高负荷活性污泥法处理城市污水系统需氧量的确定

根据高负荷活性污泥系统对溶解性有机物和颗粒性有机物去除的程度和机理不同,通过大量试验数据的回归拟合,提出了计算高负荷活性污泥系统处理城市污水需氧量的经验公式,此公式可为今后高负荷活性污泥系统的工程设计及理论研究提供一定的参考依据。     

中药配方颗粒和中药饮片临床效果比较

目的探讨中药配方颗粒和中药饮片治疗感冒患者的临床效果。方法选取营口市中医院2019年1月至2020年1月收治的感冒患者134例(风寒感冒68例,风热感冒42例,阴虚感冒24例)作为研究对象,按随机数字表法分为观察组和对照组,每组67例。两组患者采用中药配方治疗,其中对照组采用中药饮片形式,观察组采用中药配方颗粒形式,比较两组患者治疗效果、治疗满意度、症状缓解时间、痊愈时间和治疗费用。结果观察组患者治疗有效率优于对照组(P<0.05);观察组患者治疗满意度高于对照组(P<0.05);观察组患者症状缓解时间和痊愈时间短于对照组(P<0.05),且其治疗费用更低(P<0.05)。结论中药配方颗粒治疗感冒的效果优于中药饮片,操作简单,花费更少,患者满意度高。     

基于老龄化背景下的绿色生产技术推广研究——以生物农药与测土配方肥为例

[目的]探讨老龄化与农业技术推广对农户采纳绿色生产技术的影响。[方法]文章通过二元Logit模型,利用湖北省襄阳、宜昌、黄冈、潜江4市587户水稻种植户样本数据进行实证分析。[结果](1)老龄化阻碍了农户的绿色生产技术采纳行为,老年组农户相对于年轻组而言,采纳生物农药和测土配方施肥技术的概率在下降,采纳生物农药的年轻组和老年组农户分别占总样本的47.79%和37.67%,采纳测土配方肥的年轻组和老年组农户分别占25.00%和15.48%;(2)农业技术推广能够在一定程度上缓解老龄化对农户采纳绿色生产技术的阻碍。具体而言,政府宣传与政府培训均能显著促进年轻农户的绿色生产技术采纳行为;政府宣传能有效促进老年农户采纳绿色生产技术,但政府培训对其影响作用并不明显。[结论]政府应加强绿色生产技术的宣传力度和培训力度,针对中老年人降低培训难度,且为中老年人提供良好的学习环境。     

高膳食纤维濑粉工艺及特性研究

为研究高膳食纤维濑粉的最佳工艺,本试验以大米粉和玉米粉为主要原料,菊粉和魔芋胶为辅料,通过单因素试验和正交试验对濑粉配方进行优化。结果表明,高膳食纤维濑粉的工艺参数为大米粉∶玉米粉=1∶4、菊粉添加量6.5%、魔芋胶添加量2%,测定最优组的濑粉与纯大米制作的濑粉的理化指标,经比较得出高膳食纤维濑粉的品质更佳。     

地基承载力理解和确定问题探讨

文章在阐述了地基承载力意义的基础上,对现行规范推荐的地基承载力确定方法,理论公式计算法和现场载荷试验法中存在的问题和局限性进行了分析。提出地基承载力的确定是一个非常重要而又十分复杂的问题,需要根据地质条件,基础及上部结构特点、结合理论计算、载荷试验的测试数据以及工程经验综合判断确定。     

损益表的数据处理之设计与实现

文中以VF(visual foxpro)为数据库管理系统,分析与探讨了损益表的设计与实现的基本原理,并提供了相应的程序代码。     

我国车险费率市场化改革的实证研究——以深圳车险市场为例

本文以金融领域市场化改革最早的车险费率为主题,通过历史数据回顾,实证分析了车险费率市场化三个阶段的特征,总结出当前车险市场集中度趋于稳定、费率逐步回升、市场秩序逐步好转、监管成效显著等新变化,最后运用产业经济学S-C-P范式,对提高车险效益提出了相关建议。     

Back to the roots of the M/D/s queue and the works of Erlang, Crommelin and Pollaczek

A.K. Erlang introduced the M/D/ s queue in 1917, while F. Pollaczek and C.D. Crommelin formalized the theory using complex analysis and transforms. Let D ( s , λ ) denote the stationary probability of experiencing no waiting time in the M/D/ s queue with arrival rate λ and service requirement 1. We use D ( s , λ ) as a vehicle to give an overview of some of the results we obtained over the last years, including explicit characterizations of the roots, the derivation of infinite series from expressions in terms of roots using Fourier sampling and heavy-traffic limits obtained from square-root staffing. We propose to call D ( s , λ ) the Erlang D formula, for which several new results are presented and compared with the results of Pollaczek.     

Step Options

Motivated by risk management problems with barrier options, we propose a flexible modification of the standard knock‐out and knock‐in provisions and introduce a family of path‐dependent options: step options . They are parametrized by a finite knock‐out (knock‐in) rate , ρ. For a down‐and‐out step option, its payoff at expiration is defined as the payoff of an otherwise identical vanilla option discounted by the knock‐out factor exp(-ρτ_B^‐) or max(1‐ρτ^-B,0), where &\tau;_B^‐ is the total time during the contract life that the underlying price was lower than a prespecified barrier level ( occupation time ). We derive closed‐form pricing formulas for step options with any knock‐out rate in the range $[0,∞). For any finite knock‐out rate both the step option's value and delta are continuous functions of the underlying price at the barrier. As a result, they can be continuously hedged by trading the underlying asset and borrowing. Their risk management properties make step options attractive "no‐regrets" alternatives to standard barrier options. As a by‐product, we derive a dynamic almost‐replicating trading strategy for standard barrier options by considering a replicating strategy for a step option with high but finite knock‐out rate. Finally, a general class of derivatives contingent on occupation times is considered and closed‐form pricing formulas are derived.     

弦振动方程Cauchy问题广义解的结构

建立了弦振动方程Cauchy问题在L^2空间中的广义解，并证明了广义解在L^2空间中与古典解具有相向的结构．