昆明假单胞菌HL22-2海藻糖合酶基因的克隆、表达及酶学性质研究

采用热不对称交错聚合酶链式反应（Tail-PCR）克隆云南磷矿来源昆明假单胞菌（Pseudomonas kunmingensis）HL22-2的海藻糖合酶（TreS）基因HL22-2TreS，将该基因与表达载体pETM3C连接后在大肠杆菌（Escherichia coli）BL21（DE3）pLysS中进行异源表达，通过Ni-NTA柱纯化重组酶HL22-2TreS，并对其酶学特性进行分析。结果表明，HL22-2TreS基因全长3 336 bp，编码1 111个氨基酸，氨基酸序列与Genbank数据库中相关的海藻糖合酶具有极高的相似性。重组酶HL22-2TreS的分子质量约126 kDa，该酶的最适反应温度和pH值分别为40 ℃和7.0，在温度20～50 ℃及pH值6.0～9.0条件下比较稳定，Cu2+、Hg2+、Ba2+及Al3+对海藻糖合酶的活力有强烈的抑制效果。HL22-2TreS基因对麦芽糖和海藻糖的米氏常数（Km）分别为20.6 mmol/L和87.5 mmol/L，对麦芽糖具有更高的亲和性，更容易将麦芽糖转化成海藻糖。     

A novel approach to the Poisson’s ratio of the yarn

Abstract

The Poisson’s ratio is a fundamental and inherent property of the materials in their reaction to loading. Determining the correct value of the Poisson’s ratio leads to more accurate predictions of the mechanical behavior of the material, especially in employing mechanical or numerical finite element modeling methods. In this study, seven different types of medium and coarse yarn were digitally filmed in seven sections from three various angles while tensile strength testing. Then, longitudinal and transverse strains and consequently, momentary deformation index and Poisson’s ratio of the yarns were calculated. Significance level of the mean Poisson’ ratio was also determined at different angles and sections using statistical comparison test. The results showed that the transverse strain has a convergent state at the end of the test and the start of the yarn breaking occurs at the convergence point. Additionally, in upper sections of yarn near to the movable jaw of the strength tester, the amount of the longitudinal strain increases which leads to reduce in momentary deformation index and Poisson’s ratio of the yarn. Moreover, a sectional mode to measure the Poisson's ratio was presented.     

负泊松比针织结构及其应用

本文对各个负泊松比材料的作用原理进行概括和总结,并简要介绍了目前用针织技术实现负泊松比结构的方案,包括平面经编织物、三维间隔织物、纬编折叠结构织物等。最后对负泊松比结构针织物在服用和产业用方面广泛的潜在应用分别进行了介绍,并展望了负泊松比结构针织物在以后研究中的发展方向及前景。     

海洋栖热菌β-胡萝卜素15,15’双加氧酶原核表达

以海洋栖热菌（Oceanithermus sp.）DN-1基因组DNA为模板，通过PCR法扩增β-胡萝卜素15,15’双加氧酶BCMOTA基因，构建重组质粒，在大肠杆菌Escherichia coli BL21(DE3)中表达，并采用高效液相色谱（HPLC）法检测酶活性。结果表明，通过镍柱亲和层析和分子筛Sephacryl TM S-100，得到纯化重组β-胡萝卜素15,15’双加氧酶，十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析结果表明，该酶分子质量约35 kDa；该酶的最适温度为50 ℃，最适pH值为8.0。在此优化反应条件下，生成569.3 mg/L全反式视黄醛，转化率达到89.5%。     

Regression-adjusted Poisson EWMA control chart

Exponentially weighted moving average (EWMA) control chart has a significant effect in improving product quality and is widely used in various fields. In addition to continuous data, there are many Count Data in life that need to be monitored. Poisson distribution is one of the models that study the probability distribution of discrete data, and has a wide range of applications. In previous monitoring, it was considered that the mean value of Poisson distribution in normal state was a constant value after it was determined. But in the actual situation, there are many unavoidable objective conditions that will affect the final results. We cannot monitor all situations according to the same criteria. If we ignore the conditions that affect the occurrence of the event and directly monitor the final result, on the one hand, it will increase the probability of false alarms from the control chart. On the other hand, the control chart will not be able to detect problems in time due to the untimely update of conditions. In response to this situation, this paper proposes a regression-adjusted EWMA control chart to monitor the Poisson process. The control chart can continuously adjust and update the expected values according to the actual situation. It can make the monitoring process more reasonable and the monitoring results more valuable.     

Dynamic response of a beam to the train of moving forces driven by an Erlang renewal process

Dynamic response of a beam to a random train of moving forces moving with the same velocity is considered. Unlike a widely used Poisson process model, a more adequate Erlang renewal process is used as a process driving the train of forces. Normal-mode approach is used to convert the problem into that of a renewal driven train of general pulses. Consequently the modal responses are the filtered renewal processes and are expressed as integrals with respect to the response to a single pulse (passage of a force) and to the increments of the counting renewal process. The expressions for the mean values and cross-correlations of modal responses are obtained as single and double integrals, respectively. The results are presented in terms of the renewal density of the underlying Erlang counting process. Mean value and variance of the mid-span deflection of the beam are determined by numerical evaluation of the pertinent integrals. Numerical analysis is carried out for the Erlang processes with integer parameter $k=2$, $k=3$ and 4 and, for comparison, also for a Poisson process. Different traffic conditions such as the velocity and the mean arrival rate of vehicles are taken into account.     

X线能谱中重叠峰的处理

回顾了Ｘ线能谱中重叠峰的处理方法，本文述及重叠系数法和退卷积法。阐述了重叠峰的概念、重叠系数的计算和测量方法以及强度的计算。介绍了方法的原理，并列举了具体实例。     

特大型采场充填体单轴压缩条件下的力学性能

对安庆铜矿特大型采场不同配比的充填体进行无侧限单轴抗压强度试验，分析单轴抗压强度、平均杨氏模量、泊松比力学性质的变化及其规律，为特大型矿柱的开采提供前期的数据准备。结果表明，随水泥含量增多，充填体强度基本呈线性增大；平均抗压强度提高百分率随灰砂比的提高而变小；充填体的平均峰荷应变随水泥含量增加而逐渐增大；在从低配比（1：10）向高配比（1：8）转变的过程中，平均杨氏模量有一个较大的波动；充填体的泊松比随灰砂配比的变化不大。     

大红山铜矿岩石物理力学性质试验研究

对大红山铜矿435中段矿岩的单轴抗拉强度、抗压强度、抗剪强度、泊松比、弹性模量、内摩擦角以及内聚力进行了室内试验研究。试验得出一系列岩石物理力学参数,为矿山下一步生产实践做好了准备。