Preparation and Optical Properties of Spherical Bi2S3 Nanoparticles by In Situ Thermal Sulfuration Method

Zhankui Cui,Senlin Li,Junqiang Zhou,Jianli Zhang,Suxiang Ge,Zhi Zheng 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.2

Spherical Bi2S3 nanoparticles (NPs) were prepared by a facile in situ thermal sulfuration method. Different Bi2S3 samples were obtained by controlling the sulfuration time. The products were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), Raman and Fourier-transform infrared (FT-IR) methods. The optical properties were examined by UVvisible-near-infrared (UV-Vis–NIR) and photoluminescence (PL) techniques. The results show that the phase of the products after sulfuration is pure and the spherical shape of Bi NPs has been successfully transmitted to Bi2S3 samples. The light absorption edges exhibit red shift to 1060 nm while the light emission displays blue shift to 868 nm, compared with the energy bandgap of bulk Bi2S3. The reason for the special optical properties of Bi2S3 NPs by this in situ sulfuration route is considered to associate with the defects and quantum size effect of NPs.

Second-Order Sliding Mode Control with Backstepping for Aeroelastic Systems Based on Finite-Time Technique

Zhankui Song,Hongxing Li 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.2

In this paper, a backstepping second-order sliding mode control scheme (BSOSMC) is proposed for suppressing both flutter and limit cycle oscillation in the aeroelastic system. The proposed control scheme combining the sliding mode control and backstepping technique, which obtain the properties of fast response and improve the control accuracy. To obtain a better disturbance rejection property, we employ compensated control term. The compensated control term provides the complete compensation of the uncertainty and disturbance, and it relax the requirement of the bound of uncer-tainty and disturbance. The convergence and stability of the proposed control scheme are proved by using Lyapunov’s method. Finally, the simulation results demonstrate the effectiveness of the proposed control scheme.

A Novel Technique for Dressing Fixed Abrasive Lapping Pad with Abrasive Water Jet

Zhankui Wang,Yakun Yang,Zhao Zhang,Minghua Pang,Mingchao Liang,Lijie Ma,Jianxiu Su 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.6

The dressing method and dressing quality of the fixed abrasive lapping pad significantly impact the processing efficiency and surface quality of the workpiece material. Aiming at the problems of poor dressing effect and high damage degree of the lapping pad in the existing fixed abrasive dressing technology, a new technology using abrasive water jet for dressing is proposed. The self-developed abrasive water jet system was used to conduct a dressing test on a fixed abrasive lapping pad with a copper content of 30%. The influence of jet pressure, nozzle target distance, abrasive concentration and injection angle on the dressing effect were discussed, and the influence mechanism was analyzed by discrete element simulation. The results show that the dressing effect of the abrasive water jet is good. The dressing quality first increases and then decreases with the increase of jet pressure, nozzle target distance and injection angle, and increases with the increase of abrasive concentration. The influence mechanism of each parameter is closely related to the residual height of the lapping pad surface after dressing. The higher the residual height, the rougher the lapping pad surface, and the better the dressing effect of the lapping pad.

Pair of (generalized-)derivations on rings and Banach algebras

Feng Wei,Zhankui Xiao 대한수학회 2009 대한수학회보 Vol.46 No.5

Let n be a fixed positive integer, R be a 2n!-torsion free prime ring and μ, be a pair of generalized derivations on R. If (μ2(x)+ v(x), x^n = 0 for all x ∈ R, then μ and are either left multipliers or right multipliers. Let n be a fixed positive integer, R be a noncommutative 2n!- torsion free prime ring with the center CR and d, g be a pair of derivations on R. If (d^2(x) + g(x), x^n)∈ CR for all x ∈ R, then d = g = 0. Then we apply these purely algebraic techniques to obtain several range inclusion results of pair of (generalized-)derivations on a Banach algebra. Let n be a fixed positive integer, R be a 2n!-torsion free prime ring and μ, be a pair of generalized derivations on R. If (μ2(x)+ v(x), x^n = 0 for all x ∈ R, then μ and are either left multipliers or right multipliers. Let n be a fixed positive integer, R be a noncommutative 2n!- torsion free prime ring with the center CR and d, g be a pair of derivations on R. If (d^2(x) + g(x), x^n)∈ CR for all x ∈ R, then d = g = 0. Then we apply these purely algebraic techniques to obtain several range inclusion results of pair of (generalized-)derivations on a Banach algebra.

