Energy spectrum measurement and dose rate estimation of natural neutrons in Tibet region

In this work, natural neutron spectra at nine sites in Tibet region were measured using a multi-sphere neutron spectrometer. The altitude-dependence of the spectra total fluence rate and ambient dose equivalent rate were analyzed. From the normalized natural neutron spectra at different altitudes, the spectrum fractions for neutrons of greater than 0.1 MeV do not differ obviously, while those of the thermal neutrons differ greatly from each other. The total fluence rate, effective dose rate and the ambient dose equivalent rate varied with the altitude according to an exponential law.

THE CHARACTERISTICS AND VERTICAL ZONE SPECTRUM OF NATURAL DISASTERS IN THE TIANSHAN MOUNTAINS, XINJIANG

With the mountain elevation increasing and climate condition change, the laws of formation, distribution and development of the various natural disasters, which are caused by the climate, change correspondingly and the vertical zone spectrum of special mountain natural disasters is formed. This research is helpful to finding effective measures to prevent disasters, avoiding and reducing the harm of natural disasters to industrial and agricultural production. There are 12 disasters in Tianshan Mountains, which can be divided into three zones. (1) Base zone (torrential rain collapse zone): types of the various disasters in this zone are caused by suddenly rain in the low middle mountain of the arid area. The disasters occur mainly from May to August, thus, the frequent periods of their bursts are simultaneous with the maximum period of precipitation in every year. (2) Middle zone (snowmelt water icing zone): most disasters, which happen in the middle high mountain area, have close relation with variation of temperature. (3) Upper zone (snow drift avalanche zone): the movement of snow mantle creates disaster in this zone. The slope direction and height of mountain greatly influence the frequency of hazards and the formation of vertical zone spectrum of natural disasters. Due to the regional diversities of temperature and precipitation, the vertical zone spectrum of natural disasters in mountains are different in different latitude and longitude zones.

The Background Variation of Natural Source ELF and Its EM Abnormal Phenomena in Yunnan Earthquakes

In order to add earthquake monitoring methods and develop new method research,the ELF Network for Earthquake Monitoring selected 30 stations in the Capital Circle and the Sichuan-Yunnan region. Finding electromagnetic field background variation is the basis of distinguishing the seismic electromagnetic anomalies. This paper introduces the data acquisition and selection of the Shexian,Anqiu,Lijiang and Dali stations which have recorded for longer time with better data and are located on the similar latitude. Then we use the natural source electromagnetic field's auto-power spectrum to express the intensity of the electromagnetic field. By using power spectral data of many frequencies in the observation frequency band,after the data pre-processing and sliding average noising,the background variation of extremely low frequency stations and the range ability were acquired.Taking the Baoshan M5. 1 earthquake on October 30,2015 and Dali M5. 0 earthquake on May 18,2016 as examples,the authors analyzed the earthquake electromagnetic anomaly characteristic of ELF stations around the earthquakes.

An Analysis for Distribution of Natural Radionuclides in Soil, Sand and Sediment of Potenga Sea Beach Area of Chittagong, Bangladesh

A HPGe (High Purity Germanium) detector based, low background gamma-ray counting system was used for activity measurement in soil, sand and sediment samples collected from Potenga sea beach area of Chittagong, Bangladesh. The specific radioactivities of Radium (226Ra), Thorium (232Th) and Potassium (40K) were measured in the above samples. The investigation reflects the lower deposition of minerals exist in the collected samples. From the measured specific radioactivities of the above three natural radionuclides, the radium equivalent activity (Raeq), the external hazard index (Hex), the external gamma absorbed dose rate and the annual effective dose were calculated. The obtained mean values of gamma absorbed dose rate in soil and sand samples and annual effective dose in soil, sand and sediment samples were found higher than the worldwide average as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000). The Raeq values were in the range of 47.86 to 293.76 Bq·kg-1 and the Hex varied from 0.13 - 0.81, which indicated that the study area was radiologically safe for human being.

ACCURACY OF MEASUREMENT OF NATURAL GAMMA RAY SPECTRA BY HD－8004 NaI（T1）GAMMA SPECTROMETER

The measurement principle and analysis method of natural gamma-ray spectra using Nal(T1) scintillation spectrometer are briefly described first, thed block diagrams of the HD-8004 Nal(T1) gamma-ray spectrometer. Finally, sample measurements are listed and discussed. The results are quite promising. Based on the analysis of these measurements, measures to improve the accuracy of spectrum measurement are proposed. It is well hoped that these measures call contribute to the development and application of gamma-ray spectrum measurement.

