A Study on Effectiveness of Mathematics Teachers’ Collaborative Learning: Focused on an Analysis of Discourses

Xiaoying Chen,신보미 한국수학교육학회 2022 수학교육연구 Vol.25 No.1

Collaborative learning has been highlighted as an effective method of teachers’ professional development in various studies. To disclose teachers’ discourse threads in the process of collaborative learning for developing their knowledge, this paper adopted two methods including “content analysis” and “time-sequential analysis” of learning analytics. Such analyses were implemented for mining teachers’ updated knowledge and the discourse threads in the discussion during collaborative learning. The materials for analysis involved two aspects: one was from the video-taped lesson observation reports written by teachers before and after discussing, and the other was from their discourses during the discussion process. The results proved that teachers’ knowledge for teaching the centroid of a triangle was updated in the collaborative learning period, and also revealed the discourse threads of teachers’ collaboration contained “requesting information or opinions”, “building on ideas”, and “providing evidence or reasoning”, with the emphasis on “challenging ideas or re-focusing talk”

Sharing pattern feature selection using multiple improved genetic algorithms and its application in bearing fault diagnosis

Xiaoying Guan,Guo Chen 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

In order to select the effective features or feature subsets and realize an intelligent diagnosis of aero engine rolling bearing faults, this paper presents a sharing pattern feature selection method using multiple improved genetic algorithms. Based on the simple genetic algorithm, a multiple-population improved genetic algorithm was proposed, which improves the speed and effect of algorithm and overcomes the shortcomings of local optima that simple genetic algorithm is easy to fall into. Because all populations regularly share and exchange their selecting features, the proposed algorithms can quickly dig up the current effective feature patterns, and then analyze and deal with the strong correlation between the feature patterns. This will not only give clear directions for the descendant evolution, but also help to achieve high accuracy feature selection, for, the features are highly distinctive. This multiple-population improved genetic algorithm was applied to rolling bearing fault feature selection and comparisons with other methods are carried out, which demonstrates the validity of sharing pattern feature selection method proposed.

Removal of Cr(VI) from aqueous solution by surfactant-modified kaolinite

Xiaoying Jin,Mingqin Jiang,Jianhua Du,Zuliang Chen 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Removal of Cr(VI) from aqueous solution by hexadecyltrimethylammonium chloride (HDTMA) modified kaolinite (HMK) was investigated, where the maximum adsorptive capacity reached 27.8 mg/g Cr(VI) using HMK compared with only 0.7 mg/g using unmodified natural kaolinite (NK). The adsorption of Cr(VI) on HMK can be well described by the Langmuir isotherm, and the kinetic adsorption of Cr(VI) on both HMK and NK fitted a pseudo-second-order model. FTIR analysis showed that surface modified HDTMA was responsible for the high adsorptive capacity of Cr(VI). HMK was used to remove Cr(VI) from an electroplating wastewater.

SOLID-PHASE EXTRACTION OF PHTHALATE ESTERS FROM AQUEOUS SAMPLES USING MESOPOROUS SILICA-COATED MULTIWALLED CARBON NANOTUBES AND THEIR DETERMINATION BY HPLC

XIAOYING DENG,XINYU JIANG,XIAOQING CHEN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.4

We report a novel solid-phase extraction adsorbent for the preconcentration of three phthalateesters (PAEs) from aqueous samples. The material was obtained by modifying multiwalledcarbon nanotubes (MWCNTs) with mesoporous silica. The structural characterization of theadsorbent was conducted by Fourier transform infrared (FT-IR) spectroscopy, transmissionelectron microscopy (TEM) and N 2 adsorption – desorption measurement, which con¯rmed thesuccessful coating of mesoporous silica on MWCNTs and the adsorbent possessing large surfaceand porous structure. The e®ects of adsorbent amount, type and volume of eluent and samplepH on extraction e±ciency were optimized. Following extraction, the PAEs were quanti¯ed byhigh performance liquid chromatography (HPLC). Under optimal conditions, the recoveriesranged from 89.8% to 96.3%. The calibration plot was linear in the 3 – 1000 ng ? mL? 1 concen-tration range, with correlation coe±cients ranging from 0.9993 to 0.9995. The repeatability ofthe method, expressed as relative standard deviation (RSD), ranged from 3.8% to 7.7% (forn ¼ 5). Limits of detection (LODs) were between 0.28 ng mL? 1 and 0.53 ng ? mL? 1 . The relativerecoveries (RR) for spiked river water, pond water and tap water samples were in the ranges of80.9 – 98.0%, 82.7 – 96.1% and 88.3 – 95.5%, respectively. The results showed that the methodobviously had a large potential for preconcentration and determination of PAEs in environ-mental samples.

Modal parameter identification by adaptive parameter domain with multiple genetic algorithms

Guan Xiaoying,Xie Shengjia,Chen Guo,Qu Meijiao 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.12

The identification of aero-engine dynamic parameters is fundamental to establishing accurate dynamic models, which has a great effect on the accuracy of model calculation. The accurate parameter range, however, is not easy to define in practical engineering applications. In many cases, it could only be constructed out of experience. In order to reduce the impact of initial parameter interval accuracy on the identification results, the adaptive parameter domain with multiple genetic algorithms is proposed to identify the aeroengine dynamic model parameters, through which the vibration modal parameter identification is studied under the condition of initial uncertainty of the parameters. The effectiveness of the adaptive parameter domain method is verified through the third-order model with severe modal coupling, which also proves the efficiency and rapidity of finding the correct value of parameters and, indicates that it would not be necessary to introduce an exact definition of the initial interval of parameters. All these suggest that the proposed multiple genetic algorithms of the adaptive parameter domain has a good reference value for engineering applications.

