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Does a low solar cycle minimum hint at a weak upcoming cycle?

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Research in Astronomy and Astrophysics 2010年第10期10卷 950-955页

作者： zhan-Le Du hua-Ning Wang Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

The maximum amplitude （Rm） of a solar cycle, in the term of mean sunspot numbers, is well-known to be positively correlated with the preceding minimum （Rmin）. So far as the long term trend is concerned, a low level of Rmin tends to be followed by a weak Rm, and vice versa. We found that the evidence is insufficient to infer a very weak Cycle 24 from the very low Rmin in the preceding cycle. This is concluded by analyzing the correlation in the temporal variations of parameters for two successive cycles.

关键词： Sun activity -- Sun general -- sunspots

Constitutive relation of weakly anisotropic polycrystal with microstructure and initial stress

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Acta Mechanica Sinica 2007年第2期23卷 183-198页

作者： Mojia huang hua zhan Xiuqiao Lin Hai Tang Institute of Engineering Mechanics Nanchang UniversityNanchang 330029 China

Man （Nondestr Test Eval 15：191-214, 1999） derived the constitutive relation of a weakly-textured orthorhombic aggregate of cubic crystallites with effects of microstructure and initial stress. In this paper, a computational expression on the integration ∫SO（3） Q^× D^1m0dg is given. Then, by means of the computational expression, the general constitutive relation of a weakly-textured anisotropic polycrystal with the consideration of microstructure and initial stress is derived. As special cases of our general constitutive relation, two constitutive relations are given for an isotropic polycrystal and a weakly-textured anisotropic aggregate of cubic crystallites. The acoustoelastic tensor of the reference cubic crystal is derived to determine the material constants of the polycrystal. Two examples are given for understanding the physical meaning of the texture coefficients and the constitutive relations.

关键词： Generalconstitutive relation of weakly-textured polycrystal .Microstructure Initial stress .Cubic crystallites

The influence of nano-particle tracers on the slip length measurements by microPTV

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Acta Mechanica Sinica 2013年第3期29卷 411-419页

作者： Xu Zheng Gao-Pan Kong zhan-hua Silber-Li State Key Laboratory of Nonlinear Mechanics Institute of MechanicsCAS

Direct measurement of slip length is based on the measured fluid velocity near solid boundary. However, previous micro particle image velocimetry/particle tracking velocimetry （microPIV/PTV） measurements have reported surprisingly large measured near-wall velocities of pressure-driven flow in apparent contradiction with the no-slip hy-pothesis and experimental results from other techniques. To better interpret the measured results of the microPIV/PTV, we performed velocity profile measurements near a hy-drophilic wall （z = 0.25-1.5 μm） with two sizes of tracer particles （φ 50 nm and φ200 nm）. The experimental results indicate that, at less than 1 μm from the wall, the deviations between the measured velocities and no-slip theoretical values obviously decrease from 93% of φ200 nm particles to 48% of φ50 nm particles. The Boltzmann-like exponential measured particle concentrations near wall were found. Based on the non linear Boltzmann distribution of particle concentration and the effective focus plane thickness, we illustrated the reason of the apparent velocity increase near wall and proposed a method to correct the measured velocity profile. By this method, the deviations between the corrected measured velocities and the no-slip theoretical velocity decrease from 45.8% to 10%, and the measured slip length on hy-drophilic glass is revised from 75 nm to 16 nm. These results indicated that the particle size and the biased particle concentration distribution can significantly affect near wall velocity measurement via microPIV/PTV, and result in larger measured velocity and slip length close to wall.

关键词： MicroPIV/PTV · Slip length · Nano-particle tracer · Particle concentration distribution · Boltzmann distribution

Creep-Resistant Covalent Adaptable Networks with Excellent SelfHealing and Reprocessing Performance via Phase-Locked Dynamic Covalent Benzopyrazole-Urea Bonds

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Chinese Journal of Polymer Science 2024年第10期42卷 1545-1556,I0013页

作者： Miao Xie Xiao-Rong Wang zhan-hua Wang He-Sheng Xia State Key Laboratory of Polymer Materials Engineering Polymer Research InstituteSichuan UniversityChengdu610065China School of Petrochemical Engineering Liaoning Petrochemical UniversityFushun113001China

