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On the Mean Value of the Complete Trigonometric Sums with Dirichlet Characters

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Acta Mathematica Sinica,English Series 2007年第7期23卷 1341-1344页

作者： zhe Feng xu Department of Mathematics Northwest University

The main purpose of this paper is, using the analytic method, to study the mean value properties of the complete trigonometric sums with Dirichlet characters, and give an exact calculating formula for its fourth power... 详细信息

关键词： complete trigonometric sums Dirichlet character mean value

Column adsorption of Cu(Ⅱ) by polymer-supported nano-iron oxides in the presence of sulfate: Experimental and mathematical modeling

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Chinese Journal of Chemical Engineering 2017年第9期25卷 1163-1169页

作者： Hui Qiu Xiaolin Zhang zhe xu Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET) School of Environmental Science and Engineering Nanjing University of Information Science & Technology State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University

Polymer-supported hydrous iron oxides(HFOs) are promising for heavy metals removal from aqueous *** ubiquitous inorganic ligands, e.g., sulfate, are expected to exert considerable impacts on pollutants removal by these hybrid sorbents. Herein, we obtained a hybrid sorbent HFO-PS by encapsulating nanosized HFO into macroporous polystyrene(PS) resin. Both batch and column sorption experiments of Cu(Ⅱ) by HFO-PS were carried out in the presence of sulfate. Obviously, the presence of sulfate is favorable for Cu(Ⅱ) sorption onto *** performances of column Cu(Ⅱ) removal were fitted and predicted with Adams–Bohart, Clark, Thomas and BDST models. Thomas model is suggested best-fit to predict the breakthrough curves. Besides, a linear correlation is observed between breakthrough time and column length based on BDST model, which might be useful for predicting the breakthrough time for Cu(Ⅱ) removal by HFO-PS.

关键词： Composite Nanotechnology Waste water Hydrous iron oxide Fixed-bed adsorption Thomas model

2D DEM simulation of particle mixing in rotating drum: A parametric study

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Particuology 2010年第2期8卷 141-149页

作者： Yong xu Chunhui xu zhe Zhou Jing Du Daping Hu College of Sdence China Agricultural University Beijing 100083 China

Mixing behaviors of equal-sized glass beads in a rotating drum were investigated by both DEM simula- tions and experiments. The experiments indicated that higher rotation speed can significantly enhance mixing. The particle profiles predicted by 2D DEM simulation were compared with the experimental results from a quasi-2D drum, showing inconsistency due to reduction of contacts in the single-layer 2D simulation which makes the driving friction weaker than that in the quasi-2D test, better results could be reached by specifying a higher frictional coefficient between the particles and the cylinder wall. In order to explore the influences of physical properties （density, size or friction） on mixing behavior, numerical 2D simulations were carried out systematically, in which one examined specific property being examined was exaggerated while the others were kept the same as that in the control group. The DEM simulations reveal that particle density and size are the dominating factors affecting mixing behaviors, while the effect of frictional coefficient is less significant. However, segregation due to any of the factors can be diminished by specifying a proper particle size distribution （multi-size with lower size ratio）. 2009 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

关键词： Discrete Element Method Rotating drum Granule Mixing Mill Segregation

High-dimensional *** Problem over Short Intervals

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Acta Mathematica Sinica,English Series 2014年第2期30卷 213-228页

作者： zhe Feng xu Tian Ping ZHANG Department of Mathematics Northwest University College of Mathematics and Information Science Shaanxi Normal University

