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考虑二阶弯矩效应的自由扭转圆曲梁静力分析
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作者 王佳佳 丁敏 +3 位作者 蒋秀根 郭韦佟 邓婷 王宏志 《中国农业大学学报》 CAS CSCD 北大核心 2019年第3期109-116,共8页
针对拱形温室结构在轴向风荷载作用下的受力变形及屋面荷载作用下平面外稳定问题,根据考虑曲梁的大位移特征及二阶弯矩效应,建立圆曲梁的弯矩平衡方程,结合其他平衡方程、几何方程、物理方程,获得非线性圆曲梁挠度和扭转角的控制方程,... 针对拱形温室结构在轴向风荷载作用下的受力变形及屋面荷载作用下平面外稳定问题,根据考虑曲梁的大位移特征及二阶弯矩效应,建立圆曲梁的弯矩平衡方程,结合其他平衡方程、几何方程、物理方程,获得非线性圆曲梁挠度和扭转角的控制方程,得到含系数的圆曲梁几何非线性位移、变形和内力模型,给出圆曲梁几何非线性位移及内力的计算方案。鉴于圆曲梁的受力变形与圆拱平面外失稳特征变形的相似性,在此研究的基础上,分析圆拱平面外失稳问题,给出圆拱平面外分岔失稳临界荷载的计算方法。分析结果表明:本研究得到的圆曲梁几何非线性静力分析模型,可用于拱形温室屋面结构的非线性受力分析及平面外分岔及极值点失稳计算。 展开更多
关键词 圆曲梁 圆拱 二阶弯矩效应 几何非线性 静力分析
Investigating the mechanical and acoustic emission characteristics of brittlefailure around a circular opening under uniaxial loading 预览
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作者 Peng Li Fen-hua Ren +3 位作者 Mei-feng Cai Qi-feng Guo Hao-fei Wang Kang Liu 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第10期1217-1230,共14页
The size of underground openings in rock masses in metal mines is critical to the performance of the openings. In this study, the mechanical and acoustic emission (AE) characteristics of brittle rock-like specimens co... The size of underground openings in rock masses in metal mines is critical to the performance of the openings. In this study, the mechanical and acoustic emission (AE) characteristics of brittle rock-like specimens containing a circular opening with different ratios of opening diameter to sample size λ (λ = 0.1, 0.13, 0.17, 0.2, and 0.23) were investigated under uniaxial compression with AE monitoring. The results indicate that the opening size strongly affected the peak strength and the elastic modulus. Crack initiation first started from the upper surface of the specimens, not from the periphery of the openings. Tensile and shear cracks coexisted on the roof and floor of the specimens, whereas tensile cracks were dominant on the two sides. The fracture mode of samples with openings was partially affected by the relative size of the pillars and openings. The AE response curves (in terms of counts, cumulative energy, cumulative counts, and b-value) show that brittle failure was mainly a progressive process. Moreover, the AE information corresponded well with microcrack evolution in the samples and thus can be used to predict sample failure. 展开更多
关键词 rock mechanics circular opening opening size uniaxial compression acoustic emission
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Combined Bearing Capacity of Spudcans on a Double Layer Deposit of Strong-Over-Weak Clays 预览
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作者 YIN Qilin DONG Sheng 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第1期133-143,共11页
An extreme sea storm process can lead to a jack-up rig under the combined loading condition of vertical load(V),horizontal load(H),and moment(M)to have stability problems.This paper presents the analysis of combined b... An extreme sea storm process can lead to a jack-up rig under the combined loading condition of vertical load(V),horizontal load(H),and moment(M)to have stability problems.This paper presents the analysis of combined bearing capacities of a circular spudcan on layered clays with a strong layer overlying a comparatively weaker layer.Numerical models combined with displacement-based load tests,swipe tests,and constant ratio displacement probe tests are adopted to calculate the uniaxial bearing capacities,failure envelopes in combined V-H,V-M planes,and failure envelopes in a combined V-H-M load space,respectively.A parametric study on the effects of vertical load level V,the layer strength ratio su,t/su,b,and the hard layer thickness t1 on the bearing capacities is then performed.Results show that the vertical load level is a key factor that influences the values of H and M and the size of the H-M failure envelope.The existence of the underlying weak clay decreases the bearing capacities in all directions,and the vertical capacity Vult is affected more than the horizontal(Hult)and moment(Mult)capacities based on a single uniform deposit.The influence of the underlying weak clay on H-M failure envelope is mainly shown where H and M are coupled in the same direction.In contrast,little difference is observed when H and M are coupled in opposite directions. 展开更多
