English Teaching in Chinese Primary Schools

Ruiqing Li 팬코리아영어교육학회(구 영남영어교육학회) 2002 영어교육연구 Vol.14 No.2

Effect of Ultrasonic Treatment on Grain Structure, Eutectic Phase and Mechanical Properties of an Al–6.2 wt% Cu Alloy

Li Zhang,Xiaoqian Li,Ripeng Jiang,Ruiqing Li,Lihua Zhang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5

The microstructural modification of eutectic phase is a crucial factor for the mechanical properties strengthening of the Al–Cu binary alloy. In this paper, Al–6.2% Cu melts were subjected to ultrasonic treatment from 710 or 660 °C with differentdurations. The microstructural evolutions of primary α-Al grains and α-Al + θ-Al2Cu eutectic phase under ultrasonicationwere investigated based on the nucleation and growth behavior. Results indicated that with the increase of ultrasonic processingtime, the growth of dendritic or petaloid grains were completely suppressed and noticeable refinement to globularmorphology were observed for α-Al grains. Meanwhile, broad lamella-like eutectic structure transformed to debris or evenparticles with continuous ultrasonication. Accordingly, the area fraction, average length and width of coarsening eutecticlamellas were dramatically reduced. In addition, the decrease of coarsening eutectic phase rather than the refinement ofα-Al grains was found to be the main contributor to the enhancement of mechanical properties for Al–6.2% Cu alloy. Themechanisms underlying the transformation of eutectic phase under ultrasonic treatment was also interpreted based on theexperimental results.

Structural and dielectric properties in the (Ba1−xCax)(Ti0.95Zr0.05)O3 ceramics

Wei Li,Zhi-Jun Xu,Ruiqing Chu,Peng Fu,Guo-Zhong Zang 한국물리학회 2012 Current Applied Physics Vol.12 No.3

Lead-free (Ba1-xCax)(Ti0.95Zr0.05)O3 (x = 0.05e0.40) (BCZT) ceramics were prepared by solid-state reaction technique. XRD results show that the samples in the composition range of 0.05 ≤ x ≤ 0.25 exhibit pure perovskite structures and undergo a polymorphic phase transitions from orthorhombic to tetragonal phase around room temperature. The biphasic structures are detected at x ≥ 0.30 and the dielectric peaks become broad and dielectric constants decrease with increasing Ca content. Ca replacement at Ba site leads to diffuseness, whereas Ca occupancy at Ti site leads to decrease of the Tc.

Bipolar modulation of brushless DC motor with integrated control of motoring and regenerative braking

Ping Fan,Ruiqing Ma,Yuchen Zhang,Zhiqian Dang,Tianxing Li 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.2

A simple, effective method to realize the integrated control of motoring and regenerative braking of brushless DC motor is proposed in this paper. This method can automatically switch between the two states of motoring and regenerative braking according to the change of load without a braking command and current discontinuity, and can realize steady speed control. For the convenience of analysis, first, the model of the brushless DC motor and the methods of the existing motoring and regenerative braking are briefly explained. Then, the working principle of the proposed method under the two states of motoring and regenerative braking is analyzed. Finally, the effectiveness of the proposed method is verified by experiments.

Intraoperative inspection alone is a reliable guide to the choice of surgical procedure for enteroenteric fistulas in Crohn’s disease

( Zhen Guo ),( Xingchen Cai ),( Ruiqing Liu ),( Jianfeng Gong ),( Yi Li ),( Lei Cao ),( Weiming Zhu ) 대한장연구학회 2018 Intestinal Research Vol.16 No.2

