尼龙1010—聚四氢呋喃多嵌段共聚物的ESCA研究

尼龙１０１０－聚四氢呋喃多嵌段共聚物（ＰＡ－ＰＴＭＧ）是一种性能良好的聚合物。本文用Ｘ射线光电子能谱（ＥＳＣＡ）和计算机分峰技术研究了不同软硬段分子量的ＰＡ－ＰＴＭＧ的表面化学组成，进行了试样ＥＳＣＡ谱峰归属的确定。结果表明，本体嵌段效果较好，但在样品表面上Ｏ／Ｎ原子比大于体相Ｏ／Ｎ原子比，即软段富集于表面，并且分相程度高的试样较分相程度低的试样其软段在表面富集得更多。     

GIANT MAGNETO-IMPEDANCE IN Fe-BASED SOFT FERROMAGNETIC RIBBONS

ＧＩＡＮＴＭＡＧＮＥＴＯ－ＩＭＰＥＤＡＮＣＥＩＮＦｅ－ＢＡＳＥＤＳＯＦＴＦＥＲＲＯＭＡＧＮＥＴＩＣＲＩＢＢＯＮＳＣｈｅｎＣｈｅｎＭｅｉＬｉａｎｇｍｏＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，ＳｈａｎｄｏｎｇＵｎｉｖｅｒｓｉｔｙ，Ｊｉｎａｎ２５０１００...     

A Diode-pumped Low Threshold Nd:SVAP/KTP Laser

ＡＤｉｏｄｅ－ｐｕｍｐｅｄＬｏｗＴｈｒｅｓｈｏｌｄＮｄ：ＳＶＡＰ／ＫＴＰＬａｓｅｒＷＡＮＧＣｈａｎｇｑｉｎｇ；ＳＨＥＮＤｅｙｕａｎ；ＭＥＮＧＸｉａｎｌｉｎ；ＳＨＡＯＺｏｎｇｓｈｕ；ＪＩＡＮＧＭｉｎｈｕａ（ＩｎｄｉｔｕｔｅＯｆＣｒｙｓｔａｌＭａｔｅｒｉ...     

MPEG-2先进音频编码(AAC)的研究和软件仿真

ＭＰＥＧ－２３ＡＡＣ是ＩＳＯ／ＩＥＣＭＰＥＧ组织继ＭＰＥＧ－１,ＭＰＥＧ－２音频编解码标准后,制定的最新国际标准（ＩＳＯ／ＩＥＣ１３８１８－７）在６４ｋｂｐｓ／每声道低码率时能提供全透明音质,本文对其编解码算法进行了简要介绍,论文作者对ＭＰＥＧ－２ＡＡＣ进行了软件仿真,文中介绍了仿真结果,仿真时对ＡＡＣ标准所附编码范 中的一些不妥之处,作了改进,文中列举了６方面的修正。     

NO在Cs／Ru（1010）表面上吸附的ARUPS研究

在１５０Ｋ的低温下，ＮＯ在清洁的Ｒｕ（１０１０）表面上的吸附，Ｈｅｌｌ－ＡＲＵＰＳ显示在Ｅ以下９．３ｅＶ（５σ＋１π）和１４．６ｅＶ（４σ）处有两个峰，表明ＮＯ在Ｒｕ（１０１０）表面上是分子吸附，ＮＯ在Ｃｓ／Ｒｕ（１０１０）表面上的吸附，ＡＲＵＰＳ测得在Ｅ以下６．２，９．２，１１．１，１２．４和１４．９ｅＶ处有５个峰，和Ｎ２Ｏ气相的ＵＰＳ谱比较认定它们是Ｎ２Ｏ和ＮＯ共存的结果，表明ＮＯ在Ｃｓ／Ｒｕ     

MPEG-2先进音频编码(AAC)的研究和软件仿真

ＭＰＥＧ－２ＡＡＣ是ＩＳＯ／ＩＥＣ ＭＰＥＧ组织继 ＭＰＥＧ－１、ＭＰＥＧ－２音频编解码标准后,制定 的最新国际标准（ＩＳＯ／ＩＥＣ １３８１８－７）,在６４ｋｂｐｓ／每声道低码率时能提供全透明音质。本文对其编 解码算法进行了简要介绍。论文作者对ＭＰＥＧ－２ＡＡＣ进行了软件仿真,文中介绍了仿真结果,仿 真时对ＡＡＣ标准所附编码范例中的一些不妥之处,作了改进,文中列举了６方面的修正。     

MEASUREMENTS OF Fe AND Cu K-Shell IONIZATION CROSS SECTIONS BY SLOW ELECTRON IMPACT

ＭＥＡＳＵＲＥＭＥＮＴＳＯＦＦｅＡＮＤＣｕＫ－ＳｈｅｌＩＯＮＩＺＡＴＩＯＮＣＲＯＳＳＳＥＣＴＩＯＮＳＢＹＳＬＯＷＥＬＥＣＴＲＯＮＩＭＰＡＣＴＬｉＴａｉｈｕａＡｎＺｈｕＬｕｏＺｈｅｎｇｍｉｎｇＣｅｎｔｅｒｆｏｒＲａｄｉａｔｉｏｎＰｈｙｓｉｃｓ，Ｉｎｓ...     

