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| 1 | Effect of cooling rate upon the microstructure and mechanical properties of in-situ TiC reinforced high entropy alloy CoCrFeNi显示文摘Three types of in-situ TiC(5 vol%,10 vol%and 15 vol%)reinforced high entropy alloy CoCrFeNi matrix composites were produced by vacuum induction smelting.The effect of two extreme cooling conditions(i.e.,slow cooling in fu rnace and rapid cooling in copper crucible)upon the microstructure and mechanical properties was examined.In the case of slow cooling in the furnace,TiC was found to form mostly along the grain boundaries for the 5 vol%samples.With the increase of TiC reinforcements,fibrous TiC appeared and extended into the matrix,leading to an increase in hardness.The ultimate tensile strength of the composites shows a marked variation with increasing TiC content;that is,425.6 MPa(matrix),372.8 MPa(5 vol%),550.4 MPa(10 vol%)and 334.3 MPa(15 vol%),while the elongation-to-failure(i.e.,ductility)decreases.The fracture pattern was found to transit from the ductile to cleavage fracture,as the TiC content increased.When the samples cooled rapidly in copper crucible,the TiC particles formed both along the grain boundaries and within the grains.With the increase of TiC volume fraction,both the hardness and ultimate tensile strength of the resulting composites improved steadily while the elongation-to-failure declined.Therefore,the fast cooling can be used to drastically improve the strength of in-situ TiC reinforced CoCrFeNi.For example,for the 15 vol%TiC/CoCrFeNi composite cooled in the copper crucible,the hardness and ultimate tensile strength can reach as high as 595 HV and 941.7 MPa,respectively. | Jifeng Zhang Ting Jia Huan Qiu Heguo Zhu Zonghan Xie | 2020 | Journal of Materials Science & Technology2020，42，7： | 6 |
| 2 | Designing multilayer diamond like carbon coatings for improved mechanical properties显示文摘New multilayer coatings were produced by incorporating alternating soft and hard DLC layers enabled by varying the bias voltage during deposition process while maintaining a constant hard-to-soft layer thickness ratio.These coatings were deposited onto a Cr/Cr Cxgraded layer by closed field unbalanced magnetron sputtering(CFUBMS).The cross-sectional analysis of the coatings showed that the multilayer coatings possess sharp interfaces between the soft and hard layers with the hard to soft layer thickness ratio(1:1.33)constant in all the coatings.Raman analysis uncovered the increasing sp^(3)character of the DLC coatings as a result of decreasing ID/IGratio and increasing full width at half maximum(FWHM)values of the G band peak induced supposedly by an increase in bias voltage during hard layer deposition.Nanoindentation tests showed an increase in hardness of the DLC coatings which can be correlated with the increase in the sp^(3)content of the coatings as well as decreasing sp^(2)-C cluster size,as calculated from the ID/IGratio.Furthermore,the coatings exhibited excellent plastic deformation resistance and adhesion strength upon microindentation and scratch testing,respectively.Although further investigations are required to assess coating durability,the multilayer design could offer the DLC coatings with a rare opportunity to combine the high hardness with damage resistance with a constant bilayer thickness and without the need to introduce complex multilayer system. | Mohammad Sharear Kabir Zhifeng Zhou Zonghan Xie Paul Munroe | 2021 | Journal of Materials Science & Technology2021，，6： | 6 |
| 3 | Physical Growth of Children in Urban,Suburban and Rural China's Mainland:A Study of 20 Years' Change显示文摘Objective To describe secular trends on physical growth of children in China during the year of 1985‐2005 and to analyze the urban‐suburban‐rural difference and its change. Methods The measurements of height, weight and chest circumference obtained from two serial national cross‐sectional surveys for children aged 0 to 7 years in China were used to analyze the secular trends, and the growth differences among urban, suburban and rural children were compared. Results The average weight and height for both boys and girls from