Selection of burnable poison in plate fuel assembly for small modular marine reactors

Shikun Xu,Tao Yu,Jinsen Xie,Zhulun Li,Yi Xia,Lei Yao 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.4

Small modular reactors have garnered considerable attention in the recent years. Plate fuel elementsexhibit a good application prospect in small modular pressurized water reactors for marine applications. Further, improved economic benefits can be achieved by extending the core lifetime of small modularreactors. However, it is necessary to realize a large initial residual reactivity for achieving a relatively longburnup depth finally. Thus, the selection of a suitable burnable poison (BP) is a crucial factor that shouldbe considered in the design of small modular reactors. In this study, some candidate BPs are selected torealize the effective control of reactivity. The results show that 231Pa2O3, 240Pu2O3, 167Er2O3, PACS-J, andPACS-L are ideal candidates of BP, and since the characteristics of BP can increase the final burnup depthof assembly, the economic benefits are gained. Additionally, an optimal combination scheme of BPs isestablished. Specifically, it is proved that through a reasonable combination of BPs, a low reactivityfluctuation during the lifetime can be achieved, leading to a large final burnup depth

The effect of lanthanum on the solidification curve and microstructure of Al-Mg alloy during eutectic solidification

Xie, Shikun,Yi, Rongxi,Guo, Xiuyan,Pan, Xiaoliang,Xia, Xiang Techno-Press 2015 Advances in materials research Vol.4 No.2

The influence of rare earth lanthanum (La) on solidification cooling range, microstructure of aluminum-magnesium (Al-Mg) alloy and mechanical properties were investigated. Five kinds of Al-Mg alloys with rare earth content of La (i.e., 0, 0.5, 1.0, 1.5 and 2.0 wt.%) were prepared. Samples were either slowly cooled in furnace or water cooled. Results indicate that the addition of the rare earth (RE) La can significantly influence the solidification range, the resultant microstructure, and tensile strength. RE La can extend the alloy solidification range, increase the solidification time, and also greatly improve the flow performance. The addition of La takes a metamorphism effect on Al-Mg alloy, resulting in that the finer the grain is obtained, the rounder the morphology becomes. RE La can significantly increase the mechanical properties for its metamorphism and reinforcement. When the La content is about 1.5 wt.%, the tensile strength of Al-Mg alloy reaches its maximum value of 314 MPa.

Facial Expression Analysis using Active Shape Model

Reda Shbib,Shikun Zhou 보안공학연구지원센터(IJSIP) 2015 International Journal of Signal Processing, Image Vol.8 No.1

Facial expressions analysis is a vital part of the research in human-machine interaction. This chapter introduces an automatic recognition system for facial expression from a front view human face image. Obtaining an effective facial representation from initial face images is an essential phase for strong and efficient facial expression system. In this chapter we have developed a facial expression analysis system. Firstly we have tried to evaluate facial analysis base on Active shape model (ASM). In order to detect the face images, Adaboost classifier and Haar-Like feature has been adopted to achieve face detection and tracking. The ASM then has been automatically initiated in the detected face image. Then, discriminates and reliable facial feature points has been extracted applying ASM fitting technique. The geometric displacement among the projected ASM feature points coordinates and the mean shape of ASM were used to evaluate facial expression. Using support vector machine (SVM) classifier, the obtained results has reached a recognition rate of 93 %.

A pairing-free key-insulated certificate-based signature scheme with provable security

( Hu Xiong ),( Shikun Wu ),( Ji Geng ),( Emmanuel Ahene ),( Songyang Wu ),( Zhiguang Qin ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.3

Certificate-based signature (CBS) combines the advantages of both public key-based signature and identity-based signature, while saving from the disadvantages of drawbacks in both PKS and IBS. The insecure deployment of CBS under the hostile circumstances usually causes the exposure of signing key to be inescapable. To resist the threat of key leakage, we present a pairing-free key insulated CBS scheme by incorporating the idea of key insulated mechanism and CBS. Our scheme eliminates the costly pairing operations and as a matter of fact outperforms the existing key insulated CBS schemes. It is more suitable for low-power devices. Furthermore, the unforgeability of our scheme has been formally proven to rest on the discrete logarithm assumption in the random oracle model.