Background/Aims: Resection of the diseased segment and suture of the victim segment is recommended for enteroenteric fistula in Crohn’s disease (CD). The main difficulty in this procedure remains reliable diagnosis of the victim segment, especially for fistulas found intraoperatively and inaccessible on endoscopic examination. We aimed to explore whether intraoperative inspection alone is reliable. Methods: Patients undergoing conservative surgery between 2011 and 2016 for enteroenteric fistulas complicating CD were identified from a prospectively maintained database. Patients were divided according to whether the victim segment was evaluated by preoperative endoscopy + intraoperative inspection (PI group) or by intraoperative inspection alone (I group). Outcomes were compared. Results: Of 65 patients eligible for the study, 37 were in in the PI group and 28 were in the I group. The baseline characteristics were similar between the groups, except for the rate of emergency surgery (0/37 in PI group vs. 5/28 in I group, P=0.012). Fistulas involved more small intestines (4/37 in PI group vs. 15/28 in I group, P< 0.001) and fewer sigmoid colons (17/37 in PI group vs. 4/28 in I group, P=0.008) in I group due to accessibility with endoscopy. No difference was found in postoperative complications, stoma rates, postoperative recurrence, or disease at the repair site between the 2 groups (P >0.05). Conclusions: For fistulas found intraoperatively and inaccessible on endoscopic examination, intraoperative inspection was a reliable guide when choosing between en bloc resection and a conservative procedure. (Intest Res 2018;16:282-287)

Multi-time Scale Coordinated Optimization of New Energy High Permeability Power System Considering Flexibility Requirements

Su Shiwei,Tan Donghong,Li Xianghua,Li Xin,Chen Zitong,Lian Ruiqing,Lenz Soronga Blaise Kevine 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

The high proportion of grid-connected intermittent energy such as wind power and photovoltaic makes the demand for power system flexibility increase sharply. In order to improve the overall flexibility of new energy high permeability system and enhance the economy of power system, promote the new energy consumption of system. This paper presents a multi-time scale Coordinated optimization strategy for the new energy high permeability power system considering flexibility requirement (MTSCOSFR). This strategy makes full use of the adjustment ability of source-load-storage flexible resources and analyzes system flexibility requirements at different time scales, creates multi-time scale optimization scheduling models, including typical week operation simulation model, typical day operation simulation model, typical period operation simulation model. Puts the profit of carbon trading and the penalty cost of insufficient flexibility into the optimization goal. Adopts the idea of multi-time coordination and step-by-step optimization to solve the model. This paper sets two cases to discuss MTSCOSFR. The results show that the comprehensive cost of the typical weekly operation simulation is reduced to 2360 × 104$, the penalty cost of insufficient flexibility in the typical day operation simulation is reduced by 67%, the flexibility capacity increased by 500 MW, the regulation capacity increased by 300 MW, the ramp margin increased by 1500 MW/(5 min) −1. The proposed strategy can improve system flexibility and promote new energy consumption on the basis of ensuring system economy.

Assessment Based on the Forecast Error for the Transition Period between the Jianghuai Meiyu and North China Rainy Seasons in 2016

Jie Ma,Zhiping Zong,Li Jianping,Ruiqing Ding 한국기상학회 2021 Asia-Pacific Journal of Atmospheric Sciences Vol.57 No.3

During the transition period between the Jianghuai Meiyu and North China rainy seasons in 2016, there was a high-impact rainstorm event, connecting these two rainy seasons. However, both the short and medium range forecasts predicted a rain band that was too far south; this error can have serious implications for flood preparedness. This study discusses the causes of the forecast error using the ECMWF deterministic and ensemble models. The results show that the prediction of a too-weak westerly trough at the 500-hPa level is the dominant factor. Specifically, a weaker predicted 500-hPa westerly trough reduces the strength of the low vortex at 850 hPa; correspondingly, the shear line to the east of the vortex and the Meiyu front are weaker and farther south, and the monsoon is also weaker, which causes the large area of humidity convergence to be shifted southward. Finally, the heavy rainfall is located farther south with weaker intensity. And vice visa, when a stronger westerly trough is predicted, the location of rain band will be northward. This conclusion may be useful for meteorological decision making in medium range and will help to improve capabilities of risk reduction.