Covalent adaptive networks(CANs)are capable of undergoing segment rearrangement after being heated,which endows the materials with excellent self-healing and reprocessing performance,providing an efficient solution to the environment pollution caused by the plastic *** main challenge remains in developing CANs with both excellent reprocessing performance and creep-resistance *** this study,a series of CANs containing dynamic covalent benzopyrazole-urea bonds were developed based on the addition reaction between benzopyrazole and isocyanate *** calculation confirmed that relatively low dissociation energy is obtained through undergoing a five-member ring transition state,confirming excellent dynamic property of the benzopyrazole-urea *** verified by the FTIR results,this nice dynamic property can be well maintained after incorporating the benzopyrazole-urea bonds into polymer *** self-healing and reprocessing performance is observed by the 3-ABP/PDMS elastomers owing to the dynamic benzopyrazole-urea *** separation induced by the aggregation of the hard segments locked the benzopyrazole-urea bonds,which also makes the elastomers display excellent creep-resistance *** hard phase locking strategy provides an efficient approach to design CANs materials with both excellent reprocessing and creep-resistance performance.

关键词： Covalent adaptive networks Self-healing polymer Dynamic covalent bond

Modelling and Verification of Real-Time Publish and Subscribe Protocol Using UPPAAL and Simulink/Stateflow

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Journal of Computer Science & Technology 2020年第6期35卷 1324-1342页

作者： Qian-Qian Lin Shu-Ling Wang Bo-hua zhan Bin Gu State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China Beijing Institute of Control Engineering Beijing 100081China

Real-Time Publish and Subscribe (RTPS) protocol is a protocol for implementing message exchange over an unreliable transport in data distribution service (DDS). Formal modelling and verification of the protocol provide stronger guarantees of its correctness and efficiency than testing alone. In this paper, we build formal models for the RTPS protocol using UPPAAL and Simulink/Stateflow. Modelling using Simulink/Stateflow allows analyzing the protocol through simula-tion, as well as generate executable code. Modelling using UPPAAL allows us to verify properties of the model stated in TCTL (Timed Computation Tree Logic), as well as estimate its performance using statistical model checking. We further describe a procedure for translation from Stateflow to timed automata, where a subset of major features in Stateflow is supported, and prove the soundness statement that the Stateflow model is a refinement of the translated timed automata model. As a consequence, any property in a certain fragment of TCTL that we have verified for the timed automata model in UPPAAL is preserved for the original Stateflow model.

关键词： Real-Time Publish and Subscribe(RTPS) modelling verification UPPAAL Simulink/Stateflow

Anomalous response to creep deformation from dislocation density during electrically assisted creep aging

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Rare Metals 2024年第10期43卷 5268-5283页

作者： Chang Zhou Li-hua zhan Chun-Hui Liu Ming-Hui huang College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China Light Alloys Research Institute State Key Laboratory of Precision Manufacturing for Extreme Service PerformanceCentral South UniversityChangsha 410083China

Adding numerous dislocations into metallic materials before the forming stage significantly enhances their ***,this beneficial effect of dislocation defects may not have a simple monotonic relationship with increased dislocation density during electroplastic *** is due to the complex interactions among the drifting electrons,dislocations and solute *** study explores the effect of diverse initial dislocation densities on creep deformation during electrically aided creep aging of an aluminum-lithium ***,we discovered a threshold value for the dislocation density that affects electroplastic creep,i.e.,an enhanced effect from dislocations weakens when exceeding this density threshold(an anomalous response to creep).Microstructural data also reveal that such an anomalous response originates mainly from differences in various dislocation density-tailored configurations,which can influence the dislocation motions and precipitation kinetics of the strengthening T1precipitates under the same action of pulsed *** study provides important insights into the dislocation density-mediated electroplastic creep of an aluminum-lithium alloy.

关键词： Creep aging Dislocation density Al-Cu-Li alloy Pulsed currents

Hydrothermal Synthesis and Structural Characterization of Three-dimensional Metal-organic Framework [Zn_3(C_2H_2N_3)_2(C_7H_5O_2)_4]

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Chemical Research in Chinese Universities 2009年第1期25卷 1-4页

作者： SONG Zhe LI Guang-hua YU Yang SHI zhan FENG Shou-hua College of Chemistry State Key Laboratory of Inorganic Synthesis and Preparative Chemistry Jilin University Changchun 130012 P. R. China

Hydrothermal reaction between mixed ligand（1,2,4-triazole and benzoic acid） and Zn（NO3）2·6H2O afforded a three-dimensional（3D） metal-organic framework Zn3（C2H2N3）2（C7H5O2）4（C2H2N3=1,2,4-triazole, C7H5O2=benzoic acid）. The compound was crystallized in the hexagonal system with space group R3： a=2.90234（9） nm, b=2.90234（9） nm, c=1.08597（5） nm, γ=120°, V=7.9222（5） nm^3, Mr=816.68, Dc=1.541 g/cm^3, Z=9, F（000）=3708, R=0.0636, and wR=0. 1777. Its structure consists of ZnN2O2 tetrahedron and ZnN204 octahedron, which are connected by 1,2,4-triazole and benzoic acid ligands to form a 3D framework with helical units. This compound forms an interpenetrated NbO topology. The compound was characterized by single-crystal X-ray diffraction, elemental analysis, FTIR spectra, and TGA measurements.

