Sample Heating System Research Articles

Oxidation state of zirconium and tungsten on a Schottky electron source at high temperature

We investigated the zirconium-oxide-coated-tungsten (100) surface, which is widely used as the electron-emitting surface in Schottky electron sources. To extract electrons, the emitter is heated to approximately 1800 K. When the surface reaches a temperature greater than 1400 K, the work function of the (100) surface is selectively lowered by the coating of zirconium and oxygen, and surface diffusion of the atoms is rapid on the tungsten surface. The mechanism behind this process, however, is not clear because it is difficult to analyze the surface at high temperatures. In this study, we resolved this issue by improving our sample heating system and investigated the zirconium and oxygen-coated tungsten (100) surface using X-ray photoemission spectroscopy at 1500 K. The stable heating system helped us acquire highly reliable spectra, enabling us to elucidate the detailed bonding state of the atoms on the surface. We also found that a large amount of oxygen is present on the surface even at high operating temperatures. Moreover, zirconium and tungsten are partially oxidized, and the stoichiometry of these oxides is distinctly different from that of the stable oxide within the bulk.

A high sensitivity variable temperature infrared spectroscopy investigation of kaolinite structure changes.

A new approach for thermal analysis based on variable temperature infrared spectroscopy is described and evaluated. Diffuse reflection optics are employed with a sample heating system that does not employ a sealed environmental chamber. Rather than using a sample cup, a thin layer of solid particles is loaded into a "button" sample holder. The new design minimizes spectral artifacts and provides enhanced optical throughput compared to other designs, but necessitates a more restrictive sample heating temperature range. Results obtained while monitoring solid-state temperature-dependent changes are used to assess the sensitivity of the method. Infrared spectrum changes associated with reversible and irreversible kaolinite structure changes are described and characterized. Subtle temperature-dependent sample changes are revealed by positive and negative difference spectrum residuals, which are obtained by subtracting infrared spectra obtained at different temperatures. Scan-to-scan infrared spectrum relative standard deviations at 30 and 150°C were less than 1.0%, which was slightly higher than the ambient temperature reproducibility.

Improved identification and quantitation of mature endogenous peptides in the rodent hypothalamus using a rapid conductive sample heating system.

Measurement, identification, and quantitation of endogenous peptides in tissue samples by mass spectrometry (MS) contribute to our understanding of the complex molecular mechanisms of numerous biological phenomena. For accurate results, it is essential to arrest the postmortem degradation of ubiquitous proteins in samples prior to performing peptidomic measurements. Doing so ensures that the detection of endogenous peptides, typically present at relatively low levels of abundance, is not overwhelmed by protein degradation products. Heat stabilization has been shown to inactivate the enzymes in tissue samples and minimize the presence of protein degradation products in the subsequent peptide extracts. However, the efficacy of different heat treatments to preserve the integrity of full-length endogenous peptides has not been well documented; prior peptidomic studies of heat stabilization methods have not distinguished between the full-length (mature) and numerous truncated (possible artifacts of sampling) forms of endogenous peptides. We show that thermal sample treatment via rapid conductive heat transfer is effective for detection of mature endogenous peptides in fresh and frozen rodent brain tissues. Freshly isolated tissue processing with the commercial Stabilizor T1 heat stabilization system resulted in the confident identification of 65% more full-length mature neuropeptides compared to widely used sample treatment in a hot water bath. This finding was validated by a follow-up quantitative multiple reaction monitoring MS analysis of select neuropeptides. The rapid conductive heating in partial vacuum provided by the Stabilizor T1 effectively reduces protein degradation and decreases the chemical complexity of the sample, as assessed by determining total protein content. This system enabled the detection, identification, and quantitation of neuropeptides related to 22 prohormones expressed in individual rat hypothalami and suprachiasmatic nuclei.

