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将钯基材料对氢气分子的特异选择性吸附能力与声表面波的快速响应特点相结合,可实现一种快速、高灵敏和低功耗的氢气检测与报警技术。传感器由双通道差分式振荡器与沉积在传感器件表面的声表面波传播路径上的钯基气敏薄膜组成。为提升传感器响应速度,该文探讨了采用钯镍合金薄膜与钯铜纳米线作为气敏材料的氢气传感器响应特性,通过对气敏材料制备方法及参数的优化,研制了两种沉积不同钯基气敏材料的氢气传感器件,并对其性能进行了评测。实验测试结果表明:钯铜纳米线气敏材料由于具有大体积表面积比和多孔结构,大幅提高了SAW氢气传感器响应速度,针对浓度为10%、4%以及0.5%的氢气响应时间可达~2s。 相似文献
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研究了不同钯银合金原子比例复合膜对微结构光纤光栅氢气传感特性的影响.使用飞秒激光在布拉格光栅光纤包层加工螺旋微结构,将磁控溅射方法制备的不同钯银原子比例的合金膜镀在螺旋微结构表面,研制优化钯银合金比例的新型微结构布拉格光栅光纤氢气传感器.采用扫描电子显微镜和能谱仪对Pd-Ag薄膜进行表征和分析,对三种不同钯银原子含量(Pd∶Ag=2∶1,4∶1,6∶1)的微结构布拉格光栅光纤探头进行氢气传感测试.在室温条件下,钯银原子比例为4∶1的微结构探头具有最佳的氢气传感性能,钯银原子比例为2∶1的微结构探头响应速度最快,但是灵敏度最低.在4%氢气浓度下,螺旋微结构传感器的漂移量达到107pm,对比同类型布拉格光栅光纤氢气传感器,具有更高的灵敏度和更快响应速度. 相似文献
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基于飞秒激光加工的马赫-曾德尔干涉氢气传感器 总被引:1,自引:0,他引:1
介绍了一种基于光纤微加工的氢气传感技术方案。利用波长为800nm的飞秒激光脉冲在普通单模光纤上加工马赫-曾德尔(M-Z)干涉腔,并采用磁控溅射方法在加工后的M-Z干涉微腔上溅射钯(Pd)膜,制备了一种新型的光纤氢气传感器。分析了加工工艺对微腔干涉效果的影响,选择合适的加工参数以及加工后对微腔进行后续处理,可使微腔的透射光谱的分辨率得到提高。实验研究了腔长为40μm的M-Z干涉传感器分别镀36nm、110nmPd膜后,对氢气的响应。结果表明,在不同的氢气浓度下,镀Pd膜的M-Z干涉传感器都表现出对氢气的敏感特性,随着氢气浓度的增大,透射光谱会向长波长方向偏移,其中Pd膜厚度为110nm比厚度为36nm的传感器对氢气有更好的灵敏度。 相似文献
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提出了一种基于Sagnac干涉仪的保偏光子晶体光纤(PM-PCF)氢气传感器,建立了传感模型并进行了实验研究和验证。采用对靶磁控溅射技术将钯银(Pd/Ag)合金快速均匀地沉积在保偏光子晶体光纤侧面,并利用Pd吸收氢气后的形变调制保偏光子晶体光纤的双折射,通过测量Sagnac干涉仪输出光谱峰值的变化实现氢气浓度的测量。实验结果表明该传感器可检测的氢气浓度范围为0%~4%,且具有良好的重复性。室温下对低浓度氢气具有较高的灵敏度,氢气浓度由0%变化到1%时的波长偏移量达1.307nm。采用双折射温度不敏感的保偏光子晶体光纤,可很好地抑制外界温度变化对传感器的干扰。 相似文献
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介绍了一种基于光子晶体光纤(PCF)干涉仪的新型氢气传感器。该传感器采用反射式光路设计,在氢气传感单元中引入一段PCF。该PCF的一端以及一部分包层外壁在真空条件下蒸镀了一层金属钯膜,另一端接入光路,构成一套全光纤氢气传感系统。实验中记录了氢气浓度(体积分数)从0到5%变化时传感单元对应的干涉谐振波长的变化,谐振波长最大的移动可达1.2nm,相比大多数基于布拉格光栅的光纤氢气传感器,相同条件下灵敏度有很大的提高。整套传感系统未引入任何分立的光学元件,在兼顾了全光纤光路的条件下,实现了较高的检测灵敏度。 相似文献
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交联壳聚糖富集分离-石墨炉原子吸收光谱法测定痕量钯的研究 总被引:6,自引:1,他引:5
将环氧氯丙烷与壳聚糖进行交联反应制备了不溶于酸、碱的交联壳聚糖(CCTS),研究了不同pH条件下CCTS对于Pd(Ⅱ)的吸附特性,结果表明:在pH 1~4时,吸附20 min,CCTS对Pd(Ⅱ)的吸附率达98%以上;考察了吸附时间、试样体积、CCTS用量、共存元素等对CCTS吸附Pd(Ⅱ)的影响、吸附容量以及Pd(Ⅱ)的脱附;探讨了吸附机理;建立了CCTS预富集分离, 石墨炉原子吸收光谱(GFAAS)测定痕量钯的新方法。该法检出限(3σ, n=8 )为0.143 μg·L-1,相对标准偏差(RSD)小于5.47%, 用于湖水和海水中痕量钯的检测, 回收率在92%~96%之间。该法还可用于钯的回收利用。 相似文献
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为了考察钛表面氧化层的阻氘性能,要进行表面有氧化层的钛吸附和解吸氘实验,从反应动力学的角度,考察吸附和解吸氘反应的快慢,通过计算吸附和解吸氘反应的表观活化能来分析氧化层对吸附和解吸氘特性的影响。 相似文献
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Masatoshi Takeda Hiroki KurisuSetsuo Yamamoto Hamazo NakagawaKatsunobu Ishizawa 《Applied Surface Science》2011,258(4):1405-1411