关键词 COMBINED bearing capacity circular SPUDCAN LAYERED clays vertical load level strength ratio HARD layer thickness
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Effect of local longitudinal shortening on the transport of luminal contents through small intestine 预览
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作者 Ravi Kant Avvari 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第1期45-60,I0002共17页
A theoretical analysis of the rheological fluid flow due to peristalsis is studied. We have applied the classical lubrication theory to predict the near physiological behavior of the intestinal segment, mixing and tra... A theoretical analysis of the rheological fluid flow due to peristalsis is studied. We have applied the classical lubrication theory to predict the near physiological behavior of the intestinal segment, mixing and transport. A parametric study involving the changes in local longitudinal shortening (LLS) magnitude, LLS spacing, fluid viscosity, wavelength of the wave, and occlusion of lumen caused by the wave provided insights into the dynamics of the peristalsis flow of a non-Newtonian fluid. LLS appear to have little significance in modulating the flow patterns that are caused by circular contraction alone. Results also indicate that there exists trade-off between the power requirement for peristalsis at a certain occlusion against the percentage LLS. LLS appear to be more advantageous to perform the peristalsis activity at higher occlusion than lower occlusion. Having mucosal folds in the inner lining of the intestine allows for one more advantage of slowing the transit due to increased friction factor and increase in time for absorption of the nutrients. 展开更多
关键词 CIRCULAR CONTRACTION LOCAL longitudinal SHORTENING LUBRICATION THEORY
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Role of circular RNAs in gastric cancer:Recent advances and prospects 预览
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作者 Ke-Wei Wang Ming Dong 《世界胃肠肿瘤学杂志:英文版(电子版)》 CAS 2019年第6期459-469,共11页
Circular RNA(circRNA)is a newly discovered non-coding RNA with special structure,which is widely expressed in eukaryotic organisms and mainly located in the cytoplasm.circRNAs participate in gene regulation by working... Circular RNA(circRNA)is a newly discovered non-coding RNA with special structure,which is widely expressed in eukaryotic organisms and mainly located in the cytoplasm.circRNAs participate in gene regulation by working as miRNA sponges that block the inhibitory effect of miRNA on its target genes.In addition,circRNAs can bind to RNA binding proteins to regulate gene expression.Based on characteristics of stability,expression specificity and participation in gene regulation,circRNAs are expected to be biomarkers for early diagnosis of cancer or potential targets for cancer therapy.With the help of bioinformatics analysis,circRNA microarray analysis and high-throughput sequencing technology,more circRNAs were discovered to participate in the progression of gastric cancer(GC)over the past three years.This article gives an overview of these recent research focusing on the roles of circRNAs in GC and highlights the advances. 展开更多
关键词 CIRCULAR RNA Gastric cancer BIOMARKER THERAPEUTIC target Prognosis
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Expression profile of circular RNAs in myocardial ischemia/reperfusion with and without intermittent hypobaric hypoxia preconditioning
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作者 Jiliang Tan Shanshan Gu +1 位作者 Yanjun Zheng Huangtian Yang 《中国科学:生命科学英文版》 SCIE CAS CSCD 2019年第8期1104-1106,共3页
