A new surrogate method for the neutron kinetics calculation of nuclear reactor core transients

Li Xiaoqi,Zheng Youqi,Du Xianan,Xiao Bowen 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.9

Reactor core transient calculation is very important for the reactor safety analysis, in which the kernel is neutron kinetics calculation by simulating the variation of neutron density or thermal power over time. Compared with the point kinetics method, the time-space neutron kinetics calculation can provide accurate variation of neutron density in both space and time domain. But it consumes a lot of resources. It is necessary to develop a surrogate model that can quickly obtain the temporal and spatial variation information of neutron density or power with acceptable calculation accuracy. This paper uses the time-varying characteristics of power to construct a time function, parameterizes the time-varying characteristics which contains the information about the spatial change of power. Thereby, the amount of targets to predict in the space domain is compressed. A surrogate method using the machine learning is proposed in this paper. In the construction of a neural network, the input is processed by a convolutional layer, followed by a fully connected layer or a deconvolution layer. For the problem of time sequence disturbance, a structure combining convolutional neural network and recurrent neural network is used. It is verified in the tests of a series of 1D, 2D and 3D reactor models. The predicted values obtained using the constructed neural network models in these tests are in good agreement with the reference values, showing the powerful potential of the surrogate models.

Enrichment of C17:0-rich saturated fatty acids from sheep tail fat for adjuvant therapy of non-small-cell lung cancer

Xiaoqi Yu,Xiaoyi Liu,Yuanli Li,Huimin He,Xinxin Pei,Tengfei Ma,Yuanyuan Chen,Yi Wang,Hongxia Li,Wenchu Lin,Changzhi Xu,Buchang Zhang 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.8

Heptadecanoic acid (C17:0), an odd-chain saturated fatty acid (OCSFA) in ruminant lipid, has been demonstrated to be potential for treating cancers. Our results also showed that sheep tail fat (STF) with higher level of C17:0-containing saturated fatty acids (SFAs) whereas lower level of oleic acid (C18:1), performed remarkable inhibition against non-small-cell lung cancer (NSCLC) cells. To enrich the content of C17:0, a C17:0-rich SFA concentrate (HRSC) was prepared from STF by solvent crystallization and urea complexation methods (hexane/STF = 3.5/1, 4 °C for 8 h, and 80% ethanol/urea/free fatty acids = 8/1/1, 4 °C for 6 h). The content of C17:0 was up from 3.02 to 6.34% and the recovery was 4.17%. Biological experiments showed that HRSC exerted better antiproliferative effect against NSCLC cells. Moreover, HRSC performed enhanced inhibitory effect in A549 cell xenograft mouse model. Therefore, HRSC has the potential to be applied in adjuvant therapy for NSCLC.

Evaluation of antifatigue and antioxidant activities of the marine microalgae Isochrysis galbana in mice

Wenjie Li,Chaodan Luo,Yongmei Huang,Jingting Zhan,Jinli Lei,Ning Li,Xiaoqi Huang,Hui Luo 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.4

The present work aimed to estimate the possible anti-fatigue effect and potential mechanism of Isochrysis galbana (IG) in mice. The anti-fatigue activity of IG (100, 200, and 400 mg/kg) was elucidated by a weight-loaded forced swimming test, and the potential mechanism was explored by determination of fatigue-related biochemical parameters. The results showed that pretreatment with IG significantly extended the exhaustive swimming time and increased the levels of liver glycogen, muscle glycogen and blood glucose in a dose-dependent manner. Besides, the increased levels of alanine aminotransferase, aspartate aminotransferase, blood lactic acid, lactic dehydrogenase, creatine kinase, and blood urea nitrogen by exhausted swimming, were dramatically attenuated by pretreatment with IG. Furthermore, supplementation with IG significantly enhanced the glutathione peroxidase and superoxide dismutase levels, while attenuated the level of malonaldehyde. Taken together, IG possessed appreciable efficacy to alleviate fatigue, and the mechanism might be associated with favorably modulating the process of energy consumption, metabolism, and attenuating oxidative stress injury.

