广西产马尾松与湿地松针叶精油化学成分的比较

用水蒸气蒸馏法从广西产马尾松和湿地松的针叶中提取精油,探索了松针投料量和提取时间对产油率的影响,确定了最佳工艺条件为：松针投料量700 g,提取时间5 h。在此最佳条件下马尾松和湿地松针叶的产油率分别为0.45%和0.19%。用气相色谱（GC）和气相色谱-质谱（GC-MS）等方法分别对两树种的针叶精油进行了定量和定性分析,从马尾松针叶精油中分离出64种化学成分,鉴定了其中的20种成分,占挥发油总量的98.59%;从湿地松针叶精油中分离出73种化学成分,鉴定了其中的29种成分,占挥发油总量的94.23%。两树种针叶精油的主要化学成分大致相同,但在含量上有较大差别。马尾松针叶精油中α-蒎烯的含量约为湿地松的2.6倍,但其β-蒎烯含量低于后者。单萜和倍半萜是构成马尾松和湿地松针叶精油的主要成分。     

几种煤沥青热转化过程的对比

几种煤沥青热转化过程的对比冯映桐，水恒福，袁晓敏（华东冶金学院，马鞍山２４３００２）关键词　煤沥青，热转化，针状焦原料用于制取炼钢用超高功率电极的针状焦，其原料煤沥青的组成和性质首先要满足要求。本文选择了典型的五种煤沥青籍离心法预处理把影响热转化过程...     

基于χ~2检验法的通脑活络针刺法对脑梗死患者BI指数的影响

用r×s列连表的Pearson x~2检验法,讨论通脑活络针刺法、溶栓剂法与常规法在各救治时间窗对脑梗死患者BI评分的影响,并得到结论,通脑活络针刺法在各救治时间窗的"治愈率"及较好的康复程度方面显示了显著疗效.     

高效液相-电化学检测法研究针刺对家兔血浆及脑组织中单胺类神经递质的影响

 通过高效液相 电化学检测法测定了电针刺激家兔肾旁穴前后其血浆及脑组织中单胺类神经递质去甲肾上腺素 (NE)、肾上腺素 (E)、多巴胺 (DA)和 5 羟色胺 (5 HT)含量的变化 ;研究了神经递质的变化与家兔繁殖能力的关系。该实验采用ODS柱 ,流动相为V(0 0 2mol/L柠檬酸三钠 0 0 5mol/L磷酸氢二钠 )∶V(甲醇 ) =95∶5的溶液 ,用电化学检测器检测。实验证明 ,血浆及脑组织中NE ,E ,DA和 5 HT的含量在针刺肾旁穴前后都有了显著的变化 ,说明针刺能激发家兔脑内神经元的活动 ,导致相应的递质含量的变化 ,同时使得血浆中相应含量也发生变化。     

Application of the “cooled needle” technique to split and splitless sampling onto capillary columns

Cooled needle sampling using syringes was applied to splitless injection and to simulated distillation analyses. Slight changes of the construction of the previous device are also described. The changes concern the temperature profile within the injector and especially the vaporization insert. Even with the low carrier gas flow through the injector during splitless injection, discrimination by component volatility can be avoided. Precision and accuracy of simulated distillation data obtained with split sampling also can be improved by the cooled needle technique.     

Needle-Trap Device (NTD) Packed with Reduced Graphene Oxide (rGO) for Sample Preparation Prior to the Determination of Polycyclic Aromatic Hydrocarbons (PAHs) from Aqueous Samples by Gas Chromatography–Mass spectrometry (GC-MS)

A needle trap device (NTD) was developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) from liquid samples followed by determination by gas chromatography–mass spectrometry (GC-MS). The extraction was performed using the dynamic sampling approach, in which a liquid sample was pumped through the system. Due to the flexibility and softness of graphene, its application in NTD may be difficult. Herein, the effectiveness of reduced graphene oxide (rGO) packed in NTD in dynamic extraction of PAHs was evaluated. Several experimental parameters, such as the adsorbent mass, eluent type and its volume, as well as the sample volume were optimized to achieve satisfactory performance for dynamic extraction. Comparative studies showed that the extraction performance of rGO-NTD was better than using NTDs packed with other sorbents such as activated carbon. The recovery rate for reduced graphene oxide exceeded 92%. Comparison of dynamic and headspace sampling showed comparable results but the dynamic mode is more suitable for field measurements. The recovery rates of PAHs spiked in water samples were from 76.5 to 100.2% and the relative standard deviation values were from 2.7 to 7.5% under the optimal conditions. This work reveals the potential of NTD with a graphene-based material for sample preparation before chromatographic analysis of liquid samples.     

