Matthew I. Gibson  Dusko Paripovic  Harm‐Anton Klok 《Advanced materials (Deerfield Beach, Fla.)》2010,22(42):4721-4725

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Matthew J. Harrington  J. Herbert Waite 《Advanced materials (Deerfield Beach, Fla.)》2009,21(4):440-444

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  总被引：1，自引：0，他引：1  

Rainsberg MR  de Harrington PB 《Applied spectroscopy》2005,59(6):754-762

A splitless thermal desorber unit that interfaces a differential mobility spectrometry (DMS) sensor has been devised. This device was characterized by the detection of benzene, toluene, and xylene (BTX) in water. The detection of BTX in water is important for environmental monitoring, and ion mobility measurements are traditionally difficult for hydrocarbons in water because water competes for charge and quenches the hydrocarbon signals. This paper reports the use of a DMS with a photoionization source that is directly coupled to a solid-phase microextraction (SPME) desorber. The separation and detection capabilities of the DMS were demonstrated using BTX components. Detection limits for benzene, toluene, and m-xylene were 75, 50, and 5 microg mL(-1), respectively.  相似文献   

    

Vincent Rouillard  Matthew Lamb 《Packaging Technology and Science》2009,22(4):229-240

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Colin D. Wood  Bien Tan  Abbie Trewin  Fabing Su  Matthew J. Rosseinsky  Darren Bradshaw  Yan Sun  Li Zhou  Andrew I. Cooper 《Advanced materials (Deerfield Beach, Fla.)》2008,20(10):1916-1921

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Vladimir Bodrozic  Thomas M. Brown  Shabbir Mian  Daren Caruana  Matthew Roberts  Nathan Phillips  Jonathan J. Halls  Ilaria Grizzi  Jeremy H. Burroughes  Franco Cacialli 《Advanced materials (Deerfield Beach, Fla.)》2008,20(12):2410-2415

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Cynthia J. Finelli  Molly Ott  Amy C. Gottfried  Chad Hershock  Christopher O'Neal  Matthew Kaplan 《工程教育杂志》2008,97(4):397-411

Although many kinds of data can be used to guide instructional consultations, research comparing the efficacy of such data is scant, especially in engineering. In this study, multiple modes of assessment were used to evaluate the impact of consultations informed by different kinds of data. This study illuminates two key aspects of instructional consultations: (1) their efficacy varies depending on the kind of data used to guide them, with student feedback from a Small Group Instructional Diagnosis (SGID) having the largest positive impact, and (2) the instructional consultant plays a key role in helping both interpret the available data and identify strategies for improvement. These findings suggest three implications for practice: (1) whenever possible, SGID‐based consultations should be offered systematically and proactively for engineering faculty, (2) data for other kinds of consultations should be tailored to the needs of the individual instructor, and (3) instructional consultants should be available to collaborate with faculty to enhance their teaching, thereby building an engineering culture that actively supports teaching and learning.  相似文献   

    

Donna M. Qualters  Thomas C. Sheahan  Emanuel J. Mason  David S. Navick  Matthew Dixon 《工程教育杂志》2008,97(1):37-45

This paper describes a feedback process that assessed first‐year engineering student learning using a mastery exam. The results were used to improve learning and teaching in first‐year courses. To design the initial exam, basic knowledge and concepts were identified by instructors from each of the host departments (Chemistry, Math, Physics and Computer Science). In 2004, the 45‐item exam was administered to 191 second‐year engineering students, and in September 2005, the revised exam was administered to the next class of second‐year engineering students. The exam was analyzed using Item Response Theory (IRT) to determine student abilities in each subject area tested. Between exam administrations, workshops were conducted with the four department instructor groups to present exam results and discuss teaching issues. The exam provided a learning assessment mechanism that can be used to engage faculty in science, mathematics, and engineering in productive linkages for continual improvement to curriculum.  相似文献   

  总被引：1，自引：0，他引：1  

Kocabas C  Hur SH  Gaur A  Meitl MA  Shim M  Rogers JA 《Small (Weinheim an der Bergstrasse, Germany)》2005,1(11):1110-1116

A convenient process for generating large-scale, horizontally aligned arrays of pristine, single-walled carbon nanotubes (SWNTs) is described. The approach uses guided growth, by chemical vapor deposition (CVD), of SWNTs on miscut single-crystal quartz substrates. Studies of the growth reveal important relationships between the density and alignment of the tubes, the CVD conditions, and the morphology of the quartz. Electrodes and dielectrics patterned on top of these arrays yield thin-film transistors that use the SWNTs as effective thin-film semiconductors. The ability to build high-performance devices of this type suggests significant promise for large-scale aligned arrays of SWNTs in electronics, sensors, and other applications.  相似文献   

    

Fedewa RJ  Wallace KD  Holland MR  Jago JR  Ng GC  Rielly MR  Robinson BS  Miller JG 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(5):576-588

To be successful, correlation-based, phase-aberration correction requires a high correlation among backscattered signals. For harmonic imaging, the spatial coherence of backscatter for the second harmonic component is different than the spatial coherence of backscatter for the fundamental component. The purpose of this work was to determine the effect of changing the transmit apodization on the spatial coherence of backscatter for the nonlinearly generated second harmonic. Our approach was to determine the effective apodizations for the fundamental and second harmonic using both experimental measurements and simulations. Two-dimensional measurements of the transverse cross sections of the finite-amplitude ultrasonic fields generated by rectangular and circular apertures were acquired with a hydrophone. Three different one-dimensional transmit apodization functions were investigated: uniform, Riesz, and trapezoidal. An effective apodization was obtained for each transmit apodization by backpropagating the values measured from within the transmit focal zone using a linear angular spectrum approach. Predictions of the spatial coherence of backscatter were obtained using the pulse-echo Van Cittert-Zernike theorem. In all cases the effective apodization at 2f was narrower than the transmit apodization. We demonstrate that certain transmit apodizations result in a greater spatial coherence of backscatter at the second harmonic than at the fundamental.  相似文献