Sodium Alginate-Assisted Synthesis of PdAg Bimetallic Nanoparticles and their Enhanced Activity for Electrooxidation of Ethanol

Yanru Yin,Changna Wen,Ning Ma,Baoyan Wang,Lianying Zhang,Hongliang Li,Peizhi Guo 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.9

Palladium and palladium-silver bimetallic nanocrystals have been synthesized hydrothermally by using environmental-friendly sodium alginate as the stabilizer and reducing agent. The pure palladium nanoparticles were spherical-like possibly due to the principle of the lowest surface energy, however, the formation of bimetallic palladium-silver nanoparticles was much more complicated, which was thinner and more irregular nanostructures than pure palladium nanoparticles. Electrochemical measurements showed that the electrocatalytic activity toward ethanol oxidation was increased first with the increase of silver content in bimetallic nanoparticles, from pure palladium of around 1070 mA/mg, to PdAg-20 of 1160 mA/mg and to PdAg-10 of 1750 mA/mg, and declined greatly at a high content of silver, approximately 279 mA/mg. Electrochemical stability test showed that PdAg-10 and PdAg-5 were the best and worst among four palladium-based samples, respectively. Based on the experimental data, the formation mechanism of pure palladium and palladium-silver bimetallic nanoparticles and the structure-property relationship of these samples have been discussed.

Enhancing Astaxanthin Accumulation in Haematococcus pluvialis by Coupled Light Intensity and Nitrogen Starvation in Column Photobioreactors

( Wen-wen Zhang ),( Xue-fei Zhou ),( Ya-lei Zhang ),( Peng-fei Cheng ),( Rui Ma ),( Wen-long Cheng ),( Hua-qiang Chu ) 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at 200 μmo/m2/s under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.

Controlling the Precursor Morphology of Ni-rich Li(Ni0.8Co0.1Mn0.1)O2 Cathode for Lithium-ion Battery

Wen-Zhe Shen,Yi Ma,Yaochun Yao,Feng Liang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.8

Ni-rich Li(Ni0.8Co0.1Mn0.1)O2 cathode material is widely recognized as one of the most cathode materials for lithium-ion batteries due to its high specific capacity, high energy density and low cost. In this paper, the NCM cathode material precursor Ni0.8Co0.1Mn0.1(OH)2 was prepared by coprecipitation method and the optimum experimental conditions were investigated. The effects of water bath temperature on the electrochemical performances of the prepared materials were investigated by controlling the morphology. The results showed that 60 ℃ was the best bath temperature for the precursor which has a regular spheroidal morphology and uniform particles with the diameter of 10 μm. After coprecipitation, the samples calcined under oxygen atmosphere displayed good electrochemical properties. The discharge specific capacity is up to 194 mA · h · g -1 and 134 mA · h · g -1 at 0.2 ℃ and 5 ℃, respectively. The initial coulombic efficiency is 87.57% at 0.2 ℃.

Numerical analysis of a dual-wave band guided-mode resonance filter with embedded bilayer asymmetric metallic gratings

Ma Wen-Zhuang,Liu Jing,Yu Gao-Xiang,Chen Wei,Chen Yu-Shan,Deng Xu-Chu 한국물리학회 2021 Current Applied Physics Vol.27 No.-

In this paper, a novel guided-mode resonances (GMRs) based embedded dual-wavelength filter, which had the bilayer gratings located at the two sides of dielectric substrate and arranged at asymmetric position, was investigated and studied theoretically. As compared to symmetric structures that usually provided single wavelength of transmission resonance, as one normal incidence was used for transverse magnetic polarized light, the designed asymmetric structure could generate two remarkable narrow band wavelengths of transmission resonance. The parameters to affect the resonance wavelengths and the transmission resonance Q value (Q = λ/Δλ) of two bands were the distance between the two metallic gratings, the relatively lateral positions of the upper and lower gratings, the number of structure period, the thicknesses of metallic gratings, and the thickness of dielectric film. By optimizing the designed parameters, a GMR device with two resonance wavelengths located at 1239 and 1302 nm showed relative optimal performance because they had high transmission depth (99.9% and 90%) and ultra-narrow transmission bandwidth (2.8 and 1.8 nm) at the two resonance wavelengths. The presented structure can offer a potential route towards dual-band narrow-band filters and refractive index sensors in the near infrared.

