Growth Apparatus Research Articles

Comparison of population growth and photosynthetic apparatus changes in response to different nutrient status in a diatom and a coccolithophore.

In many marine ecosystems, diatoms dominate in nutrient-rich coastal waters while coccolithiophores are found offshore in areas where nutrients may be limiting. In lab-controlled batch cultures, mixed-species competition between the diatom Phaeodactylum tricornutum and the coccolithophore Emiliana huxleyi and the response of each species were examined under nitrate (N) and phosphate (P) starvation. Based on the logistic growth model and the Lotka-Volterra competition model, E.huxleyi showed higher competitive abilities than P.tricornutum under N and P starvation. For both species, cell growth was more inhibited by P starvation, while photosynthetic functions (chl a fluorescence parameters) and cellular constituents (pigments) were impaired by N starvation. The decline of photosynthetic functions occurred later in E.huxleyi (day 12) than in P.tricornutum (day 9); this time difference was associated with greater damage of the photosynthetic apparatus in P.tricornutum compared with E.huxleyi. Xanthophyll cycle pigment accumulation and the transformation from diadinoxanthin to diatoxanthin was more active in E.huxleyi than P.tricornutum, under similar N and P starvation. We concluded that E.huxleyi and P.tricornutum have different mechanisms to allocate resources and energy under nutrient starvation. It appears that E.huxleyi has a more economic strategy to adapt to nutrient depleted environments than P.tricornutum. These findings provided additional evidence explaining how N versus P limitation differentially support diatom and coccolithophore blooms in natural environments.

Fabricating Cu(In,Ga)Se2 solar cells on flexible substrates by a new roll-to-roll deposition system suitable for industrial applications

In this work, a new hybrid sputtering–evaporation system providing a scalable process for deposition of Cu(In,Ga)Se2 (CIGS) layers is presented. The growth apparatus has been designed and realized to fit a size suitable for direct industrial transfer. In this process the metal precursors are first of all sputtered on rotating transfer devices, then evaporated on the substrate by local heating in a Se atmosphere. The desired thickness and composition of the CIGS film are obtained by repeated sputtering–evaporation cycles. The cylindrical geometry of the deposition chamber has been designed to accommodate different types of flexible substrates with a maximum size of 20 × 120 cm2 in a roll-to-roll configuration. Several techniques, including secondary ion mass spectrometry, Raman and photoluminescence spectroscopies, x-ray diffraction, scanning electron microscopy, external quantum efficiency, and I–V under 1 Sun illumination, have been used to test both the as-grown CIGS layers and the solar cell devices based on them. A significant performance and good control of Ga grading and Na content were obtained for solar cells grown at 450 °C on polyimide substrates with high deposition rates. In spite of the fact that the present efficiency record for CIGS solar cells on polyimide substrates is 20.4%, the 10.1% obtained using the hybrid method presented in this work is significant because the growth apparatus meets the requirements for direct industrial transfer. In fact, this process is being transferred in a 1 MW production line, where standard CIGS layers are deposited at low temperature on flexible substrates in a single-step process with a 1 mm sec−1 substrate velocity.

The Experimental Determination of Interfacial Energies for Solid Zn in Equilibrium with Zn-Al-Sb Liquid

The equilibrated grain boundary groove shapes of solid Zn in equilibrium with Zn-Al-Sb liquid were observed from a quenched sample using a radial heat flow apparatus. The Gibbs–Thomson coefficient, solid–liquid interfacial energy, and grain boundary energy of the solid Zn were determined from the observed grain boundary groove shapes. The thermal conductivity of the eutectic solid phase for Zn-0.4 at. pct Al-0.4 at. pct Sb alloy and the thermal conductivity ratio of the liquid phase to the solid phase for Zn-0.4 at. pct Al-0.4 at. pct Sb alloy at eutectic temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively.

