用单颗粒气溶胶质谱研究海宁市秋、冬季PM_(2.5)化学组成及来源

对海宁市区PM_(2.5)来源进行分析,分别于2016年11月11日~24日以及2016年12月13日~21日期间,使用单颗粒气溶胶质谱仪(SPAMS)在海宁市环境保护监测站点位进行了为期14天和8天的定点监测,分别代表了秋季和冬季的监测结果。结果表明,监测期间海宁市总体空气质量较好,优、良天气占比为75.8%。海宁市首要污染物为机动车尾气源,燃煤源次之,工业源排在第三位。整体来看,监测期间PM_(2.5)质量浓度的升高大多伴随着燃煤及机动车尾气占比的同步升高。秋、冬季的重度污染过程与燃煤源和机动车尾气源的升高有关,其中秋季的燃煤源贡献高峰可能与监测点位西北方向的气团传输有关。     

Two near-infrared highly sensitive cyanine fluorescent probes for pH monitoring

Two near-infrared(NIR) p H-activated heptamethine indocyanine probes with quaternary ammonium unit were designed and synthesized. The absorption and emission titrations indicate that cationic structure improves the cyanine dye's aqueous solubility and these two probes exhibit highly sensitive response to p H in acid condition. Their fluorescence intensities both gradually increase about 25-fold from p H 7.60 to 3.00 with p Ka values of 4.72 and 4.45 respectively, which are suitable for studying acidic organelles in living cells. Moreover, their fluorescence intensities are linearly proportional to p H values in the range of 5.50–4.00. These results are probably attributed to the protonation of the indole nitrogen atoms, which are verified by 1H NMR spectra. Furthermore, these two probes can achieve real-time imaging of cellular p H and detection of p H in situ in living He La cells due to their excellent properties,including good reversibility, desirable photostability, high selectivity, low cytotoxicity and remarkable membrane permeability.     

本研贯通课程“高等物理化学”的实例教学

在"高等物理化学"课程教学中引入实例教学可以有效帮助学生在理论语言与实验语言之间搭建桥梁,借助计算机"可视化"手段向学生展示实体实验难以描述的抽象概念。本课程从量子力学和分子力学出发,设计了由浅入深的7个实例,用计算机模拟方法分别计算了单分子的分子光谱、化学反应路径和溶液的微观异质性,帮助学生从微观层面形象化地理解抽象的物理概念,有效克服了学生的畏难心理,显著提高了学生解决实际问题的能力,改善了理论脱离实践的现状。     

高效液相色谱-四极杆/线性离子阱质谱测定替米沙坦中N-甲基邻苯二胺残留量

建立了高效液相色谱-四极杆/线性离子阱质谱(HPLC-QTRAP-MS/MS)测定替米沙坦中N-甲基邻苯二胺残留量的分析方法。替米沙坦药物以水-乙腈(80∶20,体积比)溶解后,采用Agilent Eclipse XDB-C18色谱柱(3.5μm,2.1 mm×100 mm)进行分离,以0.1%(体积分数)甲酸水和乙腈作为流动相进行梯度洗脱,电喷雾正离子(ESI+)扫描方式下选择离子监测(SRM)模式对样品进行检测。结果表明,N-甲基邻苯二胺在2.0~50μg/L范围内线性关系良好(r0.99),检出限(S/N=3)为0.5μg/L,定量下限(S/N=10)为2.0μg/L。该方法操作简单、灵敏度高、重现性好,可用于替米沙坦中N-甲基邻苯二胺残留量的测定。     

高效液相色谱法同时测定化妆品中的10种美白活性成分及2种禁用成分

建立了同时测定化妆品中10种美白活性成分及2种禁用成分的高效液相色谱分析方法。水基、乳液等含油脂较少的样品采用0.02 mol/L磷酸二氢钾溶液(pH 6.0)直接提取;油脂含量高的样品及蜡基、粉基类的样品先加入2.5 m L二氯甲烷溶解后再用0.02 mol/L磷酸二氢钾溶液(pH 6.0)提取。提取液在9 500r/min下离心后用0.22μm滤膜过滤。样品采用Eclipse XDB-C_(18)色谱柱为固定相,以0.02 mol/L磷酸二氢钾溶液(pH 6.0)和甲醇溶液为流动相,梯度洗脱,流速为1.0 m L/min,柱温为25℃,使用二极管阵列检测器(DAD)进行检测,检测波长为230 nm和250 nm,外标法定量。结果显示:12种化合物在2.5~100 mg/L范围内线性关系良好,相关系数(r)均大于0.999 0。方法的定量下限(以信噪比为10计)为0.006 5%~0.025%,添加水平为0.025%~0.5%时回收率为87%~102%,相对标准偏差均小于4%。该方法前处理简单、回收率高、精密度好,适用于化妆品中10种美白活性成分及2种禁用成分的快速测定。     