关键词： Hydrothermal synthesis Metal-organic framework 1,2,4-Triazole Benzoic acid Helical units

Preparation of urea-formaldehyde paraffin microcapsules modified by carboxymethyl cellulose as a potential phase change material

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Journal of Forestry Research 2015年第1期26卷 253-260页

作者： zhan-hua huang Xin Yu Wei Li Shou-xin Liu Key Laboratory of Bio-based Material Science and Technology Ministry of EducationNortheast Forestry University

We prepared spherical microcapsules modified by carboxymethyl cellulose（CMC） with urea-formaldehyde（UF） resin as a shell material with a two-step process by in situ polymerization, and characterized the microcosmic features, chemical structure, and thermal performance of the microcapsules by SEM, FTIR, DSC, and TGA. We studied the effects of different experimental parameters of curing p H, the amounts of the emulsifier and emulsion speed. The CMC-UF microcapsules had good heat resistance and stability. The enthalpy of CMC-UF microcapsules reached 50.33 J g-1. Therefore, CMC-UF resin can be used as a potential wall material of phase change materials.

关键词： Spherical microcapsules Carboxymethyl cellulose Energy storage

Effect of lymph node micrometastases on prognosis of gastric carcinoma

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World Journal of Gastroenterology 2007年第30期13卷 4122-4125页

作者： Ze-Yu Wu Jing-hua Li Wen-hua zhan Yu-Long He Jin Wan Department of General Surgery Guangdong Provincial People's Hospital Guangzhou 510080 Guangdong Province China Zhongshan Medical College Sun Yat-Sen University Guangzhou 510089 Guangdong Province China Department of Gastrointestinal and Pancreatic Surgery the First Affiliated Hospital Sun Yat-Sen University Guangzhou 510080 Guangdong Province China

AIM： To evaluate the relationship between lymph node micrometastases and prognosis of patients with gastric carcinoma and to evaluate the significance of the new assessment of nodal status in determining the pN categories in the 5th edition of the UICC TNM classification.METHODS： A total of 850 lymph nodes from 30 patients with gastric carcinoma who underwent gastrectomy with lymphadenectomy were assessed by reverse transcription polymerase chain reaction assay in addition to histologic examination. Cytokeratin-20 gene marker was used in this assay.RESULTS： Routine examination by HE staining confirmed metastasis in 233 lymph nodes from 20 patients. All these 233 lymph nodes were oltokeratin-20 positive. Moreover, lymph node micrometastases were detected in an additional 67 lymph nodes in 12 of these 20 patients. Lymph node micrometastases were also detected in t0 lymph nodes from 2 of 10 patients who had no obvious metastases identified by HE staining. Totally, lymph node micrometastases were identified by the reverse transcription polymerase chain reaction assay in 77 （12.5%） lymph nodes from 14 （46.7%） patients with gastric carcinoma. Of 27 patients who underwent curative resection, 7 （25.9%） were up-staged （from Ⅰ B stage to Ⅱ stage in 1 patient, from IB stage to ⅢA stage in 1 patient, from Ⅱ stage to ⅢA stage in 1 patient, from ⅢA stage to ⅢB stage in 1 patient, from ⅢA stage to Ⅳ stage in 1 patient, from ⅢB stage to Ⅳ stage in 2 patients）. In a median follow-up of 32 （range 8-36） too, Kaplan-Meier survival analysis showed significant improvements in median survival （22.86 ± 3.17 mo, 95% CI： 16.64-29.08 mo vs 18.00 ± 7.4 mo, 95% CI： 3.33-32.67 mo） of patients with negative lymph node micrometastases over patients with positive lymph node micrometastases （log-rank, P 〈 0.05）.CONCLUSION： Lymph node micrometastases have a significant impact on the current staging system of gastric carcinoma, and are significant risk factors for prognosis of patients with gast

关键词： Gastric carcinoma Lymph node micrometastases Prognosis Stage