urban, suburban and rural areas have significantly increased in most age groups during the past 20 years; The average chest circumference increased slightly, ranging from 0.0 to 2.0 cm. From 1985 to 2005, the urban‐suburban difference in height had become smaller, and that in weight showed similar trend for children under 3 years old but became larger after 3 years old; the suburban‐rural difference both in height and weight became larger after 6 months old. The increment per decade in height was the greatest in the suburban group while the greatest increment in weight was the urban group. Conclusion Positive secular trends were observed among urban, suburban and rural areas in Chinese children under 7 years old during the 1980s and the 2000s, reflecting a rapid socio‐economic development in China. | LI Hui ZONG XinNan ZHANG Jing ZHU ZongHan | 2011 | Biomedical and Environmental Sciences2011，24，1： | 2 |
| 4 | The optimal extracting process,manufacturing technique and biological evaluation of Lithospermum erythrorhizon microcapsules 显示文摘 | ChingWen Lou ChiungYun Chang ZongHan Wu | 2015 | Materials Science and Engineering C2015，48，： | 1 |
| 5 | Microstructure and high temperature wear of the aluminum matrix composites fabricated by reaction from Al–ZrO 2 –B elemental powders显示文摘 | Heguo Zhu Cuicui Jia Jianliang Li Jun Zhao Jinzhu Song Yinqun Yao Zonghan Xie | 2011 | Powder Technology2011，，： | 1 |
| 6 | Heterogeneity of the glutathione transferase genes encoding enzymes responsible for insecticide degradation in the housefly显示文摘 | Michael Syvanen Zonghan Zhou Jonathan Wharton Claire Goldsbury Alan Clark | 1996 | Journal of Molecular Evolution1996，，3： | 1 |
| 7 | Branch values in Ahlfors’ theory of covering surfaces显示文摘In the study of the constant in Ahlfors’second fundamental theorem involving a set Eq consisting of q points,branch values of covering surfaces outside Eq bring a lot of troubles.To avoid this situation,for a given surfaceΣ0,it is useful to construct a new surfaceΣ1,such that L(■Σ1)≤L(■Σ0),and H(Σ1,Eq)≥H(Σ0,Eq).and all branch values ofΣ1 are contained in Eq.The goal of this paper is to prove the existence of suchΣ1,which generalizes a result found by Zhang(2013). | Zonghan Sun Guangyuan Zhang | 2020 | Science China Mathematics2020，63，8： | 1 |
| 8 | Fatigue Topology Optimization Design Based on Distortion Energy Theory and Independent Continuous Mapping Method显示文摘Fatigue failure is a common failure mode under the action of cyclic loads in engineering applications,which often occurs with no obvious signal.The maximum structural stress is far below the allowable stress when the structures are damaged.Aiming at the lightweight structure,fatigue topology optimization design is investigated to avoid the occurrence of fatigue failure in the structural conceptual design beforehand.Firstly,the fatigue life is expressed by topology variables and the fatigue life filter function.The continuum fatigue optimization model is established with the independent continuous mapping(ICM)method.Secondly,fatigue life constraints are transformed to distortion energy constraints explicitly by taking advantage of the distortion energy theory.Thirdly,the optimization formulation is solved by the dual sequence quadratic programming(DSQP).And the design scheme of lightweight structure considering the fatigue characteristics is obtained.Finally,numerical examples illustrate the practicality and effectiveness of the fatigue optimization method.This method further expands the theoretical application of the ICM method and provides a novel approach for the fatigue optimization problem. | Hongling Ye Zonghan Li Nan Wei Pengfei Su Yunkang Sui | 2021 | Computer Modeling in Engineering & Sciences2021，，7： | 1 |