Dear Editor,Myocardial injury following ischemia/reperfusion(I/R)is a common clinical scenario in patients suffering from ischemic heart disease(Hausenloy et al.,2016).The involvement of proteins and signaling pathway... Dear Editor,Myocardial injury following ischemia/reperfusion(I/R)is a common clinical scenario in patients suffering from ischemic heart disease(Hausenloy et al.,2016).The involvement of proteins and signaling pathways is well studied in myocardial I/R injury and protection(Hausenloy et al.,2016;Yang et al.,2012),however,more than 98%of the transcriptional output in mammals are noncoding RNAs(ncRNAs).These products range from short microRNAs(miRNAs)to long noncoding RNAs(lncRNAs,Das et al.,2018)and modulate critical pathophysiologic mechanisms,such as apoptosis,oxidative stress,Ca2+overload and inflammation,during myocardial I/R injury and protection(Das et al.,2018). 展开更多
关键词 circRNA Expression PROFILE of CIRCULAR RNAS in myocardial ISCHEMIA/REPERFUSION with and without INTERMITTENT hypobaric hypoxia PRECONDITIONING PROFILE
Nonlinear vibration analysis of a circular micro-plate in two-sided NEMS/MEMS capacitive system by using harmonic balance method 预览
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作者 Milad Saadatmand Alireza Shooshtari 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第1期129-143,I0004共16页
In this study, forced nonlinear vibration of a circular micro-plate under two-sided electrostatic, two-sided Casimir and external harmonic forces is investigated analytically. For this purpose, at first, von Karman pl... In this study, forced nonlinear vibration of a circular micro-plate under two-sided electrostatic, two-sided Casimir and external harmonic forces is investigated analytically. For this purpose, at first, von Karman plate theory including geometrical nonlinearity is used to obtain the deflection of the micro-plate. Galerkin decomposition method is then employed, and nonlinear ordinary differential equations (ODEs) of motion are determined. A harmonic balance method (HBM) is applied to equations and analytical relation for nonlineaT frequency response (F-R) curves are derived for two categories (including and neglecting Casimir force) separately. The analytical results for three cases:(1) semi-linear vibration;(2) weakly nonlinear vibration;(3) highly non linear vibration, are validated by comparing with the numerical solutio ns. After validation, the effects of the voltage and Casimir force on the natural frequency of two-sided capacitor system are investigated. It is shown that by assuming Casimir force in small gap distances, reduction of the natural frequency is considerable. The influences of the applied voltage, damping, micro-plate thickness and Casimir force on the frequency response curves have been presented too. The results of this study can be useful for modeling circular parallel-plates in nano /microelectromechanical transducers such as microphones and pressure sensors. 展开更多
关键词 NONLINEAR vibration Two-sided MEMS CAPACITOR CIRCULAR PLATE Harmonic balance method
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Nonlinear vibration analysis of a circular composite plate harvester via harmonic balance 预览
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作者 Tian-Chen Yuan Jian Yang Li-Qun Chen 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第4期912-925,共14页
Alumped parameter transversevibration model of a composite plate harvester is analyzed via harmonic balance approaches. The harvester is mainly composed of a piezoelectriccircular composite clamped by two steel rings ... Alumped parameter transversevibration model of a composite plate harvester is analyzed via harmonic balance approaches. The harvester is mainly composed of a piezoelectriccircular composite clamped by two steel rings and a proof mass on the plate.The lumped parameter model is a 1.5 degree-of-freedom strongly nonlinear system with a higher order polynomial stiffness. Aharmonic balance approach is developed to analyze the system, and the resulting algebraic equations are numerically solved by adopting an arc-length continuation technique. Anincremental harmonic balance approach is also developedfor the lumped parameter model. The two approaches yieldthe same results.The amplitude-frequency responses produced by the harmonic balance approach are validated by the numericalintegrations and the experimental data. The investigation reveals that there coexist hardening and softening characteristics in the amplitude-frequency response curves under sufficiently large excitations. The harvester with thecoexistenceof hardening and softening nonlinearitiescan outperform not only linear energy harvesters but also typical hardening nonlinear energy harvesters. 展开更多
