Effects of fatigue on the physiological parameters of labor employees

Human factors have contributed to the causes of several accidents. The physiological parameters change law of labor employees before and after fatigue is researched in this paper. The purpose of this research is to find the relationship between physiological parameters and fatigue, design corresponding fatigue monitoring and early warning system, reduce the accident rate and optimize the working environment. The labor employees’ heart rate, RR interval, respiration rate and blood pressure under fatigue state are determined in the laboratory. The change law of labor employees’ heart rate, RR interval, respiratory rate and blood pressure are analyzed based on the paired samples t test by using SPSS software. The results show that labor employees’ heart rate and RR interval have no significant difference before and after fatigue. Labor employees’ respiration rate has significant difference before and after fatigue: the respiration rate decreased after fatigue. Labor employees’ blood pressure has significant difference before and after fatigue: blood pressure of labor employees after fatigue can be elevated. The results provide a richer theoretical and practical basis in what criteria are used to determine the fatigue. It has important significance in the safety management field and accident prevention.     

渗透潜堤对沙滩剖面演化影响的物理模型试验研究

由于对海岸景观和生态环境影响较小,渗透潜堤被广泛用于沙滩整治修复和侵蚀防护。在波浪水槽中开展物理模型实验,研究潜堤对沙滩剖面演化的影响。采用浪高仪阵列和激光扫描仪采集了水面高程变化和沙滩剖面高程,分析了波浪传播的相关水动力特征,包括波高沿程分布、透射系数、波浪能谱以及非线性指标(偏度和斜度),不同入射波浪和潜堤设置情况时沙滩剖面的变形特征,统计了沙滩侵蚀关键因子(岸线蚀退距离、单宽侵蚀量等),探讨了沙滩侵蚀与波浪条件、渗透潜堤特征参数之间关系,提出了沙滩侵蚀量与渗透潜堤无量纲特征参数的估算公式。研究表明:在堤顶破碎、大孔隙介质阻力和堤前反射综合作用下,入射至近岸沙滩的波浪能量降低,潜堤具有消浪和沙滩侵蚀防护作用;泥沙整体离岸输运,潜堤向岸侧淤积;对于实验考虑的工况,潜堤位置变化对沙滩防护效果的影响较小,堤顶宽度增加更利于消浪和滩面防护,潜堤对于较强的波浪表现出更好的沙滩防侵蚀效果。     

Fast Imaging Solar Spectrograph of the 1.6 Meter New Solar Telescope at Big Bear Solar Observatory

For high resolution spectral observations of the Sun – particularly its chromosphere, we have developed a dual-band echelle spectrograph named Fast Imaging Solar Spectrograph (FISS), and installed it in a vertical optical table in the Coudé Lab of the 1.6 meter New Solar Telescope at Big Bear Solar Observatory. This instrument can cover any part of the visible and near-infrared spectrum, but it usually records the Hα band and the Ca ii 8542 Å band simultaneously using two CCD cameras, producing data well suited for the study of the structure and dynamics of the chromosphere and filaments/prominences. The instrument does imaging of high quality using a fast scan of the slit across the field of view with the aid of adaptive optics. We describe its design, specifics, and performance as well as data processing     

Optical Spectra Evolution of BL Lac Objects

Many quasi-simultaneous optical observations of nine BL Lac objects are obtained from literature. We study the relationship between the optical spectral index and the luminosity of BL Lac objects, and are tempted to exploit spectral evolution in the optical frequency ranges. Our results show that: (i) The optical spectra index of the low-frequency peaked BL Lac objects (LBLs) is steeper than the high-frequency peaked BL Lac objects (HBLs); (ii) The spectra tend to be softer when the source becomes brighter for LBLs and the intermediate BL Lac objects (IBLs) (i.e., bluer-when-brighter), and the spectra of HBLs does not vary when the brightness of HBLs changes. Possible explanations are briefly discussed for this phenomenon.     

Monochloramination of Oxytetracycline: Kinetics,Mechanisms, Pathways,and Disinfection By‐Products Formation

This study investigated the degradation kinetics, formation of disinfection by‐products (DBPs), and degradation pathways during monochloramination of oxytetracycline (OTC). The degradation kinetics can be well described by a second‐order kinetic model, first‐order in monochloramine (NH₂Cl), and first‐order in OTC. Reaction of OTC with NH₂Cl shows a high reactivity, with the apparent rate constant of 17.64/M/s at pH 7. The apparent rate constant declined as pH increased from 5 to 10. Six DBPs were detected during monochloramination of OTC, including chloroform (CF), 1,1‐dichloro‐2‐propanone (1,1‐DCP), 1,1,1‐trichloro‐2‐propanone (1,1,1‐TCP), dichloroacetonitrile (DCAN), trichloronitromethane (TCNM), and N‐nitrosodimethlyamine (NDMA). CF, DCAN and NDMA had the maximum yields at neutral pH, while 1,1‐DCP and 1,1,1‐TCP had the maximum yields at pH 4. However, TCNM concentration increased as pH increased. Degradation pathways of OTC monochloramination were then proposed. Hydroxylation and Cl‐substitution are found to be the dominant mechanisms in monochloramination of OTC.     

