Effect of the Molar Ratio of Li/Ti and Thermal Treatment on the Electrochemical Performance of Li4Ti5O12–rutile TiO2 Nanocomposite as Anode Materials

Zhen Yang,Xi-Ping Li,Jian Mao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.8

Li4Ti5O12–rutile TiO2 (LTO–RTO) dual-phase nanocomposite anode materials show excellent electrochemical performance. However, the effects of molar ratio of Li/Ti and thermal treatment on electrochemical properties of the LTO–RTO composite have been rarely reported. In this work, LTO–RTO nanocomposites were prepared by sol-hydrothermal method with different Li/ Ti molar ratios in raw materials and following calcinations at 600℃, 650℃ and 700℃ for the different holding time. The results indicate that with the decrease of Li/Ti molar ratio, the discharge capacity of the LTO–RTO nanocomposite increases at first and then decreases, and the optimal Li/Ti molar ratio is 4:4.77, which was obtained with calcination at 600℃ for 10 h. The effects of calcination temperature and holding time were further investigated. The result demonstrates that the thermal treatment has an obvious influence on the electrochemical performance due to the morphology change in the nanocomposite. The LTO–RTO nanocomposite calcinated at 650℃ for 2 h with a Li/Ti molar ratio of 4:4.77 in raw materials delivers excellent rate capability: the initial discharge capacity is 175.9, 176.3, 170.4, 167.5, 163.3 and 155.6 mA h g-1 at the rate of 0.5, 1, 3, 5, 10 and 20℃ (1 C = 175 mA h g-1), respectively.

Influence of Initial Pearlite Morphology on the Microstructure Evolution During Heat Treatment of 1.0C–1.5Cr Steel

Zhen‑Xing Li,Chang‑Sheng Li,Seong‑Hoon Kim,Dong‑Woo Suh 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

Effect of initial pearlite morphology on the microstructure evolution during spheroidization annealing and subsequent hardeningtreatment was studied in hot-rolled 1.0C–1.5Cr bearing steel. The ferrite-to-austenite transformation in spheroidizationannealing can be accelerated by refining the pearlite interlamellar spacing and pearlite colony size. Decreasing interlamellarspacing is also beneficial to increasing the number density of undissolved cementite, leading to the refining of final spheroidizedcementite. During the re-austenitizing process of hardening treatment, the smaller initial spheroidized cementiteleads to faster cementite dissolution and finer undissolved cementite particles. The prior austenite grain size after hardeningtreatment can also be decreased by refining the initial pearlite microstructure.

略論明淸戱曲對小說的主動接受

李眞瑜 中國語文硏究會 1995 中國語文論叢 Vol.9 No.-

"不+能+沒(有)+Vp1+就+Vp2"構式硏究

彭利貞,宋永圭 中國語文硏究會 2003 中國語文論叢 Vol.25 No.-

본 연구는 “不+能+沒(有)+Vp1+就+Vp2”구조를 분석하는데 목적이 있다. 본문에서는 발화(혹은 문장)에서 정태가 명제의 외부를 감싸고 있음을 가정하고, 명제부분과 정태부분과의 관계에 주목하고 또한 사건“沒Vp1”(혹은“Vp1”) 와 “Vp2”의 관계를 분석하였다. 정태(Modality)는 본질적으로 문맥구속(Context Bounded)적인 범주이므로 그 의미의 파악은 문맥을 파악하므로 그 정확한 쓰임을 알 수 있는바, 본문은 대화참여자의 변화와 시간참조점 (Temporal Deixis)의 변화가 정태동사“能”의 의미현상에 미치는 영향을 분석하였다. 당 어법구조는 이중부정 구조이며, 그 의미는 긍정이고, 부정사“不”의 부정범위는 전체 명제에 미치고, 부정의 초점은 정태부분이다. 沒의 부정의 범위는 “Vp1”으로 제한된다. 본문은 또한 “沒(有)Vp1” 와 “Vp2”의 관계를 논증하면서 두 사건은 의미상 연관된 사건이며 시간적으로는 연속적이라는 특성이 있음을 밝혔고, 본 구조의 주어는 일반적으로 [+生命]의 특징을 지니고 사건 “沒(有)Vp1” 와 “Vp2”는 일반적으로 동일한 주어를 가짐을 보였다.

