ODS MA754合金传热界面接触热阻实验研究

鉴于ODS MA754合金传热界面的接触热阻参数对全固态堆芯空间反应堆系统的热量导出具有重要影响,研发和设计了高温高压接触热阻实验装置,测量了不同温度(20~800℃)、压力(0~80 MPa)、气体氛围(He、CO_(2))以及试件表面粗糙度(1.6、3.2μm)下ODS MA754合金传热界面的接触热阻,并基于测试获得的宽量程数据点,建立了ODS MA754合金的接触热阻数据库。实验结果表明:随着接触面温度和压力的升高,界面接触热阻降低,且热阻降低的速率逐渐减小;相较于表面粗糙度为1.6μm的试件,粗糙度为3.2μm试件表面的界面接触热阻明显偏大,实验得到的定量关系可为工程样件的加工粗糙度要求提供依据;He气氛下的接触热阻远小于CO_(2)气氛,在0.1 MPa、100℃工况下,He气氛接触热阻约为CO_(2)气氛接触热阻的1/4。该研究结果可为空间反应堆的热工设计提供数据参考。

肠道微生物与细菌性肺炎易感性的因果关系:双样本双向孟德尔随机化研究及cML-MA的应用

目的通过孟德尔随机化研究方法探究肠道菌群与细菌性肺炎易感性之间的因果关系。方法使用三种不同的孟德尔随机化分析方法,对211个肠道菌群类群与细菌性肺炎之间的关系进行211次双样本分析,并进行反向孟德尔随机化分析。以随机效应逆方差加权法(IVW)作为主要结果,并采用其他方法作为补充参考。结果柔膜菌纲(OR=1.14,95%CI 1.02~1.27,P=0.02)、放线菌科(OR=1.17,95%CI 1.02~1.35,P=0.03)、放线菌目(OR=1.17,95%CI 1.01~1.35,P=0.03)以及软壁菌门(OR=1.14,95%CI 1.02~1.27,P=0.02)的丰度升高与细菌性肺炎易感性的增加有关;消化球菌科(OR=0.88,95%CI 0.78~0.98,P=0.02)、直肠拟梭菌群(OR=0.85,95%CI 0.75~0.97,P=0.02)和鞘螺菌科UCG001(OR=0.90,95%CI 0.83~0.99,P=0.03)的丰度升高与细菌性肺炎的发病风险降低相关。一系列敏感性分析以及条件孟德尔随机化分析(cML-MA)的结果表示该研究结果可靠。反向孟德尔随机化未发现反向因果关联。结论肠道微生物的丰度升高与细菌性肺炎的易感性增加或降低相关,肠道菌群在细菌性肺炎发病机制中有重要作用,提供了潜在干预措施的新思路。

3D smart mA调控技术对不同BMI患者图像采集时间质量及辐射剂量的影响

目的:分析3D智能管电流(3D smart mA)调控技术对不同体质量指数(BMI)患者图像采集时间、质量及辐射剂量的影响。方法:择取的180例行胸部CT扫描患者选自西安交通大学第一附属医院2021年6月至2022年12月期间所收治,按照BMI将患者分为三组,A组(18.5 kg/m^(2)≤BMI≤23.9kg/m^(2),n=75)、B组(23.9kg/m^(2)0.05);两位医师对肺部不同层面图像质量(IQS)评分进行评价,Kappa一致性非常好(Kappa值=0.768、0.812、0.861);三组肺部不同层面IQS评分对比,差异无统计学意义(P>0.05);三组肺部不同层面CT对比,差异有统计学意义,且随着BMI增加而下降(P<0.05),三组肺部不同层面图像标准差(SD)值对比,差异无统计学意义(P>0.05);三组容积CT剂量指数(CTDIvol)对比,差异无统计学意义(P>0.05);A组DLP、ED均低于B、C组,B组DLP、ED低于C组(P<0.05)。结论:不同BMI患者应用3D smart mA调控技术,在保证图像质量的前提下,可有效降低辐射剂量。

