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KCN crystallizes in the monoclinic Cm space group. The structure is three-dimensional. K1+ is bonded to four equivalent N3- atoms to form distorted corner-sharing KN4 trigonal pyramids. There are a spread of K–N bond distances ranging from 2.86–3.27 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. N3- is bonded in a distorted single-bond geometry to four equivalent K1+ and one C2+ atom.
KCN crystallizes in the monoclinic C2 space group. The structure is three-dimensional. K1+ is bonded to four equivalent N3- atoms to form distorted corner-sharing KN4 trigonal pyramids. There are two shorter (2.95 Å) and two longer (2.97 Å) K–N bond lengths. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. N3- is bonded in a 1-coordinate geometry to four equivalent K1+ and one C2+ atom.
KCN crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of K–N bond distances ranging from 2.85–3.02 Å. In the second K1+ site, K1+ is bonded in a distorted single-bond geometry to one N3- atom. The K–N bond length is 2.81 Å. In the third K1+ site, K1+ is bonded in a 1-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.82–3.30 Å. In the fourth K1+ site, K1+ is bonded in a 2-coordinate geometry to two N3- atoms. There are one shorter (2.81 Å) and one longer (2.96 Å) K–N bond lengths. There are four inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.36 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.41 Å. In the third C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.42 Å. In the fourth C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.37 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to three K1+ and one C2+ atom. In the second N3- site, N3- is bonded in a 1-coordinate geometry to four K1+ and one C2+ atom. In the third N3- site, N3- is bonded in a 1-coordinate geometry to four K1+ and one C2+ atom. In the fourth N3- site, N3- is bonded in a distorted single-bond geometry to three K1+ and one C2+ atom.
KCN crystallizes in the monoclinic Cc space group. The structure is three-dimensional. K1+ is bonded in a distorted rectangular see-saw-like geometry to four equivalent N3- atoms. There are a spread of K–N bond distances ranging from 2.90–3.18 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. N3- is bonded in a distorted single-bond geometry to four equivalent K1+ and one C2+ atom.
Cu(In,Ga)Se 2 thin films deposited by a single-stage co-evaporation process at 350 ºC on molybdenum coated soda lime glass substrate were annealed post-deposition in InCl 3 vapor. The amount of InCl 3 and Se was varied. Here, the annealing treatment was done at 450 ºC for 30 minutes. Increase in grain size was observed after the treatment in all cases by X-ray diffraction. Device performance was low, but improved slightly after KCN etching.
It is postulated that amino acids were produced on the early earth from dilute aqueous solution of cyanide, carbonyls and ammonia (the Strecker synthesis RNH2 + R"R""C=O + KCN yields H-N(R)-C(R")(R"")-CO2H. We have studied the products obtained from dilute aqueous solutions of cyanide, formaldehyde (R"=R""=H), ammonia (R=H) and amino acids. Solutions in the pH range from 8 to 10. at room temperature and at reactant concentrations from 0.001 M to 0.3 M have been studied. With R= H product yields were low (less than 3%). Only with R"=R""=H and R represented by the following: CH2CO2H (glycine); CH(CH3)CO2H (alanine); CH(CH2CH3)CO2H (a-amino n=butyric acids); C(CH3)2(CO2H) (a-aminoisobutyric acid); CH(CH(CH3)2)CO2H (valine); and CH(CH2CO2H)CO2H (aspartic acid), were product yields high (greater than 10%). The yields of glycine were larger with R not equal to H. The prebiotic implications of these findings will be discussed.
The alpha-amino and alpha-hydroxy acids found in the Murchison carbonaceous chondrite are deuterium enriched. These compounds are thought to have originated from common deuterium enriched carbonyl precursors, by way of a Strecker synthesis which took place in a solution of HCN, NH3, and carbonyl compounds during the period of aqueous alteration of the meteorite parent body. However, the hydroxy acids found on Murchison are less deuterium enriched than the amino acids. With the objective of determining if the discrepancy in deuterium enrichment between the amino acids and the hydroxy acids found on Murchison is consistent with their formation in a Strecker synthesis, we have measured the deuterium content of alpha-amino and alpha-hydroxy acids produced in solutions of deuterated carbonyl compounds, KCN and NH4Cl, and also in mixtures of such solutions and Allende dust at 263 K and 295 K. Retention of the isotopic signature of the starting carbonyl by both alpha amino acids and alpha hydroxy acids is more dependent upon temperature, concentration and pH than upon the presence of meteorite dust in the solution. The constraints these observations place on Murchison parent body conditions will be discussed.
