A Review on the Learning Process of the Modern Apprenticeship

( Xinxin Chen ),( Youngsup Hyun ) 경북대학교 중등교육연구소 2020 Asia Pacific Journal of Educational Research Vol.3 No.2

It is commonly acknowledged that modern apprenticeship has played a positive role in preparing the young people for school-to-work transition around the world. The purpose of this literature review aimed to study the learning process of the modern apprenticeship from the perspective of a learning mode and discussed the obstacles that affect the learning process of the modern apprenticeship in China currently. The review showed that the learning process of the modern apprenticeship includes three dimensions: interaction, content and incentive. In the interaction dimension, apprentices learn through the interactive types of perception, transmission, experience, imitation, activity and participation. In terms of content dimension, school education and on-the-job training improve the knowledge and professional skills of apprentices through a series of curriculums and practical activities. In the dimension of incentive, the acquisition of apprentices’ learning depends on their values, emotions, interests and will basically. The three dimensions of interaction, content and incentive are closely connected and affect each other. However, there are some problems hindering the learning process of modern apprenticeship in China: The quality of mentoring is not good enough and the teachings in school are too theoretical and have rare relevance to the work. Therefore, the design and implementation of the apprenticeship programs should make the learning of interaction, content and motivation adapt to each other.

电子游戏的法律规制

?欣信(Chen XinXin) 한국언론법학회 2008 언론과 법 Vol.7 No.2

A Pan-Cancer Analysis of Enhancer Expression in Nearly 9000 Patient Samples

Chen, Han,Li, Chunyan,Peng, Xinxin,Zhou, Zhicheng,Weinstein, John N.,Caesar-Johnson, Samantha J.,Demchok, John A.,Felau, Ina,Kasapi, Melpomeni,Ferguson, Martin L.,Hutter, Carolyn M.,Sofia, Heidi J.,Ta Elsevier 2018 Cell Vol.173 No.2

<P><B>Summary</B></P> <P>The role of enhancers, a key class of non-coding regulatory DNA elements, in cancer development has increasingly been appreciated. Here, we present the detection and characterization of a large number of expressed enhancers in a genome-wide analysis of 8928 tumor samples across 33 cancer types using TCGA RNA-seq data. Compared with matched normal tissues, global enhancer activation was observed in most cancers. Across cancer types, global enhancer activity was positively associated with aneuploidy, but not mutation load, suggesting a hypothesis centered on “chromatin-state” to explain their interplay. Integrating eQTL, mRNA co-expression, and Hi-C data analysis, we developed a computational method to infer causal enhancer-gene interactions, revealing enhancers of clinically actionable genes. Having identified an enhancer ∼140 kb downstream of PD-L1, a major immunotherapy target, we validated it experimentally. This study provides a systematic view of enhancer activity in diverse tumor contexts and suggests the clinical implications of enhancers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Systematic analysis of enhancer expression across ∼9,000 samples of 33 cancer types </LI> <LI> Global enhancer activation positively correlates with aneuploidy but not mutations </LI> <LI> A computational method that infers causal enhancer-target-gene relationships </LI> <LI> Enhancers as key regulators of therapeutic targets, including PD-L1 </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Self-assembling siloxane bilayer directly on SiO₂ surface of micro-cantilevers for long-term highly repeatable sensing to trace explosives