Clinical Evaluation of Tumor Markers for Diagnosis in Patients with Non-small Cell Lung Cancer in China

Ma, Li,Xie, Xiao-Wei,Wang, Hai-Yan,Ma, Ling-Yun,Wen, Zhong-Guang Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.12

Background: To evaluate the value of combined detection of serum carcinoembryonic antigen (CEA), cytokeratin 19 fragment (CYFRA21-1), and carbohydrateantigen 125 (CA125) for the clinical diagnosis of nonsmall cell lung cancer (NSCLC). Materials and Methods: Serum CEA, CYFRA21-1 and CA125 were assessed in 140 patients with NSCLC, 90 patients with benign lung disease and 90 normal control subjects, and differences of expression were compared in each group, and joint effects of these tumor markers in the diagnosis of NSCLC were analyzed. Results: Serum CEA, CYFRA21-1 and CA125 in patients with NSCLC were significantly higher than those with benign lung disease and normal controls (P<0.05). The sensitivity of CEA, CYFRA21-1 and CA125 were 49.45%, 59.67%, and 44.87% respectively. As expected, combinations of these tumor markers improved their sensitivity for NSCLC. The combined detection of CEA + CYFRA21-1 was the most cost-effective combination which had higher sensitivity and specificity in NSCLC. Elevation of serum CEA and CYFRA21-1 was significantly associated with pathological types (P<0.05) and elevation of serum CEA, CYFRA21-1 and CA125 was significantly associated with TNM staging (P<0.05). Conclusions: Single measurement of CEA, CYFRA21-1 and CA125 is of diagnostic value in the diagnosis of lung cancer, and a joint detection of these three tumor markers, could greatly improve the sensitivity of diagnosis on NSCLC. Combined detection of CEA + CYFRA21-1 proved to be the most economic and practical strategy in diagnosis of NSCLC, which can be used to screen the high-risk group.

Comparative Research on Metaphor in Chinese Brush Painting and Contemporary Poster Design

( Su-wen Ma ),( Ju-young Chang ) 한국디자인트렌드학회 2017 한국디자인포럼 Vol.54 No.-

Background Metaphorical thinking is commonly used in a variety of artistic creations. Metaphors have been used in Chinese paintings for a long time. In modern poster design, metaphor is also considered an artistic expression. What is the relationship between those two artistic forms? The goal of this research is to discover the value of chinese painting used in to modern poster design from a design perspective of metaphor. Methods Through a comparative analysis of the artworks of Bada Shanren and modern posters from the aspects of composition-image, empty space and text- and hidden codes, the aim is to seek similarities and differences regarding their use of metaphors. Result They are similar in their aim to avoid direct expression and impart meaning to art works. Although both use a form of “chinese elegance”, Chinese paintings and graphic posters have a difference approach. While the Chinese paintings have unfamiliar metaphorical tenors with familiar metaphorical vehicles, Modern graphic posters use familiar metaphorical tenors with unfamiliar metaphorical vehicles. Conclusion The above analysis reveals the similarities and differences between Chinese ink paintings and contemporary posters. Although both forms use metaphors in different ways, they are similar in their aim to avoid direct expression and impart meaning to art works. The ancient literati painters produced the poetic spirit or elegance (“Chinese elegance”) by using metaphors. In terms of aesthetic value, metaphors reflect “Chinese elegance” in both Chinese ink paintings and contemporary poster designs.

