Controlled CVD preparation and quality characterization of graphene based on biphenyl refined from low-rank coal

Wu Dun,Li Bo,Jia Cheng,Dong Min,Liang Wenxu,Gao Xia,Zhang Hui 한국탄소학회 2024 Carbon Letters Vol.34 No.3

In recent years, the efficient and clean utilization of coal has been widely concerned by scholars at home and abroad. Despite the abundance of global coal resources, the deep utilization rate of coal is still insufficient. To address this challenge, it has been explored the development and preparation of coal-based high value-added carbonaceous materials. In the present study, a novel process was developed for the preparation of graphene using biphenyl sourced from low-rank coal. Using chemical vapor deposition (CVD) technology, it was successfully implemented for us to grow high-quality graphene on copper foils. The prepared graphene products were observed and characterized using Raman spectroscopy, optical microscopy and scanning electron microscopy techniques. The results of this research provide a new perspective for the utilization of low-rank coal resources.

Geochemical characteristics of trace elements and carbon isotopes in Taiyuan Formation: a case study of Huainan Coalfield

Dun Wu,Wenyong Zhang 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.6

This paper reports systematically the redox sensitive elements (Mo, V, Cd, Cr, U and Th) and carbon and oxygen isotope data of the Late Carboniferous Taiyuan Formation limestone in the Huainan Coalfield in the southern margin of North China Platform, combined with the observation of limestone slice, and tries to explain the sedimentary environment of each layer of limestone. Through the analysis of the diagenesis of each layer of limestone, except for L7 and L12 limestone, the lithogenesis change of the remaining limestone becomes weak, which generally reflects the geochemical characteristics of the paleosol during sedimentation. There are three negative shifts of δ13C in Taiyuan Formation limestone, which may be related to the enrichment of redox sensitive elements (Cd, Cr, Mo and V) in limestone. In addition, the value of the above redox sensitive elements shows a negative drift. Combining the low V/Cr ratio and high Th/U ratio, it can be concluded that limestone of the Taiyuan Formation is likely to be deposited under an oxidizing condition.

Evaluation of Internal Costs and Benefits for Taiwanese Computer Manufacturers Adopting Green Supply Chains

Dun-Ji CHEN,Shih-Wu LIANG 한국해운물류학회 2012 The Asian journal of shipping and Logistics Vol.28 No.1

This study aims to explore internal cost variation in Taiwan’s computer industry after adopting green supply chains, and to calculate sales revenue difference with and without green supply chains, further estimating the so-called “green producer’s surplus.” that is the difference between the changes of revenue and product cost after adopting green supply chains. The multiple-output translog cost function is used to establish an empirical model based on the cost data of twelve listed companies in Taiwan. There are two kinds of outputs and four element prices considered in the empirical cost model. This study uses 2006, the year the associated environment directives were executed as the first year Taiwanese computer manufactures adopted green supply chains. The results of estimation show that, the internal cost of Taiwan’s computer industry increased 3.84% after adopting green supply chains in the European market, and the entire Taiwanese computer industry generated approximately NT$1.72 billion of producer’s surplus in 2006. Our major research contribution is to develop a valid cost function and the cost-benefit difference analysis to measure the associated changes in cost and revenue for the Taiwanese computer manufacture adopting green supply chains, and to prove the significant internal economic benefit gained by Taiwanese computer industry after implementing green supply chains.

Enhancing magnetoelectric properties of 0e3 particulate composite ceramics by introducing nano-sized sintering aids via self-combustion method

Xiangyong Zhao,Dun Wu,Bijun Fang,Feifei Wang,Yanxue Tang,Wangzhou Shi,Jianning Ding 한국물리학회 2017 Current Applied Physics Vol.17 No.10

The 0.55Pb(Ni1/3Nb2/3)O3-0.05PbHfO3-0.4PbTiO3/Ni0.875Zn0.125Fe2O4 (PNNHT/NZF) 0e3 particulate composite ceramics were prepared by the conventional solid-state reaction method via introducing the nano-sized WO3 and CuO sintering aids by the self-combustion method. Due to the introducing of nanosized sintering aids, densified PNNHT/NZF composite ceramics are synthesized sintered at low sintering temperature. Furthermore, the nano-sized sintering aids act effectively as blocking layers, leading to compact composite ceramics with homogenously dispersed and isolated microstructure morphology, inhibiting inter-phase diffusion, avoiding interfacial chemical reaction, and achieving strong inter-phase coupling. Therefore, the synthesized PNNHT/NZF composite ceramics exhibit enhanced magnetoelectric properties.

