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排序方式: 共有1336条查询结果,搜索用时 10 毫秒
221.
Zaleszczyk W Janik E Presz A Dłuzewski P Kret S Szuszkiewicz W Morhange JF Dynowska E Kirmse H Neumann W Petroutchik A Baczewski LT Karczewski G Wojtowicz T 《Nano letters》2008,8(11):4061-4065
It is shown that the growth of II-VI diluted magnetic semiconductor nanowires is possible by the catalytically enhanced molecular beam epitaxy (MBE). Zn(1-x)MnxTe NWs with manganese content up to x=0.60 were produced by this method. X-ray diffraction, Raman spectroscopy, and temperature dependent photoluminescence measurements confirm the incorporation of Mn(2+) ions in the cation substitutional sites of the ZnTe matrix of the NWs. 相似文献
222.
Ensuring reliable operation of the means of transport requires the development of methods for early detection of damage to its components made of composite materials. For diagnostic testing of composite materials during normal operation of the means of transport, the authors propose to use non-contact vibration measurement methods and their subsequent processing and analysis. The paper presents the results of laboratory tests whose aim was to assess the ability to detect early symptoms of damage to composite materials using non-contact vibration measurement methods. The measurements included mechanical curves of the glass composite samples made in a conventional manner and simultaneously their vibrations were measured in a non-contact manner using a laser vibrometer. Continuous wavelet transform was used for processing vibration signals. Calculated time-frequency scale distributions of vibration signals enabled the designation of frequency scale bands in which early, low-energy symptoms of damage to glass composites are observed. The analysis results allow to draw conclusions that the use of non-contact measurements and processing of vibration signals extends the existing range of composites research and enables detection of early, low-energy symptoms of damage to glass fibre reinforced composites. 相似文献
223.
Fabian Khateb Montree Kumngern Tomasz Kulej 《Circuits, Systems, and Signal Processing》2016,35(5):1507-1529
A new solution for a non-conventional loser-take-all (LTA) circuit is proposed in the paper. The circuit possesses several inverting and non-inverting input terminals and an additional current output, which increases its versatility and allows simplifying its possible applications. In order to show its usefulness and versatility, several new applications of the proposed LTA have also been developed, including a simple digital-to-analog converter, an n-bit programmable adder/summer, a chopper modulator and a precision rectifier. The LTA has been designed and fabricated with a 0.35 \(\upmu \hbox {m}\) CMOS I3T25 AMIS process, exploiting the recently proposed bulk-driven quasi-floating-gate technique. The LTA circuit operates from 1 V supply and dissipates 74 \(\upmu \hbox {W}\) of power. The simulations performed in Cadence environment and the measurements of a real chip confirm the attractive features of the proposed LTA. 相似文献
224.
225.
The values of the iodine (131)I uptake determined from the measurements with a NaI scintillation counter might be significantly influenced by the thyroid position in the human neck. It is shown that the ratio of the counting rate in the energy peak of 364 keV to the counting rate in the Compton scattering band can be used for the determination of the effective depth of the thyroid. The uncertainties of the standard method are discussed basing on results of calibration measurements. The investigations of 95 patients with different thyroid diseases showed that the measured iodine spectrum was considerably different from the standard for about 20% of them, indicating possible high uncertainties of the standard measurements, which assume a fixed thyroid depth of 20 mm. 相似文献
226.
Aaron Gilbert Alireza Tourani-Rad Tomasz Piotr Wisniewski 《Management International Review》2007,47(5):745-766
Abstract and Key Results
相似文献
• | Despite the importance of insider trading laws in promoting a strong financial market, the impact of regulations in minimizing the detrimental effects of insider trading is unsettled. |
• | We add to the literature by examining the impact of the introduction of the Securities Market Amendment Act 2002 in New Zealand on several aspects of the market, namely bid-ask spreads, liquidity, price volatility and the cost of capital. |
• | We find strong evidence of predicted reductions in the cost of capital, bid-ask spreads and volatility accompanied by increases in liquidity. We conclude that the change in regulations has had a positive impact on the market. |
227.
Tomasz Kostrzewa Karol Woosewicz Marek Jamrozik Joanna Drzedon Julia Siemiska Dagmara Jacewicz Magdalena Grska-Ponikowska Marcin Koaczkowski Ryszard a
ny Alicja Kuban-Jankowska 《International journal of molecular sciences》2021,22(19)
Breast cancer is the most common cancer of women—it affects more than 2 million women worldwide. PTP1B phosphatase can be one of the possible targets for new drugs in breast cancer therapy. In this paper, we present new curcumin derivatives featuring a 4-piperidone ring as PTP1B inhibitors and ROS inducers. We performed cytotoxicity analysis for twelve curcumin derivatives against breast cancer MCF-7 and MDA-MB-231 cell lines and the human keratinocyte HaCaT cell line. Furthermore, because curcumin is a known antioxidant, we assessed antioxidant effects in its derivatives. For the most potent cytotoxic compounds, we determined intracellular ROS and PTP1B phosphatase levels. Moreover, for curcumin and its derivatives, we performed real-time microscopy to observe the photosensitizing effect. Finally, computational analysis was performed for the curcumin derivatives with an inhibitory effect against PTP1B phosphatase to assess the potential binding mode of new inhibitors within the allosteric site of the enzyme. We observed that two tested compounds are better anticancer agents than curcumin. Moreover, we suggest that blocking the -OH group in phenolic compounds causes an increase in the cytotoxicity effect, even at a low concentration. Furthermore, due to this modification, a higher level of ROS is induced, which correlates with a lower level of PTP1B. 相似文献
228.
Tomasz Jan Kolanowski Weronika Wargocka-Matuszewska Agnieszka Zimna Lukasz Cheda Joanna Zyprych-Walczak Anna Rugowska Monika Drabik Micha Fiedorowicz Seweryn Krajewski ukasz Steczek Cezary Kozanecki Zbigniew Rogulski Natalia Rozwadowska Maciej Kurpisz 《International journal of molecular sciences》2021,22(22)
229.
Network-based concurrent computing and interactive data visualization are two important components in industry applications of high-performance computing and communication. We propose an execution framework to build interactive remote visualization systems for real-world applications on heterogeneous parallel and distributed computers. Using a dataflow model of a commercial visualization software AVS in three case studies, we demonstrate a simple, effective, and modular approach to couple parallel simulation modules into an interactive remote visualization environment. The applications described in this paper are drawn from our industrial projects in financial modeling, computational electromagnetics and computational chemistry. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
230.
Wojciech Wojnowski Tomasz Majchrzak Piotr Szweda Tomasz Dymerski Jacek Gębicki Jacek Namieśnik 《Food Analytical Methods》2018,11(8):2085-2092
The use of proton transfer reaction mass spectrometry (PTR-MS) for freshness classification of chicken and turkey meat samples was investigated. A number of volatile organic compounds (VOCs) were selected based on the correlation (>?95%) of their concentration during storage at 4 °C over a period of 5 days with the results of the microbial analysis. In order to verify if the selected compounds are not sample-specific, a number of samples sourced from various retailers were classified using the concentration of these compounds in the samples’ volatile fraction as input variables. The classification was performed using the support vector machines (SVM) supervised pattern recognition algorithm. It was concluded that it is possible to evaluate the shelf life of meat samples obtained from the same source based on the results of a prior analysis. The PTR-MS fingerprint approach might supplement the currently used methods of shelf life evaluation of poultry due to the short time and non-destructive nature of measurement and ease of quantitative analysis. 相似文献