CORROSION BEHAVIOR OF AUSTENITIC AND FERRITIC STEELS IN SUPERCRITICAL WATER

Luo, Xin,Tang, Rui,Long, Chongsheng,Miao, Zhi,Peng, Qian,Li, Cong Korean Nuclear Society 2008 Nuclear Engineering and Technology Vol.40 No.2

The general corrosion behavior of austenitic and ferritic steels(316L, 304, N controlled 304L, and 410) in supercritical water is investigated in this paper. After exposure to deaerated supercritical water at $480^{\circ}C$/25 MPa for up to 500 h, the four steels studied were characterized using gravimetry, scanning electron microscopy/energy dispersive X-ray spectroscopy(SEM/EDS), X-ray photoelectron spectroscopy(XPS), and X-ray diffraction(XRD). The results show that the 316L steel with a higher Cr and Ni content has the best corrosion-resistance performance among the steels tested. In addition to the oxide layer mixed with $Fe_{3}O_{4}$ and $(Fe,Cr)_{3}O_{4}$ that formed on all the samples, a $Fe_{3}O_{4}$ loose outer layer was observed on the 410 steel. The corrosion mechanism of stainless steels in supercritical water is discussed based on the above results.

Effect of Balance Drum Clearance on the Flow in the last stage Impeller Back Sidewall gap

Qian Chen,Luo Xin,Yang Congxin,Wang Bin 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2

In order to study the effect of balance drum clearance on flow distribution in back sidewall gap of last-stage impeller, numerical calculation of a multistage pump was carried out. The accuracy of the numerical calculation method was verified with the external characteristic test. The axial distribution of the radial velocity at the inlet and the bottom of the back sidewall gap at different angles was plotted. The results showed that the radial velocity near the impeller flows radially to the outlet of the impeller, and the radial velocity near the pump shell flows radially to the hub. Influenced by the high-turbulent energy fluid at the outlet of the impeller, there are obvious eddy current movement at the inlet of the back sidewall gap, and the radial velocity increases with the increase of the balance drum clearance. When the flow rate increases from 0.5Q to 1.5Q, the radial velocity decreases gradually at the same angle. The results can provide a reference for the pump design and optimization.

Lifetime Prediction and Aging Behaviors of Nitrile Butadiene Rubber under Operating Environment of Transformer

Qian, Yi-hua,Xiao, Hong-zhao,Nie, Ming-hao,Zhao, Yao-hong,Luo, Yun-bai,Gong, Shu-ling The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at $70^{\circ}C$ under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at $25^{\circ}C$ was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.

Preparation and luminescent properties of Tb3+/Sm3+ co-doped phosphate glasses for display device applications

Qian Zhang,Lei Han,Weizhen Liu,Weixiong You,Anxian Lu,Zhiwei Luo 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.1

Development of orange light emitting materials cannot be ignored. In this paper, a novel Tb3+/Sm3+ co-doped P2O5-SrO-BaOZnO-glasses have been prepared. The prepared glasses consisted predominantly of Q2 units, and a small amount of Q0 andQ1 units. For absorption spectra of glasses, eight obvious absorption bands were found. Under the excitation of 402 nm and374 nm xenon lamp, the emission spectra and fluorescence lifetimes of glasses showed big difference. Under the excitation of374 nm xenon lamp, there was significant energy transfer process between Sm3+ and Tb3+ ions in glasses. The fluorescencedecay curves conformed to a double-exponential decay function, the average fluorescence lifetimes of glasses G02 ~ G10 were2.38 ms, 2.67 ms, 1.96 ms, 1.81 ms, and 1.61 ms with the increasing of Sm2O3 content, and the glasses emitted a distinct orangelight. The distinctive properties indicate that this system glass has potential applications in display devices.