渤海稠油及其组分中杂原子化合物的负离子电喷雾-高分辨质谱分析

采用沉淀法和色谱分离法将渤海某油田稠油分离成沥青质、胶质、剩余分3个组分。采用负离子电喷雾技术(ESI)结合高分辨傅立叶变换离子回旋共振质谱仪(FT-ICR MS)研究了该稠油及各组分的分子组成。结果表明,剩余分中有较少的极性杂原子化合物能被负离子ESI电离,如N_1,N_1O_1,O_1和O_2类,其等效双键数(DBE)较小。胶质和原油中极性化合物有相同的杂原子类型,包括N_1,N_1O_1,N_1O_2,N_2,N_2O_2S_1,O_1,O_2,其中胶质和原油中N_1,O_1,O_2类化合物的DBE-碳数分布图相似。沥青质中富集高缩合度且多杂原子的酸性化合物,如含杂原子N_,S的氧化程度高的化合物(N_2O_1,N_1O_3,S_1O_3)及O_3类化合物,这些物质具有较高的界面活性,易吸附在界面上促进界面张力降低和增强界面膜强度,从而有利于乳状液稳定存在。N_1O_1,N_1O_2,N_1O_3类化合物,N_2O_1类化合物可能分别是N_1化合物,N_2化合物的氧化降解产物;随着氧化降解程度增加,降解产物的极性明显增强。     

初中学生血吸虫病检查结果与影响因素分析

目的调查和分析江西南昌地区血吸虫病流行区初中学生血吸虫病情况,及相关影响因素。方法 2015年8月至2016年8月,将江西南昌地区血吸虫病流行区中的19个重点县分为血吸虫病传播控制区和血吸虫病疫情控制区,其中传播控制区调查人数1 569名,疫情控制区调查人数1 723名,对所有的学生均采取问卷调查措施。结果疫情控制区初中学生血吸虫病检查率明显高于传播控制区初中学生血吸虫病检查率,数据比较差异具有统计学意义(P0.05);血防知识知晓及格率越高,检查率越高;学校血防教育频次越高,检查率越高;血防部分教育频次及格率越高,检查率越高,数据比较差异均具有统计学意义(P0.05)。结论江西南昌地区血吸虫病流行区初中学生血吸虫病检查率较低,需要加强对初中学生的健康教育,实现提高初中学生血吸虫病检查率的目的。     

New insights into the impact toughness of ASA (acrylonitrile-styrene-acrylate) with controllable core–shell structure synthesized by three-stage seeded emulsion polymerization

Acrylonitrile-styrene-acrylate (ASA) with controllable core–shell structure was prepared through three-stage seeded emulsion polymerization. A series of characterizations had been performed to study the effect of different core–shell ratios on the properties of ASA. The most interesting was that the impact strength of ASA exhibited a “wave” variation instead of a linear variation with the increasing loading content of poly(butyl acrylate) (PBA) core. Moreover, the threshold of impact strength appeared at 49.725?wt% PBA content, nearly 33 kJ/m². To explain this unusual variation, an impact schematic was proposed.     

Finite-time disturbance observer-based trajectory tracking control for quadrotor unmanned aerial vehicle with obstacle avoidance

This paper investigates the problem of trajectory tracking control for quadrotor unmanned aerial vehicle (UAV) in the presence of dynamic obstacles and external disturbance forces/torques. More specifically, two new sliding mode disturbance observers are firstly designed to estimate the external disturbances, in which the observation errors can converge to zero in finite time. Furthermore, utilizing the observation information, a new sliding mode surface-like variable-based position tracking control scheme and a novel nonsingular terminal sliding mode-based attitude synchronization control scheme are developed to drive the UAV tracking the reference trajectory with obstacle avoiding. Moreover, the tracking errors of the close-loop control system can converge to zero within finite time by the analyses of Lyapunov methodology. Finally, the numerical simulation results are presented to illustrate the effectiveness of the proposed control schemes.     

Volterra算子及其伴随算子线性组合的数值域

经典Volterra算子$V$及其伴随算子$V^*$在复空间$L^2[0,1]$中起着关键作用. 关于$V$和$V^*$的线性组合的性质, 我们给出了确保$z_1V+z_2V^*(z_1,z_2\in\mathbb{C})$满足增生性质的等价条件. 本文描述了$(u+iv)I+mV+nV^*(u,v,m,n\in\mathbb{R},m+n\geq0)$数值域的精确表示.