Friction and wear properties of hydraulic components with ceramic/steel-to-steel pairs

Baofu Kou,Zhenshun Li,Zhang Zhang,Ruiqing Li 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

The friction coefficient and wear amount of ceramic/steel-to-steel pairs under various concentrations of high water-based emulsion, load size, and load frequency were investigated through friction and wear test, white light interference 3D surface profiling, scanning electron microscopy, and attached energy spectrometry. The friction and wear conditions of hydraulic components made of different materials are discussed. The ceramic-to-steel pair performs better than the steel-to-steel pair in friction reduction and wear resistance. When the load is 100 N, the frequency is 1 Hz and the concentration is 6 %, and the friction coefficient and wear amount of the ceramic-to-steel pair are the lowest. The degree of abrasive and ploughing wear of various friction pairs is directly proportional to the emulsion concentration and inversely proportional to the working load and frequency. The research results can provide guidance for the manufacture and application of ceramic valves.

Renal-Clearable Hollow Bismuth Subcarbonate Nanotubes for Tumor Targeted Computed Tomography Imaging and Chemoradiotherapy

Hu, Xi,Sun, Jihong,Li, Fangyuan,Li, Ruiqing,Wu, Jiahe,He, Jie,Wang, Nan,Liu, Jianan,Wang, Shuaifei,Zhou, Fei,Sun, Xiaolian,Kim, Dokyoon,Hyeon, Taeghwan,Ling, Daishun American Chemical Society 2018 Nano letters Vol.18 No.2

<P>Although metallic nanomaterials with high X-ray attenuation coefficients have been widely used as X-ray computed tomography (CT) contrast agents, their intrinsically poor biodegradability requires them to be cleared from the body to avoid any potential toxicity. On the other hand, extremely small-sized nanomaterials with outstanding renal clearance properties are not much effective for tumor targeting because of their too rapid clearance in vivo. To overcome this dilemma, here we report on the hollow bismuth subcarbonate nanotubes (BNTs) assembled from renal-clearable ultrasmall bismuth subcarbonate nanoclusters for tumor-targeted imaging and chemoradiotherapy. The BNTs could be targeted to tumors with high efficiency and exhibit a high CT contrast effect. Moreover, simultaneous radio- and chemotherapy using drug-loaded BNTs could significantly suppress tumor volumes, highlighting their potential application in CT imaging-guided therapy. Importantly, the elongated nanotubes could be disassembled into isolated small nanoclusters in the acidic tumor microenvironment, accelerating the payload release and kidney excretion. Such body clearable CT contrast agent with high imaging performance and multiple therapeutic functions shall have a substantial potential for biomedical applications.</P>

Effects of Eu_2O_3 on the structure and electrical properties of 0.82Bi_0.5Na_0.5TiO_3―0.18Bi_0.5K_0.5TiO_3 lead-free piezoelectric ceramics

Peng Fu,Zhi-Jun Xu,Ruiqing Chu,Wei Li,Qian Xie,Guo-Zhong Zang 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Eu_2O_3 (0―0.8 wt.%)-doped 0.82Bi_0.5Na_0.5TiO_3―0.18Bi_0.5K_0.5TiO_3 (BNKT18) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. The compositional dependence of phase structure and electrical properties of the BNKT18 ceramics was studied. X-ray diffraction (XRD) data shows that 0.2―0.8 wt.% Eu_2O_3 has diffused into the lattice of BNKT18 ceramics and forms a pure perovskite phase. SEM images indicate that the grain size of BNKT18 ceramics decreases with the increase of Eu_2O_3 content, and all the modified ceramics have a clear grain boundary and a uniformly distributed grain size. At room temperature, the ferroelectric and piezoelectric properties of the BNKT18ceramics have been improved with the addition of Eu_2O_3, and the BNKT18 ceramics doped with 0.4 wt.%Eu_2O_3 have the highest piezoelectric constant (d_33 = 145 pC/N), highest relative dielectric constant (ε_r = 1134) and lower dissipation factor (tan δ = 0.045) at a frequency of 10 kHz. The BNKT18 ceramics doped with 0.2 wt.% Eu_2O_3 have the highest planar coupling factor (k_p = 0.251). The temperature dependence of the relative dielectric constant shows T_m increases with the addition of Eu_2O_3.