多重散射团族理论对CO／NiO（100）NO／NiO（100）吸附系统的分析与比较

用多理散射团族（ＭＳＣ）理论对ＣＯ／ＮｉＯ（１００）和ＮＯ／ＮｉＯ（１００）吸附系统的Ｃ１ｓ近边Ｘ射线吸收精细结构（ＮＥＸＡＦＳ）和Ｎ１ｓ ＮＥＸＡＦＳ谱进行了详细的计算和分析。理论计算表明ＣＯ／ＮｉＯ（１００）是弱物理吸附,ＣＯ分子与表面的多极静电相互作用很弱,σ共振不依赖Ｃ－Ｏ键长的变化,ＭＳＣ方法分析表明,ＣＯ是以Ｃ原子朝下,吸附在衬底的Ｎｉ－Ｏ键上,可靠性因子计算显示Ｃ原子的吸附位置距Ｎｉ     

LOW ENERGY TRIPLE DIFFERENTIAL CROSS SECTIONS FOR ELECTRON IMPACT IONIZATION OF HYDROGEN

ＬＯＷＥＮＥＲＧＹＴＲＩＰＬＥＤＩＦＦＥＲＥＮＴＩＡＬＣＲＯＳＳＳＥＣＴＩＯＮＳＦＯＲＥＬＥＣＴＲＯＮＩＭＰＡＣＴＩＯＮＩＺＡＴＩＯＮＯＦＨＹＤＲＯＧＥＮＣｈｅｎＺｈａｎｇｊｉｎａ，ｂＸｕＫｅｚｕｎｂＸｕＦｕｘｉｎａａＤｅｐａｒｔｍｅｎｔｏｆＰｈｙ...     

石化企业典型雷害成因及防护技术初探

石化企业典型雷害成因及防护技术初探娄仁杰张雷周本谋（中国石化总公司安全技术研究所，大连１１６０３１）（收稿日期：１９９８－０５－２５）ＴＹＰＩＣＡＬＣＡＵＳＥＳＯＦＦＯＲＭＩＮＧＬＩＧＨＴＮＩＮＧＤＡＭＡＧＥＳＡＮＤＬＩＧＨＴＮＩＮＧＰＲＯＴＥＣＴＩ...     

Photoelectron spectroscopy of the valence electronic structure of polymers

Photoelectron spectroscopy has been highly developed as an investigative tool of the bulk and surface chemical and electronic structure of condensed matter during the past 2 decades. The use of soft X-ray sources led to the development of electroq spectroscopy for chemical applications (ESCA),^1,2 which is also known to the physicst as X-ray photoelectron spectroscopy (XPS). These developments were followed by the use of ultraviolet sources for the study of gases³ and the bulk and surface electronic structure of solids.^4,5 Recently, the use of the continuous spectral distribution of synchrotron radiation has had a major impact upon the study of solid surfaces^6,7 and has made the largely historical terminology of XPS (or ESCA) and ultraviolet photoelectron spectroscopy (UPS) somewhat less meaningful. Angle-resolved UPS and XPS (ARUPS and ARXPS) can provide additional information about electronic band structure, surface states, and adsorbates, but are typically applied to the study of the surfaces of ideal single crystals, where crystallographic high-symmetry directions as well as the polarization of the light source can be used to high advantage.⁷ Since polymers are almost never single crystals, the angle-resolved issue will not be addressed here.     

Ultrafast electronic spectroscopy for chemical analysis near liquid water interfaces: concepts and applications

Electron spectroscopy for chemical analysis (ESCA) being conceptually a photoelectron spectroscopy is established as a chemically specific probe mostly for surface analysis. Liquid phase ESCA for volatile liquids has become possible through the development of the liquid microjet technique in vacuum enabling the measurement of liquid interface photoelectron emission at the high vapor pressure of volatile liquids. Recently we have been able to add the dimension of time to the liquid interface ESCA technique employing high-harmonics soft X-ray and UV/near IR femtosecond pulses in combination with liquid water micro beams in vacuum. The concepts as well as technical details are outlined and several characteristic applications are highlighted.     

ESCA applied to liquids. II. Valence and core electron spectra of formamide

A brief review of the technique of applying ESCA to liquid samples is given. A list of solvents suitable for ESCA studies is presented and the particul     

The dispersion of platinum on silica-correlation of esca and gas adsorption data

For five catalyst samples (Pt supported on silica) prepared by an ion exchange method, a correlation plot of chemisorption data against ESCA Pt/Si signal area ratio was a smooth curve essentially linear at low surface Pt levels but curving at high Pt values. Two samples prepared by an impregnation method were also studied. A line connecting points on the correlation plot for these samples was approximately parallel to but not coincident with the correlation curve obtained for samples prepared by ion exchange. The data strongly support the use of ESCA for measurements of metal particle size (dispersion) in catalyst systems such as these.     

