Neutronics analysis for MSR cell with different fuel salt channel geometries

The neutronic properties of molten salt reactors (MSRs) differ from those of traditional solid fuel reactors owing to their nuclear fuel particularity. Based on...     

Effect of the process parameters on the three-dimensional shape of molten pool during full-penetration laser welding process

Slow tool servo (STS) turning is superior in machining precision and in complicated surface. However, STS turning is a complex process in which many variables can affect the desired results. This paper focuses on surface roughness prediction in lenses STS turning. An exponential model, based on the five main cutting parameters including tool nose radius, feed rate, depth of cut, C-axis speed, and discretization angle, for surface roughness prediction of lenses is developed by means of orthogonal experiment regression analysis. Meanwhile, a prediction model of surface roughness based on least squares support vector machines (LS-SVM) with radial basis function is constructed. Orthogonal experiment swatches are studied, and chaotic particle swarm optimization and leave-one-out cross-validation are applied to determine the model parameters. The comparison of LS-SVM model and exponential model is also carried out. Predictive LS-SVM model is found to be capable of better predictions for surface roughness and has absolute fraction of variance R² of 0.99887, the mean absolute percent error e_M of 8.96 %, and the root mean square error e_R of 10.68 %. The experimental results and prediction of LS-SVM model show that effects of tool nose radius and feed rate are more significant than that of depth of cut on surface roughness of lenses turning.     

Application of Artificial Fish Swarm Algorithm for Synchronous Selection of Wavelengths and Spectral Pretreatment Methods in Spectrometric Analysis of Beef Adulteration

In this paper, we proposed artificial fish swarm algorithm (AF) for synchronous selection of wavelengths and pretreatment methods during quantification of beef adulteration with spoiled beef based on the analysis of ultraviolet (UV), visible and near-infrared (Vis-NIR), and UV-Vis-NIR spectra. The best partial least squares regression model was obtained when the wavelength-then-pretreatment scheme was adopted in the Vis-NIR range where 11 wavelengths were utilized to produce an RPD value of 2.68. The coefficients of determination R² and root mean squared errors of the model were 0.91 and 0.08 as well as 0.87 and 0.11 for calibration and prediction, respectively. It was demonstrated that AF was a useful tool for model optimization as compared with genetic algorithm. Moreover, the sequence for selecting wavelengths and spectral pretreatment methods had great influence in model performance and could be decided by try-out approach since the performance due to selection sequence was sensitive to spectral range and optimization algorithm employed. Nevertheless, wavelength-then-pretreatment scheme was preferred due to simpler model structure and reduced computation loads. It was shown that Vis-NIR spectroscopy was feasible in quantifying beef adulteration, and AF was an advance method for optimizing model performance. Moreover, AF could be expended in more studies for optimizing food quality and safety analysis.     

Neutronics physics analysis of a large fluoride-salt-cooled solid-fuel fast reactor with Th-based fuel

A synchrotron radiation source called TURKAY is proposed as a sub-project of the Turkish Accelerator Center Project. The storage ring of TURKAY is a low emittance synchrotron and the radiation ranges between 0.01 and 60 keV can be generated from the insertion devices and bending magnets placed on it. The injector system of the facility will mainly consist of a 150 MeV linac and full energy booster. In this study, we present design considerations and beam dynamics studies of the pre-injector linac and booster ring for TURKAY.     

基于电子鼻技术对不同类型洋葱提取液的识别

洋葱提取液作为新型的生物果蔬保鲜剂,因天然、安全等特点受到消费者信赖。然而不同类型洋葱提取液对果蔬的保鲜效果并不相同,因此对不同类型洋葱提取液的快速识别是有实践意义的。本试验以云南、甘肃、安徽、四川、山东、江苏的紫皮洋葱,甘肃、吉林、云南的黄皮洋葱和新疆的白皮洋葱为试验对象,测定植物学性状后提取洋葱的提取液,运用电子鼻检测分析提取液的挥发性物质,采用费舍尔判别(Fisher判别)和反向传播神经网络(back propagation neural network, BPNN)建立预测模型。结果表明：电子鼻的10个传感器对不同类型的洋葱提取液的响应值有显著性差异(P < 0.05),Fisher判别模型和BPNN模型均可有效的识别不同类型的洋葱提取液,其中BPNN识别的正确率比Fisher判别高。因此,电子鼻技术结合BPNN更适合不同类型洋葱提取液的识别。     

