Poly NP试验及MPNP试验快速检测肺炎克雷伯菌多粘菌素类耐药表型的应用评估

目的:探讨快速多粘菌素NP试验（rapid polymyxin NP test,Poly NP test）对多粘菌素类耐药肺炎克雷伯菌的检测价值;进一步评估改良快速多粘菌素NP试验（modified rapid polymyxin Nordmann/Poirel test,MPNP）对产MCR肺炎克雷伯菌的检出价值。方法:本研究共纳入48株菌,包括14株多粘菌素类敏感肺炎克雷伯菌（polymyxin sensitive Klebsiella pneumoniae,PolS-KP）,29株多粘菌素类耐药细菌（26株为多粘菌素类耐药肺炎克雷伯菌(polymyxin resistant Klebsiella pneumoniae,PolR-KP),3株为多粘菌素类天然耐药菌）,以及5株非发酵菌。以微量肉汤稀释法的结果为标准,采用Poly NP试验检测多粘菌素类的药敏表型。PCR及测序确定肺炎克雷伯菌的多粘菌素类染色体介导的耐药基因pmrA/pmrB,phoP/phoQ,mgrB和质粒介导的耐药基因mcr-1～mcr-8,采用MPNP试验检测是否为产MCR阳性菌株。结果:29株多粘菌素类耐药菌,3株天然耐药细菌的Poly NP试验均为阳性;26株PolR-KP中,24株为Poly NP试验阳性,2株为阴性;14株PolS-KP均为阴性,且所有结果均在2 h内出现最终颜色变化。该方法判断肺炎克雷伯菌多粘菌素类耐药表型的敏感性和特异性为93.1%和100%。26株PolR-KP中,有4株为MCR阳性,其中3株产mcr-1,1株产mcr-8;22株为染色体介导的耐药,其中12株为双组分系统PmrAB突变,4株为双组分系统PhoPQ突变,6株为mgrB基因改变。4株MCR阳性菌株的MPNP试验表现为阴性结果,其余非MCR株的PolR-KP和PolS-KP,以及多粘菌素类天然耐药菌株的MPNP均表现为阴性结果。MPNP试验不能筛选出MCR阳性的肺炎克雷伯菌。结论:Poly NP试验快速,特异性强,敏感性高,可用于临床多粘菌素类耐药肺炎克雷伯菌的快速检测。MPNP试验对MCR阳性肺炎克雷伯菌检出不佳,仍需进一步探讨适用于肺炎克雷伯菌的MCR快速表型检测方法。     

用模糊ISODATA方法评价重金属污染土壤的研究

污染土壤问题已经引起了世界范围的关注，其中污染程度的综合评价是一个非常重要的组成部分，当前的评价方法也是多种多样。针对重金属污染土壤的模糊性，采用模糊ISODATA方法对其进行了综合评价。首先利用VB6．0将该方法编程实现，然后调节参数q，得到了不同的评价结果，通过对结果进行分析，得出结论：在选定的评价标准和初始矩阵条件下，当q值小于4时，改变8可得到不同的评价结果，而当q大于等于4时，评价结果唯一，将该结果与用其它方法评价得到的结果进行对比，是可信的。该方法简便、易行，值得推广。     

钛材离子氮化工艺对其组织结构和性能的影响

本文介绍钛材离子氮化工艺对其组织结构和性能的影响。合理选择离子氮化温度、气氛氮势和处理时间,能有效控制钛材氮化层中的化合物相的种类和相对含量。通过离子氮化处理,大幅度提高了钛材的表面硬度。耐磨性能和在还原性介质中的耐蚀性能,可使钛材在高度动负荷、摩擦力和强腐蚀介质三者同时存在的苛刻环境中长期使用。     