关键词 Piezoelectricenergy HARVESTER CIRCULAR composite plate TRANSVERSE NONLINEAR vibration HARMONIC balance Arc-length CONTINUATION
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Handedness inversion of chiral mesoporous silica: A diffuse-reflectance circular dichroism study
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作者 Nan Wang Ruiyu Lin +2 位作者 Minzhao Xue Yingying Duan Shun'ai Che 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第1期139-142,共4页
Chiral mesoporous silica ribbons and rods with inversed handedness have been synthesized with the same enantio pure N-acylaminoacidat temperatures of 0℃ and 20 ℃,respectively.With involving Cu^2+ and meso-tetra(4-su... Chiral mesoporous silica ribbons and rods with inversed handedness have been synthesized with the same enantio pure N-acylaminoacidat temperatures of 0℃ and 20 ℃,respectively.With involving Cu^2+ and meso-tetra(4-sulfonatophenyl)porphyrin (TPPS)as probes,ribbons and rods revealed opposite signals in diffuse-reflectance circular dichroism (DRCD)spectra,indicating the existence of inversed supramolecular chiral imprintings through helical stacking of amphiphiles.The structural evolution was systematically studied by the freeze-dried products sampled at different time after the addition of silica precursors.The H-bonding-depended molecular orientation probably controls the chiral sense upon forming chiral molecular stacking,which would be the origin of such handedness inversion phenomenon. 展开更多
关键词 CHIRALITY HANDEDNESS INVERSION Circular DICHROISM Mesoporous AMPHIPHILE Self-assembly
Response features of nonlinear circumferential guided wave on early damage in inner layer of a composite circular tube
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作者 李明亮 刘良兵 +4 位作者 高广健 邓明晰 胡宁 项延训 朱武军 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第4期224-229,共6页
A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variation... A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variations in third-order elastic constants(TOECs)] in an inner layer of CCT are investigated. On the basis of the modal expansion approach, the second-harmonic field of primary CGW propagation can be assumed to be a linear sum of a series of double-frequency CGW(DFCGW) modes. The quantitative relationship of DFCGW mode versus the relative changes in the inner layer TOECs is then investigated. It is found that the changes in the inner layer TOECs of CCT will obviously affect the driving source of DFCGW mode and its modal expansion coefficient, which is intrinsically able to influence the efficiency of cumulative second-harmonic generation(SHG) by primary CGW propagation. Theoretical analyses and numerical simulations demonstrate that the second harmonic of primary CGW is monotonic and very sensitive to the changes in the inner layer TOECs of CCT, while the linear properties of primary CGW propagation almost remain unchanged. Our results provide a potential application for accurately characterizing the level of early damage in the inner layer of CCT through the efficiency of cumulative SHG by primary CGW propagation. 展开更多
关键词 CIRCUMFERENTIAL GUIDED wave(CGW) early damage INNER LAYER of COMPOSITE circular tube secondharmonic generation(SHG)
High performance active image sensor pixel design with circular structure oxide TFT 预览
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作者 Rui Geng Yuxin Gong 《半导体学报:英文版》 EI CAS CSCD 2019年第2期29-32,共4页
