ICP-AES法测定低钇混合稀土组分

本文拟定ICP-AES直接测定低钇混合稀土组分的方法,确定了适宜的测定条件。方法准确、快速、简便。样品分析结果与X-荧光光谱法及导数分光光度法相符。各元素测定相对标准偏差为1.4~3.3%。

中医英译历史中文化缺失问题的现象研究

本文先就中医英译历史中文化缺失的现象展开历史性梳理与分析,进而提出对中医英译文化缺失现象的补偿策略,最终得出结论,中医英译过程中,中国文化起着基础性作用,只有充分注重文化的重要性,才能将中医更好地传播到世界。

一种冷热交变环境下太阳帆应力保持方法

针对冷热交变环境导致太阳帆内部应力剧烈变化的问题,基于形状记忆合金(SMA)弹簧提出了太阳帆的张拉方案和薄膜应力保持恒定的方法,该方法利用形状记忆合金在高低温下的刚度非线性特性,有效补偿薄膜和支撑杆之间的间隙变化,以使薄膜内部应力基本保持恒定。针对六边形构型太阳帆开展了数值仿真,首先建立了太阳帆的热分析模型和力学分析模型,获取了高低温工况下的温度场。然后通过热致变形分析得到薄膜与支撑杆在高低温工况下的间隙变化,据此确定形状记忆合金弹簧的参数。最后对太阳帆在高低温工况下的薄膜内部应力进行了验证。

一流本科教育的内涵特征、结构要素与建设路径

开展一流本科教育是新时代国家关照高等教育内涵式发展的新举措。一流本科教育作为一种新主张,呈现出的新特征与新形态有助于高校精准把握学生的发展动向与培养内容。基础性、综合性、创新性与国际性是一流本科教育的主要特征。内生于学校的一流教学文化与理念秩序,和谐共生的一流人才交往与培养模式,具有探索创新精神的一流学习能力以及乐于奉献、朝气蓬勃的一流师资队伍团队是一流本科教育内在的逻辑指向与结构要素。

Numerical and experimental investigation of a new conceptual fluoride salt freeze valve for thorium-based molten salt reactor

To improve the reliability and reduce energy consumption,a conceptual design of a freeze valve is proposed for the thorium-based molten salt reactor(TMSR)concept.Fins were utilized in this new design to enhance heat transfer and realize passive shut-off function,which could not be realized by the previous design.An experimental apparatus using the fluoride salt FLiNaK was constructed to conduct a series of preliminary solidification and melting experiments.In addition,the enthalpy-porosity method of ANSYS■Fluent solver was applied to simulate the solidification process of the salt at a specified operating temperature.Temperature distributions of the fluoride salt,solidification/melting time,and frozen plug effect were analyzed under natural convection heat transfer in an open space.The calculated salt temperatures exhibited good agreement with the experimental values.The results indicated that the range of effective operating temperature is 530-600℃ for the finned freeze valve.In this study,the ideal set operating temperature of the finned freeze valve was chosen as 560℃ to achieve competent performance.Moreover,560℃ is additionally the highest set operating temperature for maintaining excellent cooling performance and sustaining deep-frozen condition of the salt plug.At this set operating temperature,the simulation data indicated that the molten salt in the flat part of the finned freeze valve will completely solidify at 10.5 min.The percentage of solid salt in the flat and lower transitional parts of the valve reaches 29.60% in 30.0 min.Furthermore,the surface temperature of the proposed freeze valve is 11.10% lower compared with that of the TMSR freeze valve at a cooling gas supply of 173 m^3/h.Therefore,the new freeze valve was proven to be capable of reducing the energy consumption and realizing the passive shut-off function.

Hippocampal and thalamic neuronal metabolism in a putative rat model of schizophrenia°

The transcription factor early growth response protein 3 （EGR3） is involved in schizophrenia. We developed a putative rat model of schizophrenia by transfecting lentiviral particles carrying the Egr3 gene into bilateral hippocampal dentate gyrus. We assessed spatial working memory using the Morris water maze test, and neuronal metabolite levels in bilateral hippocampus and thalamus were determined by 3.0 T proton magnetic resonance spectroscopy. Choline content was significantly greater in the hippocampus after transfection, while N-acetylaspartate and the ratio of N-acetylaspartate to creatine/phosphocreatine in the thalamus were lower than in controls. This study is the first to report evaluation of brain metabolites using 3,0 T proton magnetic resonance spectroscopy in rats transfected with Egr3, and reveals metabolic abnormalities in the hippocampus and thalamus in this putative model of schizophrenia.