MA-2吸收剂在国能锦界电厂15万t/a碳捕集装置上的应用研究

由中石化南京化工研究院开发的MA系列(用于低分压碳捕集)吸收剂已经在国内近10套万吨级碳捕集示范装置上成功运行。较为详细地讨论了该系列中MA-2吸收剂在国能锦界电厂15万t/a碳捕集装置上的运行情况,在设计进气量条件下,考察了气液比、捕集率等因素对再生能耗的影响并确定了较优值分别为34 m3/m3及95.2%,对应再生能耗最低为2.72 GJ/t。在上述条件下又逐步考察半富液级间冷却、富液分流、贫液MVR等节能工艺对再生能耗的影响并确定较优值,即当富液分流比为5%,级间冷却为40℃,MVR压差为50 kPa时,装置再生能耗最低仅为2.30 GJ/t。考察了不同工况下MA-2吸收剂的逃逸情况为31~59 mg/m3。

Reinforcement Learning-Based MAS Interception in Antagonistic Environments

Dear Editor, As a promising multi-agent systems(MASs) operation, autonomous interception has attracted more and more attentions in these years, where defenders prevent intruders from reaching destinations.So far, most of the relevant methods are applied in ideal environments without agent damages. As a remedy, this letter proposes a more realistic interception method for MASs suffered by damages.

Assessment of molecular markers and marker-assisted selection for drought tolerance in barley(Hordeum vulgare L.)

This review updates the present status of the field of molecular markers and marker-assisted selection(MAS),using the example of drought tolerance in barley.The accuracy of selected quantitative trait loci(QTLs),candidate genes and suggested markers was assessed in the barley genome cv.Morex.Six common strategies are described for molecular marker development,candidate gene identification and verification,and their possible applications in MAS to improve the grain yield and yield components in barley under drought stress.These strategies are based on the following five principles:(1)Molecular markers are designated as genomic‘tags’,and their‘prediction’is strongly dependent on their distance from a candidate gene on genetic or physical maps;(2)plants react differently under favourable and stressful conditions or depending on their stage of development;(3)each candidate gene must be verified by confirming its expression in the relevant conditions,e.g.,drought;(4)the molecular marker identified must be validated for MAS for tolerance to drought stress and improved grain yield;and(5)the small number of molecular markers realized for MAS in breeding,from among the many studies targeting candidate genes,can be explained by the complex nature of drought stress,and multiple stress-responsive genes in each barley genotype that are expressed differentially depending on many other factors.

Agronomic Performance, Stability Analysis and Evaluation of Anthracnose Disease Resistance of Common Bean Lines Derived by Marker-Assisted Backcrossing in Uganda

The present study focused on evaluating the agronomic performance, stability, and anthracnose resistance of common bean lines derived through Marker-Assisted Backcrossing in Uganda. Eight marker-assisted selection (MAS) backcross-derived bush bean lines with red seed types, alongside two checks, were evaluated in a randomized complete block design replicated two times in five locations for three consecutive crop-growing seasons in 2021 and 2022. The study aimed to identify lines with both high stable yields and enhanced resistance to anthracnose disease for potential release and utilization in future bean varietal development in Uganda. Agronomic traits, including days to 50% flowering, days to 90% physiological maturity, seed yield, seed yield components, and anthracnose disease reaction under natural infestation were assessed. The response to anthracnose disease was further assessed using six isolates of Colletotrichum lindemuthianum representing six different races. Results indicated that the agronomic performances of the MAS backcross-derived bush bean lines were statistically comparable to the recurrent parent NABE14. Specifically, six lines exhibited statistically equal to or higher performance than NABE14 in terms of seed yield, total number of seeds and number of pods per plant. The combined analysis of variance for seed yield showed significant (p Co-42 and Co-5 anthracnose resistance genes in the derived line. In conclusion, UGKT-B157-4, identified as the best-performing and stable genotype, demonstrates promise for release and use in future bean varietal development in Uganda, offering a combination of high yields and enhanced anthracnose disease resistance. The study provides valuable insights into the potential of Marker-Assisted Backcrossing in improving common bean varieties in the region.