Supercapacitors with ultrahigh energy density based on mesoporous carbon nanofibers: Enhanced double-layer electrochemical properties

Li, Zhen-Yu,Akhtar, M. Shaheer,Yang, O-Bong Elsevier 2015 Journal of alloys and compounds Vol.653 No.-

<P><B>Abstract</B></P> <P>High performance electrochemical double-layer (EDL) supercapacitor was fabricated with highly efficient electro-active electrode based on mesoporous carbon nanofibers (MCFs) materials. The prepared MCFs from dextrose as carbon source exhibited the high surface to volume ratio, large pore volume and high mesoporous nature. The cyclic voltammetry, electrochemical impedance and galvanostatic charge–discharge measurements were carried out to investigate the capacitive and electrochemical behavior of fabricated EDL supercapacitor based on MCFs electrode. A reasonably high specific capacitance of 201 F/g at current density of 0.6 A/g was achieved by the fabricated EDL supercapacitor based on MCFs electrode. A relation of capacitive performance, specific surface area, accessible average pore size and current density was manifested to evaluate the impact of capacitance parameters. The fabricated EDL supercapacitor based on MCFs electrode attained the ultra high energy density of 54.7 W h/kg and reasonable power density of 0.842 kW/kg at the current density of 0.6 A/g. The fabricated EDL supercapacitor manifested an excellent stability by keeping about 88% of initial capacity after 1000 cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly efficient electro-active electrode prepared by mesoporous carbon nanofibers. </LI> <LI> High performance electrochemical double layer (EDL) supercapacitor was fabricated. </LI> <LI> EDL supercapacitor with MCFs electrode showed the high specific capacitance of 201 F/g. </LI> <LI> Ultra high energy density of 54.7 W h/kg and power density of 0.842 kW/kg attained. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microstructure evolution and enhanced vacuum tribological performance of Ni-doped WS₂ composite coating

Xu, Shu-Sheng,Weng, Li-Jun,Liu, Yu-Zhen,Kang, Kyeong-Hee,Kim, Chang-Lae,Kim, Dae-Eun Elsevier Sequoia 2017 Surface & coatings technology Vol.325 No.-

<P><B>Abstract</B></P> <P>Ni-doped WS<SUB>2</SUB> composite coatings with various Ni contents were co-deposited using a radio frequency sputtering system on silicon wafer and AISI 440C stainless steel substrates. The microstructural characteristics of the WS<SUB>2</SUB>-Ni composite coatings and their tribological properties in vacuum were assessed. During introduction of Ni dopant in the WS<SUB>2</SUB>-Ni composite coating the sulfur/tungsten (S/W) ratio in the coating increased due to reduced preferential resputtering of sulfur atoms in the growing coating. The microstructure of the WS<SUB>2</SUB>-Ni composite coating varied from a fine columnar structure for Ni content equal to or less than 7.7at.% to a featureless structure as the Ni content increased further. The Ni dopant inhibited the growth of the coarse columnar WS<SUB>2</SUB> platelets which was accompanied by nanocrystallization and amorphization of the composite coating structure. WS<SUB>2</SUB>-Ni composite coatings with fine columnar structure exhibited relatively low hardness but showed a high tendency to form a lubricating transfer layer. It also demonstrated low brittleness and prolonged wear life in vacuum condition compared to coatings with dense featureless structure. The variation in tribological performance between the composite coatings resulted from the different wear mechanisms associated with their distinct microstructures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Microstructure of WS<SUB>2</SUB> coating was modified by incorporating Ni as a dopant. </LI> <LI> The introduction of Ni increased the S/W ratio of the WS<SUB>2</SUB> composite coating. </LI> <LI> High Ni content in the WS<SUB>2</SUB> coating led to high brittleness and low wear resistance. </LI> <LI> WS<SUB>2</SUB>–5at.% Ni coating showed 5 times longer wear life than pure WS<SUB>2</SUB> film in vacuum. </LI> <LI> Superior tribological properties were attributed to transfer layer and high hardness. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Rotary ultrasonic machining of woven CFRP composite in a cryogenic environment

