饮酒驾车的优化模型

本文通过分析啤酒中酒精在人体体内胃肠(含肝脏)与体液(含血液一)之间的交换机理,分别建立了在短时间内喝酒和长时间喝洒两种情况下,胃肠和体液(含血液)中的酒精含量的微分方程模型.对给出的数据,利用非线性最小二乘数据拟合及高斯-牛顿算法,确定了酒精含量以及酒精从胃肠进入血液的速度系数和酒精从血液渗透出体外的速度系数.继而,对不同喝酒方式下,血液中洒精浓度进行分析;该模型可以预测喝酒后任一时刻血液中的酒精浓度.对于第一问假设大李在第一次检查后半小时喝酒,由于体液中有残留的酒精,故第二次检查时酒精浓度为20.2448毫克/百毫升.     

饮酒与驾车的关系

本文针对酒后驾车问题,建立了一个反映体液中酒精含量变化的微分方程模型,接下来用常数变易法对模型进行求解,用最小二乘法并借助于Matlab软件对数据进行了拟合,得到了模型的具体解.然后我们利用Mathematica软件对题目中的各个问题一一做出了解答(1)很好地解释了大李碰到的问题;(2)饮酒后分别在11.6341小时、12.7169小时内驾车就会违反国家新标准;(3)对两种饮酒方式分别在饮酒后1.35067小时和2.62436小时时体液中酒精含量达到最大值;(4)如果天天饮酒,则酒精涉入量的极限安全值为8288.93毫克,相当于0.382瓶啤酒所含的酒精量.此外,我们还对一般模型进行了误差和灵敏度分析,利用微分方程的稳定性理论严格的证明了微分方程对初值和非齐次项都是渐进稳定的.     

饮酒与驾车的关系

本文针对酒后驾车问题,建立了一个反映体液中酒精含量变化的微分方程模型,接下来用常数变易法对模型进行求解,用最小二乘法并借助于Matlab软件对数据进行了拟合,得到了模型的具体解。然后我们利用Mathematica软件对题目中的各个问题一一做出了解答:(1)很好地解释了大李碰到的问题;(2)饮酒后分别在11.6341小时、12.7169小时内驾车就会违反国家新标准;(3)对两种饮酒方式分别在饮酒后1.35067小时和2.62436小时时体液中酒精含量达到最大值:(4)如果天天饮酒,则酒精涉入量的极限安全值为8288.93毫克,相当于0.382瓶啤酒所含的酒精量。此外,我们还对一般模型进行了误差和灵敏度分析,利用微分方程的稳定性理论严格的证明了微分方程对初值和非齐次项都是渐进稳定的。     

酒精代谢的数学分析

本文从生物学角度出发,根据微分方程理论.结合给定的数据,经过合理的假设,建立了血液中酒精的浓度随时间变化的基础模型。并针对不同的饮酒方式和饮酒量,分别建立了相应的模型。用拟合的方法确定参数,准确地模拟出酒精浓度变化趋势的曲线,拟合结果与原始数据吻合程度较高。同时,对一些实际问题也给出了合理的解释。     

酒精代谢的数学分析

本文从生物学角度出发,根据微分方程理论,结合给定的数据,经过合理的假设,建立了血液中酒精的浓度随时间变化的基础模型.并针对不同的饮酒方式和饮酒量,分别建立了相应的模型.用拟合的方法确定参数,准确地模拟出酒精浓度变化趋势的曲线,拟合结果与原始数据吻合程度较高.同时,对一些实际问题也给出了合理的解释.     

