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1.
Transient characteristic of heat exchange between closely positioned bodies has become an important issue owing to the continuous miniaturization of many technologies such as high-density magnetic recording, integrated circuits, and atomic force microscopy. We experimentally and numerically study the transient characteristics of nanoscale air bearings subjected to Joule heating of a nearby heating element in hard disk drives. Our results reveal that the response consists of multiple characteristic times, and at least two terms (τ 1 = 162 μs and τ 2 = 23 μs) are required to capture the transient response. We present a one-dimensional analytical model that provides a better understanding of the nature of the transient characteristics and an efficient way to obtain their trends and bounds. Our model may also explain the much faster response due to laser heating observed in heat-assisted magnetic recording system.  相似文献   
2.
以L-酒石酸正己酯-硼酸配合物为流动相添加剂,采用反相高效液相色谱法分离了班布特罗和妥洛特罗2种手性β-受体激动剂。实验考察了酒石酸正己酯和硼酸的浓度,缓冲溶液的种类、浓度、pH值,有机改性剂甲醇的含量对手性分离效果的影响。在最佳手性分离条件下,班布特罗和妥洛特罗均可以达到基线分离。  相似文献   
3.
Abstract

The multiple‐target tracking (MTT) algorithm plays an important role in radar systems. Data association is the most important technique to solve the tracking problems associating dense measurements with existing tracks. A new approach applying Likelihood to measurements and existing tracks in a radar system based on Neural Network computation is investigated in this paper. The proposed algorithm will solve both the data association and the target tracking problems simultaneously. With this approach, the matching between radar measurements and existing target tracks can achieve global relevance. Computer simulation results indicate the ability of this algorithm to keep track of targets under various conditions.  相似文献   
4.
The surface impedance of Y0.9Ca0.1Ba2Cu3O7?δ thin films was measured using the Corbino spectroscopy method. This special geometry, in which the sample dimensions are well defined by a ring pattern, is ideal for broadband high frequency reflection measurements. Using the complex reflected signal, S 11, measured by a vector network analyzer, one can find the surface impedance of the thin film, from which the complex conductivity can be deduced. In the current work we present the three-standard approach for calibration of the Corbino method and demonstrate the benefits of this approach in measuring superconducting Y0.9Ca0.1Ba2Cu3O7?δ thin films up to 20 GHz and down to 6 K. For the data analysis the well-known generalized two-fluid model was implemented, taking into account a film thickness which is much smaller than the normal state skin depth and superconducting penetration depth.  相似文献   
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6.
Abstract

A computational algorithm is proposed for catalyst pellets or reactors experiencing concentration‐dependent deactivation. In the integration of the deactivation equation in each time interval, the concentration of poison, reactant or/and product is considered to be a constant. The value of concentration is recalculated from the mass balance equation before integrating the deactivation equation. By such an approach, the number of equations is reduced; thus a two‐dimensional problem can be converted to a single‐dimensional one.  相似文献   
7.
In this article, we have proposed fast lower-error and area-efficient antilogarithmic converters. By employing new approximation schemes with two-region shift-and-add operations, our proposed converters can perform high-speed conversions from logarithmic numbers to binary numbers. Synthesis results show that our proposed converters can achieve time savings of over 32.5% and can save 42.3% of the area used compared with previously proposed methods. In addition, the percent error ranges for various logarithmic number system (LNS)-based operations used by our proposed logarithmic processor are lower than those of previous methods. Our proposed converters can be applied to LNS-based processors to ease the tremendous computation overhead and boost the performance.  相似文献   
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9.
Touchdown detection by thermal-flying height control (TFC) has been implemented to calibrate flying height (FH) of magnetic sliders for all hard disk drives. For bit patterned media (BPM) to be successful as a revolutionary technology to further increase recording areal density, it must experience the touchdown process with similar robustness as conventional continuous media. Here we numerically study the tribological impact of TFC touchdown detection on the continuous media and unplanarized BPM by three-dimensional (3D) transient finite-element models with the frictional heating and thermal-elastic-plastic materials included. Our results demonstrate that the continuous media exhibits no plastic deformation due to the TFC touchdown with an over-push as large as 2 nm, whereas the plastic strain of the BPM may reach 3 % at higher sliding velocities, and it exists over a wide range of bulge radius and disk velocity. Such plastic deformation can lead to permanent media damage and data loss. Besides, the temperature rise of the BPM (~27 K) is approximately 1.3 times of that of the continuous media (~21 K), and may have to be considered when designing a robust head-disk interface for BPM. Although planarization may improve slider’s flyability performance, our analysis shows that planarizing BPM with SiO2 deteriorates the tribological robustness of the media in particular at a high disk velocity probably due to the inhomogeneous composition and mismatch of material properties between the filling material and recording material. Hence extreme caution must be exercised when choosing a filling material.  相似文献   
10.
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