A new method for ESCA studies of liquid-phase samples

A new technique is described for obtaining ESCA spectra from liquid-phase samples. It combines temperature regulation of the liquid samples, which are continuously created as thin films on a metal backing, with the use of monochromatized A1 Kα radiation for excitation. The technique is simple to implement and can be used routinely over essentially unlimited periods of recording time in the spectrometer. The results show substantially increased quality with respect to earlier measurements in terms of signal-to-background ratio and resolution. The technique also implies a vast increase in the number of solvents usable for future liquid-phase ESCA work.     

Soft X-ray photoelectron spectroscopy of compound semiconductor surfaces and interfaces

Photoelectron spectroscopy is one of the leading techniques in the study of solid surfaces. In particular, X-ray photoelectron spectroscopy (XPS) — also known as ESCA (electron spectroscopy for chemical analysis) — is extensively used in materials science. This paper discusses the advantages of coupling the soft X-ray continuum of synchrotron radiation with this technique (SXPS). The primary advantage of high surface sensitivity is illustrated with case studies of clean semiconductor surfaces and of the initial stages of formation of metal/semiconductor and semiconductor/semiconductor interfaces. The prospects for soft X-ray photoelectron microscopy are briefly discussed.     

Optical coherence refractometry

We introduce a novel approach to refractometry using a low coherence interferometer at multiple angles of incidence. We show that for plane parallel samples it is possible to measure their phase refractive index rather than the group index that is usually measured by interferometric methods. This is a significant development because it enables bulk refractive index measurement of scattering and soft samples, not relying on surface measurements that can be prone to error. Our technique is also noncontact and compatible with in situ refractive index measurements. Here, we demonstrate this new technique on a pure silica test piece and a highly scattering resin slab, comparing the results with standard critical angle refractometry.     

Investigation of intrinsic plasmon energy losses associated with the Fe 1s core level in metallic iron

A recently developed Cu Kα₁ (hν = 8047.8 eV) X-ray source/ESCA300 electron spectrometer combination has been used to investigate the intrinsic plasmon energy losses associated with the Fe 1s core level (binding energy = 7111 eV) in metallic iron. The surface and bulk intrinsic plasmon energy losses were separated and it was found that using the theoretically calculated extrinsic energy loss cross-section to represent the bulk intrinsic energy loss cross-section gave an overall intrinsic loss probability which is approximately the same as if a Lorentzian type cross-section is used. However, this approach does not separate the surface and bulk intrinsic losses properly and is not a good approximation for peak shape analysis in the near peak region. A more realistic approximation is provided by using a Lorentzian type energy loss cross-section to represent the bulk intrinsic energy losses. It has also been shown that for the Fe 1s core level of metallic iron the probability that a photoelectron will suffer an intrinsic energy loss is higher at the surface than in the bulk. Also for this core level the excitation probability for the intrinsic plasmons is greater than that of the extrinsic plasmons. Hence ignoring the intrinsic plasmons would cause considerable error in peak shape analysis in the near peak region.     

Charge correction in XPS/ESCA. Bulk solvent as internal standard in the study of quick-frozen solutions

On the basis of the ESCA study of several model systems in quick-frozen solutions (see Table 1) one of the electron lines of the bulk solvent in each s     

Properties of segmented polyurethane zwitterionomer elastomers

Four series of polyurethane zwitterionomers based on different soft segment polyols [polyethylene oxide (PEO), polypropylene oxide (PPO), polytetramethylene oxide (PTMO), and polybutadiene (PBD)] were synthesized, and their properties were investigated using differential scanning calorimetry, dynamic mechanical spectroscopy, infrared dichroism, and stress-strain testing. Two different molar ratios of hard segment [4,4′-diphenylmethane diisocyanate (MDI)] to chain extender [N-methyl diethanol-amine (MDEA)] to soft segment polyol, each with three different levels of ionization, were prepared based on the four different polyols. Zwitterionization was accomplished by quaternizing the tertiary amine of MDEA with γ-propane sultone. For the PBD materials, the un-ionized samples exhibited a high degree of phase separation, and ionization served mainly to improve domain cohesion. Increasing ionic content improved material strength while sacrificing extensibility. For the polyether materials the un-ionized samples were not highly phase separated, and ionization improved both the degree of phase separation and hard segment domain cohesion. These morphological changes led to greatly improved mechanical properties. The tensile properties of the ionized PEO and PTMO materials were superior to the tensile properties of the PPO and PBD materials. This was attributed to the ability of the PEO and PTMO segments to crystallize under strain. The effects of segment length (by comparison with a previous study) and hard segment content on mechanical properties are also discussed.