Study on the cantilever ratio optimization of high-temperature molten salt pump for molten salt reactor based on structural integrity

Shen Xing-Chao,Fu Yuan,Zhang Jian-Yu,Yang Jin,Li Zhi-Jun 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.9

The high-temperature molten salt pump is the core equipment in the small modular molten salt reactor with media temperatures up to 700 ◦C. The cantilever ratio of the molten salt pump is usually large. Excessively large cantilever ratios cause increased deformations and rotational amplitudes at the impeller, thus affecting the operational stability of the main pump; small cantilever ratios cause heavy temperature gradients, thus affecting the structural integrity evaluation. This paper used numerical simulation methods to calculate and analyze the temperature field, stress, and structural integrity, optimized the pump shaft cantilever length of the original scheme based on structural integrity using the dichotomy method, and analyzed the rotor dynamics of the optimization results. The results of this study show that the thermal expansion load caused by the temperature difference has a significant mechanical effect on the structure; the first-order critical speed of the rotor system of the optimized schemes has been improved, and the amplitude of the unbalanced response has been significantly reduced, which not only improves the operational stability of the rotor, also contributes to the compact design of the main pump of a small modular molten salt reactor.

A band selection method for hyperspectral image classification based on improved Particle Swarm Optimization

Jie Shen,Chao Wang,Ruili Wang,Fengchen Huang,Chao Fan,Lizhong Xu 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.4

With the development of spectral imaging technology, it makes hyperspectral imagery widely used. According to the features of multiple bands and the strong mutual correlation among these bands, this paper presents a band selection method for hyperspectral imagery classification based on improved PSO (Particle Swarm Optimization). First of all, we use information divergence to describe the correlation of the bands, then build the information divergence matrix to make the classification of subspaces. Secondly, we construct the fitness function of the algorithm with the band information and categories of the Bhattacharyya distance (B distance) to improve the inertia weight updating method in PSO. Finally, based on the AVIRIS hyperspectral imagery and compared with existing method to conduct experiments, the average classification accuracy of the proposed method is 81.36%, which is distinctly improved 0.91% compared with the existed method. Meanwhile, the proposed method has a significantly faster convergence speed during the process of the band selection. Therefore, the experimental results verify the effectiveness of the proposed method in this paper.

Multi-institutional development and validation of modified albumin-bilirubin grade for predicting prognosis of hepatocellular carcinoma patients after hepatectomy

Chao LI,Ming-Da WANG,Lei LIANG,Hao XING,Lan-Qing YAO,Zi-Xiang CHEN,Feng SHEN,Dong-Sheng HUANG,Tian YANG 한국간담췌외과학회 2022 Annals of hepato-biliary-pancreatic surgery Vol.26 No.-

Differential Subsampling with Cartesian Ordering Contrast-Enhanced Magnetic Resonance Angiography for the Preoperative Assessment of Anterolateral Thigh Flap

Shen Yunfeng,Li Xiucun,Zhang Chao,Zhong Hai,Dou Weiqiang 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.8

Objective: To investigate the clinical application of differential subsampling with Cartesian ordering (DISCO) contrastenhanced (CE) magnetic resonance angiography for anterolateral thigh (ALT) flap transplantation, using operative findings as a reference. Materials and Methods: Thirty patients (21 males and nine females; mean age ± standard deviation, 45.5 ± 15.6 years) who were scheduled to undergo reconstruction with ALT flaps between June 2020 and June 2021 were included in the prospective study. Before ALT flap transplantation, patients were scanned using CE-DISCO imaging. All acquired DISCO images of the 60 lower limbs (both sides from each patient) were analyzed using maximum intensity projection and volume rendering methods. Two experienced radiologists were employed to examine the patterns of the lateral circumflex femoral artery (LCFA), its branches, and perforators and their skin termini, which were compared with the operative findings. Results: Using CE-DISCO, the patterns of the LCFA and its branches were clearly identified in all patients. Four different origins of the LCFA were found among the 60 blood vessels: type I (44/60, 73.3%), type II (6/60, 10.0%), type III (8/60, 13.3%), and type IV (2/60, 3.3%). Owing to a lack of perforators entering the skin, two patients did not undergo ALT flap transplantation. For the remaining 28 patients, the ALT flaps in 26 patients were successfully operated without flap reselection during the operation, while the remaining two patients underwent other surgical procedures due to the thin diameter of the perforator or injury of the perforator during the operation. The success rate of flap transplantation was 92.8% (26/28). All transplanted flaps exhibited good blood supply and achieved primary healing without infection or delayed healing. Conclusion: CE-DISCO imaging can be an effective method for preoperative perforator imaging before ALT flap transplantation.

