Favorable Impact Toughness of High Heat Input Coarse-Grained HAZ in an Ultra-Low Carbon High-Strength Microalloyed Steel

Fuhui Cui,Junjie Wang1,Xiangdong Gan,Dawei Yu,Ilya Vladimirovich Okulov,Qinghua Tian,Xueyi Guo 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

Liquid Mg is capable of quickly eroding the refractory Ni-based superalloy and selectively dissolve Ni, which opens up anew avenue for the recycling of superalloy scraps for comprehensive metal reclamation. This study aims at investigating theunderlining mechanism and kinetics of the selective dissolution of Ni from Inconel 718 (one type of Ni-based superalloy)with liquid Mg, by experimenting at 750, 800, and 850 °C for various amounts of time in an inert atmosphere. This selectivedissolution process is also known as liquid metal dealloying. Results show that a permeable dealloyed layer was formedresulting from the preferential dissolution of Ni over other metallic elements (e.g., Fe, Cr, Nb, Mo, and Ti). At the dealloyingforefront, the grain boundaries of the matrix γ phase were preferentially eroded by liquid Mg. The opposite concentrationgradients of Ni (4–9 wt%) and Mg (12–18 wt%) cross the dealloyed layer suggested their counter diffusion. A higher heatingtemperature substantially increased the dealloying rate.

Wireless Sensor Networks Coverage Optimization based on Improved AFSA Algorithm

Wang DaWei,Wang Changliang 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.1

Right-to-Left Displacement of an Airgun Lead Bullet after Transorbital Entry into the Skull Complicated by Posttraumatic Epilepsy : A Case Report

Chao-bin Wang,Hui Wang,Jun-shuang Zhao,Ze-jun Wu,Hao-dong Liu,Chao-jia Wang,An-rong Li,Dawei Wang,Juntao Hu 대한신경외과학회 2023 Journal of Korean neurosurgical society Vol.66 No.5

Penetrating head injury is a serious open cranial injury. In civilians, it is often caused by non-missile, low velocity flying objects that penetrate the skull through a weak cranial structure, forming intracranial foreign bodies. The intracranial foreign body can be displaced due to its special quality, shape, and location. In this paper, we report a rare case of right-to-left displacement of an airgun lead bullet after transorbital entry into the skull complicated by posttraumatic epilepsy, as a reminder to colleagues that intracranial metal foreign bodies maybe displaced intraoperatively. In addition, we have found that the presence of intracranial metallic foreign bodies may be a factor for the posttraumatic epilepsy, and their timely removal appears to be beneficial for epilepsy control.

Superior electrochemical performance of sulfur/graphene nanocomposite material for high-capacity lithium-sulfur batteries.

Wang, Bei,Li, Kefei,Su, Dawei,Ahn, Hyojun,Wang, Guoxiu Wiley-VCH 2012 Chemistry - An Asian Journal Vol.7 No.7

<P>Sulfur/graphene nanocomposite material has been prepared by incorporating sulfur into the graphene frameworks through a melting process. Field-emission scanning electron microscope analysis shows a homogeneous distribution of sulfur in the graphene nanosheet matrix. The sulfur/graphene nanocomposite exhibits a super-high lithium-storage capacity of 1580?mA h?g(-1) and a satisfactory cycling performance in lithium-sulfur cells. The enhancement of the reversible capacity and cycle life could be attributed to the flexible graphene nanosheet matrix, which acts as a conducting medium and a physical buffer to cushion the volume change of sulfur during the lithiation and delithiation process. Graphene-based nanocomposites can significantly improve the electrochemical performance of lithium-sulfur batteries.</P>

Graphene-supported SnO ₂ nanoparticles prepared by a solvothermal approach for an enhanced electrochemical performance in lithium-ion batteries

Wang, Bei,Su, Dawei,Park, Jinsoo,Ahn, Hyojun,Wang, Guoxiu Springer 2012 Nanoscale research letters Vol.7 No.1

