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51.
研究了颗粒粘结高燃速固体推进剂药柱中粘结剂与小粒药之间的溶剂双向迁移现象，并利用计算机模拟估算了溶剂迁移量的大致范围。 相似文献
52.
Sha‐Sha Li Yao‐Hui Liu Yu‐Lai Song Ling‐Nan Kong Tuan‐Jie Li Ren‐Hang Zhang 《国际钢铁研究》2016,87(11):1450-1460
53.
Perez-Bergquist A Zhu S Sun K Xiang X Zhang Y Wang L 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(8):1119-1124
54.
Ming‐Sheng Chen Wei Sha Xian‐Liang Wu 《International journal for numerical methods in engineering》2009,80(8):1124-1142
A new wavelet matrix transform (WMT), operated by lifting wavelet‐like transform (LWLT), is applied to the solution of matrix equations in computational electromagnetics. The method can speedup the WMT without allocating auxiliary memory for transform matrices and can be implemented with the absence of the fast Fourier transform. Furthermore, to handle the matrix equation of arbitrarily dimension, a new in‐space preprocessing technique based on LWLT is constructed to eliminate the limitation in matrix dimension. Complexity analysis and numerical simulation show the superiority of the proposed algorithm in saving CPU time. Numerical simulations for scattering analysis of differently shaped objects are considered to validate the effectiveness of the proposed method. In particular, due to its generality, the proposed preprocessing technique can be extended to other engineering areas and therefore can pave a broad way for the application of the WMT. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
55.
K. K. Tamma X. Zhou D. Sha 《International journal for numerical methods in engineering》1999,44(10):1545-1572
New theoretical ideas and developments describing the fundamental underlying basis for formulating a general family of time discretization operators for first‐order parabolic systems emanating from the framework of a generalized time weighted philosophy are first presented which can be broadly classified as pertaining to Type 1, Type 2 and Type 3 family of time discretization operators. As a consequence, the evolution including the clear distinction and the bridging of the relationships between time operators termed as integral operators to the so‐called integration operators in time are theoretically developed and demonstrated. The present developments seem to not only provide avenues leading to new algorithms for transient analysis but also provide generalizations and framework to recover a wide variety of existing algorithms. Consequently, under the umbrella of the present framework, a variety of plausible new approaches for generating Nth‐order accurate time discretization operators from approximations introduced to Type 1 integral operators in time are first described followed by the developments systematically leading to Type 2 time discretization operators, and subsequently to a wide class of Type 3 time integration operators including the recovery of a variety of known existing time integration operators which can be uniquely identified by Discrete Numerically Assigned (DNA) algorithmic markers. Of the various developments, of noteworthy mention and emphasis here are a new family of L‐stable Nth‐order Integration Operators (LNInO) of Type 2 for transient computations. Subsequently, some practically useful second‐order forms are specifically illustrated and highlighted. The stability and accuracy characteristics are also described for a variety of generated algorithms applicable for transient heat transfer computations. Although the primary focus is on the theoretical developments encompassing linear operators, some simple numerical examples are finally demonstrated to merely illustrate the salient features of the proposed developments. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
56.
The deformation and distribution of stress triaxiality σ_m/σ of mixed I + II mode elastic-plastic cracks under plane strain and plane stress conditions were analysed by the large strain finite element method and were compared with the HRR field. The results show that, (1) the model of crack-tip deformation under mixed I + II mode loading is sharpening-blunting, the sharpening and blunting deformation is acted on by compressive stress (σ_m/σ > 0) and tensile stress (σ_m/σ > 0), respectively; (2) in the plane strain case, the (σ_m/σ)_max of the real crack tip decreases with an increase of mode II component, but increases with an increasing strain hardening n for every mixed ratio. For the loading of K_I/K_II > 0.5, the (σ_m/σ)_max value of the real crack tip is less than that of the (σ_m/σ)_max given by the HRR field, but the opposite holds true cases where K_I/K_II > 0.5; (3) in the plane stress case, the (σ_m/σ)_max decreases a few values with an increasing mode II component, the values of (σ_m/σ)_max of every mixed ratio are far less than these of the corresponding loading condition in the plane strain case. In the plane stress case, the (σ_m/σ)_max values of every mixed ratio for any strain hardening exponent n are almost constant. This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
57.
58.
Qi Li Yuanyuan Jiang Rongcheng Han Xiaolan Zhong Siyun Liu Zhi‐Yuan Li Yinlin Sha Dongsheng Xu 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(6):927-932
Molecular imaging techniques based on surface‐enhanced Raman scattering (SERS) face a lack of reproducibility and reliability, thus hampering its practical application. Flower‐like gold nanoparticles have strong SERS enhancement performance due to having plenty of hot‐spots on their surfaces, and this enhancement is not dependent on the aggregation of the particles. These features make this kind of particle an ideal SERS substrate to improve the reproducibility in SERS imaging. Here, the SERS properties of individual flower‐like gold nanoparticles are systematically investigated. The measurements reveal that the enhancement of a single gold nanoparticle is independent of the polarization of the excitation laser with an enhancement factor as high as 108. After capping with Raman signal molecules and folic acid, the gold nanoflowers show strong Raman signal in the living cells, excellent targeting properties, and a high signal‐to‐noise ratio for SERS imaging. 相似文献
59.
采用超微粉碎工艺对荞麦进行粉碎并与小麦粉混合制备混合粉,研究了超微粉碎荞麦粉添加量（0～20%）对混合粉溶剂保持力（solvent retention capacity,SRC）、糊化特性、面团的热机械特性和面条蒸煮特性、质构特性影响。结果表明,随着超微粉碎荞麦粉添加量的增加,混合粉的蔗糖SRC、碳酸钠SRC和乳酸SRC显著增加（P<0.05）,荞麦粉添加量为20%时,混合粉的蔗糖SRC、碳酸钠SRC和乳酸SRC最高,分别为182.69%、223.02%、177.98%。混合粉峰值黏度、谷值黏度和最终黏度呈先减小后增加的趋势,在添加量为12%时最小,分别为242.00、202.00、408.50 cP。在0～20%范围内,混合粉吸水率从56.80%增加到60.50%;形成时间和稳定时间都随添加的增加而降低,形成时间从3.34 min减低到2.40 min,稳定时间从5.87 min降低到4.61 min。糊化特性、热稳定性和回生值随超微粉碎荞麦粉添加量的增加而降低。面条的硬度、黏度和回复性随超微粉碎荞麦粉的增加总体呈先增加后减小的趋势。 相似文献
60.