Letk be a positive integer and n a nonnegative integer,0 〈 λ1,...,λk＋1 ≤ 1 be real numbers and w =（λ1,λ2,...,λk＋1）.Let q ≥ max{[1/λi ]：1 ≤ i ≤ k ＋ 1} be a positive integer,and a an integer coprime to *** by N（a,k,w,q,n） the 2n-th moment of（b1··· bk c） with b1··· bk c ≡ a（mod q）,1 ≤ bi≤λiq（i = 1,...,k）,1 ≤ c ≤λk＋1 q and 2（b1＋ ··· ＋ bk ＋ c）.We first use the properties of trigonometric sum and the estimates of n-dimensional Kloosterman sum to give an interesting asymptotic formula for N（a,k,w,q,n）,which generalized the result of *** we use the properties of character sum and the estimates of Dirichlet L-function to sharpen the result of N（a,k,w,q,n） in the case ofw =（1/2,1/2,...,1/2） and n = *** order to show our result is close to the best possible,the mean-square value of N（a,k,q） φk（q）/2k＋2and the mean value weighted by the high-dimensional Cochrane sum are studied too.

关键词： D. H. Lehmer problem short intervals trigonometric sum character sum Cochrane sum

Car-following behavior modeling driven by small data sets based on mnemonic extreme gradient boosting framework

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Science China(Information Sciences) 2022年第6期65卷 271-272页

作者： Baichuan LOU Yufang LI Xiaoding LU zhe xu Department of Vehicle Engineering Nanjing University of Aeronautics and Astronautics Key Laboratory of Advanced Manufacture Technology for Automobile Parts (Chongqing University of Technology) Ministry of Education

Dear editor,In recent years, data-driven car-following models have been developed based on their ability to drill down to information in driving data and their flexibility. According to a study by Fleming et al. [1], the main limitation of existing methods is an insufficient amount of natural driving data. In addition,there are many situations during actual driving processes,such as those under extreme conditions [2] and in the early stages of car-following behavior modeling. In these cases,sparse data learning algorithms are indispensable.

关键词： car-following model sparse data learning XGBoost LSTM dynamic constraints

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The complex momentum representation approach and its application to low‑lying resonances in 17 O and^(29,31)F

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Nuclear Science and Techniques 2023年第1期34卷 43-50页

作者： Si‑zhe xu Shi‑Sheng Zhang Xiao‑Qian Jiang Michael Scott Smith School of Physics Beihang UniversityBeijing 100191China Physics Division Oak Ridge National LaboratoryOak RidgeTN 37831‑6354USA

Approaches for predicting low-lying resonances,uniformly treating bound,and resonant levels have been a long-standing goal in nuclear ***,we explored the viability of the complex momentum representation(CMR)approach coupled with new *** focus on predicting the energy of the low-lying 2p_(3∕2)resonance in 17 O,which is critical for s-process nucleosynthesis and missing in previous theoretical *** a Woods-Saxon potential based on the Koning-Delaroche optical model and constrained by the experimental one-neutron separation energy,we successfully predicted the resonant energy of this level for the first *** predictions of the bound levels and 1d_(3∕2)resonance agree well with the measurement ***,we utilize this approach to study the near-threshold resonances that play a role when forming a two-neutron halo in^(29,31)*** found that the CMR-based predictions of the bound-level energies and unbound 1f7∕2 level agree well with the results obtained using the scattering phase shift ***,we successfully found a solution for the 2p_(3∕2)resonance with energy just above the threshold,which is decisive for halo formation.

关键词： Neutron capture Low-lying resonance Complex momentum representation Resonance energy

Accurate and robust estimation of phase error and its uncertainty of 50 GHz bandwidth sampling circuit

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Science in China(Series F) 2007年第6期50卷 905-914页

作者： ZHANG zhe LIN MaoLiu xu QingHua TAN JiuBin Department of Electronics and Communication Harbin Institute of Technology Harbin 150001 China

This paper discusses the dependence of the phase error on the 50 GHz bandwidth oscilloscope＇s sampling circuitry. We give the definition of the phase error as the difference between the impulse responses of the NTN （nose-to-nose） estimate and the true response of the sampling circuit. We develop a method to predict the NTN phase response arising from the internal sampling circuitry of the oscilloscope. For the default sampling-circuit configuration that we examine, our phase error is approximately 7.03° at 50 GHz. We study the sensitivity of the oscilloscope＇s phase response to parametric changes in sampling-circuit component values. We develop procedures to quantify the sensitivity of the phase error to each component and to a combination of components that depend on the fractional uncertainty in each of the model parameters as the same value, ±10%. We predict the upper and lower bounds of phase error, that is, we vary all of the circuit parameters simultaneously in such a way as to increase the phase error, and then vary all of the circuit pa- rameters to decrease the phase error. Based on Type B evaluation, this method qualifies the impresses of all parameters of the sampling circuit and gives the value of standard uncertainty, 1.34°. This result is developed at the first time and has important practical uses. It can be used for phase calibration in the 50 GHz bandwidth large signal network analyzers （LSNAs）.