Investigation of formation heat treatment to enhance the multiscale gas transport ability of shale

In order to achieve the most economical production of shale gas, fracture networks should be as complex as possible to connect the matrix micropores, natural fractures and induced fractures efficiently. Since shale rock is very tight, hydraulic multi-fracturing in horizontal wells has been the key technology in shale gas development. However, it is still difficult to connect small-scale pores in the matrix. Meanwhile, the recovery rate of a fracturing fluid is low, resulting in severe formation damage primarily induced by water blocking or water phase trapping. In this work, formation heat treatment is studied for the first time in gas-shale to address these issues. Samples from Longmaxi Shale are used to investigate the change in the multiscale gas transport ability after a high temperature treatment. A core sample heating system is specially designed to measure a permeability change during a high temperature treatment. Field scanning electron microscopy imaging, total organic carbon and low pressure nitrogen adsorption measurements are also implemented to analyze a change in the micro structure after the high temperature treatment. The results indicate that shale permeability increases rapidly with an increase in temperature, especially when the temperature is more than 400–500 °C, which can be described as a threshold value in a percolation model. Experimental results also indicate that the quality of the shale matrix can be dramatically improved after a high temperature treatment since there is a high quartz and organic matter content in the shale. Stimulation mechanisms of a formation heat treatment in shale gas reservoirs are described as water removing, mineral and organic matter structure changes and multiscale fracture network generation. For the field application of formation heat treatment, both its advantages and issues that still need to be addressed are deeply analyzed. It is indicated that the mid-late period of shale gas production can be extended, and problems induced by a residual fracturing fluid can be solved by formation heat treatment. Constructive field operation suggestions, which combine the advantages of electrical heating and microwave heating, are presented.

An emissivity measurement apparatus for near infrared spectrum

This study develops a new experimental apparatus for infrared spectral emissivity measurements which consists mainly of the following four parts: sample heating system, blackbody furnace, optical system, and data acquisition system. This apparatus focuses on the near-infrared spectral emissivity measurement covering the temperature range from 473K to 1273K and the wavelengths between 0.8μm and 2.2μm. The apparatus and the measurement method are described in detail, and an improved method is presented to minimize measurement error. The spectral emissivity of pure titanium TA1, oxidized nickel and 304 austenitic stainless steel are measured to validate the reliability and reproducibility of experimental apparatus. The experimental results in this study are in good agreement with those of other literatures. Various uncertainty sources in emissivity measurement are analyzed, and the combined standard uncertainty of this system is less than 3.9%.

太阳能选择性涂层吸收光谱仪

本文介绍了太阳能选择性涂层光谱仪的设计原理、结构和光学测量系统，测量系统由试样加热系统、真空系统、光学系统、水冷系统、高精度积分球反射测量系统、温度检测与控制系统和计算机数据采集系统等组成。可用于室温至500℃和400~10,000 nm光谱范围内的光谱发射率特性精密测量，测量精度优于3%。为研究新型太阳能选择性涂层和制造高效率太阳能集热管，提供必要基础。 In this paper, the designing principal, the construction and the optical measurement system of the solar selective coatings spectrograph were introduced. The measurement system consists of sample heating system, vacuum system, optical system, water-cooling system, high-precision integrat- ing-sphere reflecting measurement system, temperature test and control system, computer data acquisition system and so on. The spectrograph can be used for critically measuring the spectral emissivity characteristics with wave of 300 nm - 10,000 nm from indoor temperature to 500˚C and the measurement precision is better than 3%. It provides the necessary foundation for research of new solar selective coatings and manufacture of high-efficiency solar collector.

TLD Instrumentation: A Case Study of PC Controlled TL Reader

Thermoluminescence reader is an important tool and a requisite for a researcher to study and characterize Thermoluminescence (TL) materials in different forms. Requirement for a versatile PC Controlled TL Reader has been felt for quite some time globally. Nucleonix Systems, Hyderabad, India, have developed a PC Controlled TL Reader by integrating complete electronics hardware circuits (comprising of Power Electronics, Low/High voltage Supplies, Temperature Controller, Micro Controller based data acquisition circuits having serial counter, ADC, DAC, EEPROM, PMT, PMT housing, sample heating system, drawer assembly, etc.) in a single enclosure. The system also integrated with software to calculate the activation energy (E), frequency factor (S) and order of kinetics ‘1’ for the prominent glow peaks using different equations.This Integral TL Reader unit gets connected to the Personal Computer System through serial port RS232C/USB port. The user interface to the system is through front–end VB software defined Graphics User Interface (GUI). The system also contains some of the software features like glow curve acquisition, analysis, filing, printing, plotting, overlapping, maker data reporting, etc. Additionally, system facilitates single/two/three plateau heating with variable heating rates.The primary objective of this development is to bring out versatile TL instrumentation system and also to make it affordable to many of the researchers in the Universities and other areas, including Radio-therapist, Medical Physicists in Cancer Hospitals. This system has been evaluated for its performance with CaSO4: Dy discs, powder, as well as with LiF: Mg, Ti chips. Linearity and reproducibility have been found to be quite satisfactory also within +2%. This system is quite useful to study the TL of phosphor, minerals and characterization of various solid semiconducting materials, and also can be used in personal dosimetry measurements and research studies in medical dosimetry, environmental radiation monitoring, and host of other applications in R&D Labs., etc.