Influence of heat treatment on the wear life of hydraulic fracturing tools

Chao Zheng,Yonghong Liu,Hanxiang Wang,Jie Qin,Yang Shen,Shihong Zhang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

Wear phenomenon has caused severe damage or failure of fracturing tools in oil and gas industry. In this paper, influence of heat treatment on the mechanical properties and wear resistance of fracturing tool made of lamellar graphite grey cast iron were investigated. The surface composition and microstructure were characterized by X-ray diffraction (XRD) and metallographic microscope. Sliding wear tests were performed to study the tribological behavior. Tests results showed that wear rates of treated specimens decreased by 33 %. Besides, worn morphology and wear debris were analyzed using Scanning electron microscope (SEM) and Energy dispersive Xray spectra (EDS). Wear failure mechanisms of specimens were identified. Furthermore, on-site experiment results indicated that wear loss of treated samples decreased by 37.5 %. The wear life of hydraulic fracturing tools can be improved obviously by the heat treatment.

Development of the vapor film thickness correlation in porous corrosion deposits on the cladding in PWR

Shen Yuan,Duan Zhengang,Lu Chuan,Ji Li,Jiao Caishan,Hou Hongguo,Chao Nan,Zhang Meng,Zhou Yu,Gao Yang 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.12

The porous corrosion deposits (known as CRUD) adhered to the cladding have an important effect on the heat transfer from fuel rods to coolant in PWRs. The vapor film is the main constituent in the two-phase film boiling model. This paper presents a vapor film thickness correlation, associated with CRUD porosity, CRUD chimney density, CRUD particle size, CRUD thickness and heat flux. The dependences of the vapor film thickness on the various influential factors can be intuitively reflected from this vapor film thickness correlation. The temperature, pressure, and boric acid concentration distributions in CRUD can be well predicted using the two-phase film boiling model coupled with the vapor film thickness correlation. It suggests that the vapor thickness correlation can estimate the vapor film thickness more conveniently than the previously reported vapor thickness calculation methods.

SENP2 Regulates Hepatocellular Carcinoma Cell Growth by Modulating the Stability of β-catenin

Shen, Huo-Jian,Zhu, Hong-Yi,Yang, Chao,Ji, Fu Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

SUMOylation has emerged as an important post-translational modification that modulates the localization, stability and activity of a broad spectrum of proteins. A dynamic process, it can be reversed by a family of SUMO-specific proteases (SENPs). However, the biological roles of SENPs in mammalian development and pathogenesis remain largely elusive. Here, we demonstrated that SENP2 plays a critical role in the control of hepatocellular carcinoma cell growth. SENP2 was found to be down-regulated in hepatocellular carcinoma (HCC) tissues and over-expression suppressed the growth and colony formation of HCC cells. In contrast, silencing of SENP2 by siRNAs promoted cancer cell growth. We further found that stability of ${\beta}$-catenin was markedly decreased when SENP2 was over-expressed. Interestingly, the decrease was dependent on the de-SUMOylation activity of SENP2, because over-expression of a SENP2 catalytic mutant form had no obviously effects on ${\beta}$-catenin. Our results suggest that SENP2 might play a role in hepatocellular carcinoma cell growth control by modulating the stability of ${\beta}$-catenin.

