平凡中显现精彩——KTC K-7003L显示器

在脱离前两年恶性竞争的怪圈后,LCD显示器开始进入良性竞争的阶段。经过两年“休养生息”,现在市场上绝大多数品牌都能为用户提供价格合理且质量较为令人满意的产品。正是有了这个前提,个人用户也逐渐开如将LCD显示器作为新的考虑目标。 作为一家有较长代工历史的LCD显示器生产厂商,康冠电子终于从幕后走到台前,推出了一系列LCD产品。本刊曾在9月的LCD横向评测中介绍过KTC 7002L这款产品,而本次我们收到了康冠旗下的另一款产品——KTC7003L。     

Concerning the concern over the medical model.

Comments that I. G. Sarason and V. J. Ganzer (1968) have neglected to mention an important aspect of the criticism of medical models. For some critics of medical models, the primary issue is the symptom–underlying illness paradigm, which implies that abnormal behavior results from different processes than normal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Collision cascades in pure <Emphasis Type="Italic">δ</Emphasis>-plutonium

Molecular dynamics simulations of the formation and annealing of large collision cascades in delta-phase plutonium are presented. The defect evolution is followed with time up to 2 ns. Simulations are performed with the MEAM potential at three different temperatures; at 600 K where the pure delta phase is thermodynamically stable; at 300 K where the delta phase can only be maintained in a metastable state with minor additions of gallium or aluminum; and at 180 K where plutonium should transform to the alpha phase. It is found in all three cases that the atomic structure within the cascade evolves through a glass-like state. At 600 K, this structure recovers very slowly; at 300 K it persist up to 2 ns with no discernable trend to recover eventually; and at 180 K the amorphous structure initiated by the collision cascade spreads through the entire crystal and converts it to a glass-like structure.     

Suppression of void nucleation by injected interstitials during heavy ion bombardment

In a heavy ion irradiation the injected ions come to rest at the end of range as interstitials without a vacancy partner. These extra interstitials perturb the delicate balance of vacancy and interstitial flux to voids. It is shown that the void nucleation rate is drastically reduced by the injected interstitials whenever recombination is an important process. As a result, void nucleation is suppressed in ion-bombardment experiments below a characteristic threshold temperature in the region of the ion deposition. This leads to a void free zone near the end of range in low temperature ion-bombardment experiments. The results obtained are in qualitative agreement with earlier experimental observations.     

Fusion-fission hybrid design with analysis of direct enrichment and non-proliferation features (the SOLASE-H study)

The role of a fusion-fission hybrid in the context of a nuclear economy with and without reprocessing is examined. An inertial confinement fusion driver is assumed and a consistent set of reactor parameters are developed. The form of the driver is not critical, however, to the general concepts. The use of the hybrid as a fuel factory within a secured fuel production and reprocessing center is considered. Either the hybrid or a low power fission reactor can be used to mildly irradiate fuel prior to shipment to offsite reactors thereby rendering the fuel resistant to diversion. A simplified economic analysis indicates a hybrid providing fuel to 10 fission reactors of equal thermal power is insensitive to the recirculating power fraction provided reprocessing is permitted. If reprocessing is not allowed, the hybrid can be used to directly enrich light water reactor fuel bundles fabricated initially from fertile fuel (either ThO₂ or ²³⁸UO₂). A detailed neutronic analysis indicates such direct enrichment is feasible but the support ratio for ²³³U or ²³⁹Pu production is only 2, making such an approach highly sensitive to the hybrid cost. The hybrid would have to produce considerable net power for economic feasibility in this case. Inertial confinement fusion performance requirements for hybrid application are also examined and an integrated design, SOLASE-H, is described based upon the direct enrichment concept.     