| 9 | System Strength Assessment Based on Multi-task Learning显示文摘Increase in permeability of renewable energy sources(RESs)leads to the prominent problem of voltage stability in power system,so it is urgent to have a system strength evaluation method with both accuracy and practicability to control its access scale within a reasonable range.Therefore,a hybrid intelligence enhancement method is proposed by combining the advantages of mechanism method and data driven method.First,calculation of critical short circuit ratio(CSCR)is set as the direction of intelligent enhancement by taking the multiple renewable energy station short circuit ratio as the quantitative indicator.Then,the construction process of CSCR dataset is proposed,and a batch simulation program of samples is developed accordingly,which provides a data basis for subsequent research.Finally,a multi-task learning model based on progressive layered extraction is used to simultaneously predict CSCR of each RESs connection point,which significantly reduces evaluation error caused by weak links.Predictive performance and anti-noise performance of the proposed method are verified on the CEPRI-FS-102 bus system,which provides strong technical support for real-time monitoring of system strength. | Baoluo Li Shiyun Xu Huadong Sun Zonghan Li Lin Yu | 2024 | CSEE Journal of Power and Energy Systems2024，10，1： | 0 |
| 10 | Strength and ductility synergy of Nb-alloyed Ni_(0.6)CoFe_(1.4) alloys显示文摘Designing strong, yet ductile, and body-centered cubic(BCC) medium-entropy alloys(MEAs) remains to be a challenge nowadays.In this study, the strength–ductility trade-off of Ni_(0.6)CoFe_(1.4)MEAs was tackled via introducing a BCC + face-centered cubic(FCC) dual-phase microstructure. Ni_(0.6)CoFe_(1.4)Nbx(x = 0, 0.05, 0.08, 0.10, and 0.15, in molar ratio) MEAs were prepared using vacuum induction melting. Results show that the new alloy is composed of BCC plus FCC dual phases featuring a network-like structure, and the BCC phase is the main phase in this alloy system. Moreover, the Nb0.10 MEA shows high strength and respectable tensile ductility, representing the best combination of the strength and fracture elongation among the alloys studied here. The remarkable strength of the Nb0.10 MEA is attributed to the combined effect of the solid solution strengthening, the precipitation hardening effect and the interface strengthening effect. | Jian Wu Heguo Zhu Zonghan Xie | 2023 | International Journal of Minerals,Metallurgy and Materials2023，30，4： | 0 |
| 11 | Mechanical size effect of eutectic high entropy alloy:Effect of lamellar orientation显示文摘The effect of lamellar orientation on the deformation behavior of eutectic high entropy alloy at the micrometer scale,and the roles of two rarely explored laminate orientations(i.e.,the lamellar orientation at~0°and 45°angles with the loading direction)in regulating size-dependent plasticity were investigated using in-situ micropillar compression tests.The alloy,CoCrFe NiTa_(0.395),consists of alternating layers of Laves and FCC phases.It was found that the yield stress of the 0°pillars scaled inversely with the pillar diameters,in which the underlying deformation mode was observed to transform from pillar kinking or buckling to shear banding as the diameter decreased.In the case of the 450 pillars with diameters ranging from 0.4 to 3μm,there exists a’weakest’diameter of~1μm,at which both constraint effect and dislocation starvation are ineffective.Irrespective of the lamellar orientations,the strain hardening rate decreased with decreasing pillar diameter due to the diminishing dislocation accumulation that originated from the softening nature of large shear bands in the 0°pillars,and the enhanced probability of dislocation annihilation at the increased free surfaces in the 45°pillars.The findings expand and deepen the understanding of the mechanical size effect in small-scale crystalline materials and,in so doing,provide a critical dimension for the development of high-performing materials used for nanoor microelectromechanical systems. | Yujie Chen Xianghai An Sam Zhang Feng Fang Wenyi Huo Paul Munroe Zonghan Xie | 2021 | Journal of Materials Science & Technology2021，，23： | 0 |
