重写艺术史:从驱逐西方中心主义“话语幽灵”开始

作为一门学科,“艺术史”首先产生于欧洲,其艺术史观念与写作范式一直存在着根深蒂固的“西方中心主义”色彩。随着西方学术话语的全球化扩张,西方中心主义作为“艺术史书写的话语幽灵”一直或明或暗地支配着世界各国的艺术史书写。无论是“艺术史”“欧洲艺术史”“世界艺术史”还是“全球艺术史”,艺术史书写术语的翻新固然体现了世界各国艺术史学者对“人类艺术通史”书写的憧憬与努力,但并没有改变现有艺术史书写作为西方中心主义话语实践的客观事实。从“不完整的艺术史”“不平等的艺术史”到“不真实的艺术史”,西方中心主义话语幽灵让东方艺术反复辗转于“缺席的东方”“替补的东方”和“易容的东方”三种大同小异的失语状态。要完成世界艺术史的重写与重构,必须从驱逐西方中心主义“话语幽灵”开始。

核保障用探测器的现状与发展

国际原子能机构(IAEA)建立了比较完整的核保障体系并不断加以完善,以确保有能力监督原子能技术的和平利用,以及保障相关核技术不被应用于军事用途。本文对IAEA核保障体系的建立和发展进行了描述。核保障技术的应用与发展依赖于探测技术的进步,国内在核保障技术方面做了大量的研究,基于各种探测需求开发了不同探测装置,如针对γ射线、X射线、中子的辐射探测器,针对衰变产生热量的量热计,针对不同质量数进行区分的质谱仪。对IAEA核保障设备的发展趋势进行了分析,提出了一些未来可以应用的探测器或探测技术。

1例梅花鹿狂犬病的病理学诊断及其病原遗传进化分析

为了探明1例梅花鹿病例的死亡原因,本试验通过组织病理学检查、直接免疫荧光法和免疫组织化学检测对其进行诊断,通过反转录聚合酶链反应(RT-PCR)扩增狂犬病病毒(RABV)核蛋白(N)和糖蛋白(G)基因序列,测序后进行同源性、分子进化和系统发育关系分析。结果显示,患病梅花鹿临床表现出狂暴型神经症状。组织病理学表现为典型的非化脓性脑炎,在大脑、小脑、脑干、脊髓和海马等部位的神经细胞胞浆内均有大小不等、圆形或椭圆形的嗜酸性RABV包涵体。采用直接免疫荧光法和免疫组织化学法均在小脑组织中检测到大量特异性的RABV阳性信号。基因测序和分析结果显示,分离毒株N和G基因分别长1424和1675 bp,均与2015年呼和浩特牛源毒株Rabies virus isolate CNM1101C(KC193267)核苷酸同源性最高,分别为99.5%和99.3%。分离毒株N和G基因与从河南、甘肃、湖北、福建和山东等省分离的毒株位于同一分支,属于Asian谱系。结果表明,该梅花鹿感染狂犬病,RABV分离毒株属于中国地区流行的Asian谱系,与国内流行毒株起源于共同的祖先。

时间投影室原理及其应用

时间投影室是一种广泛应用于大型物理实验的粒子鉴别探测器,它通过粒子径迹产生电离电子的漂移时间和漂移方向的投影位置确定径迹三维坐标,具备较好的能量分辨和很高的位置分辨能力。自时间投影室被发明以来,已广泛应用于国外的大科学实验装置上,在对撞机和固定靶实验等方面均发挥了很大的作用。虽然国内的科研机构在早期对时间投影室进行过一些初步研究,但由于技术的限制并没有展开过很多应用。近十年间,伴随着锦屏地下实验室的PandaX-Ⅲ实验的开展、东莞中国散裂中子源等一批科研装置的落地、环形正负电子对撞机的概念设计完成,时间投影室作为主径迹探测器在这些实验中承担了很大一部分工作,并已进行了更多的研发和使用。现阶段有必要对时间投影室在国内外的具体应用与发展进行梳理,本文先梳理出时间投影室的发展历史、工作原理和现状以及时间投影室上核心读出探测器的发展,然后介绍时间投影室在国外大科学实验装置上的应用和最新进展,最后给出时间投影室在国内科研项目上的应用。以此为时间投影室下一步的研发与应用奠定基础。

