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A new Planetary Boundary Layer model and its application to heavy rain modeling

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Chinese Science Bulletin 2005年第16期50卷 1756-1766页

作者： SUN Jian ZHOU Xiuji zhao ping Chinese Academy of Meteorological Sciences Beijing 100081 China

A new Planetary Boundary Layer (PBL) model (namely MY-4 in this paper) was developed with reference to Mellor-Yamada’s Level 4 turbulent closure concept. Having been coupled with a meso-scale model MM5, MY-4 was util-ized to simulate a heavy-rain process, which took place over South China during June 8-9, 1998. Its model outputs indi-cated that the rainfall process was well captured in terms of its intensity and geographical distribution. More importantly, in comparison with MM5’s original boundary layer models, MY-4 made the following improvements: (1) MY-4 not only simulated the major weather systems like low vortexes and low-level jets more accurately, thus improving the general weather pattern of the rainfall process, but it was also capa-ble of restraining the occurrence of false rainfall centers with maximum precipitation amounts exceeding 160 mm. (2) Having been compared with the wind profile observed at Hong Kong, it revealed that MY-4 could reproduce the wind speed fluctuations in a short time scale reasonably well, which was not yet achieved in the original PBL models in MM5. Furthermore, a more detailed comparative study was made on the results simulated by MY-4 and a PBL model (which is based on Mellor-Yamada’s Level 2.5 concept) re-spectively. It showed that the contributions of turbulences generated by the two categories of PBL models to the wind fields at a lower atmosphere were increasingly different even in the first 1-2 hours of integrations. As the analysis dem-onstrated, under the nonlinear interactions within the meso-scale MM5 model, it was the turbulences in the boundary layer that had the most important impacts on the final model outputs and MY-4 seemed to better reflect this turbulent process, hence leading to the aforementioned im-provements.

关键词：行星边界层模型重雨模型天文学

Linkage between the Asian-Pacific Oscillation and the sea surface temperature in the North Pacific

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Chinese Science Bulletin 2010年第12期55卷 1193-1198页

作者： ZHOU BoTao zhao ping CUI Xuan National Climate Center China Meteorological Administration Beijing 100081 China National Meteorological Information Center China Meteorological Administration Beijing 100081 China National Meteorological Center China Meteorological Administration Beijing 100081 China

The linkage between the Asian-Pacific Oscillation (APO) and the sea surface temperature (SST) in the North Pacific during the summertime (June-August) is preliminarily investigated through an analysis of observed *** is found that APO is significantly and positively correlated to the North Pacific SST,with the correlation coefficient being 0.58 on the interannual timescale during the period 1954-2003,which suggests that a strong (weak) APO corresponds to high (low) SST in the North *** in-phase relationship is well supported by the dynamic and thermal conditions in association with the APO *** APO is in the positive phase,the East Asian westerly jet in the upper troposphere is weakened,and the anomalous anticyclonic circulation prevails in the low-troposphere over the North ***,the negative anomaly of the sensible and latent heat fluxes is predominated in the North Pacific,indicating ocean gets heat flux from the ***,warm water advection northward is strengthened in the North *** of these provide beneficial conditions to warm the North Pacific SST,and thus the SST is increased in this region,and vice versa.

关键词：北太平洋海表温度亚洲涛动太平洋海温年际时间尺度潜热通量海表面温度

Big Data Modeling and Analysis of Microblog Ecosystem

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International Journal of Automation and computing 2014年第2期11卷 119-127页

作者： Hua-ping Zhang Rui-Qi Zhang Yan-ping zhao Bao-Jun Ma School of Computer Science Beijing Institute of Technology School of Management and Economics Beijing Institute of Technology School of Economics and Management Beijing University of Posts and Telecommunications

Recent progress of Web 2.0 applications has witnessed the rapid development of microblog in China, which has already been one of the most important ways for online communications, especially on sharing information. This paper tries to make an in-depth investigation on the big data modeling and analysis of microblog ecosystem in China by using a real dataset containing over17 million records of SinaWeibo users. First, we present the detailed geography, gender, authentication, education and age analysis of microblog users in this dataset. Then we conduct the numerical features distribution analysis, propose the user influence formula and calculate the influences for different kinds of microblog users. Finally, user content intention analysis is performed to reveal users most concerns in their daily life.

关键词： Microblog mining user activity pattern user personalization user intention microblog ecosystem.