Thermal conductivity and interfacial energy of solid Bi in the Bi–Ag eutectic system

The equilibrated grain boundary groove shapes for solid Bi (Bi–2.87 at.%Ag) in equilibrium with Bi–Ag eutectic liquid have been observed from quenched sample with a radial heat flow apparatus. The Gibbs–Thomson coefficient, solid–liquid interfacial energy and grain boundary energy of solid Bi have been determined from the observed grain boundary groove shapes. The variation of thermal conductivity with temperature for eutectic solid phase (Bi–4.7 at.%Ag) has been measured. The ratio of thermal conductivity of equilibrated eutectic liquid phase to eutectic solid phase has also been measured with a Bridgman-type growth apparatus at the melting temperature. The Gibbs–Thomson coefficient, solid–liquid interfacial energy and grain boundary energy of solid Bi in equilibrium with Bi–Ag eutectic liquid were determined to be (9.2 ± 0.6) × 10–8 K m, (52.7 ± 6.3) × 10–3 J m–2 and (102.4 ± 13.3) × 10–3 J m–2, respectively, from observed grain boundary groove shapes.

Experimental determination of interfacial energies for solid Sn in equilibrium with Sn-Mg-Zn liquid

The equilibrated grain boundary groove shapes of solid Sn in equilibrium with Sn-Mg-Zn liquid were observed from a quenched sample by using a radial heat flow apparatus. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of solid Sn were determined from the observed grain boundary groove shapes. The thermal conductivity of the eutectic solid phase for Sn-8.12 at% Mg-4.97 at% Zn alloy and the thermal conductivity ratio of the liquid phase to the solid phase for Sn-8.12 at% Mg-4.97 at% Zn alloy at eutectic temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of solid Sn in equilibrium with Sn-Mg-Zn liquid were determined to be (8.3 ± 0.6)×10-8 Km, (118.5 ± 14.2)×10-3 Jm-2 and (225.1 ± 29.3)×10-3 J m-2 respectively from observed grain boundary groove shapes. A comparison of present results for solid Sn in the Sn-8.12 at% Mg-4.97 at% Zn alloy with the results obtained in previous works for similar solid Sn in equilibrium with different binary or ternary liquid was made.

A Comparative Analysis of Microgravity and Earth Grown Thermostable T1 Lipase Crystals Using HDPCG Apparatus

Geobacillus zalihae sp. nov., which produces a putative thermostable lipase, represents a novel species, with type strain T1. The characterisation of this intrinsically thermostable T1 lipase either physicochemically or structurally is an important task. The crystallisation of T1lipase in space was carried out using a High-Density Protein Crystal Growth (HDPCG) apparatus with the vapour diffusion method, and X-ray diffraction data were collected. The microgravity environment has improved the size and quality of the crystals as compared to earth grown crystal. The effect of microgravity on the crystallisation of T1 lipase was clearly evidenced by the finer atomic details at 1.35 A resolution. Better electron densities were observed overall compared with the Earth-grown crystals, and comparison shows the subtle but distinct conformations around Na(+) ion binding site stabilized via cation-π interactions. This approach could be useful for solving structure and function of lipases towards exploiting its potentials to various industrial applications.

Установка выращивания биокристаллов с активным управлением процессом кристаллизации

Установка выращивания биокристаллов с активным управлением процессом кристаллизации

Growth Pattern Dependence of Tetrahydrofuran Hydrates in Glass Beads of Two Sizes on Growth Rate and Glass Bead Mixing Ratio

We observed the pattern formation of tetrahydrofuran (THF) clathrate hydrates in a mixture comprising a THF–17H2O solution and glass beads of two sizes (2 and 50 μm diameter) as functions of growth rate and glass bead mixing ratios (by weight). The overall hydrate growth rate, V, was controlled using a directional growth apparatus. The results showed that the growth interface of the initial hydrate layer destabilized with growth. The wavelength, λ, of the destabilized initial hydrate layer demonstrated a power law decrease as the growth rate V increased. We successfully formed various hydrate patterns and classified them into a pattern diagram according to the glass bead mixing ratio and the growth rate V. In addition, we are the first to successfully obtain a needle pattern. Image analysis showed that the segregated growth area of the hydrates and the average hydrate area increased, whereas the number density of hydrate grains decreased with decreasing V. These results are qualitatively consistent with the frost heave model. Finally, we proposed needle, nodular, and massive pattern hydrate formation models by summarizing the discussions from the frost heave model and the morphological instability model of crystal growth.