应用于时间投影室的光刻一体化微结构探测器性能研究

时间投影室(Time Projection Chamber,TPC)可以同时测量时间和位置信息,光刻一体化微结构探测器作为其读出探测器具有抗干扰性强、均匀性好、透过率高的特性。为了寻找探测器最佳的工作条件,使用55Fe豁免源测试了实验室研制的流气型光刻一体化微结构探测器在不同Ar和CO_(2)比例下的增益、能量分辨率以及在最优气体比例下的均匀性。根据测试结果,探测器在85%Ar和15%CO_(2)混合气体下增益达到最大,超过104,增益均匀性为3.26%,达到目前国际上光刻微结构探测器同等水平。对雪崩区厚度分别为100μm、160μm和220μm的3种光刻一体化微结构探测器增益及其均匀性进行比较,雪崩区厚度为160μm的探测器是更优的选择。研制了密闭型微结构探测器,通过测试证明,可以在常温常压下正常工作21天以上。闭气模式下探测器的增益与温度呈负相关,与流气模式下相反,两种模式下的能量分辨在短期内都不受小范围温度变化影响。

Predicting dynamic compressive strength of frozen-thawed rocks by characteristic impedance and data-driven methods

In cold regions,the dynamic compressive strength(DCS)of rock damaged by freeze-thaw weathering significantly influences the stability of rock engineering.Nevertheless,testing the dynamic strength under freeze-thaw weathering conditions is often both time-consuming and expensive.Therefore,this study considers the effect of characteristic impedance on DCS and aims to quickly determine the DCS of frozen-thawed rocks through the application of machine-learning techniques.Initially,a database of DCS for frozen-thawed rocks,comprising 216 rock specimens,was compiled.Three external load parameters(freeze-thaw cycle number,confining pressure,and impact pressure)and two rock parameters(characteristic impedance and porosity)were selected as input variables,with DCS as the predicted target.This research optimized the kernel scale,penalty factor,and insensitive loss coefficient of the support vector regression(SVR)model using five swarm intelligent optimization algorithms,leading to the development of five hybrid models.In addition,a statistical DCS prediction equation using multiple linear regression techniques was developed.The performance of the prediction models was comprehensively evaluated using two error indexes and two trend indexes.A sensitivity analysis based on the cosine amplitude method has also been conducted.The results demonstrate that the proposed hybrid SVR-based models consistently provided accurate DCS predictions.Among these models,the SVR model optimized with the chameleon swarm algorithm exhibited the best performance,with metrics indicating its effectiveness,including root mean square error(RMSE)﹦3.9675,mean absolute error(MAE)﹦2.9673,coefficient of determination(R^(2))﹦0.98631,and variance accounted for(VAF)﹦98.634.This suggests that the chameleon swarm algorithm yielded the most optimal results for enhancing SVR models.Notably,impact pressure and characteristic impedance emerged as the two most influential parameters in DCS prediction.This research is anticipated to serve as a reliable reference for estimating the DCS of rocks subjected to freeze-thaw weathering.

AMicroseismic Signal Denoising Algorithm Combining VMD and Wavelet Threshold Denoising Optimized by BWOA

The denoising of microseismic signals is a prerequisite for subsequent analysis and research.In this research,a new microseismic signal denoising algorithm called the Black Widow Optimization Algorithm(BWOA)optimized VariationalMode Decomposition(VMD)jointWavelet Threshold Denoising(WTD)algorithm(BVW)is proposed.The BVW algorithm integrates VMD and WTD,both of which are optimized by BWOA.Specifically,this algorithm utilizes VMD to decompose the microseismic signal to be denoised into several Band-Limited IntrinsicMode Functions(BLIMFs).Subsequently,these BLIMFs whose correlation coefficients with the microseismic signal to be denoised are higher than a threshold are selected as the effective mode functions,and the effective mode functions are denoised using WTD to filter out the residual low-and intermediate-frequency noise.Finally,the denoised microseismic signal is obtained through reconstruction.The ideal values of VMD parameters and WTD parameters are acquired by searching with BWOA to achieve the best VMD decomposition performance and solve the problem of relying on experience and requiring a large workload in the application of the WTD algorithm.The outcomes of simulated experiments indicate that this algorithm is capable of achieving good denoising performance under noise of different intensities,and the denoising performance is significantly better than the commonly used VMD and Empirical Mode Decomposition(EMD)algorithms.The BVW algorithm is more efficient in filtering noise,the waveform after denoising is smoother,the amplitude of the waveform is the closest to the original signal,and the signal-to-noise ratio(SNR)and the root mean square error after denoising are more satisfying.The case based on Fankou Lead-Zinc Mine shows that for microseismic signals with different intensities of noise monitored on-site,compared with VMD and EMD,the BVW algorithm ismore efficient in filtering noise,and the SNR after denoising is higher.