关键词： uncertainty phase error sampling oscilloscope

Gene therapy for type 1 diabetes mellitus in rats by gastrointestinal administration of chitosan nanoparticles containing human insulin gene

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World Journal of Gastroenterology 2008年第26期14卷 4209-4215页

作者： Li Niu Yan-Cheng xu zhe Dai Hui-Qin Tang Department of Endocrinology Zhongnan Hospital of Wuhan UniversityWuhan 430071 Hubei Province China

AIM:To study the expression of human insulin gene in gastrointestinal tracts of diabetic rats. METHODS: ***, an expression plasmid of the human insulin gene, wrapped with chitosan nanoparticles, was transfected to the diabetic rats through lavage and coloclysis, respectively. Fasting blood glucose and plasma insulin levels were measured for 7 d. Reverse transcription polymerase chain reaction (RT-PCR) analysis and Western blot analysis were performed to confirm the expression of human insulin gene. RESULTS: Compared with the control group, the fasting blood glucose levels in the lavage and coloclysis groups were decreased significantly in 4 d (5.63 ± 0.48 mmol/L and 5.07 ± 0.37 mmol/L vs 22.12 ± 1.31 mmol/L, respectively, P < 0.01), while the plasma insulin levels were much higher (32.26 ± 1.81 μIU/mL and 32.79 ± 1.84 μIU/mL vs 14.23 ± 1.38 μIU/mL, respectively, P < 0.01). The human insulin gene mRNA and human insulin were only detected in the lavage and coloclysis groups. CONCLUSION: Human insulin gene wrapped with chitosan nanoparticles can be successfully transfected to rats through gastrointestinal tract, indicating that chitosan is a promising non-viral vector.

关键词： Gastrointestinal tract Human insulin gene Gene expression Diabetes mellitus Chitosan nanoparticle

Construction of OVA-stabilized fluorescent gold nanoclusters for sensing glucose

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Science China Chemistry 2015年第9期58卷 1508-1514页

作者： Lu-Liang Wang Juan Qiao Li Qi Xiao-zhe xu Dan Li Department of Chemistry and Research Institute for Biomedical and Advanced Materials Shantou University Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Analytical Chemistry for Living BiosystemsInstitute of Chemistry Chinese Academy of Sciences College of Chemistry Tianjin Normal University

Protein protected gold nanoclusters have outstanding physical and chemical properties that make them excellent scaffolds for the construction of novel chemical and biological probes. In this study, a simple one-pot synthesis method was proposed for the preparation of fluorescent probes based on ovalbumin-stabilized gold nanoclusters. This strategy allowed the generation of water-soluble gold nanoclusters within 5 min. The as-prepared fluorescent probe exhibited a red fluorescence emission at 625 nm, and good thermostability. The fluorescent probe was applied to measure glucose concentrations based on the hydrogen peroxide-induced fluorescence quenching principle, and showed favorable biocompatibility, high sensitivity and good selectivity. As a result of the advantageous properties and performance of this fluorescent probe, the present assay allowed for the selective determination of glucose in the range of 5.0×10-6 to 10.0×10-3 mol/L with a detection limit of 1.0×10?6 mol/L. Moreover, the glucose content in urinary samples was analyzed using the constructed fluorescent probe: this indicated the potential of the fluorescent gold nanoclusters for applications in biological and clinical diagnosis and therapy.

关键词： AuNCs Ovalbumin GOx glucose fluorescence