have been measured in the 140-598 K range. A substantial softening of the phonon modes has been observed below the Curie temperature, which emphasized the presence of the spin-phonon coupling in the system. The spin-phonon coupling was found to be stronger in relatively more ordered La₂NiMnO₆ double perovskite. Thus, the magnitude of spin-phonon coupling was influenced by the Ni/Mn cation order.

• Journal of the Korean Magnetic Resonance Society
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• v.25 no.1
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• pp.1-7
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• 2021

Employing of 13C stable-isotopes in NMR metabolomics can give unique splitting patterns and coupling constants information originated from 13C-13C coupling interaction that provide an important structural information regarding the cellular metabolic process. But it has been known that an undesirable signal distortion in 2D heteronuclear correlation study, due to 13C-13C interaction, hampers an analysis of the coupling information. Recently, we proposed J-scaled distortion-free heteronuclear single-quantum coherence (HSQC) sequence which provides a distortion-free 13C-13C coupling information with a selective resolution enhancement of JCC splitting. In this paper, we dicuss theoretical aspect and practical feature of J-scaled HSQC pulse sequence. The conceptual explanation of orgin of the signal distortion by 13C-13C coupling interaction and design of J-scaled HSQC through exemplified results are provided in brief.

• ETRI Journal
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• v.34 no.1
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• pp.114-117
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• 2012

A small-sized ($15mm{\times}30mm$) planar monopole MIMO antenna that offers high-isolation performance is presented in this letter. The antenna is miniaturized using inductive coupling within a meander-line radiator and capacitive coupling between a radiator and an isolator. High isolation is achieved by a T-shaped stub attached to the ground plane between two radiators, which also contributes to the small size using a folded structure and the capacitive coupling with radiators. The proposed antenna operates for the WLAN band within 2.4 GHz to 2.483 GHz. The measured isolation (S21) is about -30 dB, and the envelope correlation coefficient is less than 0.1.

• Geomechanics and Engineering
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• v.15 no.5
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• pp.1125-1133
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• 2018

Real-time characterization of the rock thermal deformation and fracture process provides guidance for detecting and evaluating thermal stability of rocks. In this paper, time -frequency characteristics of acoustic emission (AE) and electromagnetic radiation (EMR) signals were studied by conducting experiments during rock continuous heating. The coupling correlation between AE and EMR during rock thermal deformation and failure was analyzed, and the microcosmic mechanism of AE and EMR was theoretically analyzed. During rock continuous heating process, rocks simultaneously produce significant AE and EMR signals. These AE and EMR signals are, however, not completely synchronized, with the AE signals showing obvious fluctuation and the EMR signals increasing gradually. The sliding friction between the cracks is the main mechanism of EMR during the rock thermal deformation and fracture, and the AE is produced while the thermal cracks expanding. Both the EMR and AE monitoring methods can be applied to evaluate the thermal stability of rock in underground mines, although the mechanisms by which these signals generated are different.

• Elastomers and Composites
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• v.51 no.3
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• pp.218-225
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• 2016

In order to examine correlation between silane coupling agent and activator which affects the physical properties of silica filled natural rubber compound, such as heat buildup, rebound property, dynamic mechanical and morphological properties were measured. With incorporation of silane coupling agent, $tan{\delta}$ at $0^{\circ}C$ was increased and at $60^{\circ}C$ was decreased, which resulted in improving of wet grip and rolling resistance. When silane coupling agent which is corresponding to 8~10% of silica was used, most favorable heat build up and $tan{\delta}$ was obtained. And also when activator was used, dispersibility of silica was improved as a result of reduction of reaggregation of silica.

• Journal of Astronomy and Space Sciences
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• v.26 no.3
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• pp.287-294
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• 2009

In helioseismology it is normally assumed that p-mode oscillations are excited in a statistically independent fashion. Unfortunately, however, this issue is not clearly settled down in that two experiments exist, which apparently look in discrepancy. That is, Appourchaux et al. (2000) looked at bin-to-bin correlation and found no evidence that the assumption is invalid. On the other hand, Roth (2001) reported that p-mode pairs with nearby frequencies tend to be anti-correlated, possibly by a mode-coupling effect. This work is motivated by an idea that one may test if there exists an excess of anticorrelated power variations of pairs of solar p-modes. We have analyzed a 72-day MDI spherical-harmonic time series to examine temporal variations of p-mode power and their correlation. The power variation is computed by a running-window method after the previous study by Roth (2001), and then distribution function of power correlation between mode pairs is produced. We have confirmed Roth's result that there is an excess of anti-correlated p-mode pairs with nearby frequencies. On the other hand, the amount of excess was somewhat smaller than the previous study. Moreover, the distribution function does not exhibit significant change when we paired modes with non-nearby frequencies, implying that the excess is not due to mode coupling. We conclude that the origin of this excess of anticorrelations may not be a solar physical process, by pointing out the possibility of statistical bias playing the central role in producing the excess.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5745-5758
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• 2017

In this paper, we develop a simple but very effective 4 by 4 Multiple-Input Multiple-Output (MIMO) antenna system for mobile phones consisting of different types of antennas to achieve low correlation property at the frequency ranges of 1710 to 2170 MHz, which covers wide LTE service bands, from band 1 to band 4. The proposed antenna system consists of two pair of antennas. Each pair consists of a planar inverted-F antenna (PIFA) and a coupling antenna which has the property of the loop. The use of two different antenna types of IFA and a coupling achieves high isolation. Proposed antenna system occupies relatively small area and positions at the four corners of a printed circuit board. The gap between the two antennas is 4 mm, in order to realize the good isolation performance. To evaluate the performance of our proposed antenna system, we perform various experiments. The proposed antenna shows a wide operating bandwidth greater than 460 MHz with isolation between the feeding ports higher than 17.5-dB. It also shows that the proposed antenna has low Envelop Correlation Coefficient (ECC) values smaller than 0.08 over the all desired frequency tuning ranges.