Chen, Ying,Xu, Pengcheng,Li, Xinxin IOP Pub 2010 Nanotechnology Vol.21 No.26

<P>This paper presents a novel sensing layer modification technique for static micro-cantilever sensors that detect trace explosives by measuring specific adsorption-induced surface stress. For the first time, a method of directly modifying a siloxane sensing bilayer on an SiO<SUB>2</SUB> surface is proposed to replace the conventional self-assembled monolayers (SAMs) of thiols on Au to avoid the trouble from long-term unstable Au–S bonds. For modifying the long-term reliable sensing bilayer on the piezoresistor-integrated micro-cantilevers, a siloxane-head bottom layer is self-assembled directly on the SiO<SUB>2</SUB> cantilever surface, which is followed by grafting another explosive-sensing-group functionalized molecule layer on top of the siloxane layer. The siloxane-modified sensor has experimentally exhibited a highly resoluble response to 0.1 ppb TNT vapor. More importantly, the repeated detection results after 140 days show no obvious attenuation in sensing signal. Also observed experimentally, the specific adsorption of the siloxane sensing bilayer to TNT molecules causes a tensile surface stress on the cantilever. Herein the measured tensile surface stress is in contrast to the compressive surface stress normally measured from conventional cantilever sensors where the sensitive thiol-SAMs are modified on an Au surface. The reason for this newly observed phenomenon is discussed and preliminarily analyzed. </P>

Hardness prediction and verification based on key temperature features during the directed energy deposition process

Zhehan Chen,Xinxin Guo,Jing Shi 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.2

During the process of metal directed energy deposition (DED), changes in temperature directly influence the melting and cooling processes, which determine the microstructure and thus hardness of the final part. Therefore, there is a certain correlation between the temperature field during the DED process and the material hardness, making it possible to predict the hardness distribution of a part by monitoring the changes in the temperature field. In this paper, some key temperature features (KTFs) are defined in accordance with the characteristics of the DED process, to present the characteristics of the temperature field. The temporal and spatial trends of the KTF values are considered, and predictions of the hardness distributions are given. The results of the microhardness testing confirm that the trends of predictions are consistent with the actual hardness trends based on measured data. The developed KTFs make the online real-time and non-destructive evaluation of the hardness of DED parts possible.

Production of Pullulan from Xylose and Hemicellulose Hydrolysate by Aureobasidium pullulans AY82 with pH Control and DL-dithiothreitol Addition

Yefu Chen,Jian Guo,Feng Li,Mingming Liu,Xinxin Zhang,Xuewu Guo,Dongguang Xiao 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.2

Xylose, the second most abundant sugar inlignocellulosic materials, is not efficiently utilized incurrent lignocellulose biotransformation processes, such ascellulosic ethanol production. The bioconversion of xyloseto value-added products, such as pullulan, is an alternativestrategy for efficient lignocellulose biotransformation. Thispaper reports the production of pullulan from xylose andhemicellulose hydrolysate by Aureobasidium pullulansAY82. The effects of DL-dithiothreitol (DTT) and pH onpullulan production from xylose were also intensivelyinvestigated. A maximal increase of 17.55% of pullulanproduction was observed in flasks added with 1.0 mMDTT. Batch fermentations with controlled pH were alsoconducted, and the optimal pH for cell growth and pullulansynthesis was 3.0 and 5.0, respectively. Based on thesefindings, two-stage pH control fermentations were performed,in which the pH of the medium was first adjusted to 3.0 forcell growth, and then changed to 5.0 for pullulan synthesis. However, the earlier the pH was changed to 5.0, the morepullulan was produced. Fermentation with controlled pH of5.0 acquired the highest pullulan production. Under theoptimized conditions (with the addition of 1.0 mM DTTand controlled pH of 5.0), the maximal pullulan productionobtained from xylose was 17.63 g/L. A. pullulans AY82also readily fermented hemicellulose hydrolysate under theseoptimized conditions, but with lower pullulan production(12.65 g/L). Fourier transform infrared spectroscopy andhigh-performance liquid chromatography showed that thestructure of the pullulan obtained in this study was identicalto that of the pullulan standard.

An Intelligent Analysis and Mining System for Urban Lighting Information

Guanlin Chen,Erpeng Wang,Xinxin Sun,Yanqiang Tang 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.3

Urban lighting information plays an important role in digital urban management. In this paper, an IAMSULI (Intelligent Analysis and Mining System for Urban Lighting Information) is proposed. Using data analysis technology, case-based reasoning technology and data mining technology comprehensively, the system aims at providing better decision support for lighting management. IAMSULI is composed of system management, geographical information management, lighting information management, lighting data analysis, comprehensive classification statistics and event management. The system can help us quickly find lighting problems, provide early warning alarm of the problems, and also supply constructive information for the urban development.