We report a high-performance active image sensor pixel design by utilizing amorphous-indium-gallium-zinc-oxide(aIGZO) thin-film transistors(TFTs) with a circular structure. The TFT, configured with the inner electrode... We report a high-performance active image sensor pixel design by utilizing amorphous-indium-gallium-zinc-oxide(aIGZO) thin-film transistors(TFTs) with a circular structure. The TFT, configured with the inner electrode as source and outer electrode as drain, typically exhibits good saturation electrical characteristics, where the device has a constant drive current despite variations in drain voltage. Due to the very high output resistance exhibited by this asymmetric TFT structure with a circular shape, the pixel circuit considered here in common-drain configuration provides a higher gain of operation than a pixel circuit implemented with rectangular a-IGZO TFTs. They can be used as driving TFTs in active image sensor circuits. They are, therefore,good candidates for digital X-ray detectors in applications such as medical diagnostic procedures. 展开更多
关键词 a-IGZO TFT ACTIVE image SENSOR circular structure high GAIN
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In situ generated pyroglutamate bridged polyoxotitaniums with strong circular dichroism signal
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作者 Guo-Liang Dong Wei-Hui Fang +1 位作者 Lei Zhang Jian Zhang 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第5期1005-1008,共4页
In this text,we use inexpensive and natural amino acid,successfully obtained the asymmetric crystallization of three PTCs,[Ti6(OiPr)14(μ2-O)(μ3-O)2(D/L-pGlu)2](D-PTC-53;L-PTC-53;H2 pGlu=pyroglutamic acid)and[Ti6(OiP... In this text,we use inexpensive and natural amino acid,successfully obtained the asymmetric crystallization of three PTCs,[Ti6(OiPr)14(μ2-O)(μ3-O)2(D/L-pGlu)2](D-PTC-53;L-PTC-53;H2 pGlu=pyroglutamic acid)and[Ti6(OiPr)14(μ2-O)(μ3-O)2(D-pGlu)2][Ti6(OiPr)14((μ2-O)(μ3-O)2(L-pGlu)2](D,L-PTC-53).Interestingly,in situ lactamide reaction starting from glutamic acid to pyroglutamic acid was observed.In addition,the chirality features of these PTCs have been thoroughly discussed.The two enantiomers crys tallize in chiral P21 space group.The optically pure pGlu ligands transform its chirality to the inorganic titanium oxo clusters.As a result,the stack of these inorganic clusters generates homochiral helical chains along the characteristic axial direction.Apart from the microscopic structural analysis,the macroscopic solid-state samples exhibit unusual strong circular dichroism(CD)signals,further verified the homochiral feature of the enantiomers. 展开更多
关键词 In SITU Gyroglutamate Polyoxotitaniums Circular DICHROISM CHIRALITY
Profiling and bioinformatics analysis of differentially expressed circular RNAs in human intervertebral disc degeneration
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作者 Shunmin Wang Jingchuan Sun +5 位作者 Haisong Yang Weiguo Zou Bing Zheng Yu Chen Yongfei Guo Jiangang Shi 《生物化学与生物物理学报:英文版》 SCIE CAS CSCD 2019年第6期571-579,共9页
The functional changes of nucleus pulposus (NP) cells are considered to be the initiating factors of intervertebral disc degeneration (IDD), and the differentially expressed circRNAs in NP cells may play an important ... The functional changes of nucleus pulposus (NP) cells are considered to be the initiating factors of intervertebral disc degeneration (IDD), and the differentially expressed circRNAs in NP cells may play an important role in the process of IDD. To identify circular RNAs (circRNAs) associated with human IDD, we isolated the NP cells from human degenerated and non-degenerated intervertebral disc and identified NP cells by microscopy and cell proliferation. CircRNA microarray expression profiles were obtained from NP cells of degenerated and non-degenerated intervertebral disc and further validated by quantitative reverse transcription PCR (qRTPCR). The expression data were analyzed by bioinformatics. Microarray analysis identified 7294 circRNAs differentially expressed in degenerated human IDD NP cells. Among them, 3724 circRNAs were up-regulated and 3570 circRNAs were down-regulated by more than 2 folds. After validating by qRT-PCR, we predicted the possible miRNAs of the top dysregulated circRNAs using TargetScan, and miRanda. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the most modulated circRNAs regulate the viability, degradation, apoptosis and oxidative stress in NP cells, and the possible mechanism underlying IDD was discussed. These results revealed that circRNAs may play a role in IDD and might be a promisi ng can didate molecular target for gene therapy. 展开更多
