Polyurethane doped with low‐concentration erbium

Polyurethane (PU) with lactate structures in its conformation can be used as a biological and biodegradable polymer. Polyurethane lactate (PUL) was doped with small quantities of an erbium (Er³⁺) complex, which hindered the N?N group. 2,2′‐Dihydroxyazobenzene was used as a ligand for the Er³⁺ complex. PUL in the presence of the used Er³⁺ complex caused water from the complex to be replaced by the polar structures from the polymer. These structures acted as crystallization germs for the structuration of the PU matrix. As a consequence, both the mechanical and thermal properties of the polymer were improved. The sample with the highest mechanical properties contained only 0.064 μmol of Er³⁺ complex/g of sample. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 659–669, 2007     

Comparison of conventional extraction under reflux conditions and microwave-assisted extraction of oil from popcorn.

Popcorn offers an environmentally friendly alternative to the commercial synthetic loose-fill packing materials. Popcorn could be used for cushioning purposes if the oil is extracted after the popping process. Conventional and microwave-assisted extraction methods were used for oil extraction from whole and ground, popped and unpopped kernels. The conventional extraction method achieved 68.5% oil recovery from whole popped kernels. However, whole unpopped kernels were not efficiently de-oiled with either of the methods. Extraction of oil from popped kernels is recommended; corn varieties with higher starch content and lower oil content should be used.     

Study of defect levels in CdTe using thermoelectric effect spectroscopy

We have studied the defect levels in as grown and post growth processed cadmium telluride (CdTe) using thermoelectric effect spectroscopy (TEES) and thermally stimulated current (TSC) techniques. We have extracted the thermal energy (E_th) and trapping cross section (σ_th) for the defect levels using the initial rise and variable heating rate methods. We have identified 10 different defect levels in the crystals. Thermal ionization energy values obtained experimentally were compared to theoretical values of the transition-energy levels of intrinsic and extrinsic defects and defect complexes in CdTe determined by first-principles band-structure calculations. On the basis of this comparison, we have associated the observed ionization levels with various native defects and impurity complexes.     

Testosterone and progesterone level alterations in the adult rat after retinoid (retinol or retinoic acid) treatment (imprinting) in neonatal or adolescent age

Newborn rats were treated with a single dose of vitamin A (retinol), or with three doses of retinoic acid (in the 1st, 3rd and 5th days). Serum testosterone and progesterone level was measured in the four months old male and female rats, respectively. Retinol significantly decreased both hormone levels, however retinoic acid decreased the progesterone level only. In the second part of the experiments adolescent rats (in the 6th and 7th week after birth) were treated and measured similar to the newborns. In this case retinol significantly diminished testosterone level, without influencing the progesterone level. Retinoic acid decreased testosterone level and elevated progesterone level. The results demonstrate the long lasting effects of retinoid treatments at a neonatal or adolescent age, pointing also to the differences in the direction of the effects. Considering that previously the receptorial and sexual-behavioral effects of perinatal vitamin A treatments were observed, the experiments call attention to such harmful influences of perinatal vitamin A treatments, which are not manifested in morphological alterations.     

Development of the high-pressure electro-dynamic gradient crystal-growth technology for semi-insulating CdZnTe growth for radiation detector applications

The high-pressure electro-dynamic gradient (HP-EDG) crystal-growth technology has been recently developed and introduced at eV PRODUCTS to grow large-volume, semi-insulating (SI) CdZnTe single crystals for room-temperature x-ray and gamma-ray detector applications. The new HP growth technology significantly improves the downstream CdZnTe device-fabrication yield compared to earlier versions of the HP crystal-growth technology because of the improved structural and charge-transport properties of the CdZnTe ingots. The new state-of-the-art, HP-EDG crystal-growth systems offer exceptional flexibility and thermal and mechanical stability and allow the growth of high-purity CdZnTe ingots. The flexibility of the multi-zone heater system allows the dynamic control of heat flow to optimize the growth-interface shape during crystallization. This flexibility combined with an advanced control system, improved system diagnostics, and realistic heat-transport modeling provides an excellent platform for continuing process development. Initial results on large-diameter (140 mm), SI Cd_1−xZn_xTe (x=0.1) ingots grown in low temperature gradients with the HP-EDG technique show reduced defect density and complete elimination of ingot cracking. The increased single-crystal yield combined with the improved charge transport allows the fabrication of large-volume, high-sensitivity, high energy-resolution detector devices at increased yield. The CdZnTe ingots grown to date produced large-volume crystals (≥1cm³) with electron mobility-lifetime product (μτ_e) in the (3–7) × 10⁻³ cm²/V range. The lower-than-desired charge-transport uniformity of the HP-EDG CdZnTe ingots is associated with the high density of Te inclusions formed in the ingots during crystallization. The latest process-development efforts show a reduction in the Te-inclusion density, an increase of the charge-transport uniformity, and improved energy resolution of the large-volume detectors fabricated from these crystals.