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ELASTIC SH WAVE PROPAGATION IN PERIODIC LAYERED COMPOSITES WITH A PERIODIC ARRAY OF INTERFACE CRACKS

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Acta Mechanica Solida Sinica 2015年第5期28卷 453-463页

作者： zhizhong yan Chunqiu Wei Chuanzeng Zhang School of Mathematics and Statistics Beijing Institute of Technology Department of Civil Engineering University of Siegen

The interaction of anti-plane elastic SH waves with a periodic array of interface cracks in a multi-layered periodic medium is analyzed in this paper. A perfect periodic structure without interface cracks is first studied and the transmission displacement coefficient is obtained based on the transfer matrix method in conjunction with the Bloch-Floquet theorem. This is then generalized to a single and periodic distribution of cracks at the center interface and the result is compared with that of perfect periodic cases without interface cracks. The dependence of the transmission displacement coefficient on the frequency of the incident wave, the influences of material combination, crack configuration and incident angle are discussed in detail. Compared with the corresponding perfect periodic structure without interface cracks, a new phenomenon is found in the periodic layered system with a single and periodic array of interface cracks.

关键词： layered composite transmission coefficient interface crack transfer matrix method

Band structures of transverse waves in nanoscale multilayered phononic crystals with nonlocal interface imperfections by using the radial basis function method

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Acta Mechanica Sinica 2017年第2期33卷 415-428页

作者： zhizhong yan Chunqiu Wei Chuanzeng Zhang School of Mathematics and Statistics Beijing Institute of Technology Beijing 100081 China Beijing Key Laboratory on MCAACI Beijing Institute of Technology Beijing 100081 China Department of Civil Engineering University of Siegen Siegen 57068 Germany

A radial basis function collocation method based on the nonlocal elastic continuum theory is developed to compute the band structures of nanoscale multilayered phononic crystals. The effects of nonlocal imperfect interfaces on band structures of transverse waves propagating obliquely or vertically in the system are studied. The correctness of the present method is verified by comparing the numerical results with those obtained by applying the transfer matrix method in the case of nonlocal perfect interface. Furthermore, the influences of the nanoscale size, the impedance ratio and the incident angle on the cut-off frequency and band structures are investigated and discussed in detail. Numerical results show that the nonlocal interface imperfections have significant effects on the band structures in the macroscopic and microscopic scale.

关键词： Radial basis function Phononic crystal Nanoscale Band structure Nonlocal imperfect interface

Wavelet-based method for computing elastic band gaps of one-dimensional phononic crystals

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Science China(Physics,Mechanics & Astronomy) 2007年第5期50卷 622-630页

作者： yan zhizhong WANG YueSheng Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China

A wavelet-based method was developed to compute elastic band gaps of one-dimensional phononic crystals. The wave field was expanded in the wavelet basis and an equivalent eigenvalue problem was derived in a matrix form involving the adaptive computation of integrals of the wavelets. The method was then applied to a binary system. For comparison, the elastic band gaps of the same one-dimensional phononic crystals computed with the wavelet method and the well- known plane wave expansion (PWE) method are both presented in this paper. The numerical results of the two methods are in good agreement while the computation costs of the wavelet method are much lower than that of PWE method. In addition, the adaptability of wavelets makes the method possible for efficient band gap computation of more complex phononic structures.

关键词： phononic crystals, elastic band gap, wavelet method, plane wave expansion (PWE) method

Band structures of elastic SH waves in nanoscale multi-layered functionally graded phononic crystals with/without nonlocal interface imperfections by using a local RBF collocation method

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Acta Mechanica Solida Sinica 2017年第4期30卷 390-403页

作者： zhizhong yan Chunqiu Wei Chuanzeng Zhang School of Mathematics and Statistics Beijing Institute of Technology Beijing Key Laboratory on MCAACI Beijing Institute of Technology Chair of Structural Mechanics Department of Civil EngineeringUniversity of Siegen

A meshless radial basis function （RBF） collocation method based on the Eringen nonlocal elasticity theory is developed to calculate the band structures of ternary and quaternary nanoscale multi-layered phononic crystals （PNCs） with functionally graded （FG） interlayers. Detailed calculations are performed for anti-plane transverse waves propagating in such PNCs. The influences of FG and homogeneous interlayers, component number, nonlocal interface imperfections and nanoscale size on cut-off frequency and band structures are investigated in detail. Numerical results show that these factors have significant effects on band structures at the macroscopic and microscopic scales.