Random Imperfection Method for Stability Analysis of a Suspended Dome

Xuechun Liu,Xinxin Zhan,Ailin Zhang,Xun Zh,Chen Tian 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.1

The traditional eigenvalue buckling mode method used for the stability analysis of suspended domes has been deemed unsafe and unreasonable. A random imperfection method is proposed in this paper that is suitable for the stability analysis of suspended domes. Using this method, the impact of initial imperfections, such as joint position deviation, eccentricity of members, variation in cable pretension and elastic modulus of materials, on the stability of nonlinear geometries as well as the stability of both nonlinear geometries and materials (i.e., ultimate bearing capacity) are studied. The analysis results using this method are compared to those obtained from the traditional eigenvalue buckling mode method. This study indicates that the random imperfection method can more reasonably demonstrate the impact of initial imperfections on the stability of suspended domes. Additionally, the shape and size of the initial imperfections applied by the random imperfection method are more reasonable, and the results are safer. The random imperfection method is successfully used in the stability analysis of a largespan suspended dome, and the results of this method are nearly equivalent to that of the model test, which verifies the method.

Thermal shock resistance of porous alumina ceramics with different internal and external porosity

Maochang Cao,Xinxin Jin,Le Chen,Limin Dong,Bo Li,Xianyou Zhang 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.4

Porous alumina ceramics with porosity of 24.42-41.10% were prepared by gel casting process with polymethylmethacrylatemicrosphere(PMMA) as pore-forming agent. The mechanical/thermal properties and porosity of the obtained ceramic areinfluenced by two structures that composed of spherical shaped micro pores(external pores) depending on PMMA content andirregular sub-micro pores(internal pores) formed by the stacking of ceramic particles. Mechanical properties and thermalconductivity decreased as the porosity increased. The thermal shock resistance of the samples was excellent when the porositywas 33.45%. This phenomenon caused by the matching of external and internal pores is inconsistent with the trend of thermalshock fracture resistance and thermal shock damage resistance varying with porosity in previous researches. In the case of thesame total porosity, the introduction of external pores improved the mechanical properties and critical temperature difference,reduced the thermal conductivity and fracture surface energy that affected the thermal stability of the material.

Green preparation of lipase@Ca3(PO4)2 hybrid nanoflowers using bone waste from food production for efficient synthesis of clindamycin palmitate

Anming Wang,Xinxin Chen,Jianyun Yu,Ningning Li,Huimin Li,Youcheng Yin,Tian Xie,Stephen Gang Wu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-

To prepare enzyme@Ca3(PO4)2 for environmentally friendly biocatalysis, Ca2+ and (PO4)3 were extractedfrom bone waste by acidification. In the nearly neutralizedfiltrate, the Ca2+ and (PO4)3 formed aCa3(PO4)2 sediment that crystallized on a template of Thermomyces lanuginosus lipase (TLL) at 4 ℃ for24 h, producing enzyme@Ca3(PO4)2-Bone hybrid nanoflowers (hNFs). Clindamycin palmitate wasefficiently synthesized by transfer of a palmityl moiety from vinyl palmitate to clindamycin free baseusing these hNFs as a biocatalyst. At 30 ℃ in petroleum ether (PE) as the solvent, the yield of the TLL hNFcatalyzedreaction was as high as 70.0%. Even at a high temperature (80 ℃), the yield in the hNF-catalyzedreaction was still 52.6%, but no product was detected when using free lipase as the catalyst. Moreover, thehNFs retained 90% of their initial activity after 10 cycles (120 h, 12 h per cycle). This green and sustainablemethod that utilizes bone waste from food production as the raw source of the inorganic component wasfacile and efficient, and the system may also be applicable for preparing other enzyme@Ca3(PO4)2 hNFsfor industrial applications.