Microlens Fabrication by the Modified LIGA Process and Hot Embossing Process

2002 ◽  
Author(s):  
Sung-Keun Lee ◽  
Hyun Sup Lee ◽  
Seung S. Lee ◽  
Tai Hun Kwon
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Thermal Treatment ◽  
Mold Insert ◽  
Hot Embossing ◽  
X Rays ◽  
Fabrication Technology ◽  
Microlens Arrays ◽  
Good Surface ◽  
Good Surface Roughness

Microlens and microlens arrays is realized using a novel fabrication technology based on the exposure of a resist, usually PMMA, to deep X-rays and subsequent thermal treatment. The fabrication technology is very simple and produces microlenses and microlens arrays with good surface roughness (less than 1 nm). The molecular weight and glass transition temperature of PMMA is reduced when it is irradiated with deep X-rays. The microlenses were produced through the effects of volume change, surface tension, and reflow during thermal treatment of irradiated PMMA. Microlenses were produced with diameters ranging from 30 to 1500 μm. Moreover, fabrication of the microlens through the hot embossing process is studied based upon a microlens mold insert fabricated by the modified LIGA process. A hot embossing machine is designed and manufactured. The hot embossing process follows steps of heating a mold to desired temperature, embossing a mold insert on substrate, cooling the mold to deembossing temperature, and deembossing.

scholarly journals Average molecular weight of surfactants in aerosols

2007 ◽  
Vol 7 (5) ◽  
pp. 13805-13838 ◽  
Author(s):  
M. T. Latif ◽  
P. Brimblecombe
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Atmospheric Aerosols ◽  
Average Molecular Weight ◽  
Molecular Size ◽  
Weight Fraction ◽  
Ozone Exposure ◽  
Before And After ◽  
Fine Mode ◽  
Active Substances

Abstract. Surfactants in atmospheric aerosols determined as methylene blue active substances (MBAS) and ethyl violet active substances (EVAS). The MBAS and EVAS concentrations can be correlated with surface tension as determined by pendant drop analysis. The effect of surface tension was more clearly indicated in fine mode aerosol extracts. The concentration of MBAS and EVAS was determined before and after ultrafiltration analysis using AMICON centrifuge tubes that define a 5000 Da (5 K Da) nominal molecular weight fraction. Overall, MBAS and to a greater extent EVAS predominates in fraction with molecular weight below 5 K Da. In case of aerosols collected in Malaysia the higher molecular fractions tended to be a more predominant. The MBAS and EVAS are correlated with yellow to brown colours in aerosol extracts. Further experiments showed possible sources of surfactants (e.g. petrol soot, diesel soot) in atmospheric aerosols to yield material having molecular size below 5 K Da except for humic acid. The concentration of surfactants from these sources increased after ozone exposure and for humic acids it also general included smaller molecular weight surfactants.

Rapid Fabrication Technology of Microlens Arrays Based on NOA73

2016 ◽  
Vol 43 (7) ◽  
pp. 0703003
Author(s):  
崔建利 Cui Jianli ◽  
张斌珍 Zhang Binzhen ◽  
段俊萍 Duan Junping ◽  
赵龙 Zhao Long ◽  
南雪莉 Nan Xueli ◽  
...  
Keyword(s):  
Fabrication Technology ◽  
Microlens Arrays ◽  
Rapid Fabrication

Surface Tension as a Function of Molecular Weight of Protonated Free and Conjugated Dihydroxy Bile Acids

1986 ◽  
Vol 71 (s15) ◽  
pp. 72P-72P
Author(s):  
C O Mills ◽  
G H Martin ◽  
E Elias
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Bile Acids

Study on the Green Processing of Impeller

2010 ◽  
Vol 136 ◽  
pp. 148-152
Author(s):  
Ming Jun Feng ◽  
C.T. Sun ◽  
Xue Feng Wang ◽  
H.J. Sun
Keyword(s):  
High Speed ◽  
Production Cost ◽  
Development Trend ◽  
Virtual Manufacturing ◽  
Machining Process ◽  
High Speed Machining ◽  
Good Surface ◽  
Green Processing ◽  
Compressor Impeller ◽  
Good Surface Roughness

According to the characteristics and cutting requirements of the compressor impeller, such as low rigidity, easy to produce deformation and vibration in machining process, the high speed machining technology was adopted to reduce time, the virtual manufacturing technology was used to solve processing problems in computer before the trial machining and improved programming speed and other key supporting technologies were adopted. The study shows that this green processing of impeller had high machining efficiency, good surface roughness and product quality, low production cost and light environmental pollution. It accords with modern green machining development trend.

The Surface Tension of Rubber Solutions

1931 ◽  
Vol 4 (3) ◽  
pp. 354-360
Author(s):  
G. W. Shacklock
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Surface Tension ◽  
Benzene Solution ◽  
Rubber Particle ◽  
Mechanical Action ◽  
The Past ◽  
Pure Product ◽  
Simple Molecules ◽  
Improved Methods

Abstract During the past few years much attention has been paid to the constitution of raw rubber. The much improved methods of production of plantation rubber have resulted in a reasonably pure product available for investigation, and chemical analysis undoubtedly shows an empirical formula of C5H8 for the hydrocarbon. From this point onward, knowledge becomes less certain. Osmotic pressure and molecular weight measurements give no confirmation of a simple molecular structure, but show, in benzene solution, a behavior comparable with that of colloids. This is supported by experiments on swelling and viscosity, and by ultramicroscopic examination, all of which lead to the conclusion that rubber is a lyophilic colloid. Hence arose the concept that the rubber particle is a polymer of simple molecules of formula C5H8 (possibly isoprene), such a structure being in agreement with the production of rubber-like substances by the action of sodium upon isoprene and butadiene (Harries, Annalen, 395, 211 (1912)). The decrease in viscosity of a rubber solution with increasing periods of mastication of the rubber is hence regarded as a measure of depolymerization due to mechanical action; the increased ease of solution after mastication is confirmatory evidence.

Machinability of BMG

2012 ◽  
Vol 521 ◽  
pp. 225-253
Author(s):  
Mustafa Bakkal
Keyword(s):  
High Temperature ◽  
Metallic Glass ◽  
Viscous Flow ◽  
Bulk Metallic Glass ◽  
Light Emission ◽  
Cutting Speed ◽  
Good Surface ◽  
High Cutting Speed ◽  
Exothermic Chemical Reaction ◽  
Good Surface Roughness

This chapter covers the series of machinability evaluation test result and discussions of Zr52.5Ti5Cu17.9Ni14.6Al10bulk metallic glass (BMG). These tests are lathe turning, drilling, milling and preliminary level grinding tests. In the continuous machining methods such as turning, drilling and grinding of BMG, above a threshold cutting speed, the low thermal conductivity of BMG leads to chip temperatures high enough to cause the chip oxidation and associated light emission. The high temperature produced by this exothermic chemical reaction causes crystallization within the chips. Chips morphology suggests that increasing amounts of viscous flow control the chip-removal process. Moreover, viscous flow and crystallization can occur during the machining of the bulk metallic glass, even under the high temperature gradient and strain rate. High cutting speed significantly reduced the forces for BMG machining due to thermal softening. However, in intermittent cutting process which is milling, there is no high temperature problem, special burr formations the rollover and the top burr were observed along the slot and achieved good surface roughness, Ra= 0.113 μm, using conventional WC-Co cutting tool. In each method, tests repeated for the conventional materials for comparison purpose. This study concludes the precision machining of BMG is possible with the selection of feasible tools and process parameters for each method.

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