Correlation of radiation creep theory with experimental evidence

A review is presented of theoretical models related to irradiation creep and to the evolution of the dislocation structure in irradiated stainless steels. The results of detailed analysis for stress-induced loop alignment and stress-induced preferential absorption (SIPA) of point defects at dislocations is presented. Stress-induced rotation of tri-interstitials is shown to be too small to account for the observed variations in loop densities on different crystallographic planes. However, it is possible to predict large variations with the SIPA mechanism. Predictions of irradiation creep by the SIPA mechanism are in agreement with measured data at intermediate fluences. At low fluences, additional contributions to irradiation creep must come from dislocation glide. The evolution of the dislocation structure can be explained by the continuous formation of interstitial type loops and by the radiation-induced recovery of the dislocation network.     

Residual stress measurements in irradiated solution-annealed type 304 stainless steel tubing

Immersion density and residual stress measurements were made on solution-annealed type 304 stainless steel capsule tubing irradiated up to fluence levels of 9 × 10²² n/cm² (E > 0.1 MeV). The measured residual stress is dependent on the competition between differential swelling which builds up differential stresses, and irradiation creep which relaxes these stresses. The measurements were analyzed using a bilinear swelling equation formulated with swelling data from the same heat of material. The temperatures and fluence levels of the swelling and slit tube data were each calculated with the same computer code. At high fluence, when swelling was in the steady-state region, the effective irradiation creep rate increased by a factor of about three. Further analysis was made assuming that stress-enhanced swelling and swelling-enhanced irradiation creep were the enhanced relaxation mechanisms.     

Light‐Stability of Poly(dialkylstannane)s

This study deals with the stability of poly(dialkylstannane)s in solution and in the bulk, in particular under exposure to light, which was found to cause degradation more severely than water or oxygen. Decomposition of the poly(dialkylstannanes) under argon atmosphere in solution proceeded by an unzipping mechanism, most likely initiated by scission of a Sn? Sn bond. While solvents and additives influenced polystannane degradation, the length of the alkyl groups was not particularly relevant, indicating that steric effects played a minor role in this process. In unreactive solvents, the polystannanes were the least stable and cyclic oligostannanes formed as decomposition products. Polystannanes in solution were found to be most stable in dichloromethane or styrene, which gave rise to the formation of Bu₂(ClCH₂)SnCl or poly(styrene), indicating that the polystannanes acted in the latter case as a photoinitiator. Addition of radical scavengers and selected dyes improved the stability of polystannanes toward light. Exposure of bulk poly(dialkylstannane)s to ambient caused the formation of (oligo‐)alkyltin‐oxides.

     

Increased asymmetries in 2-deoxyglucose uptake in the brain of freely moving congenitally acallosal mice

To investigate the role of the corpus callosum in the expression of functional brain asymmetries, we compared left and right uptake of [14C]2-deoxyglucose in 43 brain regions measured in 10 C57B1/6 mice with a normal corpus callosum and in 12 congenitally acallosal mice, after 45 min of free activity in a novel, large open-field arena. The metabolic patterns across the brain appeared to be similar in the two groups of mice, as well as the average direction of asymmetry in tracer incorporation, which was higher at right in most of the brain regions for both acallosals and controls. However, the direction of the metabolic asymmetries of any given region was not consistent across individual animals. The largest asymmetries were found in the central auditory nuclei in both groups of mice, with extreme values in some acallosals. Significantly larger asymmetries were found in acallosal mice for the brain and the cortex as a whole, as well as for the lateral geniculate and pretectal nuclei, the olfactory tubercles, and retrosplenial, infrarhinal and perirhinal cortices. The metabolic asymmetries of the thalamic sensory nuclei were correlated with the asymmetries of the corresponding sensory cortical fields in the acallosal, but not in control mice. On the other hand, asymmetries of the cortical regions were largely intercorrelated in control mice, resulting in a general activation of one hemisphere over the other, while in acallosals they were more independent, resulting in a "patchy" pattern of cortical asymmetries. These results suggest that callosal agenesis, combined with the occurrence of ipsilateral Probst bundles, leads to a loss of co-ordination in the activation of different sensory and motor areas. The impaired co-ordination might then be distributed through cortico-subcortical loops, resulting in larger asymmetries throughout the brain. Thus, a normal corpus callosum appears to balance and synchronize metabolic brain activity, perhaps by smoothing the effects of asymmetrically activated ascending systems.