Design, Analytical and Experimental Evaluations of Additive Manufacturing for Laser Melting of Polymer-Metal Colloids

Chunliang Kuo,Tingyu Chang,Jhihjie Liu,Chunhui Chung 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.6

This paper presents a novel additive manufacturing process, namely the laser melting of polymer-metal colloids (LMC), which is advantageous for repairing features and reducing contamination sources. The developed polymer-metal colloids are conveyed via the designed spindle-driven dispensing system to demonstrate consolidations of the metallic phase onto heterogeneous substrate materials via laser melting. Modelling of the flow rate, velocity and pressure fields is linked to the geometric design of the mechanical devices in the spindle-driven process. The equilibriums of the heat transfer equations in the colloid element were initiated and presented for the estimations of input laser energy. When the input heat was absorbed by the colloid element, the average energy density could be obtained by the ratio of the overall energy density and the engaged laser scanning volume. In the experimental work of the validation tests, the polymer-metal colloid was consolidated on the substrate material with three different results: unconsolidated, partially consolidated and consolidated. The consolidation and bonding of metallic fractions on the heterogeneous substrate materials in the laser melting actions were evaluated and reported.

First-principles study of LiBaF3 crystals containing interstitial fluoride

Hailing Qiao,Tingyu Liu,Qiren Zhang,Fang Cheng,Xiuwen Zhou 한국물리학회 2010 Current Applied Physics Vol.10 No.5

The positions of the interstitial fluoride atoms in LiBaF3 crystal are simulated by GULP. It is found that the formation energy is low when interstitial fluoride atoms at the center of the edge of the cube formed by Ba ions. The electronic structures and absorption bands for the perfect LiBaF3 crystal and the LiBaF3 crystal containing interstitial fluoride have been calculated using density functional theory code CASTEP. It is predicted that the interstitial fluoride atom combine with a formal lattice fluoride ion forming H center causes the 320 nm absorption band.

Unified magnetic field model of regular polygonal coils for electromagnetic assessment in WPT systems

Xu Shangguan,Pingan Tan,Tingyu Tan,Bin Song,Huadong Liu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.3

Electromagnetic environment assessment plays an indispensable part in the practical application of wireless power transfer (WPT) technology. It can ensure that the WPT system meets the electromagnetic radiation limit requirements of the corresponding frequency. To improve the flexibility and universality of the electromagnetic environment assessment of WPT systems, a general magnetic field model suitable for regular polygonal coil wireless power transmission systems is proposed based on electromagnetic theory. First, using Biot–Savart law and by considering the correlation effect of the coil structure and parameters, a unified magnetic field model suitable for regular polygonal coils is established. On this basis, the model is used to compare and analyze the influence of different coil structures and parameters on magnetic flux density, and the evolution law of the electromagnetic radiation of the WPT system is obtained. Finally, the influences of transmission distance and misalignment on the electromagnetic environment of the WPT system are studied. The validity and accuracy of the model are verified by finite element simulation (FEM) and experimental results, which lays a theoretical foundation for the evaluation of the electromagnetic environment of WPT systems and the pre-design of coils.

Silage preparation and fermentation quality of natural grasses treated with lactic acid bacteria and cellulase in meadow steppe and typical steppe

Meiling Hou,Ge Gentu,Tingyu Liu,Yushan Jia,Yimin Cai 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.6

Objective: In order to improve fermentation quality of natural grasses, their silage preparation and fermentation quality in meadow steppe (MS) and typical steppe (TS) were studied. Methods: The small-scale silages and round bale silages of mixed natural grasses in both steppes were prepared using the commercial lactic acid bacteria (LAB) inoculants Chikuso-1 (CH, Lactobacillus plantarum) and cellulase enzyme (AC, Acremonium cellulase) as additives. Results: MS and TS contained 33 and 9 species of natural grasses, respectively. Stipa baicalensis in MS and Stipa grandi in TS were the dominant grasses with the highest dry matter (DM) yield. The crude protein (CP), neutral detergent fiber and water-soluble carbohydrate of the mixed natural grasses in both steppes were 8.02% to 9.03%, 66.75% to 69.47%, and 2.02% to 2.20% on a DM basis, respectively. All silages treated with LAB and cellulase were well preserved with lower pH, butyric acid and ammonia-N content, and higher lactic acid and CP content than those of control in four kinds of silages. Compared with CH- or AC-treated silages, the CH+ AC-treated silages had higher lactic acid content. Conclusion: The results confirmed that combination with LAB and cellulase may result in beneficial effects by improving the natural grass silage fermentation in both grasslands.