The likely counterpart to γ-ray excess from the northwest region of Arp 220

The unknown γ-ray excess in the northwest region of Arp 220 was revisited by analyzing~11.8 years of the Fermi Large Area Telescope(Fermi-LAT) data in this study.We found that its photon flux was approximately three times higher than that of the previous study in the 0.2-100 GeV band,and the corresponding significance level ~8.15σ was approximately four times higher than before.The light curves of 15 and 45 time bins from the whole time all showed two active periods,and the variability of the second period was more significant than that of the first period.The spectral indices from the two active periods were not statistically different and were close to the range of γ-ray flat-spectrum radio quasars observed by Fermi-LAT.Because the position of CRATES J153246+234400 was consistent with the best-fit position of our analysis,we suggest that CRATES J153246+234400 is more likely a γ-ray counterpart for the variational region.For Arp 220,there was no significant variability in the γ-ray emission.

Similarity measurement of Chinese medicine ingredients for cold-hot nature identification

Objective:Nature theory of Chinese medicine (CM) is the core basic theory of Traditional Chinese Medicine (TCM), in which cold-hot nature is the focus of research. Studies have found that CM ingredients are the material basis for the production of medicine natures. Therefore, it is speculated that CMs with similar composition of substances should have similar medicinal nature. Modern work studies cold-hot medicine of CMs with chemical fingerprinting technology because the chemical fingerprint data of CM can reflect the whole composition of CM ingredients. Methods:To verify the hypothesis above, in this work, we study quantifying the similarity of CM ingredients to fingerprint similarity, and explore the relationship between the composition of CMs and cold-hot nature. Firstly, we utilize ultraviolet (UV) spectrum technology to analyze 61 CMs, which have clear cold-hot nature (including 30 ‘cold’ CMs and 31 ‘hot’ CMs). Secondly, with the constructed fingerprint database of CMs, a distance metric learning algorithm is studied to metric the similarity of UV fingerprints. Finally, a retrieval scheme is proposed to build a predictive identification model to identify cold-hot nature of CMs. Results:By means of numerous experiment analyses, ultraviolet spectrum data of petroleum ether solvent can better represent CMs to distinguish between cold and hot natures. Comparing with existing classical models, the proposed identification scheme has better predictive performance. Conclusion:The experimental results prove our inference that CMs with similar composition of substances should have similar medicinal nature. The proposed prediction model is proved to be effective and feasible.

烃源岩测井识别与评价方法研究进展

烃源岩测井识别与定量评价对油气资源潜力勘查、储量评估及非常规油气勘探开发至关重要。烃源岩自身岩性和成熟度等差异、测井序列对烃源岩响应灵敏程度不同以及不同方法适用性区别等导致烃源岩测井评价工作仍受到限制。目前亟需进一步挖掘地球物理测井资料中蕴含的烃源岩信息,搭建烃源岩品质与测井信息之间桥梁,并实现以自生自储为特性的非常规油气烃源岩品质测井精细表征。笔者等首先阐明烃源岩分类及其地质表征参数,并分析不同类别烃源岩在常规测井序列及成像和核磁共振等新技术测井序列上响应特征。烃源岩通常表现为“四高一低”(高GR、高AC、高CNL、高RT和低DEN)测井响应特征。除单因素分析外,可优选交会图及构建敏感参数等实现烃源岩定性识别。而烃源岩有机碳含量(TOC)等参数测井定量预测方面则可采用ΔlgR法、修正ΔlgR法(变基线和变系数)、自然伽马能谱测井法、多元回归法、Litho Scanner测井资料法以及人工智能方法实现。在分别评述不同TOC含量测井计算方法的优缺点和适用条件的基础上,指出通过TOC结合生烃潜量等参数计算可实现烃源岩品质测井综合评价。最后解析烃源岩测井识别与评价工作中存在的问题与发展趋势,以期为油气资源评价及非常规油气勘探开发提供理论指导与技术支撑。

