环保物联网中远程设备实时控制问题研究

选择Flash XMLSocket作为浏览器端和服务器端双向通信的关键技术,解决了HTTP协议中无法直接实现实时双向通信的问题;通过在监听服务器端建立Socket连接通道路由表并实时更新,解决了服务器只能被动连接数采仪导致实时控制时延较大的问题;结果表明,服务器端的控制时延很小,几乎可以忽略不计,浏览器端在足够的网络带宽下,也能保证较低的控制时延,满足了工业使用的需求。     

沉淀分离-气相色谱法测定聚氯乙烯塑料制品中的磷酸甲苯酯类增塑剂

建立了沉淀分离前处理技术结合气相色谱法测定聚氯乙烯塑料制品中磷酸甲苯酯类增塑剂含量的分析方法.采用四氢呋喃作溶剂将聚氯乙烯塑料溶解,以甲醇为沉淀剂,有效地将增塑剂从聚合物中分离出来,再采用气相色谱-火焰光度检测器进行分析.磷酸甲苯酯的3种异构体在0.1～2.0 mg/L范围内线性关系良好,相关系数大于0.999,方法平均回收率在82.9％～99.1％之间,测定结果的相对标准偏差为0.8％～5.9％,方法的检出限为50 mg/kg.本方法操作简便,准确性好,适用于聚氯乙烯塑料中磷酸甲苯酯类增塑剂含量的测定.     

高效液相色谱-串联质谱法快速测定水果中氯吡脲残留量

应用高效液相色谱-串联质谱法快速测定水果中的氯吡脲残留量。水果样品经乙腈均质提取,以N-丙基乙二胺、C18和无水硫酸镁作吸附剂净化。所得净化液以C18色谱柱为分离柱,以不同体积比混合的甲醇和5mmol·L-1乙酸铵溶液为流动相梯度洗脱进行分离,采用电喷雾正离子源多反应监测模式检测。氯吡脲的质量浓度在0.005~0.200mg·L-1范围内与峰面积呈线性关系,测定下限(10S/N)为1.0μg·kg-1。在0.01,0.05,0.10mg·L-1 3个浓度水平进行加标回收试验,回收率在86.4%~106%之间,相对标准偏差(n=6)在3.2%~9.5%之间。     

一种用于鸡蛋中氯霉素残留测定的吡啶类离子液体双水相体系

建立了由亲水性离子液体N-乙基吡啶溴化盐([Epy]Br)和K2HPO4形成的双水相体系对鸡蛋中痕量氯霉素(CAP)检测的高效液相色谱方法.优化了离子液体[Epy]Br和K2HPO4成相的条件,研究了萃取CAP的最佳体系.采用混合溶液(pH=7磷酸盐溶液,NaCl溶液,甲醇)提取样品,离子液体双水相体系富集,V(甲醇):V(水)=30:70为流动相,流速1.0 mL/min,UV检测器,检测波长278 nm,柱温25 ℃,进样量20 μL.对鸡蛋中氯霉素残留进行了测定,在0.05～15 mg/L范围内,CAP的响应峰面积与其相应浓度呈良好相关性(r=0.9994).不同浓度的回收率为90.3%～101.7%,相对标准偏差为1.7%～2.6%.本该法检测鸡蛋中氯霉素残留具有干扰小、速度快、灵敏度高等优点.最低检出限为1 μg/kg.     

吡啶离子液体双水相-高效液相色谱法同时测定牛奶中3种喹诺酮药物残留

建立了吡啶离子液体双水相-高效液相色谱同时测定牛奶中噁喹酸、萘啶酸及氟甲喹3种喹诺酮药物残留的方法. 牛奶样品经氯化钠和磷酸混合溶液提取后, 采用吡啶离子液体N-乙基-2-甲基吡啶溴化盐([EMPy]Br)和K2HPO4形成的双水相体系萃取富集, 以0.1%磷酸水溶液-乙腈为流动相, 梯度洗脱, 紫外检测. 该方法对噁喹酸、萘啶酸和氟甲喹测定的线性范围分别为0.3~15, 0.5~20和0.5~25 μg/mL, 相关系数(r)均大于0.9997, 3种药物的检出限在8~10 μg/kg之间. 对不同加标浓度的牛奶样品测定, 绝对回收率均在86.4%~94.8%范围内, 相对标准偏差为3.6%~8.3%. 该方法对牛奶中喹诺酮药物残留的检测具有简单、快速、环保和灵敏度高等优点.     

对食品中苏丹红检测标准的改进

在高效液相色谱法(HPLC)测定食品中苏丹红染料的标准方法(GB/T 19681-2005)中规定试样经处理后溶于丙酮中,而苏丹红染料标准则用正己烷溶解.试验发现:苏丹红染料在上述两种不同的溶剂中进行HPLC测定时,同样浓度的染料得出的出峰时间和峰面积显著不同.按原标准的方法,由于试样及标准所用溶剂不同,造成定性及定量检测结果的明显偏差.因此各标准染料用正己烷溶解后须先转换成丙酮溶液方能用于制作标准曲线.经这一改进后,各染料在0.15～4.0 mg·L-1线性范围内的相关系数均大于0.999.测定值的相对标准偏差均小于5%,回收率达90%以上.     

Electronic structure of heavy fermion system CePt_2In_7 from angle-resolved photoemission spectroscopy

We have carried out high-resolution angle-resolved photoemission measurements on the Ce-based heavy fermion compound CePt_2In_7 that exhibits stronger two-dimensional character than the prototypical heavy fermion system CeCoIn_5.Multiple Fermi surface sheets and a complex band structure are clearly resolved. We have also performed detailed band structure calculations on CePt_2In_7. The good agreement found between our measurements and the calculations suggests that the band renormalization effect is rather weak in CePt_2In_7. A comparison of the common features of the electronic structure of CePt_2In_7 and CeCoIn_5 indicates that CeCoIn_5 shows a much stronger band renormalization effect than CePt_2In_7. These results provide new information for understanding the heavy fermion behaviors and unconventional superconductivity in Ce-based heavy fermion systems.     

Electronic structure and nematic phase transition in superconducting multiple-layer FeSe films grown by pulsed laser deposition method

We report comprehensive angle-resolved photoemission investigations on the electronic structure of single crystal multiple-layer FeSe films grown on CaF_2 substrate by pulsed laser deposition(PLD) method. Measurements on FeSe/CaF_2 samples with different superconducting transition temperatures T_c of 4 K, 9 K, and 14 K reveal electronic difference in their Fermi surface and band structure. Indication of the nematic phase transition is observed from temperature-dependent measurements of these samples; the nematic transition temperature is 140-160 K, much higher than ~90 K for the bulk FeSe. Potassium deposition is applied onto the surface of these samples; the nematic phase is suppressed by potassium deposition which introduces electrons to these FeSe films and causes a pronounced electronic structure change. We compared and discussed the electronic structure and superconductivity of the FeSe/CaF_2 films by PLD method with the FeSe/SrTiO_3 films by molecular beam epitaxy(MBE) method and bulk FeSe. The PLD-grown multilayer FeSe/CaF_2 is more hole-doped than that in MBE-grown multiple-layer FeSe films. Our results on FeSe/CaF_2 films by PLD method establish a link between bulk FeSe single crystal and FeSe/SrTiO_3 films by MBE method, and provide important information to understand superconductivity in FeSe-related systems.