UiO-66-derived porous-carbon adsorbents: synthesis, characterization and tetracycline adsorption performance

Lin Xiaoying,Zeng Weipeng,Chen Yilan,Su Ting,Zhong Qinhua,Gong Linzhu,Liu Yamin 한국탄소학회 2022 Carbon Letters Vol.32 No.3

A porous-carbon material UiO-66-C was prepared from metal–organic frameworks UiO-66 by carbonization in inert gas atmosphere. Physicochemical properties of UiO-66-C materials were well characterized by Powder X-ray diffraction (PXRD), Scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), Raman spectrometer, N2 adsorption/desorption isotherms (BET), and the adsorption properties of the products were studied UiO-66-C has a high specific surface area up to 1974.17 m2/g. Besides, the adsorption capacity of tetracycline could reach 678.19 mg/g, the adsorption processes agreed well with the pseudo-second-order kinetic model and Langmuir isotherm model.

Structure and Performance Characteristics of Saturated Iron-core Superconducting Fault Current Limiter

Niu, Xiaoye,Chen, Zhili,Wang, Haizhen,Chen, Zhifu,Zhang, Lifeng,Niu, Guojun,Hong, Hui,Xin, Ying 대한전기학회 2014 The Journal of International Council on Electrical Vol.4 No.2

Superconducting fault current limiter (SFCL) is a kind of short-circuit current limiting device for power grid. It's a new application of superconducting technology on power equipments. Saturated Iron-core Superconducting fault current limiter (SISFCL) is one of many types of SFCL. It takes the advantage that no quenching occurs in superconducting wires during fault current limiting process. The immediately reacting and fast recovering are also its main characteristics. The structure and function of SISFCL is similar to that of traditional transformer and current limiting reactor respectively. Based on mature technologies on design and manufacture of iron core and windings of transformers, SISFCL could be made at the same voltage level as traditional transformers. But there are also significant differences between them. SISFCL will offer an effective solution to limit short-circuit current in future HV or EHV power systems because of its peculiar structures and properties. In this paper, we introduce the structure and characteristics of the SISFCL developed by Innopower. It may help readers to understand SISFCL and its enormous application value for power grids.

Efficient starvation therapy with three-pathway blocking in combination with PTT/CDT for TME reversal and tumor apoptosis

Mengchao Ding,Xiaoying Kong,Weiyan Chen,Lei Yan,He Huang,Zunzhou Lv,Peng Jiang,Ali Mu,Congcong Huang,Jinsheng Shi 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

Single cancer starvation therapy (ST) strategy can’t achieve satisfactory anti-tumor effect, mainly due tothe diversified nutritional sources of tumor cells. Herein, CuS@Axitinib-SiO2@2-Deoxy-D-glucose(2-DG)-CaCO3-RGD nanoparticles (CADCR NPs) were prepared for three-pathway blocking for efficient starvationtherapy as well as reinforced photothermal therapy (PTT) and chemodynamic therapy (CDT). AfterCADCR NPs were targeted to tumor cells, CaCO3 was ruptured in the acidic environment, releasingCa2+ to chelate glutamine and cutting off the glutamine metabolic pathway of the tumor. 2-DG was alsoreleased from mesoporous SiO2 and restrained the glycolytic pathway of tumor cells. In addition, underthe thermal stimulus of near-infrared irradiation, axitinib was released from CuS NPs, which inhibited theproliferation of tumor blood vessels, ultimately inhibiting the aerobic respiratory pathway of tumor cells. Interestingly, CADCR NPs also showed potential to reshape the tumor microenvironment (TME) and promotedthe transformation of macrophages from M2 to M1 type, increasing the expression of CD8+ T cellsin the tumor site. In conclusion, CADCR NPs achieve severe tumor starvation by simultaneously interferingwith three energy metabolic pathways, and further enhance tumor treatment with the aid of PTT,CDT, and TME improvement, which exhibits great potential for clinical cancer therapy.

Simultaneous removal of Pb(II) and Cr(III) by magnetite nanoparticles using various synthesis conditions

Ting Wang,Xiaoying Jin,Zuliang Chen,Mallavarapu Megharaj,Ravendra Naidu 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

This study concerns the removal of Pb(II) and Cr(III) using magnetite nanoparticles synthesized by coprecipitation methods with (NCM) or without (CM) nitrogen gas passing through. Removal of Pb(II) significantly decreased from 80.56 to 41.41% when Cr(III) was co-presented, while decrease of Cr(III) was negligible when Pb(II) was present, falling from 42.37 to 38.48%. The characterizations indicated that the removal mechanism occurred through adsorption rather than chemical redox reaction. A co-adsorption mechanism is based on Pb(II) involved surface complexation, while Cr(III) was firstly adsorbed onto magnetite, followed by a partially substitution of Cr(III) for Fe(III) in Cr-Fe3O4 through ion exchanges.

Enhanced degradation of malachite by iron nanoparticles encapsulated in sodium alginate beads

Shenliang Zeng,Xiaoying Jin,Dharmarajan Rajarathnam,Zuliang Chen 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.77 No.-

Encapsulation of the Fe NPs was synthesized by tea extract and dispersed within sodium alginate beads(Fe-SA-B), and used the degradation of malachite (MG). The results showed that a 92.3% of MG wasremoved using Fe NPs encapsulated sodium alginate beads (SA-Fe-B), while only 52% of MG was removedby free Fe NPs. Kinetics studies showed that a pseudo-second-order model well described the adsorptionof MG using SA-Fe-B, indicating initial adsorption of MG onto calcium alginate beads followed bydegradation through SA-Fe-B. The reusability of SA-Fe-B showed that thefirst 3 cycles were degradedabout 85% of MG.