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排序方式: 共有176条查询结果,搜索用时 15 毫秒
1.
Slawomir J. Ambroziak Ryszard J. Katulski Jaroslaw Sadowski Jacek Stefanski 《通讯和计算机》2013,(9):1247-1252
The aim of this paper is the path loss modelling for the radiolocation services in radio communication networks, particularly in cellular networks. The main results of the measurements obtained in the physical layer of the UMTS are introduced. A new method for the utilization of the multipath propagation phenomenon to improve the estimation of the distance between the MS (mobile station) and the BS (base station) is outlined. This method significantly increases the quality of location services in systems which use a radio interface with DS (direct sequence) CDMA (code division multiple access). 相似文献
2.
Natural languages have been taken as models of systems with strong statistical correlations. In such systems the usual probabilistic limiting laws (Gauss etc.) are no more valid and the concept of higher order temperatures can be applied. It has been shown that this is the case in such languages as English, German, French, Russian and Japanese, for letter and word statistics. The corresponding temperatures (up to the 5-th order), entropies and statistical moments have been calculated and their mutual relations have been checked.... erst wenn du plötzlich Fänger wirst des Balles, den eine ewige Mitspielerin dir zuwarf, ... erst dann ist Fangen-können ein Vermögen, nicht deines, einer Welt.(... only when you suddenly catch the ball which the eternal fellow player throws to you,... only then the catching ability is an accomplishment, not of you, but of the world.)R. M. Rilke (from the motto of [3])Supported by Committee of Scientific Research, Warsaw (KBN), Project Nr. 20412 91 01. 相似文献
3.
Wjatscheslaw Missal Jaroslaw KitaEberhard Wappler Frieder GoraAnnette Kipka Thomas BartnitzekFranz Bechtold Dirk SchabbelBeate Pawlowski Ralf Moos 《Sensors and actuators. A, Physical》2011,172(1):21-26
A miniaturized ceramic differential scanning calorimeter (MC-DSC) with integrated oven and crucible is presented. Despite its small size of only 11 mm × 39 mm × 1.5 mm, all functions of a conventional DSC apparatus are integrated in this novel device - including the oven. The MC-DSC is fully manufactured in thick-film and green glass ceramic tape-based low temperature co-fired ceramics (LTCC) technology. Therefore, production costs are considered to be low. Initial results using indium as a sample material show a good dynamic performance of the MC-DSC. Full width at half maximum of the melting peak is 2.4 °C (sample mass approx. 11 mg, heating rate approx. 50 °C/min). Repeatability of the indium melting point is within ±0.02 °C. The melting peak area increases linearly with the sample mass up to at least 26 mg. Simulations of a strongly simplified finite element model of the MC-DSC are in a good agreement with measurement results allowing a model-based prediction of its basic characteristics. 相似文献
4.
Anna Tylutka Barbara Morawin Edyta Wawrzyniak-Gramacka Eryk Wacka Wiktoria Nowicka Jaroslaw Hiczkiewicz Agnieszka Zembron-Lacny 《International journal of molecular sciences》2022,23(21)
The immunosenescence-related disproportion in T lymphocytes may have important consequences for endothelial dysfunction, which is a key event in vascular aging. The study was designed to assess the prognostic values of the inflammatory-immune profile to better predict and prevent vascular diseases associated with old age. Eighty individuals aged 70.9 ± 5.3 years were allocated to a low- (LGI) or high-grade inflammation (HGI) group based on CRP (<3 or ≥3 mg/L) as a conventional risk marker of cardiovascular diseases. Significant changes in inflammatory and endothelium-specific variables IL-1β, IL-6, TNFα, oxLDL, H2O2, NO, 3-nitrotyrosine, and endothelial progenitor cells (OR 7.61, 95% CI 2.56–29.05, p < 0.0001), confirmed their interplay in vascular inflammation. The flow-cytometry analysis demonstrated a high disproportion in T lymphocytes CD4+ and CD8+ between LGI and HGI groups. CRP was <3 mg/mL for the CD4/CD8 ratio within the reference values ≥ 1 or ≤2.5, unlike for the CD4/CD8 ratio < 1 and >2.5. The odds ratios for the distribution of CD4+ (OR 5.98, 95% CI 0.001–0.008, p < 0.001), CD8+ (OR 0.23, 95% CI 0.08–0.59, p < 0.01), and CD8CD45RO+ T naïve cells (OR 0.27, 95% CI 0.097–0.695, p < 0.01) and CD4/CD8 (OR 5.69, 95% CI 2.07–17.32, p < 0.001) indicated a potential diagnostic value of T lymphocytes for clinical prognosis in aging-related vascular dysfunction. 相似文献
5.