Head Pose Estimation for Car Drivers

Reda Shbib,Shikun Zhou,David Ndzi,Khalil Alkadhimi 보안공학연구지원센터(IJUNESST) 2014 International Journal of u- and e- Service, Scienc Vol.7 No.4

Testicular fat deposition attenuates reproductive performance via decreased follicle-stimulating hormone level and sperm meiosis and testosterone synthesis in mouse

Miao Du,Shikun Chen,Yang Chen,Xinxu Yuan,Huansheng Dong Asian Australasian Association of Animal Productio 2024 Animal Bioscience Vol.37 No.1

Objective: Testicular fat deposition has been reported to affect animal reproduction. However, the underlying mechanism remains poorly understood. The present study explored whether sperm meiosis and testosterone synthesis contribute to mouse testicular fat deposition-induced reproductive performance. Methods: High fat diet (HFD)-induced obesity CD1 mice (DIO) were used as a testicular fat deposition model. The serum hormone test was performed by agent kit. The quality of sperm was assessed using a Sperm Class Analyzer. Testicular tissue morphology was analyzed by histochemical methods. The expression of spermatocyte marker molecules was monitored by an immuno-fluorescence microscope during meiosis. Analysis of the synthesis of testosterone was performed by real-time polymerase chain reaction and reagent kit. Results: It was found that there was a significant increase in body weight among DIO mice, however, the food intake showed no difference compared to control mice fed a normal diet (CTR). The number of offspring in DIO mice decreased, but there was no significant difference from the CTR group. The levels of follicle-stimulating hormone were lower in DIO mice and their luteinizing hormone levels were similar. The results showed a remarkable decrease in sperm density and motility among DIO mice. We also found that fat accumulation affected the meiosis process, mainly reflected in the cross-exchange of homologous chromosomes. In addition, overweight increased fat deposition in the testis and reduced the expression of testosterone synthesis-related enzymes, thereby affecting the synthesis and secretion of testosterone by testicular Leydig cells. Conclusion: Fat accumulation in the testes causes testicular cell dysfunction, which affects testosterone hormone synthesis and ultimately affects sperm formation.

Research on Li0.3Na0.18K0.52NO3 promoted Mg20Al-CO3 LDH/GO composites for CO2 capture

Ying Yang,Kai Chen,Liang Huang,Min Li,Taiping Zhang,Mi Zhong,Ping Ning,Junya Wang,Shikun Wen 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.102 No.-

It has been reported that the addition of graphene oxide (GO) can increase the dispersion and heterogeneousnucleation of layered double hydroxide (LDH), thus providing more active sites, which is more conduciveto CO2 adsorption. Herein, we reported alkali metal nitrates ((Li0.3Na0.18K0.52)NO3) promoted LDHand GO composites (LDH/GO) as adsorbents for CO2 capture. The influence of mass ratio of LDH to GO, theimpregnation ratio of alkali metal nitrates, the calcination and adsorption temperature, as well as thecycling stability were investigated systematically. The results indicated that the CO2 capture capacityof LDH/GO composite with 30 mol% (Li0.3Na0.18K0.52)NO3 could reach 4.51 mmol g 1, which was 5.86times higher than LDH/GO1 without loading alkali metal nitrates. Moreover, it had outstanding CO2adsorption capacity in the range from 200 C to 320 C. In addition, the cyclic adsorption and desorptiontest manifested that the CO2 uptake of the material can reach 3.07 mmol g 1 after 22 cycles. We believethat this study will give a significant contribution to fabrication of LDH based composites as CO2 adsorbentsin future study.

Error compensation for snake arm maintainer under variable loads

Guodong Qin,Huapeng Wu,Aihong Ji,Huan Shen,Qian Li,Qingfei Han,Zhikang Yang,Shikun Wen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

The cable-driven snake arm maintainer (SAM) simplifies the electronics of the entire snake arm and is well suited for operation in narrow and high-risk environments. However, the structural features of the SAM, the large slenderness ratio and the effects of variable loads and rigid-flexible coupling deformation lead to large end position error. In order to improve the positional accuracy, a joint space error compensation model of a SAM is constructed using the matrix differentiation method. The error parameters under different loads and different poses are identified based on the principles of variable parameter error compensation and a linearized variable-load variable-parameter model. Parameter errors are then calculated by the Levenberg-Marquardt nonlinear damped least-squares algorithm. Finally, we verify the effectiveness of the proposed algorithm by simulation and error compensation experiments. The results of the study provide a theoretical basis for further accuracy improvement and application expansion of the SAM.