Study on the effect of thermal deformation on the liquid seal of high-temperature molten salt pump in molten salt reactor

The high-temperature molten salt pump is the core equipment in a molten salt reactor that drives the flow of the molten salt coolant.Rotor stability is key to the continuous and reliable operation of the molten salt pump,and the liquid seal at the wear ring can affect the dynamic characteristics of the rotor system.When the molten salt pump is operated in the hightemperature molten salt medium,thermal deformation of the submerged parts inevitably occurs,changing clearance between the stator and rotor,affecting the leakage and dynamic characteristics of the seal.In this study,the seal leakage,seal dynamic characteristics,and rotor system dynamic characteristics are simulated and analyzed using finite element simulation software based on two cases of considering the effect of seal thermal deformation effect or not.The results show a significant difference in the leakage characteristics and dynamic characteristics of the seal obtained by considering the effect of seal thermal deformation and neglecting the effect of thermal deformation.The leakage flow rate decreases,and the first-order critical speed of the seal-bearing-rotor system decrease after considering the seal’s thermal deformation.

Numerical study on rotordynamic coefficients of the seal of molten salt pump

Molten salt pump is applied to pump high-temperature molten salt as the primary coolant of a molten salt reactor.The pump,generally a vertical rotor system,suffers from radial force generated by the liquid seal component,and the rotordynamic characteristics of the pump are affected considerably.In this paper,the rotordynamic coefficients of the tooth-on-stator liquid seal in molten salt pump are studied.The flow in the seal region is simulated using computational fluid dynamics technique.Parameters of the inlet loss and the pre-swirl at the inlet region of the seal are calculated.The coefficients of resistance and the wall parameters are obtained from the simulation results by data fitting method.The rotordynamic coefficients are analyzed based on the bulk-flow model of liquid seal.The rotordynamic characteristics,with and without the liquid seal,of the objective molten salt pump are inspected.The first critical speed of the rotor is found to increase.Harmonic analysis shows that the pump,being sensitive to unbalance force though,can operate safely under its design specifications.

Opportunistic Relaying Schemes for Amplify and Forward Bidirectional Relay Channels with Multi antenna Sources

We consider a two-way relay network where the Amplify-and-Forward (AF) protocol is adopted by all relays in this paper.The network consists of two multi-antenna source nodes and multiple distributed single-antenna relays.Two opportunistic relaying schemes are proposed to efficiently utilize the antennas of the source nodes and the relay nodes.In the first scheme,the best relay is selected out by a max-min-max criterion before transmitting.After that,at each source,only the antenna with the largest channel gain between itself and the best relay is activated to transmit and receive signals with full power.In the second scheme,assisted by the best relay which is selected by the typical max-min criterion,both source nodes use all their antennas to exchange data,and match filter beamforming techniques are employed at both source nodes.Further analyses show that all schemes can achieve the full diversity order,and the conclusions are not only mathematically demonstrated but numerically illustrated.System performance comparisons are carried out by numerical methods in terms of rate sum and outage probability,respectively.The beamforming assisted scheme can be found to be superior to the antenna selection scheme when accurate Channel State Information (CSI) is available at the transmitters.Otherwise,the latter is very suitable.

Microphysical characteristics of precipitating cumulus cloud based on airborne Ka-band cloud radar and droplet measurements

Based on cloud-probe data and airborne Ka-band cloud radar data collected in Baoding on 5 August 2018,the microphysical structural characteristics of cumulus(Cu)cloud at the precipitation stage were investigated.The cloud droplets in the Cu cloud were found to be significantly larger than those in stratiform(STF)cloud.In the Cu cloud,most cloud particles were between 7 and 10μm in diameter,while in the STF cloud the majority of cloud particles grew no larger than 2μm.The sensitivity of cloud properties to aerosols varied with height.The cloud droplet effective radius showed a negative relationship with the aerosol number concentration(Na)in the cloud planetary boundary layer(PBL)and upper layer above the PBL.However,the cloud droplet concentration(Nc)varied little with decreased Na in the high liquid water content region above 1500 m.High Na values of between 300 and 1853 cm-3 were found in the PBL,and the maximum Na was sampled near the surface in August in the Hebei region,which was lower than that in autumn and winter.High radar reflectivity corresponded to large FCDP(fast cloud droplet probe)particle concentrations and small aerosol particle concentrations,and vice versa for low radar reflectivity.Strong updrafts in the Cu cloud increased the peak radius and Nc,and broadened cloud droplet spectrum;lower air temperature was favorable for particle condensational growth and produced larger droplets.