A low-profile metamaterial absorber with ultrawideband reflectionless and wide-angular stability

An ultrawideband reflectionless metamaterial absorber(MA)is proposed by replacing the metallic ground with the complementary split-ring resonator(CSRR)structure.The proposed MA exhibits-10 d B reflectivity spectrum from 1 GHz to 20 GHz,which maintains more than 90%absorption from 1.5 GHz to20 GHz.Furthermore,it achieves angle stability for TE and TM polarization at oblique incident angles up to 40°and 65°,respectively.To achieve broadband absorption spectrum,we have adopted a single-layer high-impedance surface(HIS)loaded with a double-layer magnetic material(MM)structure.To further realize the RCS reduction into a lower frequency range,we have employed the scattering cancellation technology into the traditional metallic ground.Finally,we have fabricated a sample exhibiting the 10 d B RCS reduction from 1 GHz to 20 GHz with a thickness of 10 mm.Measurement and simulation results confirm that the proposed MA exhibits excellent comprehensive performance,making it suitable for many practical applications.

MA600飞机刹车系统常见故障分析

MA600飞机机轮刹车系统对缩短滑跑距离、地面停放和辅助飞机转弯有着重要的作用,一旦出现故障会延误停场,甚至导致事故发生。该文主要介绍机轮刹车系统的特点,总结出常见故障并对故障原因作出简要分析,为维护人员提供可靠的参考资料,保证飞行教学工作的顺利进行,对飞行安全和出机率有着重要意义。

Experimental aspects of ^(14)N overtone RESPDOR solid-state NMR spectroscopy under MAS beyond 60 kHz

Nitrogen-14(^(14)N)overtone(OT)spectroscopy under fast magic angle spinning(MAS)conditions(>60 kHz)has emerged as a powerful technique for observing correlations and distances between ^(14)N and ^(1)H,owing to the absence of the first-order quadrupolar broadenings.In addition,^(14)N^(OT) allows selective manipulation of ^(14)N nuclei for each site.Despite extensive theoretical and experimental studies,the spin dynamics of ^(14)N^(OT) remains under debate.In this study,we conducted experimental investigations to assess the spin dynamics of ^(14)N^(OT) using the rotational-echo saturation-pulse double-resonance(RESPDOR)sequence,which monitors population transfer induced by a^(14)N^(OT) pulse.The ^(14)N^(OT) spin dynamics is well represented by a model of a two-energy-level system.Unlike spin-1/2,the maximum excitation efficiency of ^(14)N^(OT) coherences of powdered solids,denoted by p,depends on the radiofrequency field(rf-field)strength due to orientation dependence of effective nutation fields even when pulse lengths are optimized.It is also found that the p factor,contributing to the ^(14)N^(OT) spin dynamics,is nearly independent of the B0 field.Consequently,the filtering efficiency of RESPDOR experiments exhibits negligible dependence on B0 when the ^(14)N^(OT) pulse length is optimized.The study also identifies the optimal experimental conditions for ^(14)N^(OT)/^(1)H RESPDOR correlation experiments.