基于kHz~MHz频段电频谱的多孔介质中水合物饱和度评价方法:数值模拟研究

宽频电频谱蕴含了导电、电极化及其频散机制的信息,天然气水合物的介电常数在kHz~MHz频段呈现频散特性,提出了基于该频段的电频谱来反演水合物饱和度的新思路。首先建立含水合物多孔介质的电场有限元数值模型,然后探讨水合物饱和度、水合物微观赋存模式、电场频率等因素对宽频电频谱的影响规律,最后针对含悬浮型和包裹型水合物多孔介质分别提出基于两步法的三相介电混合模型,进而建立水合物饱和度计算模型。研究结果表明:(1)在含包裹型水合物多孔介质中,水合物将石英砂颗粒与孔隙水隔离,则多孔介质低频段(<kHz)电频谱不受双电层极化的影响;当频率高于水合物频散频率时,含悬浮型和包裹型水合物多孔介质的复电导率虚部和复介电常数实部随着水合物饱和度的增大而显著降低;(2)对于含悬浮型水合物多孔介质,先将孔隙水与水合物的混合物视为等效孔隙流体相,采用Bruggeman(BR)模型计算等效介电常数,后将等效孔隙流体相与骨架颗粒混合,采用Bruggeman-Hanai(BH)模型计算含水合物多孔介质的等效介电常数,利用该BR-BH三相介电混合模型计算水合物饱和度,最大绝对误差为0.08,最大相对误差为5.67%;(3)对于含包裹型水合物多孔介质,先将骨架颗粒与水合物的混合物视为等效骨架颗粒相,采用Maxwell Garnett(MG)或BR模型计算等效介电常数,后将等效骨架颗粒相与孔隙水混合,采用BH模型计算含水合物多孔介质的等效介电常数,利用MG-BH和BR-BH三相介电混合模型分别计算水合物饱和度,最大绝对误差均为0.04,最大相对误差均低于10%。该研究建立了一种新的水合物饱和度评价方法,为天然气水合物储层定量评价和动态监测技术的开发提供了理论基础。

基于绿被覆盖率上推的天然草地冠层SPAD值高光谱反演方法

叶绿素是评估草地光合作用能力和生理状况的重要指标。高光谱遥感包含丰富的光谱信息,已经成为无损估算草地叶绿素含量的重要手段。然而,通常获取的草地冠层高光谱数据与实测叶片的叶绿素含量存在尺度不匹配问题,导致高光谱反演叶绿素的精度低。为此,提出基于绿被覆盖率上推的天然草地冠层叶绿素高光谱反演方法。以内蒙古呼伦贝尔典型天然草地为研究对象,利用ASD高光谱仪获取的地面冠层高光谱数据、SPAD叶绿素仪采集的叶片叶绿素相对含量实测值和样方手机数码相片,以绿被覆盖率为媒介,将叶片尺度的叶绿素相对含量实测值上推到冠层尺度。结果表明植被指数与SPAD相关性(-0.74~0.76)普遍高于场平均法上推SPAD(-0.63~0.50)。通过原始冠层光谱反射率、一阶导数光谱和42种常用叶绿素光谱指数构建基于绿被覆盖率上推的天然草地冠层叶绿素高光谱反演模型(SPAD_cover)。单变量的最优草地冠层叶绿素反演模型R^(2)=0.689,RMSE=2.714,RPD=1.752;多元线性逐步回归的最优草地冠层叶绿素反演模型R^(2)=0.833,RMSE=2.019,RPD=2.354。实验表明基于绿被覆盖率将草地叶片叶绿素含量实测值上推至冠层尺度,可以有效提高天然草地冠层叶绿素高光谱反演精度。

某船齿轮箱海水冷却水泵的故障诊断

针对某船右齿轮箱海水冷却水泵振动异常故障,文章测量了该泵的振动速度和速度波形,通过加速度包络分析确定了振动激励源,从而发现故障原因是轴承损坏导致的泵组转子失衡,最后经更换轴承,排除了故障。

