NU-Iron,A Fluidized-Bed Reduction Process

In pilot-plant tests, U.S. Steel Corp. has shown that its two-stage iron-ore reduction process utilizing hydrogen is technically feasible. A 2000-tpd commercial unit has been designed, but economic considerations have delayed construction.     

Dislocation loops in tungstenite (WS2) crystals

TEM studies of tungstenite crystals grown by sublimation method have been investigated. Dislocation loops observed during such studies have been reported. It has been shown by different methods that these loops have a vacancy character.     

Determination of minority carrier lifetime and effective back surface recombination velocity in BSF silicon solar cells from transient measurements

The method of determining the base lifetime ?B and the effective surface recombination velocity Seff in a BSF solar cell from the transient decay of open-circuit voltage and short-circuit current is extended to include emitter recombinations. If the emitter recombinations in modern Si solar cells are neglected in interpreting the experimental data, the experimental value of Seff is found to be in large error.     

Infidelity of DNA synthesis as related to mutagenesis and carcinogenesis

An assay system has been developed for measuring the fidelity of DNA synthesis in vitro by using synthetic polynucleotide templates and purified DNA polymerases. Nearest-neighbor analysis of the synthesized product indicates that noncomplementary nucleotides are incorporated as single base substitutions. The accuracy of DNA synthesis can be decreased by (1) prior alkylation of the template, (2) increasing the relative concentration of incorrect nucleotides, and (3) addition of specific metal salts to the reaction mixture. As an initial evaluation of the utility of this system, the effects of 31 metal salts on the fidelity of DNA synthesis have been determined. The results indicate that potential metal mutagens and/or carcinogens may be detected by measuring alterations in the fidelity of DNA synthesis.     

Serum therapy for radiation-induced impairment of immune resistance to metastasis

The use of serum transfusion to remedy radiation-induced damage to established antitumor resistance was investigated in female C3H mice. The mice, which had been actively immunized against a syngeneic mammary carcinoma, were injected i.v. and s.c. with suspensions of cells from the same tumor and were then given 300 R extensive-field irradiation to the abdomen two times. Tumor cells implanted outside the irradiated area grew better in irradiated mice than in unirradiated controls. Under these experimental conditions, protection could be transferred to radiation-impaired hosts with several injections of cell-free immune serum. Transfers of normal serum provided a detectable but low degree of protection. The corrective effect of serum transfers to radiation-impaired hosts was clearly expressed against pulmonary tumor growth (i.v. challenge), provided the transfusions were started no later than the first day after the injection of the tumor cells. Serum transfusions were ineffective against the growth of tumors implanted s.c. Transfers of serum from hosts carrying large (15 mm) s.c. tumor implants had a negative effect on the resistance of irradiated recipients. The results indicate that humoral resistance factors, both normal and immune, may act against metastatic spread of solid tumors.     

A New Approach of Lateral RF MEMS Switch

This paper presents a novel lateral series microwave switch fabricated on a silicon-on-insulator (SOI) substrate with a finite ground coplanar waveguide (FGCPW) configuration which is laterally actuated by the electrostatic force. The switch is built with a cantilever beam in the direction of the signal line and a fixed electrode is located opposite the cantilever beam. The mechanical structures are fabricated using SOI deep reactive ion etching (DRIE) and shadow mask technology. The fabricated lateral RF MEMS switch has an isolation of 16 dB at 20 GHz. The insertion loss of the switch is 1 dB and return loss is 15 dB at 20 GHz. The threshold voltage is 19.2 V and switching time is 30 s.