钼在400～2500K温度的比热和电阻率

用毫秒－脉冲热量计与接触温度计测量钼的比热和电阻率，温度计采用是Ｗ－Ｒｅ热电耦，可在４００～２５００Ｋ温度范围内进行了研究。在温度高于１３００Ｋ时，并联高温计测量加以修正，利用在这个温度国内所获得的热辐数据得出并讨论了钼的比热，电阻率，半球形总辐射率以及标准光谱辐射率，并将比热与标准参考数据作了比较。     

Thin-film ferroelectrics of PZT of sol-gel processing

The ferroelectric effect has been demonstrated for sol-gel derived lead zirconate titanate (PZT) (53/47) thin films. The respective values of coercive field and remanent polarization were 4x10(6) V/m and 0.36 C/m(2). The thin-film fabrication process is simple and compatible with Si planar technology, and offers a wide variety of potential uses for counting, memory, and integrated optical circuit applications.     

Structuring free space as a hypergraph for roving robot path planning and navigation

This paper presents a method of structuring the free space of a roving robot's environment into a set of overlapping convex regions ideally suited to path planning and navigation tasks. The structure of the free space environment is maintained as a hypergraph with each convex region represented by a hyperedge identifying the boundary walls of the region. A new methodology reveals the structure of free space and constructs the hypergraph representation through a directed search for a set of fundamental circits in an abstract graphical representation of the environment geometry.     

Experimental study and model validation of selective spinal cord and brain hypothermia induced by a simple torso-cooling pad

In vivo experiments have been performed to test the effectiveness of a torso-cooling pad to reduce the temperature in the spinal cord and brain in rats. Coolant was circulated through the cooling pad to provide either mild or moderate cooling. Temperatures in the brain tissue, on the head surface, and on the spine and back surfaces were measured. During mild cooling, the temperature on the back surface was 22.82 +/- 2.43 degrees C compared to 29.34 +/- 1.94 degrees C on the spine surface. The temperature on the back surface during moderate cooling was 13.66 +/- 1.28 degrees C compared to 24.12 +/- 5.7 degrees C on the spine surface. Although the temperature in the brain tissue did not drastically deviate from its baseline value during cooling, there was a difference between the rectal and brain temperatures during cooling, which suggests mild hypothermia in the brain tissue. Using experimental data, theoretical models of the rat head and torso were developed to predict the regional temperatures and to validate the rat models. There was good agreement between the theoretical and experimental temperatures in the torso region. Differences between the predicted and measured temperatures in the brain are likely to be the result of imperfect mixing between the cold spinal fluid and the warm cerebrospinal fluid that surrounds the brain.     

A dual mesh scheme for finite element based reconstruction algorithms

The finite element (FE) method has found several applications in emerging imaging modalities, especially microwave imaging which has been shown to be potentially useful in a number of areas including thermal estimation. In monitoring temperature distributions, the biological phenomena of temperature variations of tissue dielectric properties is exploited. By imaging these properties and their changes during such therapies as hyperthermia, temperature distributions can be deduced using difference imaging techniques. The authors focus on a microwave imaging problem where the hybrid element (HE) method is used in conjunction with a dual mesh scheme in an effort to image complex wavenumbers, k(2). The dual mesh scheme is introduced to improve the reconstructed images of tissue properties and is ideally suited for systems using FE methods as their computational base. Since the electric fields typically vary rapidly over a given body when irradiated by high-frequency electromagnetic sources, a dense mesh is needed for these fields to be accurately represented. Conversely, k(2) may be fairly constant over subregions of the body which would allow for a less dense sampling of this parameter in those regions. In the dual mesh system employed, the first mesh, which is uniformly dense, is used for calculating the electric fields over the body whereas the second mesh, which is nonuniform and less dense, is used for representing the k(2) distribution within the region of interest. The authors examine the 2-D TM polarization case for a pair of dielectric distributions on both a large and small problem to demonstrate the flexibility of the dual mesh method along with some of the difficulties associated with larger imaging problems. Results demonstrate the capabilities of the dual mesh concept in comparison to a single mesh approach for a variety of test cases, suggesting that the dual mesh method is critical for FE based image reconstruction where rapidly varying physical quantities are used to recover smoother property profiles, as can occur in microwave imaging of biological bodies.     

Using knowledge structures to redesign an instructor-operator station

Frequently, user interface (UI) designers must choose between modifying an established, but suboptimal and familiar, UI or to avoid such changes. Changing the UI’s, organization may frustrate users who have become familiar with the original design, whereas failing to make changes may force users to perform at an unsatisfactory level. This paper presents two studies that investigate whether users familiar with a poorly designed UI would find items faster, and prefer a reorganized UI that conformed to domain expert knowledge, or would their familiarity with the original UI yield faster performance and higher satisfaction.This paper describes activities to redesign a menu structure in a simulator instructor–operator station (IOS) using hierarchical card sorting and cluster analysis (Romesburg, 2004). This analysis was used to reorganize the menu structure to reflect the knowledge representations of domain experts in accordance with the principle of proximity compatibility (Wickens and Carswell, 1995, Rothrock et al., 2006). The new design was validated with a separate set of users by a reaction time experiment and preference selection.     

Effects of feeding diets containing different fat supplements to swine on the visual properties and storage stability of low-fat sausage

Sixty barrows and gilts were assigned to one of five dietary treatments consisting of a control diet of corn and soybean meal and four similar test diets that contained a 10% replacement of either animal fat, safflower oil, sunflower oil or canola oil, to determine the effects of high levels of oleic acid in the diet of swine on the storage stability of fresh pork sausage. Pork trim from each treatment was used to formulate sausage that contained two fat levels (25% and 35%), and two levels of added water (3% and 11%). Thiobarbituric acid values did not differ between the control, safflower oil or sunflower oil treatments and all treatments were acceptable after 10 weeks of storage. Microbial numbers increased with the level of added water and during time in storage (up to 3 weeks). Visual evaluation showed that the control was the most red and least discolored, while the canola oil treatment was the least red and the most discolored. Results from the present study suggest that a 105 replacement of a typical corn/soybean meal diet to swine with safflower or sunflower oil did not alter the storage-stability of fresh pork sausage.     

Directed evolution for the development of conformation-specific affinity reagents using yeast display

Yeast display is a powerful tool for increasing the affinity and thermal stability of scFv antibodies through directed evolution. Mammalian calmodulin (CaM) is a highly conserved signaling protein that undergoes structural changes upon Ca(2+) binding. In an attempt to generate conformation-specific antibodies for proteomic applications, a selection against CaM was undertaken. Flow cytometry-based screening strategies to isolate easily scFv recognizing CaM in either the Ca(2+)-bound (Ca(2+)-CaM) or Ca(2+)-free (apo-CaM) states are presented. Both full-length scFv and single-domain VH only clones were isolated. One scFv clone having very high affinity (K(d) = 0.8 nM) and specificity (>1000-fold) for Ca(2+)-CaM was obtained from de novo selections. Subsequent directed evolution allowed the development of antibodies with higher affinity (K(d) = 1 nM) and specificity (>300-fold) for apo-CaM from a parental single-domain clone with both a modest affinity and specificity for that particular isoform. CaM-binding activity was unexpectedly lost upon conversion of both conformation-specific clones into soluble fragments. However, these results demonstrate that conformation-specific antibodies can be quickly and easily isolated by directed evolution using the yeast display platform.