临床实验室检测系统精密度验证方法比较及应用体会

目的比较NCCLS EP5-A2、EP15-A2及室内质控数据分析3种方法对临床实验室生化检测系统精密度验证的效果。方法按照3种方法要求采集在全自动生化分析仪OLYMPUS AU2700上检测的肌酐、尿素、磷、尿酸、谷草转氨酶、肌酸激酶、乳酸脱氢酶、三酰甘油、血糖、转肽酶10个项目的实验数据,进行精密度计算,依据科质量目标的要求及北京市不精密度建议进行验证。结果 3种方法均满足科质量目标的要求及北京市不精密度建议。结论利用室内质控数据对精密度进行验证简单易行,节省人力、物力,保证仪器在使用过程中始终满足厂家提供的性能指标及实验室质量目标的要求,可替代EP5-A2及EP15-A2对其他常规项目的检测系统进行精密度验证。

山西省水环境监测中心生活饮用水中总有机碳测定方法验证探析

为准确测定生活饮用水中总有机碳含量,山西省水环境监测中心开展了生活饮用水中总有机碳测定方法验证工作。文章通过分析中心测试条件,完成了总有机碳测定方法选择,并就测试成果进行了检出限、精密度、正确度验证,结果表明中心生活饮用水中总有机碳的测定,通过了标准方法验证。此举填补了中心总有机碳测定方面的空白,提高了《全国水文基础设施建设“十四五”规划》及《水文现代化建设规划》中“三项标准规定的全指标检测能力”。

变组分气体质量流量计的应用与现场验证

针对变组分气体测量难,不能采用恒定组分气体质量流量测量方法的问题,应用了FVC气体质量流量计,采用涡街流量传感器测量工况条件下的体积流量,利用旋涡发生体前后的压差计算流量计出口侧气体密度,计算得到质量流量。同时阐述了测量管内气体雷诺数影响校正、可膨胀性补偿,以及设计计算、计量检定方法和安装调试。现场验证表明:该流量计简单可靠,解决了变组分气体质量流量测量难题;流量计的公称通径可以比工艺管道通径小1~3档,节省了投资。

Downlink SINR and Rate Distribution of Ultra-Dense Het Nets with Burst Traffic

SINR distribution and rate overage distribution are crucial for optimization of deployment of Ultra-dense Het Nets.Most existing literatures assume that BSs have full queues and full-buffer traffic.In fact,due to ultra-dense deployment of small cells,traffic in small cell varies dramatically in time and space domains.Hence,it is more practical to investigate scenario with burst traffic.In this paper,we consider a two-tier non-uniform ultra-dense Het Net with burst traffic,where macro BSs are located according to Poisson Point Process(PPP),and pico BSs are located according to Poisson Hole Process(PHP).The closed-form expressions of SINR distribution and rate distribution are derived,and then validated through simulation.Our study shows that different from the result of full buffer case,the SINR distribution and rate distribution of users depend on the average transmission probabilities of BSs in burst traffic case.

Deduction and Validation of an Eulerian-Eulerian Model for Turbulent Dilute Two-Phase Flows by Means of the Phase Indicator Function-Disperse Elements Probability Density Function

A statistical formalism overcoming some conceptual and practical difficulties arising in existing two-phase flow (2PHF) mathematical modelling has been applied to propose a model for dilute 2PHF turbulent Hows. Phase interaction terms with a clear physical meaning enter the equations and the formalism provides some guidelines for the avoidance of closure assumptions or the rational approximation of these terms. Continuous phase averaged continuity, momentum, turbulent kinetic energy and turbulence dissipation rate equations have been rigorously and systematically obtained in a single step. These equations display a structure similar to that for single-phase flows. It is also assumed that dispersed phase dynamics is well described by a probability density function (pdf) equation and Eulerian continuity, momentum and fluctuating kinetic energy equations for the dispersed phase are deduced. An extension of the standard k-e turbulence model for the continuous phase is used. A gradient transport model is adopted for the dispersed phase fluctuating fluxes of momentum and kinetic energy at the non-colliding, large inertia limit. This model is then used to predict the behaviour of three axisymmetric turbulent jets of air laden with solid particles varying in size and concentration. Qualitative and quantitative numerical predictions compare reasonably well with the three different sets of experimental results, studying the influence of particle size, loading ratio and flow confinement velocity.

Optimal Deployment Density for Maximum Coverage of Drone Small Cells

With the proliferation of small and mini drones, Drone Small Cells(DSCs) can cooperative multiple drones to provide communication service for ground users as emergency means or supplementary ones of traditional terrestrial cellular networks. In this paper, we study the fundamental problem of optimizing the deployment density of DSCs to achieve the maximum coverage performance. Most related works do not consider cumulative inter-cell interference when studying the coverage performance of DSCs. First, we derive an approximate and closed-form expression of the cumulative inter-cell interference which comes from both probabilistic Line-of-Sight(Lo S) and Non-Line-of-Sight(NLo S) links. Then, we analyze the coverage performance of DSCs and derive the transcendental function of optimal deployment density to obtain the maximum coverage. Last, we propose an algorithm to get the optimal deployment density with low complexity. We conduct both field experiments and Matlab simulations to verify the correctness of theoretical analysis. In addition, we show the impact of some factors on the relation between the deployment density and coverage performance through extensive numerical simulations.

Construction of Coarse-Grained Models by Reproducing Equilibrium Probability Density Function

The present work proposes a novel methodology for constructing coarse-grained （CG） models, which aims at minimizing the difference between CG model and the corresponding original system. The difference is defined as a functional of their equilibrium conformationaJ probability densities, then is estimated from equilibrium averages of many independent physical quantities denoted as basis functions. An orthonormalization strategy is adopted to get the independent basis functions from su^ciently preselected interesting physical quantities of the system. Thus the current method is named as probability density matching coarse-graining （PMCG） scheme, which effectively takes into account the overall cha,~acteristics of the original systems to construct CG model, and it is a rtatural improvement of the usual CG scheme wherein some physical quantities are intuitively chosen without considering their correlations. We verify the general PMCG framework in constructing a one-site CG water model from TIP3P model. Both structure of liquids and pressure of the TIP3P water system are found to be well reproduced at the same time in the constructed CG model.

A reaction-diffusion model of forest boundary with seed dynamics

The density of forest cover based upon reaction diffusion model for mono-species of two age classes with seed dynamics is to be attempted. The prevailing densities of young, old species and airborne seedlings are resolved by homotopy perturbation method which is applied in reaction diffusion model. This model is utilized to verify the effect of the density of forest cover with the following variables namely seed reproduction, seed deposition, seed establishment rates, coefficients of aging of old tree and coefficients of mortality on the space variable.