Alcohoot:可检测酒精含量的智能手机配件

正近期,Alcohoot推出了一款具备专业功能的智能手机配件——呼气酒精含量检测仪,用户只需将它接入iOS或Android设备的音频插孔就可以测量血液酒精含量(BAC)。Alcohoot推出的这款智能手机配件专用于测量使用者体内酒精度含量,配有可伸缩3.5mm耳机插头,插入智能手机的耳机插口即可测试使用者体内的血液酒精含量(BAC)。虽说现在市面上已有不少酒精含量测试仪,但Alcohoot的好处是省去与手机或平板配对的额外操作(其他仪器大多需要蓝牙配对操作)。此外,     

AZ31镁合金在Hank’s模拟体液中的腐蚀行为研究

研究了AZ31镁合金在Hank's模拟体液中的腐蚀行为,包括腐蚀形貌、腐蚀速度和腐蚀电化学特征参数.通过扫描电子显微镜(SEM)比较了不同腐蚀环境中镁合金样品的腐蚀形貌特征.利用失重法测量了镁合金的腐蚀速度,并依此分析了Hank's模拟体液中各成分对镁合金腐蚀速度的影响.测量并分析了不同pH值下的动电位动态极化曲线.结果表明,镁合金在Hank's模拟体液中的腐蚀主要为氯离子引起的点蚀;H_2PO_4~-和HPO_4~(2-)具有缓蚀作用;pH值的升高可以提高镁合金腐蚀反应的自腐蚀电位,降低腐蚀反应的热力学倾向,稳定腐蚀过程中形成的钝化膜,从而降低了腐蚀速度.     

中国测试技术研究院化学所 四川中测标物科技有限公司

<正>AGV-I呼出气体酒精含量探测器检定装置(适用于JJG657-2006《呼出气体酒精含量探测器》检定规程)动态连续制备标准酒精气体,可任意设置标准酒精气体浓度,并已预置好检定规程要求的浓度点;不同浓度气体制备时间小于15秒,检定时效极高。可制备干气和湿气乙醇混合气体,同时适用于干法和湿法的检定校准。浓度量值直接溯源至国家一级标准物质。气体浓度量值稳定,重复性好。实时自动采集出口温度和压力,实时显示工况、标况状态下的酒精气体浓度,包括摩尔质     

Scatchard-Hildebrand热力学模型在PA印刷层迁移预测中的应用

目的探讨Scatchard-Hildebrand热力学模型对塑料印刷层中有害物质迁移分配系数预测的适用性和准确性。方法以聚酰胺(PA)印刷层中5种迁移物为代表,选取相关文献中PA印刷层中有害物质向不同模拟液中迁移的实验测试结果数据,对分配系数实验值Fexp与模型预测计算值Fsim作对比分析,并用实验数据对Scatchard-Hildebrand统计热力学模型进行校正,研究了模型修正系数Ks(Ks=ln(Fsim/Fexp))与迁移物相对分子质量(M)及其醇-水分配系数(log P)以及模拟液极性(Ps)间的关系。结果 PA印刷层中有害物质迁移分配系数的预测模型修正系数Ks与M和Ps间呈现显著的线性关系,得到了修正后的分配系数预测模型。结论修正后的Scatchard-Hildebrand热力学模型对预测塑料PA印刷层中有害物质迁移分配系数具有一定的适用性。     

含α-生育酚的PE/PVA活性包装膜对鲜切苹果品质的影响

目的研究含α-生育酚的聚乙烯/聚乙烯醇(PE/PVA)活性包装膜对鲜切苹果品质的影响。方法通过溶液-涂布法制备得到含不同浓度α-生育酚的PE/PVA薄膜,测定分析贮藏期间含不同浓度α-生育酚的PE/PVA薄膜对鲜切苹果的色泽、质量损失率、硬度、维生素C含量、可滴定酸含量以及多酚氧化酶(PPO)活性的变化。结果含α-生育酚的PE/PVA薄膜可以使鲜切苹果的褐变减缓,失重率增加,硬度、维生素C含量和可滴定酸含量下降,抑制了其PPO活性,随着包装膜中α-生育酚含量的增加,对鲜切苹果品质的保护效果越好。结论该活性包装膜可以减缓鲜切苹果的品质变化,证明向包装薄膜中添加抗菌剂、抗氧化剂等来达到延长食品货架期是有效的。     