Eclosion hormone functions in larva-pupa-adult ecdysis in Leptinotarsa decemlineata

Shen Chen-Hui,Jin Lin,Fu Kai-Yun,Guo Wen-Chao,Li Guo-Qing 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

In Drosophila melanogaster, ecdysis-triggering hormone (ETH) and eclosion hormone (EH) mutually enhance the release of each other through a positive feedback loop. Both are involved in the stimulation of ecdysis behavior series and molting-related physiological preparations. However, whether 20-hydroxyecdysone (20E) controls eh expression and whether EH plays a similar role in non-Drosophilid insects remain to be determined. In Lep tinotarsa decemlineata, we found that Ldeh mRNA levels were high in the early and/or late stages and low in the intermediate period within each larval instar, indicating that the mRNA peaks positively correlate with 20E pulses. Consistent with the indication, we confirmed that 20E signaling stimulated the transcription of Ldeh. RNA interference (RNAi)-aided knockdown of Ldeh at the final instar stage slightly impaired pupation and signifi cantly affected wing expansion. Around 20% of the Ldeh RNAi larvae remained as prepupae, completely wrapped in the old larval cuticles. These prepupae gradually darkened, dried and withered, and finally died. The remaining (about 80%) Ldeh hypomorphs became pupae and emerged as abnormal adults, bearing smaller and wrinkle elytra and hindwings. The adult tracheae in the Ldeh hypomorphs were full of liquid. In addition, the low pupation rate and high deformed adult proportion cannot be rescued by ingestion of either 20E or juvenile hormone. Thus, EH is critical for ecdysis and trachea clearance in L. decemlineata. The failure of trachea clearance may disenable air-swallowing during larva-pupa-adult transition and thus impacts wing growth and expansion.

Antioxidant activity and metabolic regulation of sodium salicylate on goat sperm at low temperature

Shen Wenzheng,Fu Yu,Bai Haiyu,Zhang Zhiyu,Cao Zhikun,Liu Zibo,Yang Chao,Sun Shixin,Wang Lei,Ren Chunhuan,Ling Ying-hui,Zhang Zi Jun,Cao Hongguo 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.4

Objective: The purpose of this study was to explore the effect of sodium salicylate (SS) on semen preservation and metabolic regulation in goats. Methods: Under the condition of low temperature, SS was added to goat semen diluent to detect goat sperm motility, plasma membrane, acrosome, antioxidant capacity, mitochondrial membrane potential (MMP) and metabonomics. Results: The results show that at the 8th day of low-temperature storage, the sperm motility of the 20 μM SS group was 66.64%, and the integrity rates of the plasma membrane and acrosome were both above 60%, significantly higher than those of the other groups. The activities of catalase and superoxide dismutase in the sperm of the 20 μM SS group were significantly higher than those of the control group, the contents of reactive oxygen species and malondialdehyde were significantly lower than those in the control group, the MMP was significantly higher than that in the control group, and the contents of Ca2+ and total cholesterol were significantly higher than those in the control group. Through metabonomics analysis, there were significant metabolic differences between the control group and the 20 μM SS group. Twenty of the most significant metabolic markers were screened, mainly involving five metabolic pathways, of which nicotinic acid and nicotinamide metabolic pathways were the most significant. Conclusion: The results indicate that SS can effectively improve the low-temperature preservation quality of goat sperm.

On the convergence to the multiple subfractional Wiener-It$\hat{o}$ integral

Shen, Guangjun,Yan, Litan,Chen, Chao 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.4

In this paper, we construct a family of continuous stochastic processes that converges in law to the multiple Wiener-It$\hat{o}$ integrals with respect to the subfractional Brownian motion with H > $\frac{1}{2}$ for the integrand f in a rather general class of functions. Wemainly use Donsker and Stroock approximations and the techniques of the multiple Wiener-It$\hat{o}$ integral with respect to the Wiener process.