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Mechanical properties of microcrystalline branching selenite gypsum samples and influence of constituting factors

Journal of Rock Mechanics and Geotechnical Engineering 2019年第2期11卷 228-241页

作者： c.caselle S.Bonetto c.colombero c.comina Department of Earth Sciences (DST) Università degli Studi di Torino Department of Environment Land and Infrastructure Engineering (DIATI)Politecnico di Torino

The high sedimentological variability of gypsum rocks has the effect that a univocal characterization of this material is not easy to establish. This is particularly true from the geomechanical point of view: when the mechanical properties of gypsum rocks are requested, it is therefore necessary to undertake detailed characterization analyses. common facies of gypsum was observed in the Upper Miocene evaporitic succession(Messinian Salinity crisis) within the whole Mediterranean Basin. In this work, mechanical tests were conducted on a site-specific facies, represented by the microcrystalline branching selenite. The tested samples came from the Monferrato area(northwestern Italy). Uniaxial compressive strength(UcS)tests were performed in order to obtain reference mechanical parameters. More rapid and economic point load test(PLT) and ultrasonic pulse velocity(UPV) measurements were additionally performed to verify their applicability as complementary/alternative methods for site characterization. Rock-type specific PLT-UcS and UPV-UcS relationships were established. A wide dispersion of the mechanical parameters was observed due to the heterogeneities of the studied material. consequently, compositional, textural and microstructural observations on selected samples were performed. Two main material classes were recognized based on average grain size and total gypsum content, underlining the significant influence of the grain sorting on the measured mechanical properties.

关键词： Gypsum Uniaxial compressive strength(UcS) Point load test(PLT) Mechanical properties Geological heterogeneity

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combining material characterization with single and multi-oxyanion adsorption for mechanistic study of chromate removal by cationic hydrogel

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Journal of Environmental Sciences 2011年第6期23卷 1004-1010页

作者： Irene M.c.Lo Samuel c.N.Tang Department of civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina

cationic hydrogel with magnetic property was synthesized via radical polymerization and its removal capacity of chromate from contaminated water was found to be 200 mg/*** Fourier transform infrared spectroscopy（FT-IR） study,the mechanism of chromate removal by hydrogel was found to be non-specific adsorption,mainly due to ion exchange,as evidenced by the positively charged functional group,trimethyl ammonium-N＋（cH3）3,in the *** were accordingly determined by testing di？erent oxyanion adsorption onto the *** results of the chromate adsorption experiments illustrated that the amount of chromate adsorbed was nearly equal to that of the chloride released from the hydrogel,which is part of the evidence for ion *** and multi-oxyanion adsorption experiments were also performed,and it was demonstrated that ion removal was species independent,but charge dependent,another characteristic of the ion exchange *** was found that the same Langmuir model can be applied to best fit the findings of single and multi-oxyanion adsorption,which further indicates the mechanism of chromate removal is attributed to ion *** view of the above,the background anions compete for adsorption sites with chromate,evidenced by inhibitive chromate removal in the presence of background electrolytes in the batch studies,further echoing the ion exchange mechanism.

关键词： adsorption magnetic hydrogel mechanism ion exchange oxyanion

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Air quality control in the ART laboratory is a major determinant of IVF success

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Asian Journal of Andrology 2016年第4期18卷 596-599页

作者： Sandro c Esteves Fabiola c Bento ANDROFERT Center for Male Reproduction Av. Dr. Heitor Penteado 1464 Campinas SP 13075-460 Brazil.

Arecently published article described how a fertility center in the UnitedStates implemented air quality control to newly designed in vitro fertilization （IVF） laboratory.1 A highly-efficient air filtration was achieved by installing a centered system supplying filtered air to the IVF laboratory and related critical areas, combining air particulate and volatile organic compound （VOc） filtration. As a consequence, live birth rates were increased by improvements in air quality. This article highlights the key aspects of air contamination in the IVF context. The topic is important not only to IVF specialists but also to Andrologists due to the great number of male infertility patients referred to assisted reproductive technology （ART） treatments. The evidence is growing that laboratory air quality is paramount importance for improved IVF outcome.

