射频辉光放电发射光谱法测定不锈钢成分的研究

研究了射频辉光放电发射光谱法(rf-GD-OES)测定不锈钢成分C,Si,Mn,P,S,Cr,Ni,Cu,Co,Al。考察了射频功率、载气气压、预溅射时间等仪器参数对不锈钢元素谱线发射强度及相对强度稳定性的影响和直流自偏压与射频功率和载气气压的关系。以此为基础,优化后的最佳分析条件为:射频功率90 W、载气气压300 Pa、预溅射时间100 s、积分时间20 s。方法用于测定不锈钢标准样品,测定值与认定值相符,精密度良好。     

射频辉光放电发射光谱法测定中低合金钢中痕量钙

通过对射频辉光放电发射光谱法分析中低合金钢样品放电行为的研究,考察了各种工作参数如分析功率、氩气压力、预燃时间和积分时间等对光谱强度与稳定性的影响。优化后的分析参数为分析功率50 W、氩气压力900 Pa、预燃时间90 s和积分时间10 s。以铁元素为内标,建立了射频辉光放电光谱法测定中低合金钢中痕量钙的分析方法,并用于中低合金钢标准样品和实际样品分析,测量结果与认定值或原子吸收光谱法测定值相吻合, RSD小于2%,满足生产科研的需要。     

中低合金钢中多元素的射频辉光放电发射光谱发射谱线性质的研究

考察了射频辉光放电发射光谱法中功率(5~18W)和放电气压(5~15Torr)对元素谱线发射强度及相对强度稳定性的影响,并分析了引起影响的原因。结果表明,功率越高,发射强度越大;放电气压对各元素谱线发射强度的影响各异。在气压6~12Torr范围内,除5W外功率变化对大多数元素相对强度稳定性影响较小,相对标准偏差介于0.5%~2%。当功率在12W时,在10Torr气压下测定中低合金钢标准样品中C,Si,Mn,P,S,Cr,Ni,W,Ti,Cu,Co,B,Al,V,Mo,Nb16种元素,测定值与认定值一致;相     

双层辉多元共渗合金元素的吸收率

在20钢基材上,利用双层辉光离子渗金属技术进行Ni-Cr-Mo-Cu多元共渗。通过回归分析,并用非线性规划得出双辉离子渗金属合金元素吸收率的最佳工艺参数为源极电压1050V,工件电压250V,极间距15.431mm,气压35Pa。     

双层辉光多元共渗合金元素的吸收率

在20钢基材上,利用双层辉光离子渗金属技术进行Ni-Cr-Mo-Cu多元共渗.通过回归分析,并用非线性规划得出双辉离子渗金属合金元素吸收率的最佳工艺参数为源极电压1050V,工件电压250V,极间距15.431mm,气压35Pa.     

氢化物发生-ICP-AES法测定钢铁中的微量碲

探讨了氢化物发生-ICP-AES法测定钢铁中微量碲的方法,对碲产生氢化物的条件进行了优化实验,最佳样品测定介质为盐酸（40mL／100mL）;最佳仪器条件：射频功率1350W,雾化气压力0．17MPa,辅助气流量4．2×10^-4m／s。在最佳条件下,体系的强度与碲离子的浓度成线性关系,线性范围是0～0．01mg／mL,检出限0．003μg／mL,相对标准偏差1．05％。     

ICP法同时测定工作场所中的锰、铜和锌

研究了用电感耦合等离子体(ICP)对工作场所中的锰、铜和锌进行同时测定的方法。优化了ICP的工作参数:射频功率发生器频率27.12 MHz,入射功率为1.2 kW,放射功率小于5W,载气流量1.2 L.min-1。三种元素的检出限在0.105~0.500之间,相对标准偏差(RSD)(n=6)均小于7%,回收率均在94.5%~103.6%之间。该方法用于工作场所中元素的测定,结果令人满意。     

反应溅射法在蓝宝石衬底上制备CeO2缓冲层

用金属铈作为靶材,采用射频反应磁控溅射法在（1 102）蓝宝石衬底上制备C轴取向CeO2外延薄膜缓冲层。结果表明在温度低于450℃或溅射功率低于50 W的条件下CeO2薄膜呈（111）取向生长;升高温度和功率CeO2薄膜的（111）取向减弱,（002）取向增强;在温度高于750℃或溅射功率高于120 W条件下CeO2薄膜呈（111）取向和（002）取向混合生长。结合X射线衍射仪和原子力显微镜表征CeO2薄膜的结构和表面形貌,获得在最优化条件下（衬底温度在680℃左右,溅射功率在80 W左右,溅射气压在25 Pa,氩氧比在15∶1）制备的CeO2薄膜具有优良的面内面外取向和平整的表面。     