<P>SnO<SUB>2</SUB> nanoparticles were dispersed on graphene nanosheets through a solvothermal approach using ethylene glycol as the solvent. The uniform distribution of SnO<SUB>2</SUB> nanoparticles on graphene nanosheets has been confirmed by scanning electron microscopy and transmission electron microscopy. The particle size of SnO<SUB>2</SUB> was determined to be around 5 nm. The as-synthesized SnO<SUB>2</SUB>/graphene nanocomposite exhibited an enhanced electrochemical performance in lithium-ion batteries, compared with bare graphene nanosheets and bare SnO<SUB>2</SUB> nanoparticles. The SnO<SUB>2</SUB>/graphene nanocomposite electrode delivered a reversible lithium storage capacity of 830 mAh g<SUP>−1</SUP> and a stable cyclability up to 100 cycles. The excellent electrochemical properties of this graphene-supported nanocomposite could be attributed to the insertion of nanoparticles between graphene nanolayers and the optimized nanoparticles distribution on graphene nanosheets.</P>

Integrated analysis of the transcriptome and metabolome in young and mature leaves of Yunnanopilia longistaminea

Wang Yuchang,Shen Bingqi,Yang Lin,Wang Dawei 한국식물생명공학회 2022 Plant biotechnology reports Vol.16 No.5

Yunnanopilia longistaminea is a unique flavor forest vegetable that is mainly determined by the vitamins, amino acids and derivatives, and flavonoids detected in its leaves. This experiment applied to broad targeted metabolomics approach based on UPLC-MS/MS to evaluate metabolic changes and the assessment of differential genes by transcriptome sequencing using the IlluminaHiSeq platform between the Y. longistaminea young leaves (YYL) and mature leaves (YML). The present results showed that a total of 488 compounds in the leaves, of which 275 (56.53%) significantly changed metabolites (SCMs). Compared to young leaves, the abundance of 163 SCMs was down-regulated and 112 SCMs were significantly increased in mature leaves. The results show that flavonoids, amino acids and derivatives, coumarins, nucleotides and derivatives, vitamins, saccharides and alcohol, tannin, and organic acids were significantly downregulated in mature leaves, whereas mature leaves had higher lipids and alkaloids than young leaves. A total of 2082 DEGs were identified, with 939 down- regulated genes and 1143 up-regulated genes in mature leaves compared to young leaves. The experimental work presented here provides the first investigations into Y. longistaminea with metabolic group and transcriptome. This study will prove useful in expanding our understanding of how to analyze biosynthesis at the molecular level, which will encourage further utilization of the Y. longistaminea and its relevant forest vegetables.

Photocatalytic conversion of nitrite in aqueous solution over nanocomposite photocatalyst Er3+:Y3Al5O12/BiPO4 using different photosources

Yidi Wang,Bowen Li,Guanshu Li,Yingying Huang,Dawei Fang,Jun Wang,Youtao Song 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.47 No.-

Three crystal phases of BiPO4 (HBIP, nMBIP and mMBIP), corresponding photocatalysts (Er3+:Y3Al5O12/HBIP, Er3+:Y3Al5O12/nMBIP and Er3+:Y3Al5O12/mMBIP) and their nanocomposite photocatalyst (Er3+:Y3Al5O12/(H-nM-mM)BIP) were prepared by hydrothermal, ultrasonic dispersion and liquid boilingmethods. The prepared photocatalysts were characterized by X-ray diffractometer (XRD), energydispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and UV–vis diffuse reflectancespectra (DRS). The catalytic activity of prepared photocatalysts was evaluated via photocatalyticconversion rate of nitrite under ultraviolet-light, visible-light and simulated solar-light irradiations. These three photocatalysts all exhibited excellent performance under simulated solar-light irradiationand reached 85.36%, 84.42% and 78.53% conversion rates, respectively, for Er3+:Y3Al5O12/mMBIP, Er3+:Y3Al5O12/nMBIP and Er3+:Y3Al5O12/HBIP. Particularly, Er3+:Y3Al5O12/(H-nM-mM)BIP was also found toplay a high catalytic activity, resulting in 78.68%, 70.04% and 82.57% conversion rates, respectively, underultraviolet-light, visible-light and simulated solar-light irradiation. In addition, the study of used timesshowed that the prepared photocatalysts can be effectively recycled without an apparent inactivation onthe photocatalytic activity. This research may provide a potential way for converting nitrite and othercontaminants by utilizing solar energy efficiently.