Ab initio calculations of electronic structures of SrMoO4 crystals containing F and F+ color centers

Jigang Yin,Qiren Zhang,Tingyu Liu,Xiaofeng guo,Min Song,Xien Wang,Haiyan Zhang 한국물리학회 2009 Current Applied Physics Vol.9 No.6

The electronic structures of SrMoO4 crystals containing F and F+ color centers with the lattice structure optimized are studied within the framework of the fully relativistic self-consistent Dirac–Slater theory, using a numerically discrete variational (DV-Xα) method. From the calculation, it is concluded that F and F+ color centers have donor energy level in the forbidden band. The electronic transition energies from the donor level to the bottom of the conduction band are 1.855 eV and 2.161 eV, respectively, which correspond to the 670 nm and 575 nm absorption bands. It is predicted that the 670 nm and 575 nm absorption bands originate from the F and F+ centers in SrMoO4 crystals. The electronic structures of SrMoO4 crystals containing F and F+ color centers with the lattice structure optimized are studied within the framework of the fully relativistic self-consistent Dirac–Slater theory, using a numerically discrete variational (DV-Xα) method. From the calculation, it is concluded that F and F+ color centers have donor energy level in the forbidden band. The electronic transition energies from the donor level to the bottom of the conduction band are 1.855 eV and 2.161 eV, respectively, which correspond to the 670 nm and 575 nm absorption bands. It is predicted that the 670 nm and 575 nm absorption bands originate from the F and F+ centers in SrMoO4 crystals.

First-principles study on electronic states of SrWO4 crystals containing F-type color centers

Min Song,Qiren Zhang,Tingyu Liu,Jigang Yin,Xiaofeng Guo,Haiyan Zhang,Xi’en Wang 한국물리학회 2009 Current Applied Physics Vol.9 No.4

The electronic structures of the SrWO4 crystals containing F-type color centers are studied within the framework of the fully relativistic self-consistent Dirac–Slater theory using a numerically discrete variational (DV-Xα) method. The calculations indicate that either F or F+ center has donor energy level within the forbidden band. The electronic transition energies from the two donor levels to the bottom of the conduction band are 1.82 eV and 2.28 eV corresponding to the 685 nm and 545 nm absorption bands, respectively. It is, therefore, concluded that the 545–685 nm absorption bands are originated from the F and F+ center in SrWO4 crystal respectively. The electronic structures of the SrWO4 crystals containing F-type color centers are studied within the framework of the fully relativistic self-consistent Dirac–Slater theory using a numerically discrete variational (DV-Xα) method. The calculations indicate that either F or F+ center has donor energy level within the forbidden band. The electronic transition energies from the two donor levels to the bottom of the conduction band are 1.82 eV and 2.28 eV corresponding to the 685 nm and 545 nm absorption bands, respectively. It is, therefore, concluded that the 545–685 nm absorption bands are originated from the F and F+ center in SrWO4 crystal respectively.

Simultaneous removal of NOx and SO2 using two-stage O3 oxidation combined with Ca(OH)2 absorption

Yang Zou,Yan Wang,Xiaolong Liu,Tingyu Zhu,Mengkui Tian,Maoyu Cai 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.11

This paper proposes two-stage O3 oxidation combined with Ca(OH)2 for simultaneous removal of NOx and SO2 (NOx: Nitrogen oxides including NO, NO2 and N2O5). In two-stage oxidation, NO was first oxidized to NO2 in an oxidation tube, and NO2 was further oxidized into N2O5 in the spray tower. NOx and SO2 were simultaneously removed in the spray tower. This method can effectively reduce the extra waste of O3 caused by the decomposition of N2O5, especially at high temperature. Effects of various factors on denitrification efficiency were investigated. The results showed that the NOx removal efficiency decreased and O3 extra consumption ratio increased with the increase of oxidation temperature or oxidation reaction time. When the O3/NO molar ratio was 1.8, one-stage O3 oxidation at 150 oC extra wasted 33.3% of O3. With the increase of O3 concentration at site 2, the NOx removal efficiency first increased and then stabilized. Compared with the one-stage O3 oxidation-absorption, the two-stage oxidation-absorption improved NOx removal efficiency from 62.5% to 89%. In addition, the increase of CaSO3 slurry concentration had little effect on the denitrification efficiency.