| 12 | Dynamic Capture Method for Out-of-step Center of Power Grid Based on Measurement Information显示文摘This paper dynamically captures the out-of-step center for a bulk power system based on measurement information.First,the position characteristics of the out-of-step center are discussed from the perspective of triangular geometry under different potential and uniform impedance distributions based on a two-machine system.The correlation between the out-of-step center and the oscillation center is analyzed.Second,combined with analytical geometry,it is inferred that the distribution characteristics of the out-of-step center voltage vector ends are a circle or a straight line,and the position of the out-of-step center corresponds to the intersection between the voltage drop of the line and the distribution characteristics;then,the accurate location of the out-of-step center and the determination of the appearance moment is realized.Finally,a dynamic equivalence method for a power grid is proposed based on the electrical parameters of the transmission line,and an alternative iterative correction of equivalent parameters is carried out by trajectory sensitivity,which provides a new way for capturing the out-ofstep center dynamically in a multimachine system.The proposed method is validated using a three-machine system,the IEEE-39 system and the Northwest China Power Grid,and shows potential for online applications. | Zonghan Li Dongxia Zhang Daowei Liu Shaobo Yang Gaoshang Zhao | 2021 | CSEE Journal of Power and Energy Systems2021，7，6： | 0 |
| 13 | Oxygen metabolism-balanced engineered hydrogel microspheres promote the regeneration of the nucleus pulposus by inhibiting acid-sensitive complexes显示文摘Intervertebral disc degeneration(IVDD)is commonly caused by imbalanced oxygen metabolism-triggered inflammation.Overcoming the shortcomings of antioxidants in IVDD treatment,including instability and the lack of targeting,remains challenging.Microfluidic and surface modification technologies were combined to graft chitosan nanoparticles encapsulated with strong reductive black phosphorus quantum dots(BPQDs)onto GelMA microspheres via amide bonds to construct oxygen metabolism-balanced engineered hydrogel microspheres(GM@CS-BP),which attenuate extracellular acidosis in nucleus pulposus(NP),block the inflammatory cascade,reduce matrix metalloproteinase expression(MMP),and remodel the extracellular matrix(ECM)in intervertebral discs(IVDs).The GM@CS-BP microspheres reduce H_(2)O_(2) intensity by 229%.Chemical grafting and electrostatic attraction increase the encapsulation rate of BPQDs by 167%and maintain stable release for 21 days,demonstrating the antioxidant properties and sustained modulation of the BPQDs.After the GM@CS-BP treatment,western blotting revealed decreased acid-sensitive ion channel-3 and inflammatory factors.Histological staining in an 8-week IVDD model confirmed the regeneration of NP.GM@CS-BP microspheres therefore maintain a balance between ECM synthesis and degradation by regulating the positive feedback between imbalanced oxygen metabolism in IVDs and inflammation.This study provides an in-depth interpretation of the mechanisms underlying the antioxidation of BPQDs and a new approach for IVDD treatment. | Ziang Li Feng Cai Jincheng Tang Yichang Xu Kaijin Guo Zonghan Xu Yu Feng Kun Xi Yong Gu Liang Chen | 2023 | Bioactive Materials2023，，6： | 0 |
| 14 | Coupling Effect between Inlet Distortion Vortex and Fan显示文摘In the process of inlet/engine matching,large-scale distortion vortexes would be generated due to lip separation,curved duct,shock-wave boundary layer interaction and other factors of inlet,resulting in complex combination distortion of total pressure and swirl,which would affect the stable and efficient operation of fans/compressors of aero-engine.On the basis of main distortion vortex characteristics of a typical S-shape inlet and its theoretical model of velocity and pressure distribution,this paper establishes an inlet boundary condition definition method to generate three-dimensional distortion vortex,and presents a study of coupling effect between steady distortion vortex and NASA Rotor 67.The results show that the fan’s performance curve would move to smaller mass flow direction under the influence of the co-rotating distortion vortex,while fan’s operation curve would change to the opposite direction if the inlet distortion vortex direction is opposite to the fan’s rotating direction.Compared with co-rotating distortion vortex,the efficiency loss caused