Thirumalai Kumaran, S.,Ko, Tae Jo,Li, Changping,Yu, Zhen,Uthayakumar, M. ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.698 No.-

<P><B>Abstract</B></P> <P>In the present study, rotary ultrasonic machining (RUM) was adopted to perform drilling of carbon fiber reinforced plastics (CFRP) in a cryogenic environment. An L27 orthogonal array was selected to conduct experiments by varying the spindle speed (denoted as N), feed rate (denoted as f), and ultrasonic power (denoted as P). The thrust force (denoted as Fz), exit burr area, and surface roughness (denoted as Ra) were measured to evaluate the machining performance. The influence of process parameters and the regression model were derived for each output quality response. Additionally, multi-objective optimization was performed using desirability analysis, and the predicted levels were used for confirmation. The results indicated that the feed rate (f) contributed more to the thrust force (Fz) by 45.85% and a maximum thrust force was recorded at 0.1 mm/rev. A decrease in spindle speed (N) was associated with an increase in feed rate (f) and ultrasonic power (P), and it resulted in minimum exit burr area. The influence of ultrasonic power (P) was highly significant in reducing burrs with a contribution of 52.45%. Conversely, the surface roughness (Ra) of the drill holes decreased at 3000 rpm, and this was attributed to the brittle fracture of the fibers at a lower temperature. Both N (30.88%) and f (30.83%) had an equal influence on producing a better surface finish in the drill holes. Furthermore, the predicted optimal settings were used to validate the results and were found to be within 95% confidence and prediction interval. Finally, the microscopic images of tool wear, burr formation, and drill hole surface morphology were analyzed and examined.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Prediction of regression model for RUM of CFRP in a cryogenic environment. </LI> <LI> Output responses such as thrust force, burr area and roughness are investigated. </LI> <LI> The adequacy of an ANOVA model is checked for each output response. </LI> <LI> Optimization is performed by desirability analysis and the results are validated. </LI> <LI> Tool wear, burr formation, and drill hole surface morphology are analyzed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pollen record of the mid- to late-Holocene centennial climate change on the East coast of South Korea and its influential factors

Song, Bing,Yi, Sangheon,Jia, Hongjuan,Nahm, Wook-Hyun,Kim, Jin-Cheul,Lim, Jaesoo,Lee, Jin-Young,Sha, Longbin,Mao, Limi,Yang, Zhongyong,Nakanishi, Toshimichi,Hong, Wan,Li, Zhen Elsevier 2018 Journal of Asian earth sciences Vol.151 No.-

<P><B>Abstract</B></P> <P>To understand historical climate change in western Pacific coastal areas, a sediment core (SOJ-2) from the stable sedimentary environment of the Songjiho Lagoon on the east coast of South Korea was obtained for centennial-resolution palynological analysis. The ages of the SOJ-2 core is well controlled by carbon 14 dating with high-resolution accelerator mass spectrometry (AMS), and the results indicated a general warm to cold climate trend from the mid-Holocene to the present, which can be divided into two different stages: a warmer stage between 6842 and 1297 cal yr BP and a colder stage from 1297 cal yr BP to the present, with fluctuations during these stages. The climate was wetter from 6842 to 6227 cal yr BP and 4520 to 1297 cal yr BP and was drier from 6227 to 4520 cal yr BP. The climate changed to cold and dry during the period from 1297–425 cal yr BP. The impact of human activity on the climate began at approximately 1297 cal yr BP and became pronounced starting in 425 cal yr BP. The general cooling trend may represent a response to decreasing solar insolation; however, the relative dryness or wetness of the climate may have been co-determined by westerlies and the East Asian summer monsoon (EASM). The climate had a teleconnection with the North Atlantic region, resulting from changes in solar activity. Nevertheless, EI Niño–Southern Oscillation (ENSO) activity played an important role in impacting the EASM changes in western Pacific coastal areas.</P> <P><B>Highlights</B></P> <P> <UL> <LI> There is a centennial resolution climate record from 6842 cal yr BP to present. </LI> <LI> The general cooling trend was probably triggered by decreasing solar insolation. </LI> <LI> The precipitation was co-determined by westerlies and the East Asian Summer Monsoon. </LI> <LI> The ENSO activity may be an important factor for East Asian Summer Monsoon change. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Colorectal Cancer Concealment Predicts a Poor Survival: A Retrospective Study