The metabolism of fatty alcohols in lipid nanoparticles by alcohol dehydrogenase

Fatty alcohols are commonly used in lipid-based drug delivery systems including parenteral emulsions and solid lipid nanoparticles (NPs). The purpose of these studies was to determine whether horse liver alcohol dehydrogenase (HLADH), a NAD-dependent enzyme, could metabolize the fatty alcohols within the NPs and thus serve as a mechanism to degrade these NPs in the body. Solid nanoparticles (<100 nm) were engineered from oil-in-water microemulsion precursors using emulsifying wax NF as the oil phase and polyoxyethylene 20-stearyl ether (Brij 78) as the surfactant. Emulsifying wax contains both cetyl and stearyl alcohols. NPs were incubated with the enzyme and NAD+ at 37 degrees C for up to 48 h, and the concentrations of fatty alcohols were quantitatively determined over time by gas chromatography (GC). The concentrations of cetyl alcohol and stearyl alcohol within the NPs decreased to only 10-20% remaining after 15-24 h of incubation. In parallel, NP size, turbidity and the fluorescence intensity of NADH all increased over time. It was concluded that horse liver alcohol dehydrogenase/NAD+ was able to metabolize the fatty alcohols within the NPs, suggesting that NPs made of fatty alcohols may be metabolized in the body via endogenous alcohol dehydrogenase enzyme systems.     

The Metabolism of Fatty Alcohols in Lipid Nanoparticles by Alcohol Dehydrogenase

ABSTRACT

Fatty alcohols are commonly used in lipid-based drug delivery systems including parenteral emulsions and solid lipid nanoparticles (NPs). The purpose of these studies was to determine whether horse liver alcohol dehydrogenase (HLADH), a NAD-dependent enzyme, could metabolize the fatty alcohols within the NPs and thus serve as a mechanism to degrade these NPs in the body. Solid nanoparticles (<100 nm) were engineered from oil-in-water microemulsion precursors using emulsifying wax NF as the oil phase and polyoxyethylene 20-stearyl ether (Brij 78) as the surfactant. Emulsifying wax contains both cetyl and stearyl alcohols. NPs were incubated with the enzyme and NAD⁺ at 37°C for up to 48 h, and the concentrations of fatty alcohols were quantitatively determined over time by gas chromatography (GC). The concentrations of cetyl alcohol and stearyl alcohol within the NPs decreased to only 10–20% remaining after 15–24 h of incubation. In parallel, NP size, turbidity and the fluorescence intensity of NADH all increased over time. It was concluded that horse liver alcohol dehydrogenase/NAD⁺ was able to metabolize the fatty alcohols within the NPs, suggesting that NPs made of fatty alcohols may be metabolized in the body via endogenous alcohol dehydrogenase enzyme systems.     

Variations of alcohol impairment in different types, causes and contexts of injuries: results of emergency room studies from 16 countries

OBJECTIVE: The purpose of this paper is to document alcohol impairment (based on a blood alcohol content (BAC) of at least 80 mg%) for different types, causes and location contexts of injuries. DESIGN AND SETTING: Data from 45 studies with 11,536 injury patients were merged to determine variations in the percent of alcohol impairment among injury patients. In each study, emergency room (ER) injury patients were given a short interview on the circumstances of their injury and BAC was measured. RESULTS: Injury severity, measured by number of body regions injured was significantly associated with BACs over 80 mg%. The highest percentage of injury type to involve alcohol was head injury/concussion. In terms of causes of injuries, patients with alcohol impairment were significantly more likely to be involved in violence than any other cause (i.e., vehicle, falling, poisoning or burns). Finally, injuries occurring at a bar or restaurant were significantly more likely to involve alcohol impairment than any other setting. CONCLUSIONS: The results demonstrate considerable variation in the circumstances where alcohol is involved in injuries. These results may be useful for the development of prevention initiatives.     