Characteristics and provenance of hazardous trace elements in soil from a typical agricultural region in eastern Anhui, China

Lu Wei,Guijian Liu,Dun Wu 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.5

With the purpose of investigate the characteristics and provenances of the hazardous trace elements (HTEs) in a typical agricultural land in the undulating plain area of eastern Anhui province, China, a total of 1170 soil samples were collected. Six HTEs, including Cd, Cr, Hg, Ni, Pb, and As, were determined. Statistical methods including box plot, Pears on correlation analysis, principal component analysis, and cluster analysis, were conducted to illustrate the provenances of HTEs. Results indicate that Cd and Hg were influenced by human activities (such as traffic transportation for Cd and Pb, and chemical pesticides for Hg). Cr, Ni, and As mainly originated from the parent materials (e.g., red detrital rocks, carbonate rocks, and late Pleistocene loess). Pb is of dual provenances of both human activity and parent material. In a word, regarding highly toxic HTEs, the soil in the study area is almost free from pollution, and only a small amount of soil samples contains slightly higher contents of As, Cd and Pb.

Optimizing the chlorine evolution reaction performance of Co(OH)2 catalyst for enhanced antifouling ability

Yating Peng,Peng Wang,Jiawei Li,Jiajia Wu,Feng Lin,Dun Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

Underwater optical instruments are commonly plagued by biofouling. As one of the most useful antifoulingstrategies, electrochemical chlorination is able to prevent biofouling efficiently, but the limited activityand selectivity in chlorine evolution reaction (CER) restrict its practical applications. To address thisproblem, we focus on the optimization of CER performance of cobalt-based catalysts. In this work, weprepared Co(OH)2 with different forms, morphologies, and intercalations. By adopting linear sweepvoltammetry and electrochemical active surface area analysis, it is demonstrated that the a-Co(OH)2exhibits better CER performance than b-Co(OH)2 does, and the manipulation of a-Co(OH)2 morphologycan help to further enhance CER performance. Meanwhile, the intercalation of a-Co(OH)2 plays a minorrole in the CER. Furthermore, based on the screened synthetic condition, the optimized a-Co(OH)2 wasapplied for practical antifouling examination, and its excellent antifouling ability was verified by theinvestigation on bacteria attachment and glass transmittance. The findings in this work not only enrichour understanding on the effects of synthetic conditions on CER performance of cobalt-based catalysts,but also provide useful insights into the development of electrochemical antifouling strategies.

Comparison Study on the Rock Cutting Characteristics of Disc Cutter under Free-face-assisted and Conventional Cutting Methods

Xuhui Zhang,Yi-Min Xia,Qing Tan,Dun Wu**** 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

To improve the excavation efficiency of Tunnel Boring Machines (TBMs), the free-face-assisted rock cutting method induced by TBM disc cutter (FM) was explored and the differences between the FM and the conventional Cutting Method (CM) were also compared based on a series of rock cutting tests. The results show that when the free face distance is less than a critical value, the FM can promote the tensile failure of the rock and the formation of big rock debris effectively. Moreover, the cutting efficiency and the cutting forces including normal force, rolling force and side force of the disc cutter under the FM are also significantly reduced and improved, respectively, compared to that under the CM. The FM can be applied in multi-stage cutterhead TBMs to improve the cutting efficiency and reduce the failure of the disc cutter, the research results indicate that the free face distance should be controlled within 80 mm to use the free face effectively.

CTNNB1 Mutation in Aldosterone Producing Adenoma

Jian-Jhong Wang,Kang-Yung Peng,Vin-Cent Wu,Fen-Yu Tseng,Kwan-Dun Wu 대한내분비학회 2017 Endocrinology and metabolism Vol.32 No.3

Discoveries of somatic mutations permit the recognition of subtypes of aldosterone-producing adenomas (APAs) with distinct clinical presentations and pathological features. Catenin β1 (CTNNB1) mutation in APAs has been recently described and discussed in the literature. However, significant knowledge gaps still remain regarding the prevalence, clinical characteristics, pathophysiology, and outcomes in APA patients harboring CTNNB1 mutations. Aberrant activation of the Wnt/β-catenin signaling pathway will further modulate tumorigenesis. We also discuss the recent knowledge of CTNNB1 mutation in adrenal adenomas.

Design and dimension optimization of cutter disassembly mechanism for shield tunneling machine

Yi-Min Xia,Mei Yang,Zhiyong Ji,Lianhui Jia,Zixiong Zhou,Dun Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

This study focuses on configuration and dimension optimization of cutter disassembly mechanism. Firstly, a cutter disassembly mechanism configuration is proposed with four components and simple actions, based on the theory of inventive problem solving (TRIZ) contradiction solutions. Furthermore, a comprehensive dimension optimization strategy was developed, including non-dimensional normalization model, kinematic performance atlases and fuzzy comprehensive evaluation method. Then, the optimal relative dimension of crucial parameters was obtained. Combined with the assembly relationship between components, dimension of all parameters was designed for cutter disassembly mechanism. The locking and disassembling process simulation was provided to illustrate the feasibility of the mechanism. The results show that the angular velocity is very smooth and the locking and disassembling actions are realizable without interference for optimized cutter disassembly mechanism. The effectiveness of the configuration and dimension optimization method is validated.