Study on surface physical and chemical mechanism of nanobubble enhanced flotation of fine graphite

Tang Chongliang,Ma Fangyuan,Wu Tingyu,Zhang Di,Wang Ye,Zhao Tonglin,Fan Zhaolin,Liu Xinyue 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

It has been concluded in a recently published investigation that the nanobubble flotation process significantlyreduces the number of fine flake graphite flotation stages and improves the flotation performance. The present study was conducted to explore the mechanisms of surface nanobubbles enhancing flake graphiteflotation by investigating effects of nanobubbles on surface properties of graphite and interactionsbetween particles and bubbles by use of contact angle analyzer, zeta potential analyzer, FourierTransform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). The study resultsshow that nanobubbles can improve the surface properties of graphite and enhance the adsorption effectof collector, which increased the contact angle of the graphite surface by 11.93 compared with conventionalflotation. Infrared spectroscopy and potential analysis showed that the nanobubbles could enhancethe hydrophobic attraction and reduce the electrostatic repulsion between the collector and the graphitesurface, which was beneficial to enhance the hydrophobic surface of the graphite and enhance theagglomeration of fine graphite particles. XPS analysis showed that the nanobubbles covered polar hydrophilicgroups (such as CAO, C@O, COOH) on the graphite surface, which enhanced the adsorption of collectorto improve the hydrophobicity of graphite surface.

Study on the doping mechanism and electronic structure for Nb5+ doping PbWO4 crystals

Teng Chen,Kaiyu Xu,Dongli Shi,Mingjie Wang,Tingyu Liu 한국물리학회 2010 Current Applied Physics Vol.10 No.1

The existing forms of the impurity Nb5+ in the Nb5+:PbWO4 (PWO) crystals are simulated by computer technology. The possible various kinds of defects in the Nb5+:PWO crystals are also simulated. By analyzing the calculation results of defect formation energies and binding energies, the optimal substitution positions of the Nb5+ ions and the charge compensating mechanism [Nb-w+V2+ o +Nb-w] in the Nb5+:PWO crystals were obtained. The electronic structures for Nb5+:PWO were calculated with density functional theory code CASTEP. It shows that the doping of Nb5+ ions could suppress the 350 nm absorption band.

Anesthetic Management and Outcomes of Endovascular Treatment of Basilar Artery Occlusion: Results From the ATTENTION Registry

Tao Chunrong,Yuan Guangxiong,Xu Pengfei,Wang Hao,Zhou Peiyang,Yi Tingyu,Li Kai,Cui Tao,Gao Jun,Li Rui,Sun Jun,Zhang Chao,Wang Li,Liu Tianlong,Song Jianlong,Yin Yamei,Nguyen Thanh N.,Li Qing,Hu Wei 대한뇌졸중학회 2023 Journal of stroke Vol.25 No.3

Background and Purpose To examine the clinical and safety outcomes after endovascular treatment (EVT) for acute basilar artery occlusion (BAO) with different anesthetic modalities. Methods This was a retrospective analysis using data from the Endovascular Treatment for Acute Basilar Artery Occlusion (ATTENTION) registry. Patients were divided into two groups defined by anesthetic modality performed during EVT: general anesthesia (GA) or non-general anesthesia (non-GA). The association between anesthetic management and clinical outcomes was evaluated in a propensity score matched (PSM) cohort and an inverse probability of treatment weighting (IPTW) cohort to adjust for imbalances between the two groups. Results Our analytic sample included 1,672 patients from 48 centers. The anesthetic modality was GA in 769 (46.0%) and non-GA in 903 (54.0%) patients. In our primary analysis with the PSM-based cohort, non-GA was comparable to GA concerning the primary outcome (adjusted common odds ratio [acOR], 1.01; 95% confidence interval [CI], 0.82 to 1.25; <i>P</i>=0.91). Mortality at 90 days was 38.4% in the GA group and 35.8% in the non-GA group (adjusted risk ratio, 0.95; 95% CI, 0.83 to 1.08; <i>P</i>=0.44). In our secondary analysis with the IPTW-based cohort, the anesthetic modality was significantly associated with the distribution of modified Rankin Scale at 90 days (acOR: 1.45 [95% CI: 1.20 to 1.75]). Conclusion In this nationally-representative observational study, acute ischemic stroke patients due to BAO undergoing EVT without GA had similar clinical and safety outcomes compared with patients treated with GA. These findings provide the basis for large-scale randomized controlled trials to test whether anesthetic management provides meaningful clinical effects for patients undergoing EVT.