Spontaneous growth of diamond from MnNi solvent-catalyst using opposed anvil-type high-pressure apparatus

In this paper an overview of the application of opposed anvil-type high-pressure and high-temperature apparatus for spontaneous growth of diamond crystals by solvent-catalyst technique is presented. The process makes use of a molten Mn47Ni53 catalyst to initiate the graphite–diamond transformation reaction. The pressure and temperature requirements to obtain reproducible spontaneous diamond crystallization were around 52.5–54kbar and 1270–1320°C. The crystals had well-shaped cubo-structured morphology with the {100} and {111} faces and grain sizes of 0.2–0.5mm. This work can stimulate future experimental exploration of spontaneous diamond crystallization by using other solvent-catalyst metals.

An Important Role of Carotenoids in Protection of Photosynthetic Apparatus under VAM Inoculation on Momordica charantia

The effect of mixed inoculums of VAM (Vesicular Arbuscular Mycorrhizas) fungi on seed growth and photosynthetic apparatus in green house was monitored. The plants were watered daily with tap water. Plants were cultivated in natural environment in mid of March (2011). A direct relation between root length and water contents suggests a defense mechanism of MP (microrihzal plants) against the fungal stress. It was also supported by the fact that the leaf area of MP was much greater as compared to the NMP (non microrihzal plants) with elevated concentration of all chlorophyllus pigments in 30 days. An increase in the surface area of the leaf and concentration of the pigments, may be for an acceleration in absorption of CO₂ for reduction of it into glucose through oxidation of water molecule. The non-significant decline in glucose contents support the above hypothesis of rapid redox reaction mechanism which was established to overcome the stress. The positive effects of mycorrhizal which were already mentioned in the literature were reported in this article in relations of survival strategies of the plant, adapted in stress conditions. An increase in the chlorophyll contents (30 d) and leaf area of plants possibly attributed with absorption of solar radiation for the protection of plants. It was also supported by the higher concentration of carotenoids (30 d) that may have an additional function of regulation of certain developmental responses and screening of light to save the plants from stress conditions.

Growth, nutrient status, and photosynthetic response to diesel-contaminated soil of a cordgrass, Spartina argentinensis

The present study was conduced to investigate the tolerance limits of Spartina argentinensis, which occurs in inland marshes of the Chaco-Pampean regions of Argentina, to diesel-contaminated soil. A glasshouse experiment was designed to investigate the effect of diesel fuel from 0% to 3% on growth and photosynthetic apparatus of S. densiflora by measuring gas exchange and photosynthetic pigments. We also performed chemical analysis of plant samples, and determined mycorrhizal index. Tiller and root biomasses declined with increasing diesel fuel concentration, as well as photosynthetic rate (A). Reductions in A could be accounted for by non-stomatal limitations. Mycorrhizal roots of S. argentinensis were reduced by the presence of diesel fuel, but did not affect its nutritional status; in fact, most element concentrations increased with diesel contamination. Despite the negative effect of diesel-contaminated soil, S. argentinensis continued growing, which could be useful management options for phytorremediation of diesel-contaminated soils.

The Experimental Determination of Interfacial Energies for Solid Cd in Equilibrium with Sn-Cd-Sb Liquid

The equilibrated grain boundary groove shapes of solid Cd in equilibrium with Sn-Cd-Sb liquid were observed from a quenched sample by using a radial heat flow apparatus. The Gibbs–Thomson coefficient, solid–liquid interfacial energy, and grain boundary energy of the solid Cd were determined from the observed grain boundary groove shapes. The thermal conductivity of the eutectic solid phase for Sn-35.80 at. pct Cd-6.71 at. pct Sb alloy and the thermal conductivity ratio of the liquid phase to the solid phase for Sn-35.80 at. pct Cd-6.71 at. pct Sb alloy at eutectic temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively.

Effects of sub-lethal glyphosate concentrations on growth and photosynthetic performance of non-target species Bolboschoenus maritimus