奥司他韦对肺炎幼鼠ACE2/Ang(1-7)/Mas受体轴及肺损伤的影响

目的 研究奥司他韦对肺炎幼鼠ACE2/Ang(1-7)/Mas受体轴、肺损伤及炎症水平的影响。方法 SPF级SD雄性幼鼠50只随机抽取12只作为健康组,剩余38只幼鼠建立流感病毒模型。建模中意外死亡2只,随机数字表法将建模成功的36只幼鼠分为模型组、奥司他韦组及对照组,每组各12只。健康组与模型组幼鼠常规饲养,奥司他韦组幼鼠给予10 mg/kg奥司他韦灌胃,1次/d,持续5 d;对照组幼鼠经尾静脉注射75 mg/mL阿奇霉素,1次/d,持续1周。另取40只SPF级幼鼠建立病毒性肺炎模型后分为激动剂组、抑制剂组、激动剂+奥司他韦组、抑制剂+奥司他韦组,共诊治7 d,1次/d。ELISA检测各组IL-6、IL-8、TNF-α水平。小动物肺功能检测仪检测各组肺功能指标。HE染色观察各组肺炎幼鼠肺组织病理形态。TUNEL检测各组幼鼠肺组织细胞凋亡。免疫印迹检测各组幼鼠ACE2、Ang(1-7)、MasR、ACE、AngⅡ蛋白表达水平。结果 与健康组相比,模型组、奥司他韦组与对照组幼鼠血清中IL-6、IL-8、TNF-α、肺组织细胞凋亡率升高(P<0.05),在经过奥司他韦干预后IL-6、IL-8、TNF-α、肺组织细胞凋亡率均降低(P<0.05)。与健康组相比,模型组FEF50、FEF75、MMF、PEF水平降低(P<0.05),肺系数升高(P<0.05),在经过奥司他韦干预后FEF50、FEF75、MMF、PEF水平升高(P<0.05),肺系数降低(P<0.05)。各组肺组织病理形态对比明显。与健康组相比,模型组、奥司他韦组、对照组、抑制剂组、激动剂组、激动剂+奥司他韦组与抑制剂+奥司他韦组ACE2、Ang(1-7)、MasR水平降低(P<0.05),ACE、AngⅡ水平升高(P<0.05);与模型组相比,奥司他韦组、对照组、激动剂组、激动剂+奥司他韦组ACE2、Ang(1-7)、MasR水平升高(P<0.05),ACE、AngⅡ水平降低(P<0.05),抑制剂组ACE2、Ang(1-7)、MasR水平降低(P<0.05),ACE、AngⅡ水平升高(P<0.05);模型组与抑制剂+奥司他韦组各指标比较差异无统计学意义(P>0.05);与对照组相比,奥司他韦组、激动剂组、激动剂+奥司他韦组ACE2、Ang(1-7)、MasR水平升高(P<0.05),ACE、AngⅡ水平降低(P<0.05);奥司他韦组与激动剂组各指标比较差异无统计学意义(P>0.05);与奥司他韦组相比,激动剂+奥司他韦组ACE2、Ang(1-7)、MasR水平升高(P<0.05),ACE、AngⅡ水平降低(P<0.05)。结论 奥司他韦通过提高ACE2/Ang(1-7)/Mas受体轴水平及降低炎症因子水平,改善肺炎幼鼠肺功能。

Ma-Minda型双向单叶螺旋函数推广类的系数估计

利用Hohlov算子,定义了解析双单叶函数类σ的新子类Ma-Minda型双向单叶螺旋函数类H_(σ)^(μ,a,b,c)(λ,β,φ);利用从属关系,得到了该类中函数的系数a_(2)和a_(3)的有界估计以及Fekete-Szeg?不等式,推广了一些前人研究的结果.

Land Use in Ma'anshan Economic and Technological Development Zone: Based on the Land Survey of Typical Enterprises

This article analyzes the typical enterprise's land use structure,land use efficiency,land use intensity and industrial structure in Ma'anshan Economic and Technological Development Zone. Based on the survey results about the typical enterprises,this article put forth the following recommendations: promoting the economical and intensive land use in the development zone by tapping connotation; enhancing the smart land use in the development zone through optimization of function layout; promoting the industrial chain linkage in the development zone through the establishment of industrial land exit mechanism.

Evaluation of Urban Park Landscape in Ma’anshan Based on Analytic Hierarchy Process(AHP)

In order to further develop the urban park landscape,the representative urban park landscape in Ma’anshan City is first evaluated and analyzed from the aspects of humanistic artistic value,social historical value and user experience value.Afterwards,the weight of each park landscape is judged by analytic hierarchy process(AHP),and it is found that the indexes in the criterion layer successively are user experience value>humanistic artistic value>social historical value;in the factor layer,excellent user experience,universal design,reasonable and perfect public services and layout suitable for urban planning are more important factors,while artistic conception creation has the lowest weight.Finally,based on the results obtained by AHP,the improvement and optimization strategy for urban park landscape in Ma’anshan City is proposed to further strengthen the development of urban parks in Ma’anshan City.