CuIn(1-x)Ga(x)S2 (CIGS2) thin-film solar cells are of interest for space power applications because of the near optimum bandgap for AM0 solar radiation in space. CIGS2 thin film solar cells on flexible stainless steel (SS) may be able to increase the specific power by an order of magnitude from the current level of 65 Wkg(sup -1). CIGS solar cells are superior to the conventional silicon and gallium arsenide solar cells in the space radiation environment. This paper presents research efforts for the development of CIGS2 thin-film solar cells on 127 micrometers and 20 micrometers thick, bright-annealed flexible SS foil for space power. A large-area, dual-chamber, inline thin film deposition system has been fabricated. The system is expected to provide thickness uniformity of plus or minus 2% over the central 5" width and plus or minus 3% over the central 6" width. During the next phase, facilities for processing larger cells will be acquired for selenization and sulfurization of metallic precursors and for heterojunction CdS layer deposition both on large area. Small area CIGS2 thin film solar cells are being prepared routinely. Cu-rich Cu-Ga/In layers were sputter-deposited on unheated Mo-coated SS foils from CuGa (22%) and In targets. Well-adherent, large-grain Cu-rich CIGS2 films were obtained by sulfurization in a Ar: H2S 1:0.04 mixture and argon flow rate of 650 sccm, at the maximum temperature of 475 C for 60 minutes with intermediate 30 minutes annealing step at 120 C. Samples were annealed at 500 C for 10 minutes without H2S gas flow. The intermediate 30 minutes annealing step at 120 C was changed to 135 C. p-type CIGS2 thin films were obtained by etching the Cu-rich layer segregated at the surface using dilute KCN solution. Solar cells were completed by deposition of CdS heterojunction partner layer by chemical bath deposition, transparent-conducting ZnO/ZnO: Al window bilayer by RF sputtering, and vacuum deposition of Ni/Al contact fingers through metal mask. PV parameters of a CIGS2 solar cell on 127 micrometers thick SS flexible foil measured under AM 0 conditions at NASA GRC were: V(sub oc) = 802.9 mV, J(sub sc) = 25.07 mA per square centimeters, FF = 60.06%, and efficiency 0 = 8.84%. For this cell, AM 1.5 PV parameters measured at NREL were: V(sub oc) = 788 mV, J(sub sc) = 19.78 mA per square centimeter, FF = 59.44%, efficiency 0 = 9.26%. Quantum efficiency curve showed a sharp QE cutoff equivalent to CIGS2 bandgap of approximately 1.50 eV, fairly close to the optimum value for efficient AM0 PV conversion in the space.
A large, transient depolarization of the plasma membrane precedes the rapid blue-light (BL)-induced growth suppression in etiolated seedlings of Cucumis sativus L. The mechanism of this voltage transient was investigated by applying inhibitors of ion channels and the plasma-membrane H(+)-ATPase, by manipulating extracellular ion concentrations, and by measuring cell input resistance and ATP levels. The depolarizing phase was not affected by Ca(2+)-channel blockers (verapamil, La3+) or by reducing extracellular free Ca2+ by treatment with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). However, these treatments did reduce the rate of repolarization, indicating an inward movement of Ca2+ is involved. No effects of the K(+)-channel blocker tetraethylammonium (TEA+) were detected. Vanadate and KCN, used to inhibit the H(+)-ATPase, reduced or completely inhibited the BL-induced depolarization. Levels of ATP increased by 11-26% after 1-2 min of BL. Input resistance of trichrome cells, measured with double-barreled microelectrodes, remained constant during the onset of the depolarization but decreased as the membrane voltage became more positive than -90 mV. The results indicate that the depolarization mechanism initially involves inactivation of the H(+)-ATPase with subsequent transient activation of one or more types of ion channels.