Numerical analysis for the free-boundary current reversal equilibrium in the AC plasma current operation in a tokamak

In recent decades, tokamak discharges with zero total toroidal current have been reported in tokamak experiments, and this is one of the key problems in alternating current(AC) operations.An efficient free-boundary equilibrium code is developed to investigate such advanced tokamak discharges with current reversal equilibrium configuration. The calculation results show that the reversal current equilibrium can maintain finite pressure and also has considerable effects on the position of the X-point and the magnetic separatrix shape, and hence also on the position of the strike point on the divertor plates, which is extremely useful for magnetic design, MHD stability analysis, and experimental data analysis etc. for the AC plasma current operation on tokamaks.

Gut-targeted therapies for type 2 diabetes mellitus: A review

Type 2 diabetes mellitus(T2DM)is a chronic metabolic disorder characterized by hyperglycemia and insulin resistance.The global prevalence of T2DM has reached epidemic proportions,affecting approximately 463 million adults worldwide in 2019.Current treatments for T2DM include lifestyle modifications,oral antidiabetic agents,and insulin therapy.However,these therapies may carry side effects and fail to achieve optimal glycemic control in some patients.Therefore,there is a growing interest in the role of gut microbiota and more gut-targeted therapies in the management of T2DM.The gut microbiota,which refers to the community of microorganisms that inhabit the human gut,has been shown to play a crucial role in the regulation of glucose metabolism and insulin sensitivity.Alterations in gut microbiota composition and diversity have been observed in T2DM patients,with a reduction in beneficial bacteria and an increase in pathogenic bacteria.This dysbiosis may contribute to the pathogenesis of the disease by promoting inflammation and impairing gut barrier function.Several gut-targeted therapies have been developed to modulate the gut microbiota and improve glycemic control in T2DM.One potential approach is the use of probio-tics,which are live microorganisms that confer health benefits to the host when administered in adequate amounts.Several randomized controlled trials have demonstrated that certain probiotics,such as Lactobacillus and Bifidobacterium species,can improve glycemic control and insulin sensitivity in T2DM patients.Mechanisms may include the production of short-chain fatty acids,the improvement of gut barrier function,and the reduction of inflammation.Another gut-targeted therapy is fecal microbiota transplantation(FMT),which involves the transfer of fecal material from a healthy donor to a recipient.FMT has been used successfully in the treatment of Clostridioides difficile infection and is now being investigated as a potential therapy for T2DM.A recent randomized controlled trial showed that FMT from lean donors improved glucose metabolism and insulin sensitivity in T2DM patients with obesity.However,FMT carries potential risks,including transmission of infectious agents and alterations in the recipient's gut microbiota that may be undesirable.In addition to probiotics and FMT,other gut-targeted therapies are being investigated for the management of T2DM,such as prebiotics,synbiotics,and postbiotics.Prebiotics are dietary fibers that promote the growth of beneficial gut bacteria,while synbiotics combine probiotics and prebiotics.Postbiotics refer to the metabolic products of probiotics that may have beneficial effects on the host.The NIH SPARC program,or the Stimulating Peripheral Activity to Relieve Conditions,is a research initiative aimed at developing new therapies for a variety of health conditions,including T2DM.The SPARC program focuses on using electrical stimulation to activate peripheral nerves and organs,in order to regulate glucose levels in the body.The goal of this approach is to develop targeted,non-invasive therapies that can help patients better manage their diabetes.One promising area of research within the SPARC program is the use of electrical stimulation to activate the vagus nerve,which plays an important role in regulating glucose metabolism.Studies have shown that vagus nerve stimulation can improve insulin sensitivity and lower blood glucose levels in patients with T2DM.Gut-targeted therapies,such as probiotics and FMT,have shown potential for improving glycemic control and insulin sensitivity in T2DM patients.However,further research is needed to determine the optimal dose,duration,and safety of these therapies.