by counter-rotating distortion vortex would be larger and total pressure ratio loss would be smaller.The vortex core size has significant influence on the stability margin of the fan,but has little influence on the efficiency and total pressure ratio characteristic.As the vortex core size increases,the range of fan’s tip region with high attack angle would become larger and cause the fan to stall in advance.Due to the non-uniform suction of the downstream fan,the inlet distortion vortex accelerates to mix with the surrounding main flow.The total pressure distortion decreases and swirl distortion increases along sections from inlet boundary to the fan leading edge. | LIU Zepeng HUANG Guoping CHEN Jie YU Zonghan | 2023 | Journal of Thermal Science2023，32，3： | 0 |
| 15 | Application of Game Theory to Basketball显示文摘Introduction Game theory is the study of how players interact and how to choose strategies in order to maximize benefits.To a certain extent,game theory can be used to advise decision makers on what decisions to make.The earliest ideas of game theory can be traced back to the 18th century,but the major development of the theory began in the 1920s with the work of mathematician Emile Borel and the | Zonghan Li | 2016 | 环球市场信息导报2016，，22： | 0 |
| 16 | Adaptive cropping shallow attention network for defect detection of bridge girder steel using unmanned aerial vehicle images显示文摘Bridges are an important part of railway infrastructure and need regular inspection and maintenance.Using unmanned aerial vehicle(UAV)technology to inspect railway infrastructure is an active research issue.However,due to the large size of UAV images,flight distance,and height changes,the object scale changes dramatically.At the same time,the elements of interest in railway bridges,such as bolts and corrosion,are small and dense objects,and the sample data set is seriously unbalanced,posing great challenges to the accurate detection of defects.In this paper,an adaptive cropping shallow attention network(ACSANet)is proposed,which includes an adaptive cropping strategy for large UAV images and a shallow attention network for small object detection in limited samples.To enhance the accuracy and generalization of the model,the shallow attention network model integrates a coordinate attention(CA)mechanism module and an alpha intersection over union(α-IOU)loss function,and then carries out defect detection on the bolts,steel surfaces,and railings of railway bridges.The test results show that the ACSANet model outperforms the YOLOv5s model using adaptive cropping strategy in terms of the total mAP(an evaluation index)and missing bolt mAP by 5%and 30%,respectively.Also,compared with the YOLOv5s model that adopts the common cropping strategy,the total mAP and missing bolt mAP are improved by 10%and 60%,respectively.Compared with the YOLOv5s model without any cropping strategy,the total mAP and missing bolt mAP are improved by 40%and 67%,respectively. | Zonghan MU Yong QIN Chongchong YU Yunpeng WU Zhipeng WANG Huaizhi YANG Yonghui HUANG | 2023 | Journal of Zhejiang University-Science A(Applied Physics & Engineering)2023，24，3： | 0 |
| 17 | Properties of Ahlfors constant in Ahlfors covering surface theory显示文摘This paper is a subsequent work of[Invent.Math.,2013,191:197-253].The second fundamental theorem in Ahlfors covering surface theory is that,for each set E_(q)of q(≥3)distinct points in the extended complex plane C,there is a minimal positive constant H_(0)(E_(q))(called Ahlfors constant with respect to E_(q)),such that the inequality(q-2)A(Σ)-4π#(f^(-1)(E_(q))∩U)≤H_(0)(E_(q))L(ЭΣ)holds for any simply-connected surfaceΣ=(f,U),where A(Σ)is the area ofΣ,L(ЭΣ)is the perimeter ofΣ,and#denotes the cardinality.It is difficult to compute H_(0)(E_(q))explicitly for general set E_(q),and only a few properties of H_(0)(E_(q))are known.The goals of this paper are to prove the continuity and differentiability of H_(0)(E_(q)),to estimate H_(0)(E_(q)),and to discuss the minimum of H_(0)(E_(q))for fixed q. | Wennan LI Zonghan SUN Guangyuan ZHANG | 2021 | Frontiers of Mathematics in China2021，16，4： | 0 |
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