Mechanism of formation of low level jets in the South China Sea during spring and summer of 1998

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Chinese Science Bulletin 2003年第2期48卷 1265-1270页

作者： ping zhao Jian Sun Xiuji Zhou Chinese Acad Meteorol Sci Beijing 100081 Peoples R China

The mechanism responsible for the formation of the low-level jet (LLJ) over the South China Sea during spring and summer of 1998 was analyzed through using the assimilated grid data provided by the South China Sea mon-soon experiment (SCSMEX). More analyses were empha-sized on a heavy rainfall process in the Zhujiang Delta area between 8th and 10th June 1998 in which a LLJ played a key role. Furthermore, the MM5 meso-scale model was utilized in studying the effects of the weather systems on the LLJ. The results showed that the kinetic energy associated with the LLJ transferred upward when the LLJ formed, which results in the fact that the big velocity of the LLJ expanded upward to higher level. Simulation verifies that a synop-tic-scale low pressure in the low troposphere of the west of South China moved toward the east, with a low-troposphere synoptic-scale high pressure in the western Pacific moving toward the west. In this process, the approach of both sys-tems leads to the reinforcement of pressure gradient force between them, making the kinetic energy needed by the for-mation of the LLJ increase. Through this process the LLJ formed and developed over the South China Sea between the low and high pressures. Because the formation of the LLJ indicates the enhancement of summer monsoon in the South China Sea, the mechanism responsible for formation of the LLJ could be used in explaining an enhancement of summer monsoon in the South China Sea.

关键词： low level jet numerical simulation monsoon over the South China sea

APPLICATION OF PENALTY FUNCTION METHOD IN ISOPARANIETRIC HYBRID FINITE ELEMENT ANALYSIS

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Applied Mathematics and Mechanics(English Edition) 2005年第8期26卷 1017-1025页

作者： CHEN Dao-zheng（陈道政） JIAO zhao-ping（焦兆平） College of Civil and Architectural Engineering Hefei University of Technology Hefei 230009 P. R. China Panyu Vocational Technology College Guangzhou 511483 P. R. China

By the aid of the penalty function method, the equilibrium restriction conditions were introduced to the isoparametric hybrid finite element analysis, and the concrete application course of the penalty function method in three-dimensional isoparametdc hybrid finite element was discussed. The separated penalty parameters method and the optimal hybrid element model with penalty balance were also presented. The penalty balance method can effectively refrain the parasitical stress on the premise of no additional degrees of freedom. The numeric experiment shows that the presented element not only is effective in improving greatly the numeric calculation precision of distorted grids but also has the universality.

关键词： hybrid element equilibrium restriction condition penalty function method

Processing of high-precision ceramic balls with a spiral V-groove plate

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Frontiers of Mechanical Engineering 2017年第1期12卷 132-142页

作者： Ming FENG Yongbo WU Julong YUAN zhao ping Department of Machine InteUigence & Systems Engineering AkitaPrefectural University Akita 015-0055 Japan Ultra-Precision Machining Center Zhejiang University of TechnologyHangzhou 310014 China

As the demand for high-performance bearings gradually increases, ceramic balls with excellent proper- ties, such as high accuracy, high reliability, and high chemical durability used, are extensively used for high- performance bearings. In this study, a spiral V-groove plate method is employed in processing high-precision ceramic balls. After the kinematic analysis of the ball-spin angle and enveloped lapping trajectories, an experimental rig is constructed and experiments are conducted to confirm the feasibility of this method. Kinematic analysis results indicate that the method not only allows for the control of the ball-spin angle but also uniformly distributes the enveloped lapping trajectories over the entire ball surface. Experimental results demonstrate that the novel spiral V- groove plate method performs better than the conventional concentric V-groove plate method in terms of roundness, surface roughness, diameter difference, and diameter decrease rate. Ceramic balls with a G3-1evel accuracy are achieved, and their typical roundness, minimum surface roughness, and diameter difference are 0.05, 0.0045, and 0.105 μm, respectively. These findings confirm that the proposed method can be applied to high-accuracy and high-consistency ceramic ball processing.