舔砖产品的成分及其在反刍动物生产中的应用

舔砖是将反刍动物日常所需的营养物质(矿物质元素、维生素等)经科学合理配方加工而成的一种块状饲料,具有提高机体抗氧化水平、免疫能力、干物质采食量、饲料消化率和繁殖性能等生物活性功能。目前,舔砖已经广泛应用于反刍动物生产中,以改善反刍动物机体的健康状况。文章综述了舔砖的种类成分、原料配方、加工工艺以及其对反刍动物生长性能、生产性能和抗氧化水平的影响,以期为舔砖产品在反刍动物生产中的应用提供参考。

Forced Inspiratory Flow Volume Curve in Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Objective: Obstructive sleep apnea-hypopnea syndrome (OSA) is a disease of obstructive apnea or hypopnea caused by a repeated partial or complete collapse of the upper airway during sleep. The inspiratory part of the flow-volume curve (F-V curve) can be used as an auxiliary means to evaluate upper airway obstruction in adults. This study is to evaluate the ability of the F-V curve to predict the OSA and explore inspiratory indicators related to airway obstruction during sleep. Methods: There were 332 patients included in this cross-sectional study, who were accompanied by snoring, daytime sleepiness and other symptoms, with suspicion of OSA. According to the nocturnal polysomnography, the subjects were distributed into mild to moderate OSA group, severe OSA group and non-OSA group. A pulmonary function test was used to collect the subjects’ spirometry and F-V curves. Results: There was no significant difference in a variety of indices derived from the F-V curve between OSA and normal subjects, including 25% inspiratory flow rate, middle inspiratory flow rate, 75% inspiratory flow rate, peak flow rate, and forced inspiratory flow rate in the first second. The pulmonary function parameters were significantly correlated with the weight, age and sex of the subjects. Conclusion: These findings suggest that the inspiratory curve of pulmonary function cannot evaluate the upper airway abnormalities in patients with obstructive apnea-hypopnea syndrome.

基于Bulk MicroMegas探测器的高能中子束空间分布测量

为验证中国原子能科学研究院(CIAE)自研的100 MeV回旋加速器中的高能中子束是否符合设计要求,利用自研的Bulk MicroMegas微结构气体探测器对该加速器中子场的空间分布进行了首次试验测量。首先通过模拟计算得到不同厚度聚乙烯(PE)转化膜对不同能量高能中子的转化效率、反冲质子的动能谱与角通量谱、反冲质子在Bulk MicroMegas气体探测器内的沉积能量谱以及中子与探测器结构物质反应产物占比等;然后利用Bulk MicroMegas探测器测量该回旋加速器产生的高能中子场在不同能量和距离处28个点位的中子通量分布,并根据通量分布计算中子束斑半径。结果表明,Bulk MicroMegas微结构气体探测器可以实现对高能中子场束斑边界成像,中子通量随束斑半径的变化关系符合常见束斑边界拟合函数;束斑半径测量结果与模拟计算结果接近。

一例羊驼肺炎型巴氏杆菌病的诊断

2021年8月27日内蒙古自治区大青山野生动物园1只成年雌性羊驼突然发病,口鼻流出少量泡沫样液体,呼吸困难,体温高达41℃,于发病1 d后死亡。死亡羊驼尸体角弓反张,剖检可见浆液纤维素性胸膜炎,胸腔积有大量淡黄色透明胸水,肺胸膜和胸壁胸膜表面附着较多丝网状、片状黄白色的纤维素性渗出物;肺尖叶、心叶和副叶严重实变,表面呈暗红色,肺小叶间质轻度增宽,肺脏切面呈现红白相间的大理石样纹理;其他器官组织表现以出血斑点为特征的败血症变化。特征性病理组织学变化为典型的纤维素性肺炎、出血性淋巴结炎。通过细菌的分离培养,在血琼脂培养基上生长出较多的银白色圆形小菌落,革兰氏染色可见单一、两极浓染的革兰氏阴性小杆菌,与巴氏杆菌的形态一致。分离菌株16S rRNA基因PCR扩增获得大小为1414 bp的目的片段,与GenBank中的多杀性巴氏杆菌败血亚种(Pasteurella multocida subsp.septica strain CCUG 17977,GenBank登录号为AF294411)核苷酸相似性最高,为90.6%。说明该羊驼感染了巴氏杆菌。