Advanced glycation end products promote meniscal calcification by activating the mTOR-ATF4 positive feedback loop

Yang Sheng,Xie JiaJun,Pan ZhiJie,Guan HongMei,Tu YueSheng,Ye YuanJian,Huang ShouBin,Fu ShiQiang,Li KangXian,Huang ZhiWei,Li XiaoQi,Shi ZhanJun,Li Le,Zhang Yang 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

The meniscus is vital for maintaining knee homeostasis and function. Meniscal calcification is one of the earliest radiological indicators of knee osteoarthritis (KOA), and meniscal calcification is associated with alterations in biomechanical properties. Meniscal calcification originates from a biochemical process similar to vascular calcification. Advanced glycation end products (AGEs) and their receptors (RAGEs) reportedly play critical roles in vascular calcification. Herein, we investigated whether targeting AGE-RAGE is a potential treatment for meniscal calcification. In our study, we demonstrated that AGE-RAGE promotes the osteogenesis of meniscal cells and exacerbates meniscal calcification. Mechanistically, AGE-RAGE activates mTOR and simultaneously promotes ATF4 accumulation, thereby facilitating the ATF4-mTOR positive feedback loop that enhances the osteogenic capacity of meniscal cells. In this regard, mTOR inhibits ATF4 degradation by reducing its ubiquitination, while ATF4 activates mTOR by increasing arginine uptake. Our findings substantiate the unique role of AGE-RAGE in the meniscus and reveal the role of the ATF4-mTOR positive feedback loop during the osteogenesis of meniscal cells; these results provide potential therapeutic targets for KOA.

Dynamic responses and robustness performance to moving boundary of double-stepped cable during deep-sea mining

Li Yilun,Guo Shuangxi,Guo Yucheng,Yu Xiaoqi,Chen Weimin,Song Jixiang 대한조선학회 2023 International Journal of Naval Architecture and Oc Vol.15 No.-

As the exploration and exploitation of deep-sea oil and gas, along with promising polymetallic nodule&sulfides mining, have been developing toward ultra-deep waters, some innovative concepts of marine cable configuration suitable for ultra-deepwater are proposed, such as stepped cable, hybrid cable and double-stepped cable. For deep-water cables with complex configurations, the structural responses become more complicated due to their non-uniform structural properties. Because the distributed buoyancy modules along cable length might introduce more significant local bending segments. Moreover, the impacts of moving boundary, caused by the motions of top vessel and bottom mining vehicle, should be considered. Through combing the finite element simulations with the hydrodynamic models, the dynamic response analysis approach of ultra-deepwater cables is established in this study. Then the double-stepped cable responses, including axial tension, displacement along with the change of overall configurations caused by moving top vessel and bottom mining vehicle, are calculated. Moreover, wave propagation behaviors during cable response are comprehensively examined, and the influences of non-uniform structural properties on cable response and wave propagation are analyzed using the wave propagation theory of structure with axially varying properties based on the Bessel function. The results show that the presented double-stepped cable can provide suitable configurations during the dynamic response, which has good compliance performance and can effectively buffer its response caused by moving boundary excitation. Finally, we found that the response spatial-temporal evolutions present some interesting phenomena, such as the axially non-uniform characteristics lead to non-monotonic changes in response amplitude and wavelength, with local peaks occurring in the low-tension region, owing to the distributed buoyancy modules, along with axiallyvarying and discontinuous structural properties. And, there exists significant mixed effect coming from both standing waves and traveling waves.

Effects of Temperature on Melt Electrospinning: Experiment and Simulation Study

Xiaoqi Mu,Yuansheng Zheng,Xueqin Li,Binjie Xin,Lantian Lin 한국섬유공학회 2021 Fibers and polymers Vol.22 No.4

In this study, the jet formation progress, jet motion, resultant fiber diameter, fiber mat morphology, inner structuresand mechanical properties of the fibers prepared at different heating temperatures via melt electrospinning system werestudied, in a comprehensive and systematic manner. The temperature distribution of the melt electrospinning configurationwas simulated, in order to provide a good deal of insight into the experimental results. High-speed photography was adoptedto capture the images of jet formation process and jet motion during melt electrospinning. The experimental results showedthat higher heating temperature at the spinneret results in shorter jet formation time, smaller fiber diameter, more disorderedfiber mat, lower degree of crystallinity and strength. The simulation works was carried out, aimed at facilitating to deeplyunderstand the experimental results.

The Effects of Electric Field on Jet Behavior and Fiber Properties in Melt Electrospinning

Xueqin Li,Yuansheng Zheng,Xiaoqi Mu,Binjie Xin,Lantian Lin 한국섬유공학회 2020 Fibers and polymers Vol.21 No.5

The electric field and temperature are the two important factors that influence the diameter and properties of fiberin the melt electrospinning process. It is commonly known that the polymer jet behavior is governed by the electric fieldwithin spinning area. In present work, a comprehensively-designed and properly-conducted analysis was carried out toinvestigate into the effects of electric field on the jet behaviors, diameters, crystalline structure and mechanical properties ofthe resultant fibers. An auxiliary electrode was invited to enhance the electric field strength. The high-speed photography wasadopted to capture the jet motion, and also, the numerical simulation was used to understand the electric field distribution. Bymaking use of the whipping amplitude and whipping frequency, the characteristics of jet behavior were described. It wasfound that by applying an auxiliary electrode, the average fiber diameter reduced from 61.01 μm to 9.06 μm, and thecrystallinity and strength of the fiber was improved with the help of the higher electric filed intensity. In addition, the moreuniform electric field would produce finer and more uniform fiber because of the more stable jet motion.