关键词： bearing ceramic ball spiral V-groove,kinematic analysis trajectory

The intrinsic SFRF and sSFRF of galaxies:comparing SDSS observation with IllustrisTNG simulation

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Research in Astronomy and Astrophysics 2020年第12期20卷 229-242页

作者： ping zhao Haojie Xu Antonios Katsianis Xiao-Hu Yang Department of Astronomy School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute and Shanghai Key Laboratory for Particle Physics and CosmologyShanghai Jiao Tong UniversityShanghai 200240China

The star formation rate function(SFRF) and specific star formation rate function(s SFRF) from observations are impacted by the Eddington bias, due to uncertainties in the estimated star formation rate(SFR). We develop a novel method to correct the Eddington bias and obtain the intrinsic SFRF and sSFRF from the Sloan Digital Sky Survey(SDSS) Data Release 7. The intrinsic SFRF is in good agreement with measurements from previous data in the literature that relied on UV SFRs but its high star-forming end is slightly lower than the corresponding IR and radio tracers. We demonstrate that the intrinsic sSFRF from SDSS has a bimodal form with one peak found at sSFR ~10-9.7 yr^-1 representing the star-forming objects while the other peak is found at sSFR ~10-12 yr^-1 representing the quenched population. Furthermore, we compare our observations with the predictions from the Illustris TNG and Illustris simulations and affirm that the "TNG" model performs much better than its predecessor. However,we show that the simulated SFRF and CSFRD of TNG simulations are highly dependent on resolution,reflecting the limitations of the model and today’s state-of-the-art simulations. We demonstrate that the bimodal, two peaked s SFRF implied by the SDSS observations does not appear in TNG regardless of the adopted box-size or resolution. This tension reflects the need for inclusion of an additional efficient quenching mechanism in the TNG model.

关键词： statistical galaxies:formation galaxies:distances and redshifts hydrodynamics

Effect of heat treatment on cyclic deformation properties of Fe-26Mn-10AI-C steel

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Journal of Iron and Steel Research International 2019年第2期26卷 200-210页

作者： He Li Jian-ping zhao Zhan-yu Wang Li Ding School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816JiangsuChina Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipnient Nanjing 211816JiangsuChina

Fully reversed tensile-compression low-cycle fatigue tests were performed at room temperature under strain amplitude of 0.4%.The monotonic tensile results show that Fe-26Mn-10A1-C steels are fully austenite and(he optimal combination of ultimate tensile strength and total elongation was present at 950°C with 65 GPa%.The fatigue results show that the specimen at 1050°C has the maximum fatigue life of 162,000 cycles,which is much longer than twinning-induced plasticity(TWIP)steels of the same strain *** hot-forging specimen shows high similarity with TWIP steels with rapid initial cyclic hardening followed by cyclic softening and cyclic *** solution heat treatment,it is noteworthy that,after rapid initial cyclic softening,another rapid cyclic hardening and a following decrease with fluctuation were observed at 1000°*** is reas on able to believe that it is caused by K-carbides precipitated during cyclic *** interesting phenomenon is cyclic stress subsidence observed at 1050°C during its saturation stage at the last quarter of the fatigue life,and the span is about 12.5%of whole fatigue life.

关键词： Fe-Mn-AI-C steel Low-cycle fatigue Cyclic hardening Cyclic softening Cyclic stress subsidence

Mechanical properties of Fe-based amorphous–crystalline composite: a molecular dynamics simulation and experimental study

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Rare Metals 2021年第9期40卷 2560-2567页

作者： Han-Wen Zheng Xiao-Yong Shu Yang Li Jian-ping zhao College of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China Key Laboratory of Design and Manufacture of Extreme Pressure Equipment Nanjing 211816China

A new Fe-based amorphous–crystalline composite without non-metallic elements, Fe_(55)Cr_(15)Mo_(15)Ni_(10)W_(5), was prepared by melt-spinning. The formation ability and structure information were investigated by X-ray diffractometer(XRD), energy-dispersive spectrometer(EDS) and scanning electron microscope(SEM). The mechanical properties of the amorphous–crystalline composite were investigated by nanoindentation. A molecular dynamics simulation study was performed to simulate the formation of Fe_(55)Cr_(15)Mo_(15)Ni_(10)W_(5) amorphous alloy. The mechanical properties were obtained by compression simulations simultaneously. The results indicate that the Fe_(55)Cr_(15)Mo_(15)Ni_(10)W_(5) ribbon is an amorphous–crystalline composite structure with good ductility, and the hardness of the amorphous–crystalline composite is about 75%higher than that of master ingot. The simulation mechanical properties are in good agreement with the results of nanoindentation at the nanoscale.

关键词： Fe-based amorphous–crystalline composite Nanoindentation Molecular dynamics simulation Mechanical property