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Distance Between α-Orientations of Plane Graphs by Facial Cycle Reversals

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Acta Mathematica Sinica,English Series 2019年第4期35卷 569-576页

作者： Wei Juan ZHANG jian guo qian Fu Ji ZHANG School of Mathematical Sciences Xiamen University School of Mathematical Sciences Xinjiang Normal University

Cycle reversal had been shown as a powerful method to deal with the relation among orientations of a graph since it preserves the out-degree of each vertex and the connectivity of the orientations. A facial cycle reversal on an orientation of a plane graph is an operation that reverses all the directions of the edges of a directed facial cycle. An orientation of a graph is called an α-orientation if each vertex admits a prescribed out-degree. In this paper, we give an explicit formula for the minimum number of the facial cycle reversals needed to transform one α-orientation into another for plane graphs.

关键词： α-Orientation facial cycle reversal distance plane graph

The S^2NS Digraphs and the Cycle Linear System of a Digraph

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Acta Mathematicae Applicatae Sinica 2002年第2期18卷 333-340页

作者： jian-guo qian, Sheng-jun MiaoDepartment of Mathematics, Xiamen University, Xiamen 361005, ChinaDepartment of Mathematics and Physics, Weihai Vocational College, Weihai 264200, China Department of Mathematics Xiamen University Xiamen China Department of Mathematics and Physics Weihai Vocational College Weihai China

It is known that the study of the qualitative properties of a matrix A (which depend only on the sign pattern of A) can be turned into the study of the graph theoretical properties of the signed digraph S(A). The underlying digraph of the signed digraph of a strong sign nonsingular matrix (abbreviated S NS matrix) with a negative main diagonal is called an S NS digraph. In the study of S NS digraphs, the minimal forbidden configuration (or MFC for short) plays an important role. Three (classes of) MFS's were constructed by Thomassen, Brualdi and Shader, and Shao. In this paper, we show that a digraph D is an S2NS digraph if and only if its 'cycle linear system' is solvable. This simplifies a parallel result obtained by Shao and Hu. As an application of the result, a graph theoretical characterization for a digraph to be an S NS digraph is given. At the end of the paper, we construct infinitely many new MFCs to show that for each even number k(k>0), there are basic MFCs with fc terminal components (here, with no loss of generality, we assume that the number of the initial components of a digraph is no less than that of its terminal components throughout the following).

关键词： Matrix S^2 NS digraph Cycle linear system

The Mechanism of Heating Rate on the Secondary Recrystallization Evolution in Grain Oriented Silicon Steel

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 275-282页

作者： GAO qian LI Jun WANG Xianhui CAO Laifu GONG jian LI Bo Central Iron and Steel Research Institute Group Beijing 100081China Shougang Zhixin Electromagnetic Material R&D(Beijing)Co. Ltd.Beijing 101300China Beijing Shougang Co. Ltd.Qian’an 064404China

Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing,in which the evolution of magnetic properties,grain orientations and precipitates were *** illustrate the Zener factor,the diameter and number density of precipitates of interrupted testing samples were statistically *** effect of precipitate ripening on the Goss texture and magnetic property was *** indicated that the trend of Zener factor was similar under different heating rates,first increasing and then decreasing,and that the precipitate maturing was greatly inhibited as the heating rate *** recrystallization was developed at the temperature of 1010℃when a heating rate of 5℃/h was used,resulting in Goss,Brass and{110}oriented grains growing abnormally and a magnetic induction intensity of ***,increasing the heating rate to 20℃/h would inhibit the development of undesirable oriented grains and obtain a sharp Goss ***,when the heating rate was extremely fast,such as 40℃/h,poor secondary recrystallization was developed with many island grains,corresponding to a decrease in magnetic induction intensity to 1.87 *** a suitable heating rate of 20℃/h,the sharpest Goss texture and the highest magnetic induction of 1.94 T with an onset secondary recrystallization temperature of 1020℃were found among the experimental variables in this *** heating rate affected the initial temperature of secondary recrystallization by controlling the maturation of precipitates,leading to the deviation and dispersion of Goss texture,thereby reducing the magnetic properties.