This paper addresses a hydrogen outgassing mechanism in titanium materials with extremely low outgassing property by investigating the distribution of hydrogen atoms concentration in depth below the surface, and the activation energy for desorption of dissolved hydrogen atoms into the boundary region between the surface oxide layer and the bulk titanium and that of adsorbed hydrogen atoms on the surface. The distribution of hydrogen atoms concentration in depth below the surface was analyzed by a time-of-flight secondary ion mass spectrometry (TOF-SIMS). The activation energy for desorption of dissolved hydrogen atoms was estimated by the thermal desorption spectroscopy (TDS) measurement with various heating rates. The activation energy for desorption of adsorbed hydrogen atoms was estimated by the temperature dependence of the outgassing rate in titanium material. In the titanium material, hydrogen atoms show maximum concentration at the boundary between the surface oxide layer and the bulk titanium. Concentration of hydrogen atoms decreases rapidly at the surface oxide layer, while it decreases slowly in the deep region below the surface layer-bulk boundary by the vacuum evacuation without/with the baking process. The activation energy for desorption of 1.02 eV of dissolved hydrogen atoms into the surface layer-bulk boundary is about three times as large as that of 0.38 eV of the adsorbed hydrogen atoms on the surface. These results suggest that the hydrogen outgassing mechanism in the titanium material is composed the follows processes, i.e. the slow hydrogen atoms diffusion at the surface layer-bulk boundary, quick hydrogen atoms diffusion at the surface oxide layer and rapid desorption of adsorbed hydrogen atoms on the surface. This outgassing mechanism gives very low hydrogen concentration near the surface, which results in the extremely low outgassing rate in titanium materials. 相似文献
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C. Nützenadel A. Züttel D. Chartouni G. Schmid L. Schlapbach 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(2):245-250
Metal hydrides are used for electrochemical or gaseous storage of hydrogen because considerable amounts of hydrogen are reversibly
absorbed and desorbed at interstitial sites. Palladium is often used as a model system. Nanophase material is of interest
because properties related to the hydrogen absorption are size dependent. In this study, clusters from the size of 55 to 1415
atoms are investigated and compared with bulk Pd. It turns out that not only the amount of hydrogen per palladium that can
be intercalated changes but also kinetics and chemical potentials are dependent on the cluster size. The clusters used for
this study were chemically synthesised and stabilised by a ligand shell.