Graphene Oxide/Polyester Fabric Composite by Electrostatic Self-Assembly as a New Recyclable Adsorbent for the Removal of Methylene Blue

Di Wang,Dawei Li,Pengfei Lv,Qingqing Wang,Yang Xu,Qufu Wei 한국섬유공학회 2018 Fibers and polymers Vol.19 No.8

A novel graphene oxide/polyester (GO/PET) composite fabric as a recyclable adsorbent was prepared via electrostatic self-assembly. The structure, morphology, and properties of the GO/PET composite fabrics were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and contact angle (CA), respectively. The absorption property was evaluated by the absorption amount and removal efficiency of methylene blue (MB) solution on the GO/PET composite fabric. The results indicated that the absorption amount was found to be 21.80 mg/g and the removal efficiency reached 99.93 % under the experimental conditions of GO concentration of 2 mg/ml, initial concentration of 50 mg/l, and area of 64 cm2. The experimental parameters were investigated including the concentration of GO, the initial concentration of MB solutions, and adsorbent area. Simultaneously, according to a series of dynamic analysis, the absorption process revealed that the kinetics was well-described by pseudo-second-order model. This study showed that the GO/PET composite fabric could be a recyclable, efficient adsorbent material for the environmental cleanup.

A Ghost-Imaging System Based on a Microfluidic Chip

Kaimin Wang,Xiaoxuan Han,Hualong Ye,Zhaorui Wang,Leihong Zhang,Jiafeng Hu,Meiyong Xu,Xiangjun Xin,Dawei Zhang 한국광학회 2021 Current Optics and Photonics Vol.5 No.2

Microfluidic chip technology is a research focus in biology, chemistry, and medicine, for example. However, microfluidic chips are rarely applied in imaging, especially in ghost imaging. Thus in this work we propose a ghost-imaging system, in which we deploy a novel microfluidic chip modulator (MCM) constructed of double-layer zigzag micro pipelines. While in traditional situations a spatial light modulator (SLM) and supporting computers are required, we can get rid of active modulation devices and computers with this proposed scheme. The corresponding simulation analysis verifies good feasibility of the scheme, which can ensure the quality of data transmission and achieve convenient, fast ghost imaging passively.

Octahedral tin dioxide nanocrystals as high capacity anode materials for Na-ion batteries

Su, Dawei,Wang, Chengyin,Ahn, Hyojun,Wang, Guoxiu The Royal Society of Chemistry 2013 Physical chemistry chemical physics Vol.15 No.30

<P>Single crystalline SnO<SUB>2</SUB> nanocrystals (∼60 nm in size) with a uniform octahedral shape were synthesised using a hydrothermal method. Their phase and morphology were characterized by XRD and FESEM observation. TEM and HRTEM analyses identified that SnO<SUB>2</SUB> octahedral nanocrystals grow along the [001] direction, consisting of dominantly exposed {221} high energy facets. When applied as anode materials for Na-ion batteries, SnO<SUB>2</SUB> nanocrystals exhibited high reversible sodium storage capacity and excellent cyclability (432 mA h g<SUP>−1</SUP> after 100 cycles). In particular, SnO<SUB>2</SUB> nanocrystals also demonstrated a good high rate performance. <I>Ex situ</I> TEM analysis revealed the reaction mechanism of SnO<SUB>2</SUB> nanocrystals for reversible Na ion storage. It was found that Na ions first insert into SnO<SUB>2</SUB> crystals at the high voltage plateau (from 3 V to ∼0.8 V), and that the exposed (1 × 1) tunnel-structure could facilitate the initial insertion of Na ions. Subsequently, Na ions react with SnO<SUB>2</SUB> to form Na<SUB><I>x</I></SUB>Sn alloys and Na<SUB>2</SUB>O in the low voltage range (from ∼0.8 V to 0.01 V). The superior cyclability of SnO<SUB>2</SUB> nanocrystals could be mainly ascribed to the reversible Na–Sn alloying and de-alloying reactions. Furthermore, the reduced Na<SUB>2</SUB>O “matrix” may help retard the aggregation of tin nanocrystals, leading to an enhanced electrochemical performance.</P> <P>Graphic Abstract</P><P><I>Ex situ</I> TEM analysis revealed the reaction mechanism of SnO<SUB>2</SUB> nanocrystals for reversible Na ion storage. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3cp52037d'> </P>