Glyphosate use has increased over the last decades for the control of invasive plant species in wetland ecosystems. Although glyphosate has been considered ‘environmentally’ safe, its repeated use could increase the toxicological risk derived from diffuse pollution of surface and groundwater on non-target vegetation. A glasshouse study was designed to determine the effect produced by the addition of different sub-lethal doses of glyphosate herbicides (5–30mgL−1) to the nutrient solution on the growth and photosynthetic apparatus of Bolboschoenus maritimus. Although B. maritimus plants were able to grow and survive after 20d of exposure to glyphosate, the presence of this herbicide affected their growth, through a direct interaction with the root system. Particularly, at 30mgL−1 glyphosate, B. maritimus showed ca. 30% of biomass decrease. The reduction in B. maritimus growth was due to a decrease in net photosynthetic rate (A), which ranged between values ca. 11.5 and 5.5μmolm−2s−1 CO2 for the control and the highest glyphosate treatment, respectively. The response of A to glyphosate could be largely accounted for by non-stomatal limitations, since stomatal conductance was similar in all glyphosate treatments. Thus, A decrease was prompted by the negative impact of herbicide on photochemical (PSII) apparatus, the reduction in the absorption of essential nutrients, the reduction of photosynthetic pigments and possibly the reduction in Rubisco carboxilation capacity. Moreover, glyphosate excess caused photoinhibitory damage. In conclusion, in this study we have shown that herbicide water pollution could be a source of indirect phytotoxicity for B. maritimus.

Reproductive and Locomotory Capacities of Caenorhabditis elegans Were Not Affected by Simulated Variable Gravities and Spaceflight During the Shenzhou-8 Mission

Reproduction and locomotion are essential features of animals that help to facilitate their interaction with the surrounding environment. Previous studies have produced inconsistent results on behavioral response to spaceflight by the model animal Caenorhabditis elegans (C. elegans) in liquid culture. Using standard agar-based nematode growth medium (NGM), we show here that both reproductive and locomotory capacities of C. elegans were not significantly changed by centrifuge-produced hypergravity or clinostat-simulated microgravity. To investigate the effect of actual spaceflight on C. elegans, a nematode test unit was specifically designed to maintain its normal growth on solid NGM slides and to allow automatic RNA fixation on board the Shenzhou-8 spaceflight. We did not detect alteration in either brood size of immediate progenies from postflight nematodes or locomotory behavior, including speed of locomotion, frequency of reversals, and rate of body bends of space-flown nematodes collected directly from nematode test units. Our results provide clear evidence that the nematode test unit is an appropriate apparatus for nematode growth on standard NGM and can be used for on-orbit analysis of C. elegans, including onboard RNA fixation for molecular analysis and real-time video acquisition for behavioral analysis, which are critical for further studies in unmanned spaceflight and outer space exploration.

Solid–liquid interfacial energy of solid succinonitrile solution in equilibrium with succinonitrile–neopentylglycol eutectic liquid

The grain boundary groove shapes for solid succinonitrile solution (SCN–5mole% NPG) in equilibrium with the succinonitrile (SCN)–neopentylglycol (NPG) eutectic liquid (SCN–9.55mole% NPG) have been directly observed by using a horizontal linear temperature gradient apparatus at 317.1K equilibrium temperature. From the observed grain boundary groove shapes, the Gibbs–Thomson coefficient (Г) and solid-liquid interfacial energy (σSL) of solid SCN solution have been determined to be (5.43±0.50)×10−8Km and (8.09±1.21)×10−3Jm−2, respectively. The grain boundary energy of solid SCN solution has been determined to be (14.22±2.28)×10−3Jm−2 from the observed grain boundary groove shapes. The thermal conductivity for SCN–9.55mole% NPG eutectic solid phase and the thermal conductivity ratio of eutectic liquid phase to eutectic solid phase at the melting temperature have also been measured with a radial heat flow apparatus and Bridgman type growth apparatus, respectively.

Thermo-electrical properties in Pb-Sb hypereutectic alloy

Pb-17 wt% Sb hypereutectic alloy was directionally solidified upward with three different growth rates (8 μm/s, 18 μm/s, 42 μm/s, 166 μm/s and 497 μm/s) at a constant temperature gradient (3.6 K/mm) in the Bridgman-type growth apparatus. The dependence of characteristic microstructure parameters such as primary dendrite arm spacing (λ1) and secondary dendrite arm spacing (λ2) on the growth rate (V) were determined by using a linear regression analysis. Variations of electrical resistivity (ρ) for cast samples for temperatures in the range of 300–550 K were measured by using a standard dc four-point probe technique. The variations of thermal conductivity with temperature for the same alloys were determined from the WiedemannFranz and SmithPalmer equations by using the measured values of electrical resistivity. The enthalpy of fusion for the same alloys were determined by means of a differential scanning calorimeter from a heating trace during the transformation from solid to liquid. The corrosion resistance was analyzed by Tafel extrapolation and linear polarization resistance methods conducted in a 5% sodium chloride solution in contact with air maintained at room temperature. Effects of the growth rate on the electrical resistivity and corrosion resistance were also investigated.