Li, Xiao-Pan,Xie, Zhen-Yu,Fu, Yi-Fei,Yang, Chen,Hao, Li-Peng,Yang, Li-Ming,Zhang, Mei-Yu,Li, Xiao-Li,Feng, Li-Li,Yan, Bei,Sun, Qiao Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.7

Objectives: Understanding the situation of cancer awareness which doctors give to patients might lead to prognostic prediction in cases of of colorectal cancer (CRC). Methods: Subsets of 10,779 CRC patients were used to screen the risk factors from the Cancer Registry in Pudong New Area in cancer awareness, age, TNM stage, and gender. Survival of the patients was calculated by the Kaplan-Meier method and assessed by Cox regression analysis. The views of cancer awareness in doctors and patients were surveyed by telephone or household. Results: After a median observation time of 1,616 days (ranging from 0 to 4,083 days) of 10,779 available patients, 2,596 of the 4,561 patients with cancer awareness survived, whereas 2,258 of the 5,469 patients without cancer awareness and 406 of the 749 patients without information on cancer awareness died of the disease. All-cause and cancer-specific survival were poorer for the patients without cancer awareness than those with (P < 0.001 for each, log-rank test). Cox multivariate regression analysis showed that cancer concealment cases had significantly lower cancer-specific survival (hazard ratio (HR) = 1.299; 95 % confidence interval (CI): 1.200-1.407)and all-cause survival (HR = 1.324; 95 % CI: 1.227-1.428). Furthermore, attitudes of cancer awareness between doctors and patients were significantly different (P < 0.001). Conclusion: Cancer concealment, not only late-stage tumor and age, is associated with a poor survival of CRC patients.

Synergistic Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Platelet-Rich Plasma in Streptozotocin-Induced Diabetic Rats

( Zhen Zhen Lian ),( Xiao Jing Yin ),( Hua Li ),( Li Li Jia ),( Xiu Zhen He ),( Yong Bo Yan ),( Nai Hua Liu ),( Ka Yiu Wan ),( Xiao Kun Li ),( Shao Qiang Lin ) 대한피부과학회 2014 Annals of Dermatology Vol.26 No.1

Background: Diabetic wounds are a major clinical challenge, because minor skin wounds can lead to chronic, unhealed ulcers and ultimately result in infection, gangrene, or even amputation. Studies on bone marrow derived mesenchymal stem cells (BMSCs) and a series of growth factors have revealed their many benefits for wound healing and regeneration. Platelet-rich plasma (PRP) may improve the environment for BMSC development and differentiation. However, whether combined use of BMSCs and PRP may be more effective for accelerating diabetic ulcer healing remains unclear. Objective: We investigated the efficacy of BMSCs and PRP for the repair of refractory wound healing in a diabetic rat model. Methods: Forty-eight rats with diabetes mellitus induced by streptozotocin were divided into four groups: treatment with BMSCs plus PRP, BMSCs alone, PRP alone, phosphate buffered saline. The rate of wound closure was quantified. A histopathological study was conducted regarding wound depth and the skin edge at 7, 14, and 28 days after surgery. Results: Wound healing rates were significantly higher in the BMSC plus PRP group than in the other groups. The immunohistochemistry results showed that the expression of platelet/endothelial cell adhesion molecule 1, proliferating cell nuclear antigen, and transforming growth factor-β1 increased significantly in the BMSC plus PRP group compared to the other treatment groups. On day 7, CD68 expression increased significantly in the wounds of the BMSC plus PRP group, but decreased markedly at day 14 compared to the controls. Conclusion: The combination of BMSCs and PRP aids diabetic wound repair and regeneration. (Ann Dermatol 26(1) 1∼10, 2014)