Sample heating system for spin-polarized scanning electron microscopy

A sample-heating system for spin-polarized scanning electron microscopy (spin SEM) has been developed and used for microscopic magnetization analysis at temperatures up to 500°C. In this system, a compact ceramic heater and a preheating operation keep the ultra-high vacuum conditions while the sample is heated during spin SEM measurement. Moreover, the secondary-electron collector, which is arranged close to the sample, was modified so that it is not damaged at high temperatures. The system was used to heat a Co(1000) single-crystal sample from room temperature up to 500°C, and the magnetic-domain structures were observed. Changes of the domain structures were observed around 220 and 400°C, and these changes are considered to be due to phase transitions of this sample.

Thermal stability of granular-type FePt-MgO perpendicular recording media with soft underlayers

Thermal stability of written bits on [MgO xnm/FePt ynm]/sub 3//MgO4-nm/SiO/sub 2/ 4-nm/Fe-Ta-C 200-nm/Glass perpendicular media with two different structure having different stability factor has been investigated by magnetic force microscopy (MFM) equipped with in-situ sample heating system up to 200/spl deg/C. The disk with x= 2nm, and y= 2.5nm, shows no observable degradation even at 200/spl deg/C, indicating high thermal stability of this disk. On the other hand, for the disk with x= 4nm, and y= 3nm, some reversed domains are observed in the center area of 10kfci bits at 200/spl deg/C and some minor changes are found in the transition area of the higher frequency bits. The decay at a higher temperature is interpreted in terms of estimated thermal stability factor from MFM signal decay.

Multimass thermal desorption spectroscopy as a monitoring device for chemical reaction products

To observe the products of surface reaction mechanisms we combined a standard quadrupole mass spectrometer featuring high-speed scanning options with fast data acquisition and a computer-controlled sample heating system. This combination served to obtain a general view (like a ‘‘fingerprint’’) of the reaction occurring on a Pt(100) crystal upon heating the adsorbate covered surface, as well as to allow for a detailed analysis of the gas compounds leaving the surface within a single measurement. The method is denoted by multimass thermal desorption spectroscopy (MTDS). The MTDS device is capable of recording 850 amu/s providing up to 15 complete mass spectra per second of 50 amu width while heating the surface linearly. The data contain the ion currents of both the reaction products and their fractions (cracking patterns) generated in the spectrometer. Thus it is possible to distinguish between gas species with equal mass numbers by subsequent numerical evaluation.

大口径半導体ウェーハ表面処理装置

An ultra-high vacuum apparatus for surface cleaning, thin film deposition and surface analysis is successfully developed for three inch diameter wafers. The apparatus consists of four chambers; sample entry chamber, sample transport chamber, surface treatment chamber, and surface analysis chamber, all of which are evacuated with oil free pumps. The sample transport chamber is newly designed to introduce sample directly into both surface treatment chamber and analysis chamber, in order to prevent undesired residual gas incorporation between the two chambers. The transport mechanism will be applicable to a future vacuum production line. Newly designed sample heating system is fabricated using tungsten wire heater and divided sapphire surroundings, which can elevate sample temperature up to 1200°CC.Si wafers rinsed in various chemical solution were cleaned by heat treatment in the sample treatment chamber. Surface cleannes was examined by RHEED and AES measurements. Cleaned surface appeared at temperature from 775°C to 830°C, depending on chemical composition of the solutions.