关键词： @@

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Unveiling the inner structure of electron pulses generated from a laser-wakefield accelerator

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Light(Science & Applications) 2023年第10期12卷 1992-1994页

作者： Malte c.Kaluza Institute of Optics and Quantum Electronics Max-Wien-Platz 107743JenaGermany Helmholtz-Institute Jena Fröbelstieg 307743JenaGermany

A novel diagnostic method has been used to gain deeper insight into the transverse structure and its evolution of electron pulses generated from a laser-wakefield accelerator.

关键词： structure field laser

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Primary identifications and palynological observations of Perilla in china

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Journal of Systematics and Evolution 2010年第2期48卷 133-145页

作者： Mokgolodi Neo c. college of Biological Sciences and Biotechnology Beijing Forestry University

Unresolved controversies concerning the classification of the monotypic genus Perilla *** hindered the complete understanding and subsequent sustainable use of these vital food,oil,and medicinal plants to their full *** the present study,we used scanning electron microscopy to obtain palynological evidence from 21 samples of Perilla plants from seven provinces in china as a potential further attribute for *** findings showed that pollen grains from plants of 11 samples were oblate,whereas those of the other 10 were suboblate;there were no prolate pollen grains *** grains from all samples had diverse exine *** on whether they had continuous tecta on the ornamentations,the pollen grains from the 21 samples were classified into two categories:(i) 14 with irregular reticulates;and (ii) seven with continuous tecta with no *** of the samples was *** ornamentation pattern and size of pollen grains jointly provided evidence that it is appropriate for use in classifying the genus Perilla into five varieties of one ***,by comparison,it is concluded that the shapes and exine ornamentations of Perilla are unique among those of the seven genera already investigated in the subfamily *** these pollen features,Perilla can be easily distinguished from the two other subtribes (Menthinae *** Thyminae Briq.) in the same tribe,supporting the view that Perilla and the other four related genera can be classified into one subtribe (Perillinae).

关键词： classification cluster analysis Perilla pollen grain scanning electron microscopy taxonomy variety

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Traveling wave effect on the seismic response of a steel arch bridge subjected to near fault ground motions

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Earthquake Engineering and Engineering Vibration 2007年第3期6卷 245-257页

作者：徐艳 George c Lee McEER University at BuffaloNY 14260 USA Department of Bridge EngineeringTongji UniversityShanghai 200092China McEER University at BuffaloNY 14260USA

In the 1990s, several major earthquakes occurred throughout the world, with a common observation that near fault ground motion （NFGM） characteristics had a distinct impact on causing damage to civil engineering structures that could not be predicted by using far field ground motions. Since then, seismic responses of structures under NFGMs have been extensively examined, with most of the studies focusing on structures with relatively short fundamental periods, where the traveling wave effect does not need to be considered. However, for long span bridges, especially arch bridges, the traveling wave （only time delay considered） effect may be very distinct and is therefore important. In this paper, the results from a case study on the seismic response of a steel arch bridge under selected NFGMs is presented by considering the traveling wave effect with variable apparent velocities. The effects of fling step and long period pulses of NFGMs on the seismic responses of the arch bridge are also discussed.

关键词： traveling wave effect arch bridge near fault ground motion fling step long period pulses

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Structural features of substituted triazole-linked chalcone derivatives as antimalarial activities against D_(10) strains of Plasmodium falciparum: A QSAR approach

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Journal of central South University 2015年第10期22卷 3738-3744页

作者： Mukesh c.Sharma Division of Drug Design & Medicinal chemistry Research Lab School of Pharmacy Devi Ahilya University Takshila Campus

A quantitative structure–activity relationship(QSAR) was performed to analyze antimalarial activities against the D10 strains of Plasmodium falciparum of triazole-linked chalcone and dienone hybrid derivatives using partial least squares regression coupled with stepwise forward–backward variable selection method. QSAR analyses were performed on the available Ic50 D10 strains of Plasmodium falciparum data based on theoretical molecular descriptors. The QSAR model developed gave good predictive correlation coefficient(r2) of 0.8994, significant cross validated correlation coefficient(q2) of 0.7689, r2 for external test set)(2predr of 0.8256, coefficient of correlation of predicted data set)(2sepred,r of 0.3276. The model shows that antimalarial activity is greatly affected by donor and electron-withdrawing substituents. The study implicates that chalcone and dienone rings should have strong donor and electron-withdrawing substituents as they increase the activity of chalcone. Results show that the predictive ability of the model is satisfactory, and it can be used for designing similar group of antimalarial compounds. The findings derived from this analysis along with other molecular modeling studies will be helpful in designing of the new potent antimalarial activity of clinical utility.