矿物质舔砖对蒙古羊免疫、抗氧化指标及生长性能的影响

试验旨在研究投放不同的矿物质营养舔砖对蒙古羊生长性能、血清矿物质元素含量、血清抗氧化指标和血清免疫指标的影响。选择50只健康的空怀蒙古羊,随机分为5组,分别为Ⅰ组(补饲自主加强配方)、Ⅱ组(补饲高端配方)、Ⅲ组(补饲自主常规配方)、Ⅳ组(补饲市场常规配方)以及对照组,分别测试羊只平均日增重、血清中微量元素及常量元素含量、血清抗氧化指标和血清免疫指标。结果表明:补饲矿物质营养舔砖提高了蒙古羊血清中铁(Fe)、锰(Mn)、钴(Co)、钼(Mo)的含量,Ⅱ组效果最好,改善了蒙古羊矿物质元素营养状况,显著提高了蒙古羊血清中过气化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性及总抗氧化能力(T-AOC),显著提高了血清中免疫球蛋白G(IgG)的含量,显著降低了丙二醛(MDA)含量,有效改善了蒙古羊的抗氧化能力和免疫性能。综合考虑,高端配方矿物舔砖可以满足蒙古羊矿物质补充的要求。

基于监督信息邻域粒距离的属性约简方法

在邻域粗糙集的研究中,主要通过邻域关系来实现信息的粒化。传统的邻域关系容易引起信息的不一致,导致将确定可分的样本划分到边界域里,使得属性约简的结果不理想。将监督信息(标签信息)引入邻域粒,提出了一种新的属性约简方法。该方法利用样本邻域的监督信息构造出监督信息邻域粒距离,并基于此定义近似正域。将原边界域中确定可分的样本划分到正域中,从而更精准地刻画邻域系统的分类能力。实验结果表明,所提出的方法不仅能够有效删除冗余属性,而且还能提高分类性能,证明了在属性约简中考虑监督信息邻域粒距离的可行性和有效性。

探测器开放式场笼电场模拟与优化

开放式场笼广泛应用于多种测量粒子能量和位置的气体探测器,场笼内电场主要受到场笼外部强电场、场笼电极布局、场笼周期性结构破坏3种因素影响,不同因素影响的范围和程度各不相同。通过改变场笼电极与探测器外壳的距离、电极中心距、电极宽度、电极厚度,增加半电极结构、局部镜像电极等方式,可影响上述的一种到多种因素。本文通过计算电场分布及模拟电子的输运过程,评估各参数对电场的影响程度及其局限性,总结各参数选取的原则,为不同实验中探测器场笼的设计提供优化指导。

Evaluation of underground blast-induced ground motions through nearsurface low-velocity geological layers

Surface ground motion produced by underground blasts is significantly influenced by near-surface geological conditions.However,near-surface low-propagation velocity layers were always ignored in past analyses of ground motions due to their thin thickness.With the rising concern about surface ground motions produced by the ascendant scale and frequentness of underground excavation and mining,close attention is gradually paid to ground blast vibrations.Therefore,systemic experiments were conducted and took seven months in an underground mine to clarify the variation of motion from underground rock to surface ground.The attenuation of surface ground peak particle velocities(PPVs)is compared to that in underground rock,and horizontal amplitudes are compared to vertical amplitudes.Differences between bedrock and surface ground vibrations are analyzed to illustrate the site effect of near-surface lower-propagation velocity layers.One-dimensional site response analysis is employed to quantify the influence of different geological profiles on surface ground vibrations.The experimental data and site response analysis allowed the following conclusions:(1)geological site effects mainly produce decreasing dominant frequency(DF)of surface ground vibrations;(2)the site amplification effect of blast vibration needs to be characterized by peak particle displacement(PPD);(3)shear waves(S-waves)begin to dominate and surface Rayleigh waves(R-waves)develop as blast-induced ground vibrations travel upward through rock and lower-velocity layers to the surface.The comparison of response relative displacement to a critical value is best to assess the potential for cracking on surface structures.

使用Xcelium Machine Learning技术加速验证覆盖率收敛

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