Vascular Endothelial Growth Factor (VEGF) Gene Polymorphisms and Breast Cancer Risk in a Chinese Population

Luo, Ting,Chen, Long,He, Ping,Hu, Qian-Cheng,Zhong, Xiao-Rong,Sun, Yu,Yang, Yuan-Fu,Tian, Ting-Lun,Zheng, Hong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Vascular endothelial growth factor (VEGF) is a potent regulator of angiogenesis and thereby involved in the development and progression of solid tumours. Associations between three VEGF gene polymorphisms (-634 G/C, +936 C/T, and +1612 G/A) and breast cancer risk have been extensively studied, but the currently available results are inconclusive. Our aim was to investigate associations between three VEGF gene polymorphisms and breast cancer risk in Chinese Han patients. We performed a hospital-based case-control study including 680 female incident breast cancer patients and 680 female age-matched healthy control subjects. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect the three VEGF gene polymorphisms. We observed that women carriers of +936 TT genotypes [odds ratio (OR) =0.46, 95% confidence interval (CI) = 0.28, 0.76; P=0.002] or 936 T-allele (OR=0.81, 95% CI= 0.68, 0.98; P=0.03) had a protective effect concerning the disease. Our study suggested that the +1612G/A polymorphism was unlikely to be associated with breast cancer risk. The -634CC genotype was significantly associated with high tumor aggressiveness [large tumor size (OR=2.63, 95% CI=1.15, 6.02; P=0.02) and high histologic grade (OR=1.47, 95% CI= 1.06, 2.03; P=0.02)]. The genotypes were not related with other tumor characteristics such as regional or distant metastasis, stage at diagnosis, or estrogen or progesterone receptor status. Our study revealed that the VEGF -634 G/C and +936 C/T gene polymorphisms may be associated with breast cancer in Chinese Han patients.

Pyrolysis of wood species based on the compositional analysis

Qian Liu,Kaige Wang,Zhongyang Luo,Kefa Cen,Shurong Wang 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2

Based on the Van Soest method, the components in Chinese fir and fast-growing poplar were quantified, and the fiber present was separated into three fractions: neutral detergent fiber, acid detergent fiber and strong acid detergent fiber. Microstructure of the fibers was investigated by a Fourier transform infrared spectrometry. Cellulose and hemicellulose both represent the characteristics of polysaccharides, while lignin has dissimilar structure. Pyrolysis of fir, poplar and the detergent fibers was carried out on a thermogravimetric analyzer coupled with FTIR spectrometry. After the removal of extractives and soluble minerals, pyrolysis of NDF shows the haracteristics of the three main components. Hydrocarbons, aldehydes, ketones, acids, alcohols and others are generated due to the primary pyrolysis of hemicellulose and cellulose in single stages. Phenols and alcohols are the dominant volatiles released from pyrolysis of lignin in two successive stages, respectively.

Combination of canagliflozin and puerarin alleviates the lipotoxicity to diabetic kidney in mice

Qian Zhu,Qu Zhou,Xiao-li Luo,Xu-jie Zhang,San-yu Li 대한약리학회 2023 The Korean Journal of Physiology & Pharmacology Vol.27 No.3

Diabetic kidney disease is one of the most serious complications of diabetes. Although diabetic kidney disease can be effectively controlled through strict blood glucose management and corresponding symptomatic treatment, these therapies cannot reduce its incidence in diabetic patients. The sodium-glucose cotransporter 2 (SGLT2) inhibitors and the traditional Chinese herb “Gegen” have been widely used in diabetes-related therapy. However, it remains unclear whether the combined use of these two kinds of medicines contributes to an increased curative effect on diabetic kidney disease. In this study, we examined this issue by evaluating the efficacy of the combination of puerarin, an active ingredient of Gegen, and canagliflozin, an SGLT2 inhibitor for a 12-week intervention using a mouse model of diabetes. The results indicated that the combination of puerarin and canagliflozin was superior to canagliflozin alone in improving the metabolic and renal function parameters of diabetic mice. Our findings suggested that the renoprotective effect of combined puerarin and canagliflozin in diabetic mice was achieved by reducing renal lipid accumulation. This study provides a new strategy for the clinical prevention and treatment of diabetic kidney disease. The puerarin and SGLT2 inhibitor combination therapy at the initial stage of diabetes may effectively delay the occurrence of diabetic kidney injury, and significantly alleviate the burden of renal lipotoxicity

Multi-threshold remote sensing image segmentation with improved ant colony optimizer with salp foraging

Qian Yunlou,Tu Jiaqing,Luo Gang,Sha Ce,Heidari Ali Asghar,Chen Huiling 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.6