Shape optimization for 2D diffusive scalar transport

A new theoretical formulation is presented for the shape optimization problem associated with maximizing or minimizing the diffusive scalar transport from a two-dimensional body. In particular, we consider the diffusive transport of heat from an isothermal body into a medium with constant temperature at the far-field. The formulation also applies to mass and momentum transport. The diffusion problem, which is governed by the Laplace equation, is addressed using conformal mapping techniques where the two-dimensional domain is mapped onto a simpler domain where an analytical solution can be readily obtained. The objective function of the optimization problem is the length of the object in the transformed domain and the variables of the optimization are the parameters of the Schwarz-Christoffel transformation. The length of the object in the transformed domain is related to the scalar displacement, which corresponds to a far-field temperature drop or rise (slip velocity in case of momentum transport), that depends on the shape of the body and it quantifies the enhancement or reduction in transport rate. The mathematical formulation is validated by addressing two fundamental shape optimization problems associated with maximizing or minimizing the transport rate (drag in case of momentum transport) from a two-dimensional body of unit span: i) for a given surface area to obtain the shape that maximizes the transport rate from a body, ii) for a given volume to obtain the shape that minimizes the transport rate from a body. For both cases we compute numerically that the cylinder is the optimal shape. The versatility of the formulation is further demonstrated by including constraints with respect to the length of the body.     

纳米细菌纤维素/聚乙烯醇复合水凝胶在模拟体液中的疲劳行为

聚乙烯醇(PVA)复合水凝胶作为半月板及软骨等长期承重植入体,在生理环境中的疲劳行为关系到植入体的持久性和稳定性。采用弥散增强的方法将纳米细菌纤维素(BC)均匀分散在PVA水凝胶基体中,制备了纳米BC/PVA复合水凝胶。在模拟体液(SBF)环境中,采用压缩疲劳过程分析、疲劳前后刚度变化分析及疲劳前后尺寸稳定性分析3种方法,测试和评价了复合水凝胶的抗疲劳性能和力学稳定性。结果表明:纳米BC/PVA复合水凝胶在模拟人体环境中具有良好的抗疲劳性能,能够满足体内植入物的抗疲劳性能需求;纳米BC的加入可以有效提升复合水凝胶的力学稳定性和抗疲劳性能,但随着纳米BC含量的进一步升高,复合水凝胶的抗疲劳性能有所减弱,当PVA与纳米BC质量比为30∶1时,纳米BC/PVA复合水凝胶疲劳前期与后期最大位移变化量最小(0.002mm),疲劳前后刚度变化最小(5.41%),且疲劳前后尺寸稳定性最强,变形量仅为0.427mm,抗疲劳性能达到最佳。     

Evidence for an early onset of endogenous alcohol production in bodies recovered from the water: implications for studying alcohol and drowning

Endogenous alcohol production can increase the blood alcohol concentration (BAC) of drowning victims following submersion and confound epidemiological studies of the role of alcohol. This study seeks to determine how soon after a drowning death a victim's BAC is influenced by post-mortem alcohol production. The drop in mean lung weight that occurs over time in the water was hypothesized to serve as a proxy for the time course of decomposition, and thus provide an empirical measure to determine how soon after death to first suspect endogenous alcohol. The autopsy lung weights of 562 previously healthy males who drowned were compared across six submersion time groups (0-11.9, 12-23.9, 24-47.9, 48-95.9, 96-167.9 and >or=168 h) and two times of year (winter and non-winter). The hypothesis that a drop in lung weight is sensitive to the time course of decomposition was supported by (1). a statistically significant drop in mean lung weight that occurred 12-23.9 h post-submersion in the non-winter months, but not until 96-167.9 h in the colder winter months; and (2). a significant drop in lung weight was not observed in the group of cases with zero BAC. With a parallel finding that an increase in the proportion of cases with a positive BAC first occurred at the 12-23.9 h submersion group during the warmer non-winter months, we concluded that production of alcohol can occur in bodies recovered from the water as early as 12 h after death. Because excluding drownings with submersion durations greater than 12 h would exclude almost half of our cases from epidemiological studies of alcohol and drowning, additional evidence from the forensic literature was used to develop an adjustment procedure to account for endogenous alcohol production for submersion times of up to 1 week.     