Two New Dy(III) and Cu(II) Coordination Polymers: Crystal Structures and Anti-liver Cancer Activity

Two new three-dimensional coordination polymers (H₂NMe₂)[Dy₄(µ₃?OH)₄(NMF)₃(H₂O)(L₁)₃](H₂O)₂ (1, NMF?=?N-methylformamide, H₃L₁?=?3,5-bis(4-(1H-tetrazol-5-yl)phenoxy)benzoic acid) and [Cu(L₂)₂(H₂O)](H₂O)₂ (2, H₂L₂?=?4-(4-pyridyl)-isophthalic acid) have been successfully prepared using two N,O-mixed donor organic ligands. The structures of these complexes have been successfully determined by single crystal X-ray diffraction. In addition, in vitro antitumor activity of compounds 1 and 2 on four human liver cancer cells (SMMC7721, Bel-7402, MHCC97 and HCCLM3) was further determined and the results show that the two compounds showed promising activity.     

Research on the effect of the heavy nuclei amount on the temperature reactivity coefficient in a small modular molten salt reactor

Small modular thorium-based graphite-moderated molten salt reactors(sm TMSRs), which combine the advantages of small modular reactors and molten salt reactors, are regarded as a wise development path to speed deployment time. In a sm TMSR, low enriched uranium and thorium fuels are used in once-through mode, which makes a marked difference in their neutronic properties compared with the case when a conventional molten salt breeder reactor is used. This study investigated the temperature reactivity coefficient(TRC) in a sm TMSR, which is mainly affected by the molten salt volume fraction(VF) and the heavy nuclei concentration in the fuel salt(HN). The fourfactor formula method and the reaction rate method were used to indicate the reasons for the TRC change, including the fuel density effect, the fuel Doppler effect, and the graphite thermal scattering effect. The results indicate that only the fuel density has a positive effect on the TRC in the undermoderated region. Thermal scattering from both salt and graphite has a significant negative influence on the TRC in the overmoderated region. The maximal effective multiplication factor, which shows the highest fuel utilization, is located at 10% VF and 12 mol% HN and is still located in the negative TRC region. In addition, on increasing the heavy nuclei amount from 2 mol% HN to12 mol% HN(VF = 10%), the total TRC undergoes an obvious change from-11 to-3 pcm/K, which implies that the change in the HN caused by the fuel feed online should be small to avoid potential trouble in the reactivity control scheme.     

大石头露天煤矿高温火区爆破技术应用

分析了高温火区产生的原因,论述了影响高温火区爆破实施的因素,进行了炮孔降温试验及炸药抗高温试验,最终应用于生产爆破,并制定严格的施工规范,成功地实现了高温火区爆破,取得了良好的爆破效果,达到了预期目标。     

Differential Expression of Copper-Zinc Superoxide Dismutase Gene of Polygonum sibiricum Leaves, Stems and Underground Stems, Subjected to High-Salt Stress

In aerobic organisms, protection against oxidative damage involves the combined action of highly specialized antioxidant enzymes, such as copper-zinc superoxide dismutase. In this work, a cDNA clone which encodes a copper-zinc superoxide dismutase gene, named PS-CuZnSOD, has been identified from P. sibiricum Laxm. by the rapid amplification of cDNA ends method (RACE). Analysis of the nucleotide sequence reveals that the PS-CuZnSOD gene cDNA clone consists of 669 bp, containing 87 bp in the 5' untranslated region; 459 bp in the open reading frame (ORF) encoding 152 amino acids; and 123 bp in 3' untranslated region. The gene accession nucleotide sequence number in GenBank is GQ472846. Sequence analysis indicates that the protein, like most plant superoxide dismutases (SOD), includes two conserved ecCuZnSOD signatures that are from the amino acids 43 to 51, and from the amino acids 137 to 148, and it has a signal peptide extension in the front of the N-terminus (1-16 aa). Expression analysis by real-time quantitative PCR reveals that the PS-CuZnSOD gene is expressed in leaves, stems and underground stems. PS-CuZnSOD gene expression can be induced by 3% NaHCO(3). The different mRNA levels' expression of PS-CuZnSOD show the gene's different expression modes in leaves, stems and underground stems under the salinity-alkalinity stress.