Microwave-Assisted Synthesis of Fine Particle Oxides Employing Wet Redox Mixtures

Interaction of electromagnetic radiation with a physical mixture of metal nitrates and amides/hydrazides is observed to initiate high-temperature reactions, useful for realizing several high-temperature ceramic materials. A judicious choice of such redox mixtures undergoes exothermic reactions when they couple with microwave radiation. The coupling of electromagnetic radiation with metal salts and amides/hydrazides depends on the dielectric properties of the individual components in the reaction mixture. The approach has been used to prepare γ-Fe₂O₃, Fe₃O₄, MgCr₂O₄, α-CaCr₂O₄, and La_0.7Ba_0.3MnO₃.     

Pulsed laser deposition of indium antimonide

Single crystalline oriented films of indium antimonide have been grown on cadmium telluride substrates by the pulsed laser deposition technique. The films were (111) oriented which is the substrate orientation. The composition of the grown films were found to deviate from that of the target owing to loss of antimony during evaporation. This deviation from stoichiometry led to film-substrate reaction, resulting in mixed interface. The antimony deficiency in the films were controlled by correcting the stoichiometry, which led to avoiding mixed interfaces. The stoichiometric films showed good surface morphology and well defined sharp interfaces. The IR transmission spectrum showed sharp band to band absorption and effective detection in the MWIR. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995     

Field Measurements with a 5.25 GHz Broadband MIMO-OFDM Communication System

Theoretical capacity calculations and corresponding simulations show significant capacity/throughput gains from MIMO systems. Whether these gains are achievable in a real system, deployed in a practical environment, depends on a variety of factors, such as the choice of the communication algorithms, analog impairments and the "quality" of the wireless channel to sustain MEMO communications. In this paper, a 5.25 GHz broadband MIMO-OFDM testbed is described along with field measurements conducted with it. The MIMO-OFDM communication algorithms and also the impact of analog impairments on the performance of the system are described. Detailed system calibration results are described which serve as a baseline for results of field measurements. The results of wireless measurements are compared with the theoretical capacity, computed with the channel estimates obtained during the demodulation process. The average achievable capacity in the indoor wireless environment is shown to be 9.97 bps/Hz (bits per sec per Hz) while the capacity loss due to analog impairments and the choice of algorithms is about 2.33 bps/Hz. Also, field measurements conducted with the system in various environments are presented comparing the average throughput/capacity achieved in each of these environments.     

Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL): initial reliability and validity data

OBJECTIVE: To describe the psychometric properties of the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL) interview, which surveys additional disorders not assessed in prior K-SADS, contains improved probes and anchor points, includes diagnosis-specific impairment ratings, generates DSM-III-R and DSM-IV diagnoses, and divides symptoms surveyed into a screening interview and five diagnostic supplements. METHOD: Subjects were 55 psychiatric outpatients and 11 normal controls (aged 7 through 17 years). Both parents and children were used as informants. Concurrent validity of the screen criteria and the K-SADS-PL diagnoses was assessed against standard self-report scales. Interrater (n = 15) and test-retest (n = 20) reliability data were also collected (mean retest interval: 18 days; range: 2 to 36 days). RESULTS: Rating scale data support the concurrent validity of screens and K-SADS-PL diagnoses. Interrater agreement in scoring screens and diagnoses was high (range: 93% to 100%). Test-retest reliability kappa coefficients were in the excellent range for present and/or lifetime diagnoses of major depression, any bipolar, generalized anxiety, conduct, and oppositional defiant disorder (.77 to 1.00) and in the good range for present diagnoses of posttraumatic stress disorder and attention-deficit hyperactivity disorder (.63 to .67). CONCLUSION: Results suggest the K-SADS-PL generates reliable and valid child psychiatric diagnoses.     

粉煤灰和木钙双掺用于胶结充填的正交组合试验

通过粉煤灰和木钙双掺用于尾砂胶结充填的交组合试验，提示了双掺的作用机理，建立了试验指标的二次回归程，得出了双掺时粉煤灰和木钙的最佳掺量。     

Fertilizer use saves fuels in India

Dung supplies are inadequate to provide enough farmyard manure (FYM) and cheap dung-cakes. Use of FYM necessitates supply of other fuels for cooking. Fertilizers consume only 5% of the thermal energy embodied in FYM. Replacement of the currently used amount of FYM by fertilizers will save fuels and costs. If all of the plant nutrients are to be supplied by FYM to a hectare of wheat crop, 2.9 tonnes of coal are needed to replace the dung-cakes lost; fertilizer use will save Rs. 1444/ha. It is suggested that FYM use be minimized and fertilizer use increased for fuel thrift.     

Extraction of fission palladium by Aliquat 336 and electrochemical studies on direct recovery from ionic liquid phase

The wide electrochemical window and ion exchange properties of a room-temperature ionic liquid (RTIL) have been exploited for the extraction of palladium from nitric acid medium into ionic liquid phase — followed by direct electrodeposition of the metal from the organic phase. Extraction of palladium by commercial Aliquat 336 ionic liquids, tri-n-octylmethylammonium chloride (TOMAC) and tri-n-octylmethylammonium nitrate (TOMAN), was studied as a function of [HNO₃], [NO₃⁻] and [TOMAN]. The distribution ratio (D_Pd(II)) of palladium in TOMAN increased with an increase in the concentration of nitric acid and passed through a maximum at 1.0 M nitric acid. In contrast, the D_Pd(II) value of palladium in TOMAC decreased continuously with an increase in the concentration of nitric acid. Substantial amounts of water and nitric acid were also co-extracted into the organic phase with palladium.