煤系针状焦原料在成焦过程中的XRD结构分析

低QI(原生喹啉不溶物)含量的软沥青（SCTP）是制备煤系针状焦的优选原料,研究其在成焦过程中的结构变化有助于高品质针状焦的研制。基于样品的X射线衍射（XRD）数据,利用Smarsly团队开发的CarbX软件对其全谱拟合,定量出SCTP在不同炭化温度（400,500,600,800,1 000,1 200和1 400 ℃）下的微晶结构参数,进而在纳米尺度下研究SCTP的热致结构变化情况。结果表明,随炭化温度升高,微晶堆垛的石墨烯层大小L_a从初始沥青的10.3 Å逐步增大到1 400 ℃的47.9 Å,但在500 ℃前L_a增加缓慢,只有当温度超过800 ℃后,L_a才显著增大,这表明需要800 ℃以上的高温才能使交联石墨烯层内的原子重组,进而导致微晶长大。然而,石墨烯碳网的C—C键长l_cc受温度的影响很小,在1.41~1.42 Å范围内变化。由于SCTP在液相炭化成半焦过程中存在中间相转化,导致微晶堆垛高度L_c在500 ℃前逐步增大,在500 ℃时达到最大（L_c=31.1 Å）,随后由于半焦进一步热解缩聚,使L_c逐步减小,在1 000 ℃时达到最低点（L_c=15.4 Å）,超过1 000 ℃后又开始增大。与L_c的变化趋势相同,堆垛的石墨烯层数N从原始沥青的2.66层增加到500 ℃的约9.05层,随后减小到1 000 ℃的4.55层,超过1 000 ℃后又开始增大。由于500 ℃前样品仍处于沥青态,所以此阶段微晶的石墨烯层间距a₃都较大,约为3.50 Å。当在500 ℃变为半焦后,a₃迅速减小至3.44 Å。随后温度升高,a₃在1 000 ℃达到最小（a₃=3.39 Å）,1 000 ℃后又开始增大,这表明焦炭经历了收缩再膨胀过程。通过CarbX软件拟合样品的XRD数据,除了可得到样品炭微晶的主要尺寸（L_a,L_c,N,a₃）信息外,还可获得这些参数的分散性（k_a,k_c,σ₃,ε₃）以及堆垛的取向性（q）、均匀性（η）和无序碳含量（c_un）等信息,有利于深入了解样品的微观结构,有助于优质针状焦的生产。     

Selective adsorption and removal ability of pine needle-based activated carbon towards Al(III) from La(III)

Rare earth elements are an important strategic resource. As one of the most valuable member, lanthanum plays a key role in lanthanide. However, trace Al(III) impurity in lanthanum materials can seriously damage the performance of lanthanum materials. In this paper, a nitrogen-containing activated carbon, AC-PN-700, was synthesized using pine needle as raw material and KOH as activator. The AC-PN-700 was characterized by surface area analyzer, elemental analysis and FT-IR. The adsorption and selective ability of AC-PN-700 towards Al(III) were investigated. The BET specific surface area of AC-PN-700 was 596.4 m².g^?1, and the average pore diameter was 2.7?nm. Depend on its large specific surface, well-developed internal pore structure and abundant nitrogen-containing functional groups, the AC-PN-700 possesses strong adsorption affinity and excellent recognition selectivity towards Al(III). The adsorption capacity of AC-PN-700 towards Al(III) could reach to 3.89?mg.g^?1, removal rate towards Al(III) was almost 100%, and relative selectivity coefficients with respect to La(III) is 9.5. The empirical Freundlich isotherm was found to describe well the equilibrium adsorption data. In addition, AC-PN-700 possesses better regeneration ability and reusability.     

煤系针状焦微晶结构的XRD与Raman分峰拟合定量研究

采用XRD和Raman光谱分析技术,结合分峰拟合的数学方法,对不同生产厂家的三种煤系针状焦Coke-N,Coke-H,Coke-P进行了研究。由XRD分析结果计算出了三种针状焦的石墨化度、晶体结构类型以及晶粒尺寸(La和Lc),通过对XRD的分峰拟合处理,得出了三种针状焦中趋于规整结构的碳微晶含量(Ig)。通过对样品的XRD分析可知,Coke-N和Coke-P的石墨化程度及Lc相接近,并且明显大于Coke-H;La之间的关系为:Coke-NCoke-PCoke-H。通过Raman光谱结合分峰拟合的数学方法对样品进行了定量分析。研究结果表明,三种针状焦在拉曼位移1 000~2 000cm-1处有5个一阶谱拟合峰(G,D1,D2,D3,D4)。对样品的拉曼一阶谱拟合后所得出的每个拟合峰面积进行计算,可以用来定量分析三种针状焦中碳微晶结构的分布情况。由I_G/I_(All),I_(D1)/I_G,I_(D2)/I_G,I_(D3)/I_G,I_(D4)/I_G的计算可知,Coke-N和Coke-P的微晶结构比Coke-H的微晶结构更规整。在Coke-N中理想石墨碳微晶所占比例为0.33,而Coke-H和Coke-P分别为0.086和0.311。另外,Coke-H在三个样品中的无定形碳比例明显大于另外两个样品。Raman光谱分析结果与XRD的分析结果相吻合。由此可以看出,采用XRD和拉曼光谱分析技术可以从微观层面判定宏观质量不同的煤系针状焦差异的实质。     

一种实心针静电纺丝装置的场强模拟及优化

提出一种实心针静电纺丝方法, 采用实心针作为静电发射极, 并将其置于由绝缘材料制成的导液棒轴心, 导液棒处于储液盒底部的圆锥沉头通孔内部并可以做升降运动以控制供液量, 需要时还可以起到通流的作用, 有效地解决了多针头静电纺丝堵塞和无针头静电纺丝开放式供液的问题. 利用COMSOL有限元分析软件对影响场强大小及分布的各参数进行场强模拟, 研究增大场强并减小边缘效应的改进方法, 并采用研发的不完全齿轮横动机构纺丝头做往复横动进行纺丝实验, 验证了实心针静电纺丝装置有效降低了能耗和边缘效应, 避免了针头堵塞及溶剂挥发问题.