关键词： high temperature annealing heating rate secondary recrystallization grain oriented silicon steel

Epitaxial synthesis and electronic properties of monolayer Pd2Se3

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Chinese Physics B 2020年第9期29卷 543-548页

作者： Peng Fan Rui-Zi Zhang Jing Qi En Li guo-jian qian Hui Chen Dong-Fei Wang Qi Zheng Qin Wang Xiao Lin Yu-Yang Zhang Shixuan Du Hofer W A Hong-Jun Gao Institute of Physics and University of Chinese Academy of Sciences Chinese Academy of Sciences(CAS)Beijing 100190China CAS Center for Excellence in Topological Quantum Computation Beijing 100190China School of Natural and Environmental Sciences Newcastle UniversityNewcastle upon Tyne Ne77 RUUK

Two-dimensional(2D)materials received large amount of studies because of the enormous potential in basic science and industrial *** Pd2Se3 is a fascinating 2D material that was predicted to possess excellent thermoelectric,electronic,transport,and optical ***,the fabrication of large-scale and high-quality monolayer Pd2Se3 is still ***,we report the synthesis of large-scale and high-quality monolayer Pd2Se3 on graphene-SiC(0001)by a two-step epitaxial *** atomic structure of Pd2Se3 was investigated by scanning tunneling microscope(STM)and confirmed by non-contact atomic force microscope(nc-AFM).Two subgroups of Se atoms have been identified by nc-AFM image in agreement with the theoretically predicted atomic *** tunneling spectroscopy(STS)reveals a bandgap of 1.2 eV,suggesting that monolayer Pd2Se3 can be a candidate for photoelectronic *** atomic structure and defect levels of a single Se vacancy were also *** spatial distribution of STS near the Se vacancy reveals a highly anisotropic electronic *** two-step epitaxial synthesis and characterization of Pd2Se3 provide a promising platform for future investigations and applications.

关键词： 2D material Pd2Se3 scanning tunneling microscope/spectroscopy non-contact atomic force microscope

Charge density wave states in phase-engineered monolayer VTe_(2)

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Chinese Physics B 2022年第7期31卷 71-76页

作者： Zhi-Li Zhu Zhong-Liu Liu Xu Wu Xuan-Yi Li Jin-An Shi Chen Liu guo-jian qian Qi Zheng Li Huang Xiao Lin Jia-Ou Wang Hui Chen Wu Zhou Jia-Tao Sun Ye-Liang Wang Hong-Jun Gao Institute of Physics and University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100190China MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices School of Integrated Circuits and ElectronicsBeijing Institute of TechnologyBeijing 100081China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100084China

Charge density wave(CDW)strongly affects the electronic properties of two-dimensional(2D)materials and can be tuned by phase *** 2D transitional metal dichalcogenides(TMDs),VTe_(2)was predicted to require small energy for its phase transition and shows unexpected CDW states in its ***,the CDW state of H-VTe_(2)has been barely ***,we investigate the CDW states in monolayer(ML)H-VTe_(2),induced by phase-engineering from T-phase VTe_(2).The phase transition between T-and H-VTe_(2)is revealed with x-ray photoelectron spectroscopy(XPS)and scanning transmission electron microscopy(STEM)*** H-VTe_(2),scanning tunneling microscope(STM)and low-energy electron diffraction(LEED)results show a robust 2√3×2√3CDW superlattice with a transition temperature above 450 *** findings provide a promising way for manipulating the CDWs in 2D materials and show great potential in its application of nanoelectronics.

关键词： charge density wave H-VTe_(2) phase engineering transitional metal dichalcogenides

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棒状杆菌固定化细胞生产L(+)-酒石酸

生物工程学报 2000年第2期16卷 188-192页

作者：张建国钱亚娟浙江大学生命科学学院杭州310027

以卡拉胶为载体,固定化棒状杆菌(Corynebacteriumsp.)JZ1菌株细胞,再经活化处理,顺式环氧琥珀酸水解酶(ESH)酶活力总回收率在100%以上。摇瓶反应10批,酶活力没有明显降低。1500L酶柱中连续运行90d,酶稳定性很好。固定化后酶反应的最适温... 详细信息

以卡拉胶为载体,固定化棒状杆菌(Corynebacteriumsp.)JZ1菌株细胞,再经活化处理,顺式环氧琥珀酸水解酶(ESH)酶活力总回收率在100%以上。摇瓶反应10批,酶活力没有明显降低。1500L酶柱中连续运行90d,酶稳定性很好。固定化后酶反应的最适温度(45℃)和最适pH(90)没有改变,而热稳定性。

关键词：卡拉胶固定化细胞酒石酸棒状杆菌

High-performance poly(aromatic pyridine) copolymers with crown ether moieties for high temperature polymer electrolyte membrane fuel cells

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Science China Chemistry 2025年

作者： qian Wang Songhao Zhao Yunpeng guo Wei Wei Lele Wang Jingshuai Yang Department of Chemistry College of Sciences Northeastern University Institute of Metal Research Chinese Academy of Sciences