Evaluating the performance of a WRF microphysics ensemble through comparisons with aircraft observations

observation data obtained in a mesoscale convective system are compared to Weather Research and Forecasting(WRF)model simulations using four microphysics schemes(Morrison,WSM6,P3,SBM)with different complexities.The main purpose of this paper is to assess the performance of the microphysics ensemble in terms of cloud microphysical properties.Results show that although the vertical distributions of liquid water content(LWC)and ice water content(IWC)simulated by the four members are quite different in the convective cloud region,they are relatively uniform in the stratiform cloud region.Overall,the results of the Morrison scheme are very similar to the ensemble average,and both of them are closer to the observations compared to the other schemes.Besides,the authors also note that all members still overpredict the LWC by a factor of 2–8 in some regions,resulting in large deviation between the observation and ensemble average.

空气污染英语新闻报道翻译校正策略研究

对空气污染英语新闻报道翻译的校正策略进行研究,通过功能对等理论对报道的译文进行校正,在翻译空气污染英语新闻报道的题目时,要考虑读者的感受,并结合国外英语文化的风格,使报道的译文与报道的原文对等。遵循奈达功能对等理论的四个原则。分析了直译和意译两种翻译方法,介绍了增词补译、减词省译和修辞差异处理三个意译的方式,结合奈达功能对等理论的四个原则对英文和中文之间的差异进行处理。并对新闻报道内容中的句式和新词进行处理和校正,完成空气污染英语新闻报道翻译的校正。

Current status of stem cell therapy for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive memory loss and cognitive dysfunction. Currently there is no effective treatment. Given the depth of current stem cell research, researchers have attempted to compensate for neuronal loss in the brains of patients with Alzheimer's disease using stem cell technology. This article will review the pathogenesis of AD, the latest advances in stem cell therapy, and the challenges and prospects of its development.

不同药物联合血液净化治疗感染性休克合并ARDS患者的效果比较

目的比较不同药物联合血液净化治疗感染性休克合并急性呼吸窘迫综合征(ARDS)患者的效果。方法选取我院收诊的97例行血液净化的感染性休克合并ARDS患者,以信封法将其分为观察组(n=51,联用乌司他丁)与对照组(n=46,联用注射用甲泼尼龙琥珀酸钠)。比较两组的治疗效果。结果治疗后48、72 h,两组的氧合指数(OI)均升高,降钙素原(PCT)、C反应蛋白(CRP)水平均降低,且观察组的OI高于对照组(P<0.05);两组的PCT、CRP水平比较,差异无统计学意义(P>0.05)。治疗后48、72 h,观察组的液体输入量少于对照组,尿量多于对照组(P<0.05)。治疗后48、72 h,两组的急性生理学及慢性健康状况评分系统Ⅱ(APACHEⅡ)、序贯器官衰竭(SOFA)评分均降低,且观察组低于对照组(P<0.05)。观察组的机械通气、住院时间均短于对照组(P<0.05)。观察组的不良反应总发生率显著低于对照组(P<0.05)。结论乌司他丁、注射用甲泼尼龙琥珀酸钠联合血液净化均能有效控制感染性休克合并ARDS患者的病情,但乌司他丁具有更强的肺部保护作用,能更有效地改善OI,安全性更好。

板坯连铸结晶器三维流场模拟仿真研究

采用Fluent数值模拟软件计算了稳态三维板坯结晶器流场。模拟得到流股到达窄面后沿上下分流形成两个回流区。分析了上液面流速、钢液冲击点、上下涡心位置对流场的影响。模拟计算了不同拉速、铸坯宽度、水口浸入深度、水口测孔倾角下结晶器流场分布,定量分析了流场参数并对参数进行了优化。得出当拉速为1.4 m/min、铸坯宽度为1.2 m、水口浸入深度为180 mm、水口的侧孔倾角为15°时结晶器流场最为合理,铸坯质量能够得到保证。

Waldenstrom's macroglobulinemia associated with Hodgkin's lymphoma:a case report

Waldenstrom＇s macroglobulinemia/lymphoplasmacytic lymphoma （WM/LPL） is a low-grade B-cell non- Hodgkin＇s lymphoma with an indolent clinical course. Higher-grade non-Hodgkin lymphoma （NHL） and therapy- related myelodysplasia/acute leukemia （t-MDS/AML） have been reported in patients with WM/LPL in previous studies. However, only two cases with WM/LPL were reported to develop to Hodgkin lymphoma （HL）. Here, we report the first case of WM/LPL who developed classical HL simultaneously 3 years after initial nucleoside analog-based chemotherapy.