关键词 IDD nucleus pulposus DEGENERATION CIRCULAR RNA MICROARRAY
Generation of two-color polarization-adjustable radiation pulses for storage ring light source 预览
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作者 Wei-Hang Liu Yi Wu +2 位作者 Yi Jiao Zheng-He Bai Sheng Wang 《核技术:英文版》 SCIE CAS CSCD 2019年第4期123-131,共9页
To date, two-color pulses are widely used in pump–probe experiments. For a ring-based light source, the power of the spontaneous radiation fluctuates randomly in the longitudinal direction. It is difficult to produce... To date, two-color pulses are widely used in pump–probe experiments. For a ring-based light source, the power of the spontaneous radiation fluctuates randomly in the longitudinal direction. It is difficult to produce twocolor double pulses by optical methods. In this paper, we introduce a method based on the echo-enabled harmonic generation scheme that generates two-color pulses in a storage ring light source. By adopting crossed undulators and a phase shifter, the polarization of the two-color pulses can be easily switched. A numerical simulation based on a diffraction-limited storage ring, the Hefei Advanced Light Source, suggests that the time delay and spectral separation of the two pulses can be adjusted linearly by changing the pulse duration and chirp parameters of the seed laser. A circular polarization degree above 80% could be achieved. 展开更多
关键词 Two-color PULSES Echo-enabled harmonic GENERATION Diffraction-limited storage ring CROSSED UNDULATORS Circular polarization
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Circular RNAs and human glioma 预览
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作者 Jinglei Liu Kun Zhao +1 位作者 Nunu Huang Nu Zhang 《癌症生物学与医学:英文版》 CAS CSCD 2019年第1期11-23,共13页
As a newly discovered type of RNA, circular RNAs(circRNAs) are widespread throughout the eukaryotic genome. The expression of circRNAs is regulated by both cis-elements and trans-factors, and the expression pattern of... As a newly discovered type of RNA, circular RNAs(circRNAs) are widespread throughout the eukaryotic genome. The expression of circRNAs is regulated by both cis-elements and trans-factors, and the expression pattern of circRNAs is cell type-and diseasespecific. Similar to other types of non-coding RNAs, functions of circRNAs are also versatile. CircRNAs have been reported previously to function as microRNA(miRNA) sponges, protein sponges, coding RNAs or scaffolds for protein complexes.Recently, several circRNAs have been reported to play important roles in human malignancies, including glioma. Here, we reviewed several reports related to circRNAs and glioma, as well as the potential diagnostic and therapeutic applications of circRNAs in brain cancer. In general, some circRNAs, such as circSMARCA5 and circCFH, are found to be expressed in a gliomaspecific pattern, these circRNAs may be used as tumor biomarkers. In addition, some circRNAs have been found to play oncogenic roles in glioma(e.g., circNFIX and circNT5E), whereas others have been reported to function as tumor suppressors(e.g.,circFBXW7 and circSHPRH). Furthermore, circRNA is a good tool for protein expression because of its higher stability compared to linear RNAs. Thus, circRNAs may also be an ideal choice for gene/protein delivery in future brain cancer therapies. There are some challenges in circRNA research in glioma and other diseases. Research related to circRNAs in glioma is comparatively new and many mysteries remain to be solved. 展开更多
关键词 CIRCULAR RNA GLIOMA MIRNA SPONGE translation protein SCAFFOLD MIRNA target
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Relationship between Maternal PBMC HBV cccDNA and HBV Serological Markers and its Effect on HBV Intrauterine Transmission 预览
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作者 WANG Dan Dan YI Lin Zhu +7 位作者 WU Li Na YANG Zhi Qing HAO Hai Yun SHI Xiao Hong WANG Bo FENG Shu Ying FENG Yong Liang WANG Su Ping 《生物医学与环境科学:英文版》 SCIE CAS CSCD 2019年第5期315-323,共9页