应用于固体样品直接分析的射频辉光光谱中等离子体空间解析的初步研究

设计了一种新的实验设备用于研究发射光谱的射频辉光中原子和离子的空间分布。通过测量沿等离子体羽流的不同原子和离子的发射强度来研究发生在等离子体内部的激发/离子化过程。该报导对辉光源与质谱联用的优化有较大意义,如离子提取的最佳位置。初步研究了连续和脉冲射频辉光光谱中等离子体的空间解析,尤其对影响发射信号的输入功率、压强及占空比等参数进行了评价。     

辉光放电发射光谱法测定钢板镀锌层中铅镉铬

通过条件试验,确定了辉光放电发射光谱仪(GD-OES)的最佳分析参数为:分析功率30 W、氩气气压620 Pa、预溅射时间200 s、积分时间10 s。选用多种基体标准样品,通过溅射率校正建立校准曲线,定量分析镀锌板镀层中铅、镉、铬元素含量及分布状况,得到镀锌层中各元素随深度变化的分析谱图,方法定义了镀层中元素积分计算方法,从而得到镀层中铅、镉、铬元素含量。以纯锌标准样品进行检出限测定,各元素的检出限分别为3.65(铅)、1.33(镉)、0.21(铬) μg/g;以纯锌标准样品进行短期精密度考察,3个元素测定结果的相对标准偏差(RSD, n=15)分别为2.8%(铅)、1.3%(镉)、6.6%(铬)。制备了典型涂镀样板,采用实验方法进行测定,并采用电感耦合等离子体质谱法进行比对分析,结果一致性较好。实验方法适用于快速定量测定钢表面1～50 μm厚度的镀锌板镀层中铅、镉、铬元素含量。     

玻尔兹曼分布研究辉光放电等离子体中铁原子谱线的激发机制

采用玻尔兹曼分布法,通过不同的放电参数,例如外加电压、电流和气压等,研究了辉光放电等离子体中激发能量为4.1～7.0 eV的铁原子谱线激发机制。低激发能量曲线很好地拟合了正玻尔兹曼分布,然而较高激发能量的原子谱线与线性玻尔兹曼曲线有很大偏差。其结果可能是由于较低等级激发由热碰撞引起,而另一方面,铁原子高位等级的激发则是铁原子和氩或氖亚稳原子间的碰撞引起的。     

电感耦合等离子体原子发射光谱法测定偏钒酸钾中钾

试样经盐酸和硝酸消解后用水稀释和定容,以电感耦合等离子体原子发射光谱法(ICP-AES)测定试液中钾含量。通过控制取样量和定容体积,有效将钾元素检测信号的强度值调控到适宜水平,确保方法具有良好的动态线性范围。考察了基体效应、光谱干扰以及背景影响等因素,通过采取优选雾化器压力、等离子体激发功率、观测高度等仪器工作参数以及元素分析谱线、背景校正位置等措施,并结合基体匹配和同步背景校正方式,消除了碱金属离子、高钒基体、氩气分子谱带等对试液雾化传输、ICP平衡与激发、背景噪音和元素测定等影响因素。结果表明:钾的质量分数在40%以下校准曲线呈良好线性关系,相关系数为0.999 3。对本法的精密度和回收率进行试验,得到RSD小于1.0%,平均回收率为103%。方法用于实际样品中钾测定,测定结果与四苯硼酸钾重量法的测定结果相一致。     

电感耦合等离子体质谱法测定硒时多元素干扰的碰撞/反应研究及其在地质样品中的应用

采用电感耦合等离子体质谱仪(ICP-MS)在常规模式下测定硒时,由等离子体中大量氩原子所形成的多原子离子干扰不容忽视,使得硒的准确测定成为难题。控制碰撞气流量为4.5 mL/min,载气流量为0.85 L/min,ICP功率为1 300 W,采用碰撞/反应模式,以氢氦(体积比为7∶93)混合气为碰撞气体,⁸⁰Se为测定同位素,降低了多原子离子的干扰,建立了一种电感耦合等离子体质谱法测定地质样品中硒的分析方法。在优化的实验条件下,方法检出限为0.08 μg/g。采用实验方法对地质样品标准物质GBW07106、GBW07401、GBW07404及实际样品中的硒进行测定,结果与认定值或标准方法NY/T1104—2006测定值基本一致,相对标准偏差(RSD,n=5)不大于6.0%。     

Enhanced mass resolving power, sensitivity, and selectivity in laser desorption Fourier transform ion cyclotron resonance mass spectrometry by ion axialization and cooling

Ion cooling and axialization produced by azimuthal quadrupolar excitation in the presence of ion-neutral collisions are applied to laser desorption Fourier transform ion cyclotron resonance mass spectrometry (LD/FT/ICR-MS). With this technique, the large kinetic and internal energies of ions generated by laser desorption processes can be cooled effectively by collisions of ions with neutral argon atoms (at > 5 x 10(-7) Torr). After sufficient cooling in the source compartment of a dual ion trap, the axialized ions may be transferred to the analyzer compartment for detection at much lower pressure (and thus much higher mass resolving power). Enhancements in both FT/ICR mass resolving power and sensitivity are observed; moreover, ion isolation with high selectivity at high pressure is also demonstrated.     