平方根容积卡尔曼滤波器

针对容积卡尔曼滤波器在递推过程中,计算量大、数值不稳定等问题,提出了平方根容积卡尔曼滤波器。该滤波器不仅增强了数值鲁棒性,确保了状态协方差矩阵的正定性,且在一定程度上提高了滤波精度。仿真结果表明,该滤波器的滤波精度与容积卡尔曼滤波相比提高了约10%,且均高于扩展卡尔曼滤波;随着状态维数的增加,该滤波器的估计性能越加优于扩展卡尔曼滤波器。因此对系统维数较高的场合,该滤波器是一种非常有效的非线性滤波算法。     

用于浮法玻璃的制氮工艺流程的分析优化

以需求量为2 000 Nm/h的500~700 t/d浮法玻璃的制氮工艺(目前主流生产线)为例,综合论证企业采用的3种方案,提供优化的配置方案和工艺流程,针对不同企业具体情况,提供了选择工艺流程的理论依据,具有显著的实际指导意义。     

Nanocrystalline Barium Strontium Titanate Ceramics Synthesized via the “Organosol” Route and Spark Plasma Sintering

Dense nanocrystalline barium strontium titanate Ba_0.6Sr_0.4TiO₃ (BST) ceramics with an average grain size around 40 nm and very small dispersion were obtained by spark plasma sintering at 950°C and 1050°C starting from nonagglomerated nanopowders (~20 nm). The powders were synthesized by a modified “Organosol” process. X‐ray diffraction (XRD) and dielectric measurements in the temperature range 173–313 K were used to investigate the evolution of crystal structure and the ferroelectric to paraelectric phase transformation behavior for the sintered BST ceramics with different grain sizes. The Curie temperature T_C decreases, whereas the phase transition becomes diffuse for the particle size decreasing from about 190 to 40 nm with matching XRD and permittivity data. Even the ceramics with an average grain size as small as 40 nm show the transition into the ferroelectric state. The dielectric permittivity ε shows relatively good thermal stability over a wide temperature range. The dielectric losses are smaller than 2%–4% in the frequency range of 100 Hz–1 MHz and temperature interval 160–320 K. A decrease in the dielectric permittivity in nanocrystalline ceramics was observed compared to submicrometer‐sized ceramics.     

适于应用型创新人才培养的化学实验教学改革探索

根据应用型创新人才的培养目标,结合我校化学实验教学在课程体系、师资队伍、教材内容、教学观念、教学方法、教学形式、考核方式等方面进行的教学改革研究和实践,探索适用于应用型创新人才培养的化学实验教学改革方向。     

芘修饰芴衍生物PTF的结构和光学性质

采用量子化学方法研究了一种芘修饰芴衍生物PTF的结构和光学性质。结果表明,该化合物呈现蝴蝶型结构,空穴注入传输性能强,发蓝光,这在理论上进一步证实其可作为蓝光材料或空穴材料应用于OLED。     

回采动压下软岩巷道全断面封闭支护技术研究

软岩巷道支护技术一直是煤矿生产中研究的重点,尤其是在回采动压下施工巷道,支护不当将导致巷道大量返修,给安全、生产等带来了很大的隐患,因此寻求一种理想的支护方式支护动压下的软岩巷道已成为新的研究课题。开滦荆欢矿业分公司东井采用全断面封闭支护技术收到了较好效果。     

First-principles calculations and experimental studies of Sn-Zn alloys as negative electrode materials for lithium-ion batteries

The physical characters and electrochemical properties of various phases in a Sn-Zn electrode,such as formation energy,plateau potential,specific capacity,as well as volume expansion,were calculated by the first-principles plane-wave pseudo-potential method based on the density functional theory.Sn-Zn films were also deposited on copper foils by an electroless plating technique.The actual composition and chemical characters were explored by scanning electron microscopy (SEM),X-ray diffraction (XRD),plasma atomic emission spectrometry (ICP),and constant current charge/discharge measurements (CC).The results show that separation phases with tin and zinc including a small quantity of Cu6Sn5 phase were obtained,the initial lithium insertion capacity of the Sn-Zn film was 661 mAh/g,and obvious potential plateaus of about 0.4 V and 0.7 V were displayed,which is in accordance with the results of theoretical calculations.The capacity of the Sn-Zn film decreased seriously with the increase of cycle number.