Effect of pyrolytic temperature on the adsorptive removal of p-benzoquinone, tetracycline, and polyvinyl alcohol by the biochars from sugarcane bagasse

Guoting Li,Weiyong Zhu,Lingfeng Zhu,Xiaoqi Chai 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.7

Sugarcane bagasse was pyrolyzed under oxygen-limited conditions from 100 to 600 oC and used for the adsorptive removal of oxidation intermediate p-benzoquinone, tetracycline, and polyvinyl alcohol. The three organic pollutants have different polarities and solubilities. The carbon content increased from 57.7% of the raw bagasse to 75.3% of the biochar pyrolyzed at 600 oC, while the O content decreased from 13.2% to 6.1%. Accordingly, the biochar surface became more hydrophobic with increasing pyrolytic temperature. Interestingly, the adsorption affinity of biochars towards the three pollutants improved with an increase in the pyrolytic temperature. The adsorption of tetracycline molecules was almost unaffected by its being negatively charged with increasing solution pH. A mechanism of π- π electron-donor-acceptor interaction might contribute to the adsorption of tetracycline and p-benzoquinone, while Hbond interaction between polyvinyl alcohol and the biochar might be dominant during adsorption. The Elovich model fitted the kinetic model well, indicating that the diffusional rate-determining step was more pronounced. An isotherm study indicated that the contribution of partitioning was also dominant in the adsorption processes. Wide application of the prepared biochars is expected for the efficient adsorptive removal of organic pollutants.

The Relative Influence of Diet and Physical Activity on Obesity in China

Cui Zhao-Hui,Li Yan-Ping,Di Yu-Feng,Ba Lei,Hu Xiaoqi,Ma Guan-Sheng The Korean Society of Community Nutrition 2004 Journal of community nutrition Vol.6 No.3

The purpose of this study is to investigate the relative influence of diet and physical activity on obesity. The subjects were 155 adults aged 35-52 years from 24 neighborhood committees in 4 urban districts of Beijing (male : 78, female : 77). They were divided into normal weight, overweight and obese groups according to their BMI. The general information of the subjects was collected by interview-administered questionnaire. Dietary intake was obtained by three-day(two weekdays and one weekend day) food weighted method, physical activity was assessed by a validated combination of data obtained from activity monitors, bicycling information and activity records. There were no significant differences of age, gender, height, educational, family economic level, smoking and drinking between different groups. The proportion of flour intake was higher in obese group compared to normal weight and overweight groups, and that of vegetables is lower in obese group. The physical activity (PAL) was not significantly different between two groups of the normal, overweight and obese groups. After the adjustment for confounding factors using logistic regression model, we found that the proportion of flour intake was positively associated with obesity, while the proportion of vegetable intake was inversely associated with obesity. It is concluded that dietary patterns were associated with obesity and diets composed of more vegetables and less staple combined with physical activities could contribute to obesity prevention.

Analysis and study of compact inductive power transfer systems for EV charging

Ai, Yongle,Hu, Xiaoqi,Li, Xing,Zhang, Xin The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.5

The double-sided LCC topology provides an efficient compensation method for electric vehicle (EV) wireless charging systems. However, the existence of two compensation coils results in an electric vehicle wireless charging device with a large volume, high power consumption, and low efficiency. To solve these problems, this paper proposes a wireless charging structure in which the compensation coils are separately integrated into the transmitting and receiving coils. First, the number of turns of the transmitting coil is optimized to maximize the coupling coefficient of the transmitting coil. Secondly, to minimize the redundant coupling effect, the relative placement of the compensation coils is studied. Based on the proposed coil integration method, it is possible to ignore the redundant coupling between the compensation coils and the transmitting and receiving coils. Then, the Ansys Maxwell and Ansys Twin Builder are used to build a joint simulation circuit to construct the proposed wireless charging system. Simulation and experimental results show that the system output power is 3.09 kW with a gap of 150 mm, and that the transmission efficiency is 95.49%. In addition, the integrated solution has a high transmission efficiency in the presence of front-to-back misalignment and vertical misalignment of electric vehicles.