关键词： quantitative structure–activity relationship(QSAR) chalcone antimalarial Plasmodium falciparum stepwise forward–backward partial least squares

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cold plasma redistribution throughout geospace

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Science china(Technological Sciences) 2016年第9期59卷 1340-1345页

作者： Foster John c. Massachusetts Institute of Technology Haystack Observatory

The redistribution of the electrically charged cold plasma of ionospheric origin involves the equatorial,low,mid,auroral,and polar-latitude regions in a multi-step,system-wide process linking the regions of *** with ground and space-based instruments characterize the geospace plume-regularly occurring channels of enhanced plasma density flowing at both ionospheric and magnetospheric *** in the SAPS channel transports the eroded material to the noontime cusp in the ionosphere and to the dayside magnetopause at high *** the fluxes of cold plume plasma traverse the cusp and enter the polar cap,they form the polar tongue of *** the cusp the plume plasma provides a rich source of heavy ions for the magnetospheric injection and acceleration via the mechanisms operative on those field lines.

关键词： plasmasphere ionosphere geospace GPS TEc ionospheric electric field plume

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Efficiency of the motion amplification device with viscous dampers and its application in high-rise buildings

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Earthquake Engineering and Engineering Vibration 2009年第4期8卷 521-536页

作者： Henry c.Huang WSP Asia Ltd.

After nearly a decade of application and investigation, a motion amplification device with viscous dampers for energy dissipation has been recognized as an effective solution to mitigate wind or seismic excitation, especially for stiff structural systems. As a result of compensation of amplified motion, it has been proved that the efficiency of viscous damper largely depends on the motion amplification device configuration, particularly for device stiflhess. In this paper, a ＂scissor-jack＂ type of motion amplification device, called a ＂toggle brace damper＂ system, is studied. It is demonstrated that the efficiency of such a device reflected by its amplification factor is not merely a function of its geometric configuration, but is highly dependent on the support elements＇ stiffness as well, similar to the mechanism of a leverage arm. Accordingly, a mathematical model in terms of complex modulus of the viscous damper with consideration of the support brace＇s stiffness is established. The results indicate that the efficiency of the motion amplification device with viscous dampers significantly depends on the stiffness of the support elements. Other parameters, such as toggle brace configuration and damping values of the viscous damper, are studied and compared. As an application example, numerical analyses are conducted to study the dynamic performance of a 39-story office tower installed with toggle brace dampers constructed on soft soil in a reclaimed area, under a combined effect of the vortex shedding of an adjacent existing 52-story building and earthquakes. The results show that viscous dampers with a motion amplification system using a properly designed toggle brace device proved to be an effective solution to alleviate the external excitations.

关键词： motion amplification device vibration mitigation viscous damper energy dissipation toggle brace damper

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Adjustable Mechanism for Walking Robots with Minimum Number of Actuators

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chinese Journal of Mechanical Engineering 2011年第5期24卷 760-766页

作者： GUHA Anirban AMARNATH c Department of Mechanical Enginering Indian Institute of Technology Bombay

Recent literature on walking robots deals predominantly with multi-degrees-of-freedom leg mechanisms and machines capable of adopting several *** paper explores the other end of the spectrum suggesting mechanisms derived from a four bar coupler curve for a one degree of freedom walking *** of the walk indicates that body of the robot is able to move with low variation in *** best strategy for changing the gait to enable the robot to walk over obstacles and the effect of change in length of different links are explored to open up the possibility of a two degree of freedom walking robot with the capability of changing its gait,suitable as a low cost unit for several *** rugged units would permit the use of an Ic engine as the primary source of power and could be of utility in installations where electronics may not be *** simple walking machines the foot of a leg is usually required to trace a D shaped curve with respect to the *** this paper we begin with a Hoecken mechanism capable of tracing such a *** foot is required to move parallel to itself and the same could be achieved using a six or eight link mechanism.A few such devices have been synthesized in this paper and their motion properties *** study also covers the possibility of providing adjustments to vary the step length and height of the foot＇s movement.

关键词： walking robot degree of freedom coupler curve gait

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