Objective To investigate the relationship between maternal peripheral blood mononuclear cells (PBMC) hepatitis B virus(HBV) covalenty closed circular deoxyribonucleic acid(cccDNA) and other HBV serological markers and... Objective To investigate the relationship between maternal peripheral blood mononuclear cells (PBMC) hepatitis B virus(HBV) covalenty closed circular deoxyribonucleic acid(cccDNA) and other HBV serological markers and its effects on HBV intrauterine transmission. Methods We enrolled 290 newborns and their hepatitis B surface antigen(HBsAg) positive mothers. HBV cccDNA in PBMC and HBV DNA in serum were detected by a real‐time PCR‐TaqM an probe while HBV serological markers were detected with an electrochemiluminescence immunoassay. Results There was a positive correlation between the levels of PBMC HBV cccD NA and serum HBV DNA and HBeA g(r = 0.436 and 0.403, P < 0.001). The detection rate of pattern A [‘HBsA g(+), HBeA g(+), and anti‐HBc(+)’] was significantly higher in the PBMC HBV cccD NA positive group than in the control group(χ^2 = 48.48, P < 0.001). There was a significant association between HBV intrauterine transmission and PBMC HBV cccD NA(χ^2 = 9.28, P = 0.002). In the presence of serum HBV DNA, HBeA g, and PBMC HBV cccD NA, the risk of HBV intrauterine transmission was three times higher(OR = 3.69, 95% CI: 1.30‐10.42) than that observed in their absence. The risk of HBV intrauterine transmission was the greatest(OR = 5.89, 95% CI: 2.35‐14.72) when both PBMC HBV cccD NA and pattern A were present. A Bayesian network model showed that maternal PBMC HBV cccD NA was directly related to HBV intrauterine transmission. Conclusion PBMC HBV cccDNA may be a direct risk factor for HBV intrauterine transmission. Our study suggests that serological markers could be combined with PBMC‐related markers in prenatal testing. 展开更多
关键词 Hepatitis B virus INTRAUTERINE transmission Peripheral blood MONONUCLEAR cells Covalently closed circular deoxyribonucleic acid SEROLOGICAL markers
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LG11-mode vortex Nd:YAG laser by applying second-order circular Dammann grating for annular pumping
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作者 张权 余俊杰 +2 位作者 施必然 唐凡春 李建郎 《中国光学快报:英文版》 SCIE EI CAS CSCD 2019年第5期34-38,共5页
The excitation of liigh-order Laguerre-Gaussian (LG) modes in a neodymiuni-doped yttrium aluminum gamet (Nd:YAG) laser resonator was presented by applying the diffraction of a second-order circular Dammann grating (CD... The excitation of liigh-order Laguerre-Gaussian (LG) modes in a neodymiuni-doped yttrium aluminum gamet (Nd:YAG) laser resonator was presented by applying the diffraction of a second-order circular Dammann grating (CDG) for annular pumping. In the study, the 808 nm pump light was shaped into a double-ring structure by the CDG and matched spatially with that of an ideal LGn mode. As a result, the laser resonator generated an LGn vortex mode, and the laser power reached 204 mW with 14.5% slope efficiency. Also, when the cavity mirror was tilted, the laser output could switch to the LG01vortex mode. The results showed the convenience and versatility of CDG in an annular-pumped vortex laser. 展开更多
关键词 Laguerre-Gaussian(LG) CIRCULAR Dammann grating(CDG) ANNULAR PUMPING
Magnetoelastic combined resonance and stability analysis of a ferromagnetic circular plate in alternating magnetic field 预览
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作者 Yuda HU Bingbing MA 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第7期925-942,共18页
The nonlinear combined resonance problem of a ferromagnetic circular plate in a transverse alternating magnetic field is investigated. On the basis of the deformation potential energy, the strain potential energy, and... The nonlinear combined resonance problem of a ferromagnetic circular plate in a transverse alternating magnetic field is investigated. On the basis of the deformation potential energy, the strain potential energy, and the kinetic energy of the circular plate, the Hamilton principle is used to induce the magnetoelastic coupling transverse vibration dynamical equation of the ferromagnetic circular plate. Based