干旱荒漠区隐伏金矿覆盖层中金的分布与迁移：以新疆金窝子金矿田210金矿带为例

以新疆金窝子金矿田210金矿带为例,实验研究了该区地气和土壤活动态测量等深穿透地球化学方法的效果。实验表明地气测量和土壤活动态测量可以有效地反映覆盖层下隐伏矿体。揭露矿体覆盖层的钻孔研究表明,金活动态形式具有“C”型分布特征。采集矿体上方地表异常位置土壤孔隙中地气、土壤样品,使用透射电子显微镜(TEM)实测样品中微粒物质的粒径、形貌和成分,在地气和土壤中观测到了Au-Cu、Au-Bi成矿元素纳米微粒,此微粒是形成地表深穿透地球化学异常的物质,来源于覆盖层下隐伏矿体。微粒到达地表,可以形成地气和土壤活动态异常。纳米微粒具有可从土壤颗粒表面分离的性质,在其向上迁移过程中,可以从吸附固定状态解吸,此性质可以用于解释活动态异常在钻孔垂直剖面上的“C”型分布。     

三峡地区雾渡河断裂构造特征及最新活动性研究

根据野外调查获得的第一手资料,结合前人有关雾渡河断裂的研究成果,论述了雾渡河断裂的区域地质背景、构造应力场、深部构造特征、地貌水系样式,其中重点解决了雾渡河断裂的运动学特征和断裂活动时代.根据所采断裂上覆第四纪沉积物样品的TL测年数据(76.43±6.49 ka),确定雾渡河断裂晚更新世以来活动不明显.     

Modeling Eri and Asteroseismic Tests of Element Diffusion

Taking into account the helium and metal diffusion,we explore the possible evolutionary status with a seismic analysis,of the MOST (Microvariability and Oscillations of STars) target:the star e Eft.We adopt different input parameters to construct models to fit the available observational constraints in,e.g.,Teff,L,R and [Fe/H].From the computation we obtain the average large spacings of ∈ Eri to be about 194±1 μHz.The age of the diffused models was found to be about 1 Gyr,which is younger than the age determined previously by models without diffusion.We found that the effect of pure helium diffusion on the internal structure of the young low-mass star is slight,but that of metal diffusion is obvious.The metal diffusion leads the models to have much higher temperature in the radiative interior,and,correspondingly a higher sound speed there,hence a larger frequency and spacings.     

Submarine slope stability analysis during natural gas hydrate dissociation

ABSTRACT

The purpose of this paper is to analyze the stability of submarine slope during the natural gas hydrate dissociation. A model is deduced to calculate the excess pore fluid pressure. In addition, a new method is proposed to define and calculate the factor of safety (FoS) of the submarine slope. Case study is also performed, results of which show that dissociation of hydrates would decrease the stability of submarine slope. If the cohesion of the hydrate-bearing sediments is small, the submarine slope would become unstable because of the shear failure. If the cohesion of the hydrate-bearing sediments is large enough, the tensile failure would happen in the hydrate-bearing sediments and the excess pore pressure may explode the submarine slope. Under the drained condition, the submarine slope may remain stable because the buildup of excess pore fluid pressure could not take place. Moreover, FoS would be underestimated by the assumption that natural gas hydrates dissociate in the horizontally confined space, but would be overestimated by only taking into account of the base of the natural gas hydrate-bearing sediments. The compressibility factor of natural gas should also be considered because treating natural gas as ideal gas would underestimate the stability of submarine slope.     

Spatiotemporal variability of algae in monitoring aquatic environment in the Panjiakou Reservoir (Northern China)

The spatial and temporal variations of algae within a large drinking water reservoir with mesotrophy (Panjiakou Reservoir, Northern China) were investigated in relation to variations in environmental factors over a 6-month period (May to October) in 2013 and 2014. The analysis based on in-situ samples upstream to downstream (Puhekou, Jiajia’an, Yanziyu Panjiakou and Baqian) showed that three harmful algae species of Cyanophyta, Chlorophyta and Bacillariophyta prevail in the reservoir. The variations in algal concentrations presented a seasonal cycle with high values in the flood season and low values in the drought season and a spatial concentration in main water storage area of the reservoir. Compared with the environmental factors of pH value, permanganate index, ammonia nitrogen and total nitrogen, water temperature, dissolved oxygen content and total phosphorus were significant related to algae concentrations with correlation coefficients of 0.76, 0.62 and 0.85, respectively. The impact analysis of three factors on prevailing algae species indicated that Chlorophyta was the main contributor to the algal photosynthesis of the Panjiakou Reservoir. An extremely high value of algal concentrations with little variety in August 2013 revealed that pollution carried by tremendous runoff may induce algae blooms later.