Cathodic plasma polymerization and treatment by anode magnetron torch: II. The influence of operating parameters on the argon sputtering rate distribution

1999 ◽  
Vol 17 (6) ◽  
pp. 3157-3165 ◽  
Author(s):  
J. G. Zhao ◽  
H. Yasuda
Author(s):  
P.J. Killingworth ◽  
M. Warren

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.


Author(s):  
A. Tanaka ◽  
M. Yamaguchi ◽  
T. Hirano

The plasma polymerization replica method and its apparatus have been devised by Tanaka (1-3). We have published several reports on its application: surface replicas of biological and inorganic specimens, replicas of freeze-fractured tissues and metal-extraction replicas with immunocytochemical markers.The apparatus for plasma polymerization consists of a high voltage power supply, a vacuum chamber containing a hydrocarbon gas (naphthalene, methane, ethylene), and electrodes of an anode disk and a cathode of the specimen base. The surface replication by plasma polymerization in negative glow phase on the cathode was carried out by gassing at 0.05-0.1 Torr and glow discharging at 1.5-3 kV D.C. Ionized hydrocarbon molecules diffused into complex surface configurations and deposited as a three-dimensionally polymerized film of 1050 nm in thickness.The resulting film on the complex surface had uniform thickness and showed no granular texture. Since the film was chemically inert, resistant to heat and mecanically strong, it could be treated with almost any organic or inorganic solvents.


Author(s):  
Hirano T. ◽  
M. Yamaguchi ◽  
M. Hayashi ◽  
Y. Sekiguchi ◽  
A. Tanaka

A plasma polymerization film replica method is a new high resolution replica technique devised by Tanaka et al. in 1978. It has been developed for investigation of the three dimensional ultrastructure in biological or nonbiological specimens with the transmission electron microscope. This method is based on direct observation of the single-stage replica film, which was obtained by directly coating on the specimen surface. A plasma polymerization film was deposited by gaseous hydrocarbon monomer in a glow discharge.The present study further developed the freeze fracture method by means of a plasma polymerization film produces a three dimensional replica of chemically untreated cells and provides a clear evidence of fine structure of the yeast plasma membrane, especially the dynamic aspect of the structure of invagination (Figure 1).


Author(s):  
David C Joy

The electron source is the most important component of the Scanning electron microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in an SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required e.g a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.Historically, the first step up from the sealed glass tube ‘cathode ray generator’ was the simple, diode, tungsten thermionic emitter.


2012 ◽  
Vol 18 (69) ◽  
pp. 237
Author(s):  
فاتن فاروق البدري ◽  
علا علي فرج

تهدف دراسة التوزيعات الإحصائية إلى الحصول على التوصيفات الأفضل لمجموعة المتغيرات والظواهر والتي كل منها يمكن أن يسلك سلوك واحد من هذه التوزيعات. وتعد دراسة عمليات التقدير لمعلمات هذه  التوزيعات من الأمور المهمة والتي لا غنى عنها في دراسة سلوك هذه المتغيرات ونتيجة لذلك جاء هذا البحث محاولة للوصول إلى أفضل طريقة تقدير معلمات توزيع هو واحد من أهم التوزيعات الإحصائية وهو التوزيع الخطي العام لمعدلات الفشل، (Generalized Linear Failure Rate Distribution) وذلك من خلال دراسة الجوانب النظرية بالاعتماد على طرق الاستدلال الإحصائي مثل طريقة الإمكان الأعظم وطريقة المربعات الصغرى وبالإضافة إلى الطريقة المختلطة(طريقة مقترحة) . وتضمن البحث إجراء المقارنات بين طرائق التقدير الثلاثة لمعلمات التوزيع الخطي العام لمعدلات الفشل (GLFRD)، بالاعتماد على مقياسين إحصائيين مهمين هما متوسط مربعات الخطأ (MSE)، ومتوسط الخطأ النسبي المطلق (MAPE)، للحصول على طريقة التقدير الأفضل.


Sign in / Sign up

Export Citation Format

Share Document