Hydromechanics of low-Reynolds-number flow. Part 6. Rotation of oblate bodies

Summary Uniform ring distributions of fundamental singularities for Stokes flows, Stokeslets and rotlets, are applied to obtain exact solutions for rotating oblate bodies in an unbounded viscous fluid. The technique used in the present investigation is the inverse-problem approach. Instead of determining the types of singularities and their spatial distributions for a given body geometry, the body shape is determined for a given distribution of singularities. The rotating axis of a body is perpendicular to the plane containing the ring and it passes through the center of the circular ring. The direction of rotlets is parallel to the rotating axis, while the Stokeslets are tangent to the ring and lie in its plane. By changing the radius of the ring and/or changing the strengths of Stokeslets and rotlets, we obtain a family of rotating oblate bodies including simply-connected and doubly-connected bodies. Two special cases involving a slightly deformed sphere and a spinning slender torus are also discussed.     

Effects of low-dose alcohol exposure on simulated merchant ship piloting by maritime cadets

The US Department of Transportation (DOT) regulates on-the-job alcohol use by operators of certain categories of commercial transport. For aircraft, trains, and commercial vessels, operators are subject to sanctions for having > or = 0.04 g% blood alcohol concentration (BAC). This study examines the effects of alcohol (between 0.04 and 0.05 g% BAC) on simulated merchant ship handling. A two-group randomized factorial design was used to compare beverage alcohol to placebo while controlling for baseline performance on a previous day. The study was conducted in the Maritime Simulation Center at Maine Maritime Academy, Castine, ME. Participants were 38 volunteer deck officer cadets in their junior or senior year, at least 21 years of age, with previous experience on a bridge simulator. Following a baseline trial on Day 1, on Day 2 participants were randomized to receive alcohol (0.6 g/kg for males and 0.5 g/kg for females) or placebo. After allowing time for absorption, participants completed a bridge simulator task. For baseline and performance trials, participants were randomized to one of four bridge simulator scenarios, each representing passage of a fully loaded container vessel through a channel with commercial traffic. The aggregate scenario score given by blinded maritime educators measured performance. A main effect for alcohol was found indicating that performance was significantly impaired by this low dose of alcohol relative to performance in the placebo condition. These findings are consistent with current federal regulations that limit low-dose alcohol exposure for the operators of commercial transport vehicles. Further research is required to determine effects at lower BACs.     

Flexible body dynamics in a local frame with explicitly predicted motion

This paper deals with formulation of dynamics of a moving flexible body in a local frame of reference. In a conventional approach the local frame is normally fixed to the corresponding body and always represents the positions and angles of the body: the positions and angles are represented by Cartesian coordinates and Euler angles or Euler parameters, respectively. The elastic degrees of freedom are expressed by, e.g. nodal coordinates in a finite element analysis, modal coordinates, etc. However, the choice of these variables as the generalized coordinates makes the resulting equations of motion extremely complicated. This is because the representation of the rotation of a body is highly non‐linear and this non‐linearity makes the coefficient matrices dependent on the coordinates themselves. In this paper, we propose an alternative way of treating the issue by explicitly predicting the body motions and regularly updating the local frame. First, the motion of the local frame is assumed to explicitly follow the associated moving body. Then, the equations of motion are derived in a set of generalized coordinates that express both rigid‐body and elastic degrees of freedom in the local frame. These equations are solved by a time integration with a given time interval. The motion of the local frame in the interval is estimated from a prediction of the rigid‐body motions. Then, the gap between the predicted and the actual motions is evaluated. Finally, the predictions are iteratively corrected by the obtained responses in the rigid‐body motions so that the gap should remain within an imposed tolerance. Copyright © 2009 John Wiley & Sons, Ltd.