Construction of a lentiviral vector over - expressing BDNF and its transfection into adipose derived stem cell lines in vitro

Objective:To construct a recombinant lentiviral vector that co-express ZsGreen and BDNF and establish an Adipose derived stem cell (ADSC) line with stable BDNF expression down- regulation.Methods: BDNF were designed and inserted into the lentiviral vector p HBLV-CMVIE-Zs Green-Puro. After identification by DNA sequencing, the lentiviral vectors carrying BDNF were packaged in 293 cells. The transfection efficiency was observed under fluorescence microscope;the lentiviral particles were collected to infect mouse ADSCs, and BDNF level were assessed using real-time PCR and Western blotting.Results: DNA sequencing demonstrated successful construction of the BDNF lentivirus vectors. Real- time PCR and Western blotting showed a high level BDNF mRNA and protein.Conclusion: We have successfully established an ADSC model with stable BDNF expression which establish the basis for the potential application of ADSCs-BDNF in the treatment of AD.

Brønsted酸催化萘酚与丙炔醇的环化反应合成苯并色烯

苯并色烯广泛存在于天然产物、生物活性分子和有机功能材料中.报道了在温和条件下,以丙炔醇和β-萘酚为原料合成苯并色烯的策略,并以优秀的收率合成了一系列苯并色烯.该方案具有适用范围广、官能团兼容性好、条件温和等优点,且H2O是唯一副产物.此外,该方法操作简便,克级反应可以维持优秀收率,具有实际应用前景.

Comparative phylogenomics and phylotranscriptomics provide insights into the genetic complexity of nitrogen-fixing root-nodule symbiosis

Plant root-nodule symbiosis(RNS)with mutualistic nitrogen-fixing bacteria is restricted to a single clade of angiosperms,the Nitrogen-Fixing Nodulation Clade(NFNC),and is best understood in the legume family.Nodulating species share many commonalities,explained either by divergence from a common ancestor over 100 million years ago or by convergence following independent origins over that same time period.Regardless,comparative analyses of diverse nodulation syndromes can provide insights into constraints on nodulation—what must be acquired or cannot be lost for a functional symbiosis—and the latitude for Plant Communications Genomic landscape of nodulation variation in the symbiosis.However,much remains to be learned about nodulation,especially outside of legumes.Here,we employed a large-scale phylogenomic analysis across 88 species,complemented by 151 RNA-seq libraries,to elucidate the evolution of RNS.Our phylogenomic analyses further emphasize the uniqueness of the transcription factor NIN as a master regulator of nodulation and identify key muta-tions that affect its function across the NFNC.Comparative transcriptomic assessment revealed nodule-specific upregulated genes across diverse nodulating plants,while also identifying nodule-specific and nitrogen-response genes.Approximately 70%of symbiosis-related genes are highly conserved in the four representative species,whereas defense-related and host-range restriction genes tend to be lineage specific.Our study also identified over 900000 conserved non-coding elements(CNEs),over 300000 of which are unique to sampled NFNC species.NFNC-specific CNEs are enriched with the active H3K9ac mark and are correlated with accessible chromatin regions,thus representing a pool of candidate regula-tory elements for genes involved in RNS.Collectively,our results provide novel insights into the evolution of nodulation and lay a foundation for engineering of RNS traits in agriculturally important crops.

Fermentation of mead using Saccharomyces cerevisiae and Lactobacillus paracasei: Strain growth, aroma components and antioxidant capacity

Positive effects of fermented foods consumption on humans have stimulated lots of research attention.The aim of this study was to determine the effect of Lactobacillus paracasei M-8R on the physicochemical and antioxidant properties of mead during its fermentation.The mixed fermentation mead with Lactobacillus paracasei M-8R had an alcohol content of 17%,higher total polyphenols(107.14 mg GAE/L)and total flavonoids(74.53 mg RE/L)and the highest antioxidant capacity.The control sample(fermented only by yeast)was successive:11.2%,94 mg GAE/L and 68.74 mg RE/L.The most abundant volatile flavor compounds(80 species)were detected in the mead fermented by Saccharomyces Only.Combined with sensory evaluation,the mixed fermentation of Saccharomyces cerevisiae G10 and Lactobacillus paracasei M-8R is considered as the more promising fermentation method for mead production.