Remote sensing images can provide direct and accurate feedback on urban surface morphology and geographic conditions. They can be used as an auxiliary means to collect data for current geospatial information systems, which are also widely used in city public safety. Therefore, it is necessary to research remote sensing images. Therefore, we adopt the multi-threshold image segmentation method in this paper to segment the remote sensing images for research. We first introduce salp foraging behavior into the continuous ant colony optimization algorithm (ACOR) and construct a novel ACOR version based on salp foraging (SSACO). The original algorithm’s convergence and ability to avoid hitting local optima are enhanced by salp foraging behavior. In order to illustrate this key benefit, SSACO is first tested against 14 fundamental algorithms using 30 benchmark test functions in IEEE CEC2017. Then, SSACO is compared with 14 other algorithms. The experimental results are examined from various angles, and the findings convincingly demonstrate the main power of SSACO. We performed segmentation comparison studies based on 12 remote sensing images between SSACO segmentation techniques and several peer segmentation approaches to demonstrate the benefits of SSACO in remote sensing image segmentation. Peak signal-to-noise ratio, structural similarity index, and feature similarity index evaluation of the segmentation results demonstrated the benefits of the SSACO-based segmentation approach. SSACO is an excellent optimizer since it seeks to serve as a guide and a point of reference for using remote sensing image algorithms in urban public safety.

Cathodic reduction characteristics of 2-chloro-4-nitrophenol in microbial electrolysis cell

Qianli Yu,Wei Xiong,Donggen Huang,Cui Luo,Qiang Yang,Tao Guo,Qi Wei 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.6

Microbial electrolysis cell (MEC) has been constructed to study the degradation characters of 2-chloro-4-nitrophenol (2C4NP) in waste water. The effects of applied voltage, initial concentration of substrate and co-matrix species on the reduction and degradation of 2C4NP were studied. Qualitative and quantitative analysis of 2C4NP residues and degradation intermediate by using UV-Vis, HPLC, HPLC/MS/MS, IC and other analytical testing techniques. The degradation mechanism of 2C4NP in MEC cathode was proposed. The results showed that electron and electroactive microorganisms would produce coupling effect and accelerate the degradation of 2C4NP under adding 0.5 V DC; Under the condition of satisfying the C/N ratio of electroactive anaerobic microorganism, the addition of organic substances such as glucose and sodium acetate which were easily degraded by microorganisms would hinder the degradation of 2C4NP in the cathode compartment. 2C4NP can be effectively degraded by adding appropriate amount of glucose as carbon source with the low C/N. 2C4NP undergoes reduction, dechlorination, denitrification and assimilation in the cathode compartment to form 2-chloro-4-aminophenol, 4-aminophenol, 2-chlorophenol, 2-chloro-4-hydroxyphenol, nitrophenol, hydroquinone, 4-hydroxyhexadienoic acid semialdehyde, valeric acid, oxalic acid and many other intermediate products. According to the degradation intermediates, the degradation mechanism of 2C4NP in the cathode compartment was presumed.

Effect of notch position on creep damage for brazed joint

Luo, Yun,Jiang, Wenchun,Zhang, Qian,Zhang, Weiya,Woo, Wanchuck,Tu, Shan-Tung,Hao, Muming Elsevier Applied Science 2016 Advances in engineering software Vol.100 No.-

<P><B>Abstract</B></P> <P>In this paper, we investigated the effect of notch position on creep damage for Hastelloy C276-BNi2 brazed joint. Three different types of notches locate in edge of base metal (base notch), edge of filler metal (surface notch) and center of filler metal (inside notch) were compared, and the influence of notch geometric parameters on creep damage was also investigated. The results show that the different notch position and dimension generate different creep damage distributions and have a great influence on creep life. The creep failure is the easiest to occur in surface notch, then the base notch, and the last is inside notch. The brazed joint with higher maximum principal stress and von Mises stress generates creep failure easier. For the base notch, the failure time increases with the increase of base notch distance and the creep failure location moves gradually from the center of filler metal to notch tip. The notch locating away from filler metal is beneficial to reduce the creep damage in filler metal and enhance the creep life. For the inside notch, the failure time decreases with notch length increases and the maximum creep damage locates at notch tip. With the increase of inside notch width, the failure time increases first and then keep steadiness, and the failure location moves away from notch tip. The effects of notch position and dimension should be fully considered in creep failure analyses and life assessments of brazed joints.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The creep failure is easy generate in surface notch. </LI> <LI> The far away notch is helpful to reduce the creep damage of filler metal. </LI> <LI> As H increases, the failure location moves from filler metal to base metal. </LI> <LI> As H increases, the failure time increases first then keeps stable. </LI> <LI> The failure time decreases with L increases while it increases with W increases. </LI> </UL> </P>