Simple high vacuum evaporation system with low‐temperature substrate

In previous low temperature studies of fractured yeast membranes that were examined in a conventional SEM, Wergin and Erbe demonstrated that resolution could be enhanced by substituting conventional sputter coating of gold with high vacuum evaporation of platinum/carbon. Although this procedure did not clearly resolve membrane particles, the frozen sample could be removed from the SEM and the Pt/C “coat” or replica could be recovered for further examination. Using instruments with greater resolution such as a TEM, as well as a field emission (FE) SEM, to examine the replica did reveal the membrane particles on the replica; therefore the authors concluded that failure to resolve these membrane structures in a conventional SEM probably resulted from limitations of the instrument rather than the coating procedure. Recently, we had the opportunity to interface a FESEM with a cryosystem; this combination was used to determine if samples shadowed in a high vacuum evaporator could be transferred to a cold stage in a FESEM to resolve the macromolecular structure of yeast plasma membranes.

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Obtaining complementary images with sputter coating and high-vacuum evaporation in an field emission SEM equipped with a cryostage

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084673 ◽

1991 ◽

Vol 49 ◽

pp. 74-75

Author(s):

William P. Wergin ◽

Eric F. Erbe ◽

Deryck J. Mills

Keyword(s):

Low Temperature ◽

Field Emission ◽

High Vacuum ◽

Vacuum Evaporation ◽

Yeast Suspension ◽

Cold Stage ◽

Sputter Coating ◽

Transfer Device

An Oxford CT 1500 Cryotrans System was mounted on a Hitachi S-4000 FESEM to perform low temperature manipulations and observations. The sample, consisting of a yeast suspension, was frozen in each of six hinged gold specimen holders, which were clamped onto a complementary freeze-etch specimen cap. The cap was mounted on a precooled modified Oxford holder (Fig. 1), and transferred to the dedicated cryochamber and cryostage where the yeast was fractured, etched and sputter coated with Pt. A second sample, mounted in the same type of gold holders, was frozen, fractured, etched, shadowed with platinum and coated with carbon in a Denton DV-503 high vacuum evaporator equipped with a modified DFE-2 freeze-etch module.1 The standard Oxford specimen transfer device was used to insert the holder through the cryochamber and onto the cold stage in the microscope.

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High-Vacuum Evaporation and a Cryostage to Observe Fractured Yeast

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103346 ◽

1988 ◽

Vol 46 ◽

pp. 256-257

Author(s):

William P. Wergin ◽

Eric F. Erbe ◽

Eugene L. Vigil

Keyword(s):

Electron Microscope ◽

Low Temperature ◽

Standard Specimen ◽

High Vacuum ◽

Specimen Holder ◽

Sputter Coating ◽

Fresh Frozen ◽

Gain Access ◽

Scanning Electron ◽

Transfer Device

Investigators have long realized the potential advantages of using a low temperature (LT) stage to examine fresh, frozen specimens in a scanning electron microscope (SEM). However, long working distances (W.D.), thick sputter coatings and surface contamination have prevented LTSEM from achieving results comparable to those from TEM freeze etch. To improve results, we recently modified techniques that involve a Hitachi S570 SEM, an Emscope SP2000 Sputter Cryo System and a Denton freeze etch unit. Because investigators have frequently utilized the fractured E face of the plasmalemma of yeast, this tissue was selected as a standard for comparison in the present study.In place of a standard specimen holder, a modified rivet was used to achieve a shorter W.D. (1 to -2 mm) and to gain access to the upper detector. However, the additional height afforded by the rivet, precluded use of the standard shroud on the Emscope specimen transfer device. Consequently, the sample became heavily contaminated (Fig. 1). A removable shroud was devised and used to reduce contamination (Fig. 2), but the specimen lacked clean fractured edges. This result suggested that low vacuum sputter coating was also limiting resolution.

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High Vacuum Evaporation System.

10.21236/ada309326 ◽

1996 ◽

Author(s):

Manijeh Razeghi

Keyword(s):

High Vacuum ◽

Vacuum Evaporation

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Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽

10.3390/machines9010001 ◽

2020 ◽

Vol 9 (1) ◽

pp. 1

Author(s):

Jing Wang ◽

Zhihua Wan ◽

Zhurong Dong ◽

Zhengguo Li

Keyword(s):

Low Temperature ◽

High Speed ◽

Performance Test ◽

High Reliability ◽

High Vacuum ◽

Test System ◽

Low Noise ◽

Speed Ratio ◽

Space Harmonic ◽

Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

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