自然情境下的结构化教学模式对孤独症谱系障碍儿童康复的初步应用

目的:研究自然情境下的结构化教学模式对孤独症谱系障碍(ASD)儿童的影响。方法:将40例ASD儿童随机分为对照组和观察组各20例。对照组接受常规康复治疗,观察组在此基础上接受自然情境下的结构化教学模式治疗。治疗前后分别采用儿童期孤独症评定量表(CARS)、孤独症治疗评估量表(ATEC),儿童功能独立性评定量表(WeeFIM)进行评估。结果:治疗后,2组CARS、ATEC评分均较治疗前明显降低(P<0.01),且观察组CARS、ATEC的语言、社交、感知觉及总分均低于对照组(P<0.05);治疗后,2组WeeFIM评分较治疗前明显升高(P<0.01),且观察组WeeFIM的认知功能评分及总分均高于对照组(P<0.01)。结论:自然情境下的结构化教学模式可以有效改善ASD患儿的语言、社交和认知功能。

针灸神经调控领域的研究现状

目的:针灸神经调控机制已成为近年来针灸学相关领域研究的热门,现拟以该机制为切入点,回顾国家自然科学基金立项课题的资助情况,探讨研究现状。方法:对立项起始时间为2013-2022年度针灸学相关领域国家自然科学基金申请代码为H3107经络与腧穴、H3117中医养生与康复、H3118中医针灸学中关于针灸神经调节机制的基金项目进行统计,分析资助情况、研究内容与病症治疗谱、针灸干预类型、相关调控机制与信号通路。结果:该领域基金项目共有252项,研究较多的疾病包含脑缺血、阿尔茨海默病、脊髓损伤等,主要调控机制与信号通路涉及神经环路、自噬、凋亡、翻译、应激等。结论:近10年国家自然科学基金对针灸神经调控领域的资助力度总体呈波动上升态势,相关研究涉及疾病范围广,关注的机制与通路多,但对中枢神经系统的一些重要作用点及多发性硬化、神经肌肉接口疾病等神经系统疑难病症的研究仍有待深入。

低计数特征的自然伽马能谱测井数据滤波方法研究

岩石天然放射性强度较弱,自然伽马能谱测井所测得的能谱计数较低,低计数特征使得地层衰变随机误差影响被放大,造成测量能谱质量差、测井曲线统计噪声大的情况。该文通过对比多种能谱滤波结果,使单深度点能谱最大程度还原准确能谱信息;利用曲线形态,针对求解的U、Th、K含量曲线进行深度域的滤波处理,综合从高噪声、低计数的数据中准确提取地层信息;利用中国石油集团测井有限公司的过钻具自然伽马能谱仪器的实测数据验证该方法的有效性。结果表明:对于计数低、谱形差的自然伽马能谱,高斯滤波、卷积滤波效果相对较好,该文提出结合这2种方法的复合滤波可以准确地还原出高保真的能谱形状;深度域的滤波,卡尔曼滤波相对自适应滤波方法有一定优势;依次经过能谱滤波和深度滤波后,结果的准确性和重复性有了大幅提升。该文所介绍的针对低计数特征的自然伽马能谱测井滤波方法,可以有效提高U、Th、K的测量精度。

结合轻量卷积的非自回归语音合成方法

对如何有效捕捉音素之间的关联及如何合成韵律丰富的音频进行研究,提出一种结合轻量卷积的非自回归语音合成模型LCTTS。引入轻量卷积建立起音素之间的联系,解决发音出错问题。通过添加音高和能量预测器预测生成语音的韵律,解决音频韵律缺乏问题。训练模型获取梅尔频谱,结合预先训练好的声码器转化为音频。实验结果表明,提出的LCTTS模型优于先前提出的SpeedySpeech模型,在Emotional Speech Database数据集上平均意见得分获得2.8%的提升,梅尔倒谱失真测度下降0.15。

中国市域自然保护区时空格局演变特征

市域是自然保护地整合优化的具体实施单元,揭示市域自然保护区的时空格局演变特征和发展趋势对于全面建设中国特色自然保护地体系具有重要的现实意义。基于1975—2020年间隔5 a的10期中国自然保护区名录,通过标准差椭圆、探索性空间数据分析、空间Markov链等方法首次从市域尺度探讨了中国自然保护区的时空动态演变特征和发展趋势,并引入地学信息图谱构建其变化模式。结果表明:(1)中国市域自然保护区比例呈现先快速增长后逐步稳定的趋势,但整体仍以低值区为主。市域间自然保护区比例差异明显,逐步形成了“西高东低”的空间格局。重心整体表现为“东南-西北-东北”的迁移过程,重心移动距离和速度逐渐缩小。1990年以后,中国市域自然保护区比例始终呈现“东北-西南”向的空间分布格局。(2)市域自然保护区比例存在显著的空间相关性且相关性总体呈上升之势,但空间集聚水平的变化逐年缩小。局部空间异质性较强,高高和低低集聚区均呈扩张态势。(3)从变化模式图谱来看,中国市域自然保护区比例等级以“前期变化-低频-逐步提升”(ESC-LQ-T1)的方式进行,主要图谱类型为“空缺区转为低值区”。市域自然保护区比例等级类型转移具有稳定性和显著的时空异质性,后期出现了“俱乐部收敛”现象,且邻域背景在其动态变化过程中发挥着重要作用。未来要加强对空缺区和低值区市域单元的自然资源进行摸底评估,将其最有价值的区域纳入自然保护区,同时推广区域联合保护机制,促进自然保护地体系高质量建设。

