scholarly journals A high efficiency flow cytometer.

1977 ◽  
Vol 25 (7) ◽  
pp. 784-789 ◽  
Author(s):  
M J Skogen-Hagenson ◽  
G C Salzman ◽  
P F Mullaney ◽  
W H Brockman

A flow chamber has been developed which collects about 60% of the total cell fluorescence for analysis compared to about 2.5% for conventional flow systems. The chamber, an ellipsoid of revolution, is gold-plated for increased reflectivity. Fluorochrome-stained cells enter the flow cell directly above the primary focus of the ellipsoid at the rate of 1000 cell/sec. A focused argon-ion laser beam enters the flow cell parallel to the semiminor axis and intersects the cell stream at the primary focus. Fluorescent light emanating from this point is reflected toward the secondary focus, where it exits the chamber for analysis. The high efficiency flow cytometer has been used to obtain nucleotide fluorescence distributions from samples of Micrococcus glutamicus bacteria stained with propidium iodide and of spermatozoa stained by the acriflavine-Feulgen procedure.

1989 ◽  
Vol 43 (7) ◽  
pp. 1139-1145 ◽  
Author(s):  
Richard S. Lysakowski ◽  
Raymond E. Dessy ◽  
Gary L. Long

Laser-Enhanced Ionization (LEI) signals have been detected for Na, Li, and Ba analytes in a microwave-induced plasma (MIP). A 300-mW continuous-wave (cw) dye laser pumped by a 5-W argon-ion laser was used to promote measurably increased ionization rates for these elements. A low-power, high-efficiency microwave plasma at 1 atmosphere with nitrogen and nitrogen-containing support gas was employed as the atom reservoir. The effects of varying applied microwave power, support gas composition, electrode voltage, and geometry were studied and results are given. The experimental variables that most significantly affect LEI signal intensity are: (1) electrode geometry, spacing, voltage, and distance above the cavity; (2) applied microwave power; (3) gas composition in an argon and nitrogen mixture; and (4) laser intensity. Experimental results are presented from the studies of Na LEI signals as a function of each one of these variables. Preliminary analytical studies yield Na detection limits in the low ng/mL range, showing this method to be competitive with other laser-based ionization methods.


1983 ◽  
Vol 46 (3-4) ◽  
pp. 241-243 ◽  
Author(s):  
Philippe Bado ◽  
Charles Dupuy ◽  
Kent R. Wilson ◽  
Richard Boggy ◽  
John Bowen ◽  
...  

Author(s):  
H.S. Mavi ◽  
S. Rath ◽  
Arun Shukla

Laser-induced etching of silicon is used to generate silicon nanocrystals. The pore structure depends on the substrate type and etching laser wavelength. Porous silicon (PS) samples prepared by Nd:YAG laser (1.16 eV) etching of n-type substrate showed a fairly uniform and highly interconnected network of nearly circular pores separated by thin columnar boundaries, while no circular pits were produced by argon- ion laser (2.41 eV) etching under similar conditions. The size and size distribution of the nanocrystals are investigated by Raman and photoluminescence spectroscopies and analyzed within the framework of quantum confinement models.


1983 ◽  
Vol 23 ◽  
Author(s):  
Han-Sheng Lee

ABSTRACTN-channel MOS transistors were fabricated on silicon films that had been recrystallized by an argon ion laser at different power levels. These transistors showed electrical characteristics similar, but somewhat inferior to those devices fabricated on single crystal silicon substrates. These differences are attributed to the presence of trapping states at the grain boundaries of the crystallites in the recrystallized silicon. A coulombic scattering model is presented to explain these differences. In the case of films annealed at low laser power, an additional factor of nonuniform trap state distribution is invoked to explain device characteristics. This model provides an adequate explanation for the observed transport properties of transistors fabricated from recrystallized silicon films.


1972 ◽  
Vol 5 (10) ◽  
pp. 1807-1814 ◽  
Author(s):  
A Maitland ◽  
J C L Cornish
Keyword(s):  

1988 ◽  
Vol 8 (4) ◽  
pp. 3-9
Author(s):  
Norio MIYOSHI ◽  
Takahiro SEKI ◽  
Shuichi KINOSHITA ◽  
Takashi KUSHIDA ◽  
Tsuyoshi NISHIZAKA ◽  
...  

1982 ◽  
Vol 3 (1) ◽  
pp. 35-38
Author(s):  
Masatoshi Esaki ◽  
Hideo Hiratsuka ◽  
Mamoru Hiyama ◽  
Osamu Ueda ◽  
Yukio Toda ◽  
...  

1984 ◽  
Vol 38 (1) ◽  
pp. 78-83 ◽  
Author(s):  
R. Thurn ◽  
W. Kiefer

We report on a new Raman microprobe technique where micron-sized solid particles are trapped in stable optical potential wells using only the force of radiation pressure from a continuous gas laser. We demonstrate this technique with Raman spectra from spherical and non-spherical particles of sizes ranging between 10–30 μm. The particles are stably supported by a vertical directed focused TEM00-mode cw argon ion laser of ∼500 mW. The latter simultaneously serves as the exciting light source. Several suggestions for improvements of this technique are made.


2007 ◽  
Vol 119 ◽  
pp. 315-318
Author(s):  
Won Jae Lee ◽  
Easwaramoorthi Ramasamy ◽  
Dong Yoon Lee ◽  
Jae Sung Song

Dye sensitized solar cells (DSSC) have great potential alternative to expensive conventional solar cells, since high efficiency and relatively simple fabrication process. However, in large size cell, there is a key factor that delayed the entry of such cells in commercial market. Performance of large size cell is lower than small size cells, since a carrier loss occurs in high resistive TCO glass substrate. Here we demonstrate a simple method to reduce resistive loss and efficient collection of photo generated carriers via strip type cells with metal grids. Using strip type cells, we constitute series and parallel type DSSC panels in order to achieve required voltage and current respectively. Stripe cells were prepared from commercial TiO2 powder by screen printing method. In addition, metal grids were established adjacent to sealant line. Using these as unit cell, portable DSSC panels were assembled and I-V performance was carried out in indoor light condition (fluorescent light, 30mW/cm2) and standard condition (Pin 100 mW/cm2, AM 1.5).


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