on the basic electromagnetic theory, the expressions of the magnet force and the Lorenz force of the circular plate are presented. A displacement function satisfying clamped-edge combined with the Galerkin method is used to derive the Duffing vibration differential equation of the circular plate. The amplitude-frequency response equations of the system under various combined resonance forms are obtained by means of the multi-scale method, and the stability of the steady-state solutions is analyzed according to the Lyapunov theory. Through examples, the amplitude-frequency characteristic curves with different parameters, the amplitude of resonance varying with magnetic field intensity and excitation force, and the time-course response diagram, phase diagram, Poincar′e diagram of the system vibration are plotted, respectively. The effects of different parameters on the amplitude and stability of the system are discussed. The results show that the electromagnetic parameters have a significant effect on the multi-valued attribute and stability of the resonance solutions, and the system may exhibit complex nonlinear dynamical behavior including multi-period and quasi-periodic motion. 展开更多
关键词 MAGNETOELASTICITY FERROMAGNETIC circular plate COMBINED RESONANCE multi- scale method ALTERNATING magnetic field
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1.8-kV circular AlGaN/GaN/AlGaN double-heterostructure high electron mobility transistor
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作者 赵胜雷 王之哲 +5 位作者 陈大正 王茂俊 戴扬 马晓华 张进成 郝跃 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期391-394,共4页
In this paper, we present a 1.8-kV circular AlGaN/GaN/AlGaN double-heterostructure high electron mobility transistor(DH HEMT) with a gate-drain spacing LGD= 18.8 μm. Compared with the regular DH HEMT, our circular st... In this paper, we present a 1.8-kV circular AlGaN/GaN/AlGaN double-heterostructure high electron mobility transistor(DH HEMT) with a gate-drain spacing LGD= 18.8 μm. Compared with the regular DH HEMT, our circular structure has a high average breakdown electric-field strength that increases from 0.42 MV/cm to 0.96 MV/cm. The power figure of meritVBR2/RON for the circular HEMT is as high as 1.03 ×109 V2·Ω-1·cm-2. The divergence of electric field lines at the gate edge and no edge effect account for the breakdown enhancement capability of the circular structure. Experiments and analysis indicate that the circular structure is an effective method to modulate the electric field. 展开更多
关键词 AlGaN/GaN/AlGaN DH HEMTS CIRCULAR structure BREAKDOWN voltage
Experimental investigation on flow characteristics in circular tube inserted with rotor-assembled strand using PIV
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作者 Lichen He Weimin Yang +3 位作者 Changfeng Guan Hua Yan Lin Zheng Xiahua Zuo 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第1期1-9,共9页
Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube insert... Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube inserted with rotor-assembled strand was conducted and the flow characteristics on transverse section and longitudinal section were analyzed.The results showed that swirling flow was produced in the tube inserted with rotors and it was particularly strong within the swing diameter of the rotor on the section that contains the rotor;the average turbulence intensity and the radial velocity were improved notably;the velocity vectors on the longitudinal section remained along the direction of a straight line;both the swirling flow and average turbulence intensity were higher for the rotor with three blades than for the rotor with two blades except that the radial velocity was approximate, but they were all reduced by enlarging the lead of the rotor.Characterization of the flow patterns in a circular tube contributes to understanding the heat transfer efficiency and scale inhibition performance of the rotor-assembled strand and provides guidance for its application. 展开更多
关键词 Particle image VELOCIMETRY (PIV) Swirling flow Rotor-assembled STRAND Circular tube
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