应用自然伽马能谱法恢复碳酸盐岩沉积时的古水深——以山西兴县关家崖马五5亚段为例

古水深分析对还原古环境与盆地构造演化历史具有重要的意义。目前古水深恢复多以定性为主,对样品可靠性的要求较高,且易受资料条件限制,而自然伽马能谱法具有易获取、成本低、受控因素少等优点,可结合水深函数半定量恢复水深,但该方法多被用于陆相碎屑岩的研究中,是否适用于海相碳酸盐岩尚需验证。以鄂尔多斯盆地关家崖剖面奥陶系马家沟组五5亚段为例,利用自然伽玛能谱法恢复了碳酸盐岩沉积时的古水深,恢复结果与碳同位素法、生物遗迹法、岩石组构法显示的结果一致。研究验证了自然伽马能谱法在恢复碳酸盐岩沉积时的古水深方面具有较高的可信度与实用性。

基于空间谱的钢轨波磨识别技术研究

伴随轨道车辆运行里程的增加和运行速度的提升,轮轨间的异常磨耗也逐渐凸显,为及时了解钢轨表面波浪形磨耗的存在现状,对波磨的波长及波深的识别研究成为一类重要的研究方向。目前列车变速下的波磨波长识别方法有所欠缺,基于加速度二次积分的波磨波深识别方法由于零点漂移问题也存在计算结果不够准确的问题。使用空间谱代替时间谱采集和处理列车轴箱加速度数据,对波磨波长计算公式进行改进,避免速度变化对波长识别带来的影响;将采集和计算得到的数据整合成数据集并进行自然邻点插值,得到完整的波长-波深-幅值数据库,对波磨波深进行量化识别;同时提出完整的钢轨波磨故障识别流程,为实际工程应用提供参考。研究结果表明,基于空间谱的傅里叶变换能够精确获取波磨分布的异常频率,并通过改进后的波长计算公式得到波磨波长,在不同速度段变化下仿真得到的识别误差低于5%,实现了变速条件下的准确识别;使用自然邻点插值方法处理数据契合波磨相关数据的分布特性,插值结果遵循列车轴距滤波规律,基于该方法的波磨波深识别数据误差小于7%。上述方法实现了不同复杂运行工况下的波磨波长与波深的准确识别,可用于指导线路上钢轨异常磨耗的打磨工作。

自然伽马能谱录井数据的影响因素

自然伽马能谱录井技术在岩性识别、地层划分、储层识别等方面发挥了重要的作用,然而操作人员的操作差异、钻进过程中钻井取心以及井漏等钻井复杂导致的岩屑量不足均会造成测量数据出现偏差。通过开展自然伽马能谱数据影响因素实验,分析了检测时长、岩屑样品充填方式、岩屑颗粒粗细、样品干湿程度、样品质量对测量数据的影响程度,认为样品质量是影响自然伽马能谱录井最重要的因素,其辐射伽马总剂量率与岩屑质量呈线性关系。基于实验结果,形成了一套适用于现场的规范性操作,在取样条件受限导致样品质量不足时,利用辐射伽马总剂量率与样品质量线性关系可进行参数校正。

上海科技馆大修工程钢结构防腐涂层维护方案试验研究

通过中性盐水喷雾试验,对上海科技馆大修工程钢结构防腐涂层三种维护方案对比分析评判,选出了最佳维护方案,为行业内类似工程问题提供了一条便捷有效的解决途径。依据试验及规范进行推测,上海科技馆防腐涂层使用年限可能接近甚至超过建筑设计使用年限50 a的目标。