关键词： Multi-layered phononic crystals Functionally graded interlayers Nanoscale Nonlocal elasticity theory Radial basis functions

A comparative study of wave localization in locally resonant Thue–Morse, Rudin–Shapiro and Period-Doubling aperiodic structures

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Acta Mechanica Solida Sinica 2017年第3期30卷 271-284页

作者： zhizhong yan yangyang Wang Chuanzeng Zhang School of Mathematics and Statistics Beijing Institute of Technology Department of Civil Engineering University of Siegen

The localization characteristics of the in-plane elastic waves in locally resonant aperiodic phononic crystals are examined in this study. In particular, the phononic crystals generated according to the Thue-Morse, Rudin-Shapiro and Period-Doubling sequences are theoretically investigated by using the extended transfer matrix method. For comparison, the binary and ternary locally resonant systems are considered, and their band structures are characterized by using the localization factors. Moreover, the influences of structural arrangement, material combination, incidence angle, number of components, length ratio, and random disorder on the band structures are also discussed. Some novel and interesting phenomena are observed and discussed.

关键词： Phononic crystals Aperiodicity Wave localization Localization factor Transfer matrix method

电视胸腔镜辅助环抱式肋骨接骨板治疗多发肋骨骨折临床效果观察

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腹腔镜外科杂志 2024年第6期29卷 411-414,419页

作者：闫治中段现玲于善海刘相鼎张玉印张年鑫李伟莒县人民医院胸外科山东日照276500 莒县人民医院手术室山东日照276500

目的:探讨电视胸腔镜辅助环抱式肋骨接骨板内固定术治疗多发肋骨骨折的效果。方法:回顾分析2017年1月至2023年11月收治的70例多发肋骨骨折患者,均行胸腔镜辅助环抱式肋骨接骨板固定术,记录手术时间、术中出血量、治疗后疼痛视觉模拟评... 详细信息

目的:探讨电视胸腔镜辅助环抱式肋骨接骨板内固定术治疗多发肋骨骨折的效果。方法:回顾分析2017年1月至2023年11月收治的70例多发肋骨骨折患者,均行胸腔镜辅助环抱式肋骨接骨板固定术,记录手术时间、术中出血量、治疗后疼痛视觉模拟评分、住院时间、骨折愈合情况及并发症发生率。结果:肋骨固定3~14根,手术时间(55.5±14.2)min,术中出血量(24.3±5.1)mL,术后引流量(160.7±20.5)mL,术后复查胸部CT显示肋骨复位良好,经内固定治疗后胸壁稳定,胸壁畸形均矫正满意,肋骨接骨板无松动、断裂,术后无明显并发症发生。结论:电视胸腔镜辅助环抱式肋骨接骨板内固定术治疗多发肋骨骨折效果满意,尤其合并血气胸者具有较高的临床应用价值。

关键词：多发肋骨骨折胸腔镜检查肋骨接骨板

RBF collocation method and stability analysis for phononic crystals

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Applied Mathematics and Mechanics(English Edition) 2016年第5期37卷 627-638页

作者： Chunqiu WEI zhizhong yan Hui ZHENG Chuanzeng ZHANG School of Mathematics and Statistics Beijing Institute of Technology Beijing Key Laboratory on MCAACI Beijing Institute of Technology Department of Civil Engineering University of Siegen

The mesh-free radial basis function （RBF） collocation method is explored to calculate band structures of periodic composite structures. The inverse multi-quadric （MQ）, Gaussian, and MQ RBFs are used to test the stability of the RBF collocation method in periodic structures. Much useful information is obtained. Due to the merits of the RBF collocation method, the general form in this paper can easily be applied in the high dimensional problems analysis. The stability is fully discussed with different RBFs. The choice of the shape parameter and the effects of the knot number are presented.