This study concentrates on the development of high temperature polymer electrolyte membranes（HT-PEMs）, which are essential components for HT-PEM fuel cells（HT-PEMFCs）. Although the phosphoric acid（PA）-doped polybenzimidazole（PBI） has been regarded as the successful HT-PEM, this system still suffers from several challenges, including the use of carcinogenic monomers, complex synthesis procedures, and poor solubility in organic solvents. To develop more cost-effective, readily synthesized and high-performance alternatives, this study employs a simply superacid-catalyzed Friedel-Crafts reaction to synthesize a series of poly（triphenyl-co-dibenzo-18-crown-6 pyridine） copolymers, denoted as P(TPx%-co-CEy%), using ptriphenyl, dibenzo-18-crown-6 and 4-acetylpyridine as monomers. The copolymerized hydrophilic and bulky crown ether unites introduce large free volumes and multiple interaction sites with PA molecules, as elucidated by theoretical *** microphase separation structures are formed as confirmed by atomic force microscope（AFM）, transmission electron microscopy（TEM） and small-angle X-ray scattering（SAXS）. Thus P(TPx%-co-CEy%) membranes exhibit excellent PA absorption and proton conduction abilities. For example, after immersing in 85 wt% PA at 30 °C, the P(TP91%-co-CE9%) membrane achieves a PA doping content of 205% and a high conductivity of 0.138 S cm-1at 180 °C, while maintaining a tensile strength of 7.5 MPa at room temperature. Without humidification and backpressure, the peak power density of an H2-O2cell equipped with P(TP91%-co-CE9%)/205%PA reaches nearly 1200 mW cm-2, representing one of the highest performances reported for PA-doped HT-PEMs to date. This work demonstrates the enormous potential of poly（triphenyl-co-crown ether pyridine） membranes in the HT-PEMFC applications.

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Modifying metabolic and immune hallmarks of cancer by a copper complex

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Science China Chemistry 2025年

作者： Chengyan Chu Yunhua Zhang Chengyuan qian Xiuzhi Yang Yicun Shang Zijian guo Xiaoyong Wang State Key Laboratory of Pharmaceutical Biotechnology School of Life Sciences Nanjing University State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical Engineering Nanjing University

Metabolic adaptation of cancer cells is a key tactic for maintaining their tumorigenicity and viability in the tumor immune microenvironment （TIME）.Concurrent modulation on the metabolic pathway and immune system could change the living condition of cancer cells and potentiate the efficacy of anticancer drugs.A copper complex （DDCu） was designed to influence the energy metabolism of cancer cells and reshape the *** restrained the production and transportation of lactate by inhibiting the expression of lactate dehydrogenase and monocarboxylate transporter 4,thereby altering the metabolic pathway of cancer cells and improving the acidic tumor ***,DDCu was reduced to Cu+by cellular glutathione to react with lipoylated proteins of the tricarboxylic acid cycle and destabilize the Fe–S cluster proteins,leading to the aggregation of dihydrolipoamide S-acetyltransferase and cuproptosis in cancer ***,DDCu promoted the polarization of macrophages from the M2 to M1 phenotype,activated CD4+and CD8+T cells,and reversed the *** a result,DDCu inhibited the tumor growth through a synergy between metabolic regulation and immunomodulation.

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Effect of pouring time on microstructure and mechanical properties of centrifugal cast Ti-46Al alloy tubes

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China Foundry 2025年

作者： Gang Huang qian Dang Cong-cong Su Jing Zhao Chi Zhang guo-huai Liu Zhao-dong Wang The State Key Laboratory of Rolling and Automation Northeastern University School of Materials Science and Engineering Shenyang University of Technology

The grain size of TiAl alloy castings prepared by traditional casting process is coarse, thus showing poor mechanical properties. In this study, a new type of high performance Ti-46Al alloy tube prepared by vacuum centrifugal casting technology was introduced. This research comprehensively examined the influence of pouring time on the microstructure and mechanical performance of the castings, employing both experimental approaches and ProCast simulation methodologies. The findings indicate that prolonging the pouring time facilitates a microstructural evolution from coarse columnar grains to refined equiaxed grains. Under the condition of pouring temperature of 1,600 °C, rotation speed of 800 r·min-1and pouring time of 6 s, the tensile strength of Ti-46Al alloy at room temperature reaches 650 MPa, and the tensile strength at 800 °C reaches 705 MPa, which is significantly higher than that of traditional as-cast Ti-Al alloy.

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