Generalized Jordan triple higher derivations on semiprime rings

Feng Wei,Zhankui Xiao 대한수학회 2009 대한수학회보 Vol.46 No.3

In this paper we prove that every generalized Jordan triple higher derivation on a 2-torsion free semiprime ring is a generalized higher derivation. This extend the main result of [9] to the case of a semiprime ring. In this paper we prove that every generalized Jordan triple higher derivation on a 2-torsion free semiprime ring is a generalized higher derivation. This extend the main result of [9] to the case of a semiprime ring.

GENERALIZED JORDAN TRIPLE HIGHER DERIVATIONS ON SEMIPRIME RINGS

Wei, Feng,Xiao, Zhankui Korean Mathematical Society 2009 대한수학회보 Vol.46 No.3

In this paper we prove that every generalized Jordan triple higher derivation on a 2-torsion free semiprime ring is a generalized higher derivation. This extend the main result of [9] to the case of a semiprime ring.

PAIR OF (GENERALIZED-)DERIVATIONS ON RINGS AND BANACH ALGEBRAS

Wei, Feng,Xiao, Zhankui Korean Mathematical Society 2009 대한수학회보 Vol.46 No.5

Let n be a fixed positive integer, R be a 2n!-torsion free prime ring and $\mu$, $\nu$ be a pair of generalized derivations on R. If < $\mu^2(x)+\nu(x),\;x^n$ > = 0 for all x $\in$ R, then $\mu$ and $\nu$ are either left multipliers or right multipliers. Let n be a fixed positive integer, R be a noncommutative 2n!-torsion free prime ring with the center $C_R$ and d, g be a pair of derivations on R. If < $d^2(x)+g(x)$, $x^n$ > $\in$ $C_R$ for all x $\in$ R, then d = g = 0. Then we apply these purely algebraic techniques to obtain several range inclusion results of pair of (generalized-)derivations on a Banach algebra.

The Biocompatibility of Multi-Source Stem Cells and Gelatin-Carboxymethyl Chitosan-Sodium Alginate Hybrid Biomaterials

Wang Xinzhe,Li Siqi,Yu Honglian,Lv Jianzhi,Fan Minglun,Wang Ximing,Wang Xin,Liang Yanting,Mao Lingna,Zhao Zhankui 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.3

BACKGROUND: Nowadays, biological tissue engineering is a growing field of research. Biocompatibility is a key indicator for measuring tissue engineering biomaterials, which is of great significance for the replacement and repair of damaged tissues. METHODS: In this study, using gelatin, carboxymethyl chitosan, and sodium alginate, a tissue engineering material scaffold that can carry cells was successfully prepared. The material was characterized by Fourier transforms infrared spectroscopy. In addition, the prepared scaffolds have physicochemical properties, such as swelling ratio, biodegradability. we observed the biocompatibility of the hydrogel to different adult stem cells (BMSCs and ADSCs) in vivo and in vitro. Adult stem cells were planted on gelatin-carboxymethyl chitosan-sodium alginate (Gel/SA/CMCS) hydrogels for 7 days in vitro, and the survival of stem cells in vitro was observed by live/died staining. Gel/SA/CMCS hydrogels loaded with stem cells were subcutaneously transplanted into nude mice for 14 days of in vivo culture observation. The survival of adult stem cells was observed by staining for stem cell surface markers (CD29, CD90) and Ki67. RESULTS: The scaffolds had a microporous structure with an appropriate pore size (about 80 lm). Live/died staining showed that adult stem cells could stably survive in Gel/SA/CMCS hydrogels for at least 7 days. After 14 days of culture in nude mice, Ki67 staining showed that the stem cells supported by Gel/SA/CMCS hydrogel still had high proliferation activity. CONCLUSION: Gel/SA/CMCSs hydrogel has a stable interpenetrating porous structure, suitable swelling performance and degradation rate, can promote and support the survival of adult stem cells in vivo and in vitro, and has good biocompatibility. Therefore, Gel/SA/CMCS hydrogel is a strong candidate for biological tissue engineering materials.