平面激光诱导荧光法研究取样锥下电感耦合等离子体的离子空间分布

为提高电感耦合等离子体质谱仪(ICP-MS)的检测灵敏度,理解电感耦合等离子体(ICP)激发源中取样锥对分析元素电离机理的影响至关重要。借助于激光诱导荧光技术,研究了ICP-MS和电感耦合等离子体原子发射光谱仪(ICP-AES)中,钡原子、基态及亚稳态离子在等离子体内的空间分布差异,重点说明取样锥对分析元素原子化及离子化机理的影响。在ICP-MS中,相较于ICP-AES,水冷取样锥的插入对分析元素轴向分布有复杂影响;取样锥锥前0~2mm内,钡原子及离子荧光信号显著降低,可归因于取样锥对等离子体温度的影响及第一真空室真空压力对分析元素的加速作用;而取样锥锥前2~10mm范围内,由于取样锥的存在,一价钡离子的数密度显著升高。因此推断在高温等离子体内,存在大量的二价钡离子;而在ICP-MS中,一价钡离子荧光信号的增强为中性原子、一价及二价离子之间相互转化的结果。     

Circadian entrainment and phase shifting in mammals with melatonin

BACKGROUND: Diathermy procedures are indispensable in interventional endoscopy. Argon beam coagulation is an innovative no-touch electrocoagulation technique in which high-frequency alternating current is delivered to the tissue through ionized argon gas. METHOD AND PATIENTS: Before clinical application, we conducted in-vitro studies to investigate the depth and diameters of tissue coagulation in fresh operative specimens from the stomach, small intestine and colon. Five different power/gas flow settings between 40 and 155 W and 2 and 7 l/min were used. The impact time (1-10s) and the incident angle of the probe (45 degrees and 90 degrees) were also varied. The maximum depth of necrosis was 2.4 mm, the maximum diameter 1.1 cm. No perforation occurred even in critical areas such as the colon and duodenum. We therefore performed argon beam coagulation in 66 consecutive patients. Two power/gas flow settings of 40 and 70 W and 2 and 3 l/min, respectively, were used. The impact time and incident angle were varied individually. RESULTS: In 49 of the 50 patients with oozing haemorrhage from angiodysplastic lesions, polypectomy sites, erosions or ulcers or oozing of blood due to vascular penetration by tumours, definitive haemostasis was achieved in one to two sessions. In all 11 patients with residual sessile adenoma tissue, complete removal was possible. Oesophageal patency was restored in all five patients with stenosing tumours. In one patient with angiodysplasia of the caecal pole, an asymptomatic accumulation of gas in the submucosa was observed which resolved spontaneously. In two patients with extensive oesophageal carcinoma, there was a transitory--also asymptomatic--accumulation of gas in the mediastinum and peritoneal cavity but no evidence of perforation. CONCLUSION: Argon plasma electrocoagulation is an effective and relatively low-cost alternative to laser therapy in gastrointestinal endoscopy.     

高温空气燃烧技术蜂窝陶瓷传热模拟研究

利用计算流体力学（CFD）软件,结合正交实验,研究了空气高温燃烧中蜂窝陶瓷的孔径、壁厚、高度以及烟气、空气的流速、温度、切换时间等各参数对换热性能和压力损失的影响,提出了一个最优方案,并对最优方案进行了详细分析。最优方案的加热期温度效率为94．6％,冷却期温度效率为93．7％,压力损失为457．7Pa。     

Quadrupole mass filtering for registration of blood gas partial pressures

With a newly developed quadrupole mass spectrometer several blood gas partial pressures are recorded simultaneously and continuously. In the mass filter the separation of the ions to be detected takes place in a hyperbolic electric field with variable direct and alternating voltages with a constant frequency of 2.4 MHz. For blood gas analysis a fully relaxed experimental animal was artifically ventilated and provided with arterial and venous catheters. Each catheter consisted flexible steel tubing (external diameter 0.6 mm) slotted near the end and covered with a silicone rubber membrane. The distance from the measuring tip to the mass spectrometer was 150 cm. Experiments with blood, in vivo equilibrated with gas mixtures, showed good reproducibility; the mean error of the helium partial pressure, for example, was less than 4%. During respiration using a gas mixture with 40% argon, the time constant t63% was found to be 55 s for the whole experimental arrangement including the experimental animal.