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1.
Shannon Lee Scott L. Carnahan Georgiy Akopov Philip Yox Lin-Lin Wang Aaron J. Rossini Kui Wu Kirill Kovnir 《Advanced functional materials》2021,31(16):2010293
Noncentrosymmetric (NCS) tetrel pnictides have recently generated interest as nonlinear optical (NLO) materials due to their second harmonic generation (SHG) activity and large laser damage threshold (LDT). Herein nonmetal-rich silicon phosphides RuSi4P4 and IrSi3P3 are synthesized and characterized. Their crystal structures are reinvestigated using single crystal X-ray diffraction and 29Si and 31P magic angle spinning NMR. In agreement with previous report RuSi4P4 crystallizes in NCS space group P1, while IrSi3P3 is found to crystallize in NCS space group Cm, in contrast with the previously reported space group C2. A combination of DFT calculations and diffuse reflectance measurements reveals RuSi4P4 and IrSi3P3 to be wide bandgap (Eg) semiconductors, Eg = 1.9 and 1.8 eV, respectively. RuSi4P4 and IrSi3P3 outperform the current state-of-the-art infrared SHG material, AgGaS2, both in SHG activity and laser inducer damage threshold. Due to the combination of high thermal stabilities (up to 1373 K), wide bandgaps (≈2 eV), NCS crystal structures, strong SHG responses, and large LDT values, RuSi4P4 and IrSi3P3 are promising candidates for longer wavelength NLO materials. 相似文献
2.
Scientometrics - Engaging in the international academic environment is now facilitated by a range of Academic Social Networks (ASNs) that are being used by an increasing number of early career and... 相似文献
3.
All leaders in health care today are charged with the responsibility of transforming present practices into new and different ones that are needed for the future. The structural side of transforming is ultimately easier than the human side. However, the most frequent failures come from not concentrating sufficiently on the behavioral side of the change. Structural and psychological change must occur simultaneously and embrace each other for best results. 相似文献
4.
The interaction between thin films of hydrogenated amorphous silicon and sputter-deposited chromium has been studied. Following
deposition of the chromium films at room temperature, the films were annealed over a range of times and temperatures below
350°C. It was found that an amorphous silicide was formed only a few nanometers thick with the square of thickness proportional
to the annealing time. The activation energy for the process was 0.55±0.05 eV. The formation process of the silicide was very
reproducible with the value of density derived from the thickness and Cr surface density being close to the value for crystalline
CrSi2 for all films formed at temperatures ≤300°C. The specific resistivity of the amorphous CrSi2 was ≈600 μΩ·cm and independent of annealing temperature. 相似文献
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7.
Knowledge conceptualization tool 总被引:3,自引:0,他引:3
Fujihara H. Simmons D.B. Ellis N.C. Shannon R.E. 《Knowledge and Data Engineering, IEEE Transactions on》1997,9(2):209-220
Knowledge acquisition is one of the most important and problematic aspects of developing knowledge-based systems. Many automated tools have been introduced in the past, however, manual techniques are still heavily used. Interviewing is one of the most commonly used manual techniques for a knowledge acquisition process, and few automated support tools exist to help knowledge engineers enhance their performance. The paper presents a knowledge conceptualization tool (KCT) in which the knowledge engineer can effectively retrieve, structure, and formalize knowledge components, so that the resulting knowledge base is accurate and complete. The KCT uses information retrieval technique to facilitate conceptualization, which is one of the human intensive activities of knowledge acquisition. Two information retrieval techniques employing best-match strategies are used: vector space model and probabilistic ranking principle model. A prototype of the KCT was implemented to demonstrate the concept. The results from KCT are compared with the outputs from a manual knowledge acquisition process in terms of amount of information retrieved and the process time spent. An analysis of the results shows that the process time to retrieve knowledge components (e.g., facts, rules, protocols, and uncertainty) of KCT is about half that of the manual process, and the number of knowledge components retrieved from knowledge acquisition activities is four times more than that retrieved through a manual process 相似文献
8.
Stirman Shannon Wiltsey; DeRubeis Robert J.; Crits-Christoph Paul; Brody Pamela E. 《Canadian Metallurgical Quarterly》2003,71(6):963
To determine the extent to which published randomized controlled trials (RCTs) of psychotherapy can be generalized to a sample of community outpatients, the authors used a method of matching information obtained from outpatient charts to inclusion and exclusion criteria from published RCT studies. They found that 80% of the patients in their sample who had diagnoses represented in the RCT literature were judged eligible for at least 1 published RCT; however, 58% of the patients had primary diagnoses such as adjustment disorder or dysthymia, which were not represented in the existing psychotherapy outcome literature. The most common reasons that patients in their sample did not match with published RCTs for psychotherapy are listed, and the implications of these findings for research and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
K Shannon P Stapleton X Xiang A Johnson H Beattie F El Bakri B Cookson G French 《Canadian Metallurgical Quarterly》1998,36(10):3105-3110
Representative isolates from 10 distinct extended-spectrum beta-lactamase-producing strains of Klebsiella pneumoniae that caused hospital outbreaks in the United Kingdom from 1991 to 1994 were examined for relationships between their enzymes and plasmids. The beta-lactamases were identified by a combination of isoelectric focusing and gene sequencing. SHV-2 beta-lactamase was produced by isolates from four outbreaks, SHV-5 was involved in three, and SHV-4, TEM-15, and TEM-26 were involved in one outbreak each. All of the extended-spectrum beta-lactamases were encoded by self-transmissible plasmids, with sizes ranging from about 70 to 160 kb. No similarities between the restriction digest patterns of the extended-spectrum beta-lactamase-encoding plasmids were detected, except to some extent between those that produced TEM-15 and TEM-26. Thus, outbreaks of hospital infection with these organisms in the United Kingdom from 1991 to 1994 involved distinct organisms and resistance plasmids and appeared to be unrelated. 相似文献
10.
M Shannon 《Canadian Metallurgical Quarterly》1998,106(6):313-316
Childhood lead poisoning is characteristically a disease that occurs between the second and third years of life, generally resulting from the child's ingestion of lead-based paint or dust. However, lead poisoning may also appear in the first year of life. The case of a 4-month-old infant is reported in which the preparation of infant formula in a lead-soldered samovar (urn) resulted in venous blood lead levels as high as 46 microg/dl. The samovar had been brought into the United States by the parents while on a visit to Iran. The infant was placed on chelation therapy with parenteral CaNa2EDTA followed by oral meso-2,3-dimercaptosuccinic acid (DMSA) and d-penicillamine. This resulted in a rapid and substantial reduction in the blood lead level. Lead poisoning in infancy may have unusual etiologies such as in utero transmission of lead by lead-poisoned women. Because sources of lead poisoning in infancy may be unusual, a detailed environmental investigation may be necessary to identify the exact source. Children exposed to lead in the first 2 years of life have a special vulnerability to the neurotoxicity of lead, with the risk of enduring developmental handicaps. Continued public health initiatives to remove lead from the environment, in conjunction with routine lead screening of young children, will be key in meeting the goal of the Centers for Disease Control and Prevention to eliminate childhood lead poisoning by the year 2011. 相似文献