压水堆中环形轴向非均匀MA嬗变棒的中子学性能研究

为提高次锕系核素(Minor Actinides,MA)在压水堆中的嬗变效率,同时利用MA核素展平堆芯轴向功率分布,研究工作以177压水堆堆芯结构作为参考,利用蒙特拉洛程序RMC计算研究环形轴向非均匀MA嬗变棒的中子学性能。嬗变棒为中空的环形结构,嬗变材料为MA与UO2的均匀混合物,其中MA质量份额为1 wt%、3wt%以及5 wt%,MA核素在嬗变棒上沿轴向进行非均匀填充,分别开展了三、五、七段式嬗变棒的中子学性能研究。研究结果发现:(1)该嬗变棒具有优良的嬗变性能,当环形嬗变材料厚度的2 mm时,轴向分5段的环形轴向非均匀嬗变棒的嬗变率最高,可达64.55%;(2)相较于环形轴向均匀嬗变棒,该环形轴向非均匀嬗变棒具有良好的轴向功率展平效果,可将轴向功率峰因子由1.778降低至1.390;(3)压水堆堆芯装载MA嬗变棒后,可显著优化堆芯在高硼浓度下的慢化剂温度反应性效应,使堆芯在1300×10^(-6)的硼浓度下依然具有负的温度效应。

Registration of Rural Collective Land:A Case Study of Ma'anshan City in Anhui Province

Making unified registration of rural collective land and granting legal rights of rural collective and farmer land are necessities for protecting the fundamental interests of farmers,implementing the party's rural policies,and the source of unified real estate registration,and will lay a solid foundation for smooth implementation of registration of real estate. According to requirements of Notice of the General Office of the People's Government of Anhui Province on Implementing the Confirmation and Registration of Ownership of Rural Collective Land,in order to integrate urban and rural development and safeguard the rights and interests of farmers,since January 2010,Ma'anshan Municipal Government has made an overall deployment in the whole city to carry out the confirmation and registration of rural collective land. However,complex property situation of the collective land and the problems of existing registration system have brought about many problems. Through the research and analysis,we came up with recommendations for improving the registration of rural collective land.

Similarity Analysis of Beetle Communities in Jiuzhaigou,Xiaozhaizigou, Caopo, Ma'anshan and Baihe Nature Reserves of Sichuan Province,China

In this study, beetle communities in Jiuzhaigou, Xiaozhaizigou, Caopo, Ma＇anshan and Baihe nature reserves of Sichuan Province were compared and analyzed. F index, G index and G-F index of beetle communities in five nature reserves were analyzed to calculate the similarity coefficient C between these five na- ture reserves. According to the results, beetle communities exhibited high dissimilarity between Jiuzhaigou and Xiaozhaizigou, Caopo and Jiuzhaigou, Caopo and Xiaozhaizigou, Ma＇anshan and Xiaozhaizigou, Ma＇anshan and Jiuzhaigou, Baihe and Xiaozhaizigou, Baihe and Caopo, Baihe and Ma＇anshan; beetle communities exhibited moderate dissimilarity between Ma＇anshan and Caopo, Baihe and Jiuzhaigou.