Interface energy of solid cadmium (Cd) phase in the Cd-Pb (Cadmium-Lead) binary alloy

The grain boundary groove shapes for the Cadmium (Cd) phase in equilibrium with the Lead (Pb)-Cd eutectic liquid were obtained with radial heat flow apparatus. From the obtained grain boundary groove shapes, the Gibbs-Thomson coefficient, solid-liquid and grain boundary energy for the Cd phase in equilibrium with the Pb-Cd eutectic liquid were determined to be (8.35 ± 0.41) x 10-8 Km, (128.00 ± 12.8) × 10-3 Jm-2 and (239.33 ± 26.32) × 10−3 Jm-2, respectively. The thermal conductivities of the solid and liquid phases at the eutectic composition and temperature were also measured by using radial heat flow and Bridgman-type directional growth apparatus, respectively. Key words: Crystal growth, phase equilibria, thermal conductivity, Gibbs-Thomson coefficient, grain boundary energy.

The measurement of interfacial energies for solid Sn solution in equilibrium with the Sn–Bi–Ag liquid

The equilibrated grain boundary groove shapes of solid Sn solution in equilibrium with Sn–Bi–Ag liquid were observed from a quenched sample by using a radial heat flow apparatus. The Gibbs–Thomson coefficient, solid–liquid interfacial energy, and grain boundary energy of the solid Sn solution were determined from the observed grain boundary groove shapes. The thermal conductivity of the solid phase for Sn-10 at.%Bi-2 at.%Ag alloy and the thermal conductivity ratio of the liquid phase to the solid phase for Sn-10 at.%Bi-2 at.%Ag alloy at the melting temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively. A comparison of present results for solid Sn solution in the Sn–10 at.%Bi–2 at.%Ag alloy with the results obtained in previous works for similar solid Sn in equilibrium with different binary or ternary liquid was made. From the comparison, it can be concluded that for solid Sn solution in equilibrium with different liquid, the Gibbs–Thomson coefficient seems to be constant and does not depend on the composition of liquid but solid–liquid interfacial energy changes little bit with composition of liquid at a constant temperature.

Effective Hole Mobility in SiGe Buried-Channel Quantum Well MOSFETs on SOI by Low-Pressure CVD

The effective hole mobility of buried-channel SiGe quantum well metal-oxide-semiconductor field-effect-transistors (MOSFETs) on silicon-on-insulator (SOI) was verified. The buried-channel structures consisted of a single quantum well and triple quantum wells which were deposited on a SIMOX (separation by implantation of oxygen) substrate at 550°C by low-pressure chemical vapor deposition (CVD). The growth apparatus was built based on ultra-clean technology. The Ge fraction of the alloy was 0.2 and 0.4 and a MOSFET with a 5.9 nm-thick gate oxide was fabricated on the well layers. The effective hole mobility versus effective electric field for the devices was obtained at room temperature. The mobility of triple Si0.8Ge0.2 quantum well device was enhanced by nearly 2 times compared to the single quantum well device. This enhancement which depended upon the ground energy level of the triple quantum wells was caused by the increase of holes trapped in the buried channel. The enhancement of single Si0.6Ge0.4 quantum well device was 60%, although the hole mobility was promoted as the Ge fraction in the alloy increased. The reason was due to the crystalline quality degradation.

Influence of growth rate on microstructure, microhardness, and electrical resistivity of directionally solidified Al-7 wt% Ni hypo-eutectic alloy

Al-7 wt% Ni alloy was directionally solidified upwards with different growth rates, V (8.3–489.5 μm/s) at constant temperature gradient, G (4.2 K/mm) using a Bridgman-type growth apparatus. The dependence of the dendritic microstructures such as primary dendrite arm spacing (λ1) and secondary dendrite arm spacing (λ2) on the growth rate were determined using a linear regression analysis. The present experimental results were also compared with similar previous experimental results. Measurements of microhardness (HV) and electrical resistivity (ρ) of the directionally solidified samples were carried out. The dependence of the microhardness and electrical resistivity on the growth rate (V) was also analyzed. According to these results, it has been found that, for increasing values of V, the values of HV and ρ increase. However, the values of HV and ρ decrease with increasing values of λ1 and λ2.