关键词： radial basis function (RBF) phononic crystal (PC) stability

Ca^(2+)-independent ZmCPK2 is inhibited by Ca^(2+)-dependent ZmCPK17 during drought response in maize

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Journal of Integrative Plant Biology 2024年第7期66卷 1313-1333页

作者： Xiaoying Hu Jinkui Cheng Minmin Lu Tingting Fang Yujuan Zhu Zhen Li Xiqing Wang Yu Wang yan Guo Shuhua yang zhizhong Gong State Key Laboratory of Plant Environmental Resilience Frontiers Science Center for Molecular Design BreedingCenter for Crop Functional Genomics and Molecular BreedingCollege of Biological SciencesChina Agricultural UniversityBeijing 100193China College of Life Sciences Institute of Life Science and Green DevelopmentHebei UniversityBaoding 071002China

Calcium oscillations are induced by different ***-dependent protein kinases(CDPKs/CPKs)are one major group of the plant calcium decoders that are involved in various processes including drought *** CPKs are ***,we identified ZmCPK2 as a negative regulator of drought resistance by screening an overexpression transgenic maize *** found that ZmCPK2 does not bind calcium,and its activity is mainly inhibited during short term abscisic acid(ABA)treatment,and dynamically changed in prolonged ***,ZmCPK2 interacts with and is inhibited by calcium-dependent ZmCPK17,a positive regulator of drought resistance,which is activated by ***17 could prevent the nuclear localization of ZmCPK2 through phosphorylation of ***2 interacts with and phosphorylates and activates ZmYAB15,a negative transcriptional factor for drought *** results suggest that drought stress-induced Ca^(2+)can be decoded directly by ZmCPK17 that inhibits ZmCPK2,thereby promoting plant adaptation to water deficit.

关键词： CDPK drought response phosphorylation stomatal movement transcriptional regulation

Endoplasmic reticulum stress and autophagy in cerebral ischemia/reperfusion injury:PERK as a potential target for intervention

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Neural Regeneration Research 2025年第5期20卷 1455-1466页

作者： Ju Zheng Yixin Li Ting Zhang yanlin Fu Peiyan Long Xiao Gao Zhengwei Wang zhizhong Guan Xiaolan Qi Wei Hong yan Xiao Key Laboratory of Endemic and Ethnic Diseases Ministry of Education&Key Laboratory of Medical Molecular Biology of Guizhou ProvinceGuizhou Medical UniversityGuiyangGuizhou ProvinceChina Guizhou Center for Disease Control and Prevention GuiyangGuizhou ProvinceChina Department of Histology and Embryology Guizhou Medical UniversityGuiyangGuizhou ProvinceChina Collaborative Innovation Center for Prevention and Control of Endemic and Ethnic Regional Diseases Co-constructed by the Province and Ministry GuiyangGuizhou ProvinceChina

Several studies have shown that activation of unfolded protein response and endoplasmic reticulum(ER)stress plays a crucial role in severe cerebral ischemia/reperfusion *** occurs within hours after cerebral ischemia,but the relationship between ER stress and autophagy remains *** this study,we established experimental models using oxygen-glucose deprivation/reoxygenation in PC12 cells and primary neurons to simulate cerebral ischemia/reperfusion *** found that prolongation of oxygen-glucose deprivation activated the ER stress pathway protein kinase-like endoplasmic reticulum kinase(PERK)/eukaryotic translation initiation factor 2 subunit alpha(e IF2α)-activating transcription factor 4(ATF4)-C/EBP homologous protein(CHOP),increased neuronal apoptosis,and induced ***,inhibition of ER stress using inhibitors or by si RNA knockdown of the PERK gene significantly attenuated excessive autophagy and neuronal apoptosis,indicating an interaction between autophagy and ER stress and suggesting PERK as an essential target for regulating *** autophagy with chloroquine exacerbated ER stress-induced apoptosis,indicating that normal levels of autophagy play a protective role in neuronal injury following cerebral ischemia/reperfusion *** from this study indicate that cerebral ischemia/reperfusion injury can trigger neuronal ER stress and promote autophagy,and suggest that PERK is a possible target for inhibiting excessive autophagy in cerebral ischemia/reperfusion injury.

关键词： apoptosis ATF4 autophagy C/EBP homologous protein cerebral ischemia/reperfusion injury eIF2α endoplasmic reticulum stress PERK