Katarzyna Zdanowicz Jaroslaw Daniluk Dariusz Marek Lebensztejn Urszula Daniluk 《International journal of molecular sciences》2022,23(21)
The incidence of gallstone disease has increased in recent years. The pathogenesis of cholelithiasis is not fully understood. The occurrence of the disease is influenced by both genetic and environmental factors. This article reviews the literature on cholelithiasis in children, with the exception of articles on hematological causes of cholelithiasis and cholelithiasis surgery. The aim of this review is to present the latest research on the pathogenesis of gallstone disease in children. The paper discusses the influence of all factors known so far, such as genetic predisposition, age, infections, medications used, parenteral nutrition, and comorbidities, on the development of gallstone disease. The course of cholelithiasis in the pediatric population is complex, ranging from asymptomatic to life-threatening. Understanding the course of the disease and predisposing factors can result in a faster diagnosis of the disease and administration of appropriate treatment. 相似文献
6.
Malgorzata Kardynska Jaroslaw Smieja Pawel Paszek Krzysztof Puszynski 《International journal of molecular sciences》2022,23(12)
Mathematical modeling of signaling pathways and regulatory networks has been supporting experimental research for some time now. Sensitivity analysis, aimed at finding model parameters whose changes yield significantly altered cellular responses, is an important part of modeling work. However, sensitivity methods are often directly transplanted from analysis of technical systems, and thus, they may not serve the purposes of analysis of biological systems. This paper presents a novel sensitivity analysis method that is particularly suited to the task of searching for potential molecular drug targets in signaling pathways. Using two sample models of pathways, p53/Mdm2 regulatory module and IFN--induced JAK/STAT signaling pathway, we show that the method leads to biologically relevant conclusions, identifying processes suitable for targeted pharmacological inhibition, represented by the reduction of kinetic parameter values. That, in turn, facilitates subsequent search for active drug components. 相似文献
7.
Jeremy Agte Olivier de Weck Jaroslaw Sobieszczanski-Sobieski Paul Arendsen Alan Morris Martin Spieck 《Structural and Multidisciplinary Optimization》2010,40(1-6):17-33
This paper is a summary of topics presented and discussed at the 2006 European–U.S. Multidisciplinary Optimization (MDO) Colloquium in Goettingen, Germany, attended by nearly seventy professionals from academia, industry, and government. An attempt is made to accurately reflect the issues discussed by this diverse group, qualified by interest, experience, and accomplishment to present an opinion about the state-of-the-art, trends, and developments in Multidisciplinary Design Optimization. As such, its main purpose is to provide suggestions and stimulus for future research in the field. The predominant content of the colloquium was centered on aerospace, with a few contributions from the automotive industry, and this is reflected in the article. Due to the timeframe that has passed since the conclusion of the workshop, the authors have updated topics where appropriate to reflect observed developments over the past 3 years. Finally, rather than dwelling extensively on past accomplishments and current capabilities in MDO we focus on the needs and identified shortcomings from the colloquium which lead to potential future research directions. A brief MDO background is provided to set the discussion in its proper context. 相似文献
8.