Storage strategies for containers in container yards

Yao Wen Ma,Su Min Jeon,Kap Hwan Kim 한국경영과학회 2008 한국경영과학회 학술대회논문집 Vol.2008 No.5

Container storage problem is a critical issue for the efficient operation of container terminal. The storage yard in the study is horizontal layout, in which one quay crane is served by several yard cranes and one vessel is served by several blocks during vessel operation. This study addresses various storage strategies for horizontal container lay yard layout. The storage strategies include the strategy for selecting blocks, reserving spaces for a group of containers in advance, and selecting yard stacks. The proposed strategies are tested by a simulation study.

Identification and Characterization of Protein Encoded by orf382 as L-Threonine Dehydrogenase

( Fei Ma ),( Tian Wen Wang ),( Xing Yuan Ma ),( Ping Wang ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.6

In the genome annotation of Escherichia coli MG1655, the orf382 (1,149 bp) is designated as a gene encoding an alcohol dehydrogenase that may be Fe-dependent. In this study, the gene was amplified from the genome by PCR and overexpressed in Escherichia coli BL21(DE3). The recombinant 6×His-tag protein was then purified and characterized. In an enzymatic assay using different hydroxyl-containing substrates (n-butanol, L-threonine, ethanol, isopropanol, glucose, glycerol, L-serine, lactic acid, citric acid, methanol, or D-threonine), the enzyme showed the highest activity on L-threonine. Characterization of the mutant constructed using gene knockout of the orf382 also implied the function of the enzyme in the metabolism of L-threonine into glycine. Considering the presence of tested substrates in living E. coli cel ls and previous literature, we believed that the suitable nomenclature for the enzyme should be an L-threonine dehydrogenase (LTDH). When using L-threonine as the substrate, the enzyme exhibited the best catalytic performance at 39°C and pH 9.8 with NAD+ as the cofactor. The determination of the Km values towards L-threonine (Km = 11.29 μM), ethanol (222.5 μM), and n-butanol (8.02 μM) also confirmed the enzyme as an LTDH. Furthermore, the LTDH was shown to be an ion-containing protein based on inductively coupled plasma-atomic emission spectrometry with an isoelectronic point of pH 5.4. Moreover, a circular dichroism analysis revealed that the metal ion was structurally and enzymatically essential, as its deprivation remarkably changed the α-helix percentage (from 12.6% to 6.3%).

Storage strategies for containers in container yards

Yao Wen Ma,Su Min Jeon,Kap Hwan Kim 대한산업공학회 2008 대한산업공학회 춘계학술대회논문집 Vol.2008 No.5

Container storage problem is a critical issue for the efficient operation of container terminal. The storage yard in the study is horizontal layout, in which one quay crane is served by several yard cranes and one vessel is served by several blocks during vessel operation. This study addresses various storage strategies for horizontal container lay yard layout. The storage strategies include the strategy for selecting blocks, reserving spaces for a group of containers in advance, and selecting yard stacks. The proposed strategies are tested by a simulation study.

Energy analysis of the deformation and failure process of sandstone and damage constitutive model

Tao Wen,Huiming Tang,Junwei Ma,Junwei Ma 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.2

The damage theory was introduced to clarify and simulate the strain softening property of rocks. On the basis of the theory, an energy method was utilized to portray the rock mechanical properties from microscopic perspective. Firstly, from the perspective of rock microstructure, damage variable (expressed as D) was redefined by dividing the rock into three portions: undamaged materials, damaged materials and micro-defects, and an impact factor was introduced as the connection between the damaged material and the micro-defects. Meanwhile, the method for determining the impact factor was presented. Secondly, the damage variable was redefined in light of energy dissipation, then damage evolution analysis was conducted based on triaxial tests. An improved rock damage constitutive model was further obtained in another expression to reflect the energy change law. Subsequently, the relationship between D and the deformation and failure process of rocks was analyzed on account of the damage evolution equation formularized by fitting to a logistic function, which can measure the influence of energy dissipation on the propagation of micro-defects. By comparing between experimental results and theoretical results of illustrative examples, the effectiveness of the improved model was validated, and the its application was also discussed.