752 research outputs found

    On the Dynamic Stability of Block Sliding on Rock Slopes

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    This paper deals with the dynamic analysis of block sliding on rock slope along plane surfaces, such as joints, bedding planes and faults. According to the results obtained in the shaking tests the dynamic friction along a sliding surface is dependent on the velocity of relative motion, and can be determined by using the proposed method of test. On the basis of conducted experiments a differential equation was established. The integration of the dynamics equation by numerical method provides a basis for evaluation of slope stability in terms of critical displacement and dynamic instability

    Monitoring and Back-Analysis in Dongjian Arch Dam

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    The monitoring of displacement is one of major measures to ensure the safety of an arch dam. And the back-analysis is a key link in the safety evaluation. This paper presents a case history of monitoring and back-analysis of displacement in Dongjiang Arch Dam, China. The elasticity modulus of dam foundation were determined by back-analysis of displacement for lower water level in the reservoir. The prediction of displacement of dam was compared with the results of monitoring. The suggested procedure of 3D finite element computation coupling solid and temperature stresses can be used for other types of rock engineering

    Employees’ voluntary disclosures about business outlook and labor investment efficiency

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    We examine how employee business outlook affects firm-level labor investment efficiency by using data from Glassdoor. We hypothesize that due to the popularity and informativeness of employee voluntary disclosure through social media as a form of crowd wisdom in labor markets, more positive business outlook disclosed by employees can significantly reduce firms’ labor adjustment costs by attracting more job applicants in a timely matter, resulting in higher labor investment efficiency. Consistent with the hypothesis, we document that positive employee business outlook enhances labor investment efficiency by reducing both over-investment and under-investment in labor. Extending our first hypothesis, we also hypothesize and find that when peer firms’ employee business outlook is more positive than that of focal firms, focal firms’ labor adjustment costs increase because of the relative disadvantage in obtaining talented labor in labor markets, resulting in less efficient labor investment. We mitigate the endogeneity concerns by employing sub-sample analysis and using Anti-SLAPP laws as an exogenous shock

    Deformation Prediction for an Underground Opening

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    For excavation of a large underground opening, how to predict the deformation caused by excavation is a subject of interest to the engineers. In this paper, the main underground opening of Lubuge Hydroelectric Power Station will be cited to explain the method predicting its deformation. The successful application shows that the method called MDBD could, perhaps, be used for deformation prediction of other large underground excavations if they satisfy some special conditions basically

    Formulation and evaluation of transdermal drug-delivery system of isosorbide dinitrate

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    The purpose of this study was to develop a reservoir-type transdermal delivery system for isosorbide dinitrate (ISDN). The developed patch consisted of five layers from bottom to top, namely, a temporary liner, an adhesive layer, a rate-controlling membrane, a reservoir and a backing. The effects of chemical penetration enhancers, reservoir materials and rate-controlling membranes on the release behaviour of ISDN from the transdermal patch were studied, and the; in vitro; release of ISDN from the developed patch was studied and compared with the commercially available ISDN patch. The results showed that there was no significant difference in permeation rates between the developed reservoir-type patch and the commercially available ISDN patch (;p;>; 0.05). Moreover, the cumulative release ratio of the commercially available ISDN patch in 48 h was up to 89.8%, whereas the developed patch was only 34.9%, which meant the sustained release time of the developed patch was much longer than the commercially available ISDN patch, and would promote the satisfaction of the patient.;O objetivo do presente estudo foi desenvolver um sistema de liberação transdérmico do tipo reservatório para o dinitrato de isossorbida (ISDN, abrevitura em Inglês). A formulação transdérmica desenvolvida constou de cinco camadas de baixo para cima, ou seja, um revestimento temporário, uma camada adesiva, uma membrana controladora da taxa de liberação, um reservatório e um reforço. Estudaram-se os efeitos dos potenciadores de penetração química, materiais do reservatório e membranas de controle da taxa de liberação no comportamento da formulação transdérmica de dinitrato de isossorbida. A liberação; in vitro; da formulação transdérmica de dinitrato de isossorbida desenvolvida foi estudada em comparação com a formulação de dinitrato de isossorbida disponível comercialmente. Os resultados mostraram que não existem diferenças significativa nas taxas de permeação entre o tipo de reservatório desenvolvido e o de dinitrato de isossorbida desenvolvido comercialmente (;p;>;0,05). Ademais, a taxa de liberação cumulativa da formulação de dinitrato de isossorbida disponível comercialmente em 48 horas foi de até 89,8% e a da formulação desenvolvida, de apenas de 34,9%, o que provou que a liberação sustentada da formulação desenvolvida foi muito maior do que a de dinitrato de isossorbida desenvolvida comercialmente, o que promoveria a satisfação do paciente.

    Jitter analysis of a superconducting nanowire single photon detector

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    Jitter is one of the key parameters for a superconducting nanowire single photon detector (SNSPD). Using an optimized time-correlated single photon counting system for jitter measurement, we extensively studied the dependence of system jitter on the bias current and working temperature. The signal-to-noise ratio of the single-photon-response pulse was proven to be an important factor in system jitter. The final system jitter was reduced to 18 ps by using a high-critical-current SNSPD, which showed an intrinsic SNSPD jitter of 15 ps. A laser ranging experiment using a 15-ps SNSPD achieved a record depth resolution of 3 mm at a wavelength of 1550 nm.Comment: 7 pages, 6 figure

    Difference analysis method of grid connection influence between CRE and DRE based on bus state trajectory

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    This paper presents a method to investigate the impact of centralized and distributed renewable energy on the power grid system, aiming to discern their differences. First, we derived the coupling relationship between renewable energy permeability and access point voltage under a simplified model. Second, we proposed a holomorphic embedding model designed for non-global variation, enabling the construction of the bus state trajectory index. This index is employed to analyze the influence of centralized and distributed renewable energy access on power grid stability and voltage under low-permeability conditions. Furthermore, under high permeability, we determined the limit permeability of centralized and distributed renewable energy. Last, we provided renewable energy configuration recommendations to enhance the system’s receptive capacity
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