葶苈大枣泻肺汤通过ACE2-Ang-(1-7)-Mas轴对心梗后心衰模型大鼠心室重构的影响

目的探讨经方葶苈大枣泻肺汤对心肌梗死后心力衰竭模型大鼠心室重构的作用机制。方法应用左冠状动脉前降支结扎术构建心肌梗死后心力衰竭大鼠模型,分8组:假手术组、模型组、A779组(1 mg/kg)、A779(1 mg/kg)+葶苈大枣泻肺汤等效剂量组(0.8 g/kg)、A779(1 mg/kg)+葶苈大枣泻肺汤高剂量组(1.6 g/kg)、葶苈大枣泻肺汤等效剂量组(0.8 g/kg)、葶苈大枣泻肺汤高剂量组(1.6 g/kg)和氯沙坦钾组(10 mg/kg),各组分别给予等体积蒸馏水或者相应的药物,灌胃4周。采用Masson染色法测定大鼠心肌组织中胶原纤维分布;采用碱水解法测定心肌组织羟脯氨酸(Hyp)含量;采用免疫组化法检测心肌组织中Ⅰ型胶原蛋白(COLⅠ)、Ⅲ型胶原蛋白(COLⅢ)的表达水平;采用酶联免疫吸附测定法检测大鼠血清中基质金属蛋白酶2(MMP-2)、MMP-9、金属蛋白酶组织抑制因子1(TIMP-1)、可溶性致瘤性抑制因子2(sST-2)等心肌纤维化相关指标;采用Western blot法检测心肌组织中血管紧张素转换酶2-血管紧张素-(1-7)-Mas[ACE2-Ang-(1-7)-Mas]轴相关蛋白的表达。结果与假手术组比较,模型组、A779组心肌细胞排列紊乱,胶原纤维沉积明显增多,心肌纤维化明显,Hyp含量和MMP-2、MMP-9、sST-2水平显著升高,COLⅠ、COLⅢ阳性表达显著增强,TIMP-1水平和ACE2、Ang-(1-7)、Mas蛋白表达水平显著降低(P<0.05)。与模型组比较,葶苈大枣泻肺汤等效剂量组和高剂量组上述指标均可得到不同程度的改善。与A779组比较,A779+葶苈大枣泻肺汤等效剂量组及A779+高剂量组心肌排列及胶原分布可一定程度地改善,Hyp含量和MMP-2、MMP-9水平降低,COLⅠ、COLⅢ阳性表达显著减少(P<0.05),但Ang-(1-7)和Mas蛋白表达水平未显著升高。结论葶苈大枣泻肺汤可通过提高ACE2-Ang-(1-7)-Mas轴蛋白的表达改善心肌梗死后心力衰竭模型大鼠的心室重构。

海绵共附生真菌Aspergillus giganteus MA 46-5吲哚喹唑啉类生物碱成分

对1株富产吲哚喹唑啉类生物碱(IQAs)的海绵共附生真菌Aspergillus giganteus MA 46-5的IQAs类成分进行了研究。根据IQAs的结构特征,在TLC、LC-MS和GNPS(global natural products social molecular networking)技术的共同指导下,从大米培养基的乙酸乙酯部位分离得到10个IQAs类生物碱。通过NMR、HR-ESI-MS、OR和CD等方法并结合文献比对鉴定其分别为:tryptoquivaline(1)、nortryptoquivaline(2)、deoxytryptoquivaline(3)、deoxynortryptoquivaline(4)、aspertoryadin C(5)、aspertoryadin G(6)、quinadoline A(7)、fiscalin E (8)、quinadoline B(9)和prelapatin B(10)。8和10为首次从Aspergillus属中得到,2、4~7为首次从Aspergillus giganteus中分离得到。

扬子板块、澳大利亚板块、印度板块在新元古代晚期(750~540 Ma)古板块再造:来自古地磁制约

扬子板块在新元古代时期作为Rodinia超大陆的重要组成部分,其位置一直存在争议。为探讨扬子板块在新元古代晚期的位置,综合前人发表过的古地磁数据,利用古地磁研究方法,对扬子板块与澳大利亚板块、印度板块在新元古代晚期的相对位置关系进行研究。根据地层对比、锆石测年等诸多证据,将扬子板块置于印度板块北缘(现今位置)、澳大利亚板块西北缘(现今位置)。基于扬子、印度、澳大利亚运动学特征分析,认为扬子板块在Rodinia超大陆裂解时运动至高纬度地区,750~635 Ma期间,扬子板块处于中高纬度地区,在635 Ma时开始快速向低纬度地区运动。虽然将扬子置于印度北缘,但认为二者并不相连,而是到了570 Ma左右发生碰撞后连接到一起,并一同加入冈瓦纳大陆。