Received 9 October 1998 and Received in final form 10 May 1999 相似文献
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应用LAS-2000二次离子质谱表面分析系统作了如下测量:(1)测出HL-1装置的总出气量以及其主要出气组分的出气量百分比和出气峰值温度等参数;(2)对等离子体-表面相互作用进行了SIMS/蒙特卡洛互补分析,测出等离子体边界层中氢气量径向特征长度和氢粒子注入硅片的特征深度,估算出氢通量平均动力温度;(3)对硅收集探针的SIMS/AES分析表明,HL-1等离子体删削层中主要杂质组分为O、C、Ni、Mo和Cr,同时给出原子密度相对百分比;在HL-1装置中用原位蒸钛来吸氧、碳杂质,从而提高了等离子体纯度和品质;(4)定期检测表明,装置的器壁表面污染呈减弱趋势,这说明HL-1真空系统的设计研制及运行维护技术措施等是合适的。 相似文献
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Magnesium doping in hierarchical zinc oxide nanostructures has been carried out using an aqueous method. The XRD results confirmed the hexagonal wurtzite structure for the magnesium doped zinc oxide nanoparticles. On doping with Mg2+, there is a change in morphology of the hierarchical nanostructures to nanorods. The optical absorption and photoluminescence properties of the nanostructures depend on the magnesium doping level. A blue shift of the band gap absorption and the near band edge emission is observed on Mg doping. 相似文献
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Combined electrochemical and dilatometry measurements were used to characterize the transport of hydrogen through thin RuO2 layers coated on palladium wire electrodes. Hydrogen dissolved in aqueous solutions penetrated through the oxide in a pH-dependent mechanism that combined diffusion of molecular hydrogen and pH-dependent proton hopping through redox sites within the oxide lattice. When cathodically charged, hydrogen was generated and absorbed at the oxide-solution interface only after Ru (IV) reduction occurs, and then, transported into the metal. 相似文献
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The effect of hydrogen on the photovoltage and I-V characteristics of palladium/anodic oxide/gallium arsenide Schottky diodes is studied. The oxide thickness that is optimal in terms of the hydrogen sensitivity of the diodes and the depth of atomic hydrogen penetration into the oxide are determined. The mechanism behind the hydrogen effect consists in the chemical adsorption of atomic hydrogen on the gallium arsenide surface, which decreases the barrier height and increases the recombination component of the current. It is shown that a thin tunnel-transparent anodic oxide film is nonuniform in thickness and that hydrogen exposure raises the probability of tunneling through the oxide. It is found that the method of hydrogen detection from the photovoltage response offers a higher sensitivity and detectivity but has a lower speed than the reverse current method. 相似文献
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Joanna Prazmowska Tomasz Piasecki Adam Szyszka Regina Paszkiewicz Marek Tłaczała 《Central European Journal of Physics》2011,9(2):392-397
In the paper results of investigation of the influence of low concentration hydrogen on stress changes in thin catalytic metal
films were discussed. The concentration of H2 was altered from 6 ppm to 1% of hydrogen (6N) in nitrogen (6N). Silicon beams covered with palladium or platinum films of
various thicknesses were anchored at one end and their deflection at the other end was measured by atomic force microscope.
Stress changes were determined by application of modified Stoney formula and compared with results of computer modelling.
The influence of stress caused by hydrogen absorption on the alteration of output characteristics of AIII-N based hydrogen
sensors was excluded. The time dependence of stress in metallic films for various hydrogen concentrations indicated dissociation
limited mechanism of hydrogen absorption. 相似文献
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The interaction of a palladium nanocontact with a hydrogen molecule has been studied using molecular static method. The influence
of impurity on the atomic structure and mechanical properties of the palladium nanocontact has been demonstrated. The characteristic
interatomic distance has been determined in this contact. It has been found that the hydrogen molecule dissociates by interaction
with nanocontact atoms. 相似文献
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I. N. Nikolaev R. R. Galiev 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2008,2(1):98-103
The morphological features of palladium thin films deposited on different substrates are described. Film deposition has been performed by means of the pulsed laser evaporation method. It is shown that the grain structure of palladium films is formed independently of the substrate roughness. Particular emphasis is placed on the correlation between gas-sensitive metal-insulator-semiconductor (MIS) sensor properties and the nanostructure of palladium films used as metal electrodes in these sensors. It is concluded that a change in the morphology of palladium films has no direct influence on the degradation of the hydrogen sulphide sensitivity of MIS sensors that arises after sensor annealing in air enriched with hydrogen. 相似文献
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The nature of the optical absorption band arising in amorphous MoO3 and WO3 films on insertion of hydrogen atoms was investigated carrying out this process over a wide temperature range. Hydrogen atoms
were inserted in oxide films detached under the action of light from organic molecules adsorbed on the oxide surface. The
absorption spectra were successfully fitted with three Gaussian functions each being assigned to the definite type of color
centers.
Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998. 相似文献