Promising curaua fiber‐reinforced polyester composite for high‐impact ballistic multilayered armor 下载免费PDF全文
Sergio Neves Monteiro Fabio de Oliveira Braga Edio Pereira Lima Luis Henrique Leme Louro Jaroslaw Wieslaw Drelich 《Polymer Engineering and Science》2017,57(9):947-954
A typical multilayered armor system (MAS) is composed of a harder front ceramic tile, which is able to erode heavy ammunition, such as the 7.62 mm bullet, followed by a second layer to further reduce the impact energy. Aramid fabric is a common choice for the second layer. In the present work, polyester matrix composites reinforced with 10 to 30 vol% of curaua fibers, despite having much lower strength and stiffness than aramid fabric, displayed similar trauma indentation in a standard clay witness simulating the human body. Impedance matching and scanning electron microscopy analyses suggest effective energy absorption through ceramic fragment capture by curaua composites. Additionally, because of the high cost of aramid fabric, a full MAS with curaua fiber composite is much cheaper than a MAS composed of aramid fabric. Taking into consideration, both the economical and environmental advantages of natural fibers, it is concluded that curaua fiber‐reinforced polyester composite could replace aramid fabric as the second layer in MASs for personal ballistic protection. POLYM. ENG. SCI., 57:947–954, 2017. © 2016 Society of Plastics Engineers 相似文献
9.
Charles Musca Jaroslaw Antoszewski John Dell Lorenzo Faraone Józef Piotrowski Zenon Nowak 《Journal of Electronic Materials》1998,27(6):740-746
This paper describes a new multi-heterojunction n
+pp photovoltaic infrared photodetector. The device has been developed specifically for operation at temperatures of 200–300K
in the long wavelength (8–14 μm) range of the infrared spectrum. The new structure solves the perennial problems of poor quantum
efficiency and low dynamic resistance found in conventional long wavelength infrared photovoltaic detectors when operated
near room temperature. Computer simulations show that devices with properly optimized multiple heterojunctions are capable
of achieving the performance limits imposed by the statistical nature of thermal generation-recombination processes. In order
to demonstrate the technology, multiple heterojunction devices have been fabricated on epilayers grown by isothermal vapor
phase epitaxy of HgCdTe and in situ As p-type doping. The detector structures were formed using a combination of conventional dry etching, angled ion milling,
and angled thermal evaporation for contact metal deposition. These multi-junction n
+pp HgCdTe heterostructure devices exhibit performances which make them useful for many applications. D* of optically immersed
multiple heterostructure photovoltaic detectors exceeding 108cmHz1/2/W were measured at λ=10.6 μm and T=300K. 相似文献
10.
Andrzej Dziedzic Leszek J. Golonka Jaroslaw Kita Heiko Thust Karl-Heinz Drue Reinhard Bauer Lars Rebenklau Klaus-Jurgen Wolter 《Microelectronics Reliability》2001,41(5)
This paper presents systematic investigations of electrical and stability properties of various low temperature co-fired ceramics (LTCC) resistors. One of the goals of this work was to check the compatibility of LTCC materials (tapes, resistive and conductive inks) from various manufacturers. Three commercially available green tapes and three LTCC resistor/conductor systems were examined. The resistive inks with 1 kΩ/sq. nominal sheet resistance were used. Buried (inside) and surface resistors were laminated and fired according to the tape manufacturers’ recommendations. The influence of dimensional effect on sheet resistance and hot temperature coefficient of resistance, the temperature dependence of resistance in a wide temperature range (from −180°C to +130°C), long-term stability of thermally aged as-fired resistors (150°C, 500 h) and durability to high-voltage micro- or nanosecond pulses (50 ns pulses with 4000 V/mm maximum electric field or 10 μs ones with 700–1000 V/mm electrical field) were carried out for electrical and stability characterisation of LTCC resistors. Non-destructive scanning acoustic microscope diagnostics was applied for structure investigation and estimation of lamination and cofiring process quality of buried LTCC resistors. 相似文献