非铁磁性金属薄层涡流测厚法

介绍用涡流法弥补超声法检测厚度〈1 mm的薄层非铁磁性金属的不足.推导了涡流线圈感抗简化公式,试验测量了厚度为25～250 μm的铝和25～500 μm的不锈钢,得出了其厚度与幅值的关系曲线,理论计算与试验结果吻合较好.最后根据简化公式进行了理论仿真.研究表明,涡流方法适合测量电导率低的薄层金属厚度,选用合适的低频,采用铁心线圈或考虑相位信息与提离的关系后,该方法可有效监控非铁磁性金属薄层的厚度变化.     

Semidynamic and dynamic transmission algorithms for multiplexing voice with data

The design of hybrid transmission algorithms for the multiplexing of voice and data over a common digital channel is of interest to various communication networks, including cellular radio and high-speed topologies. In environments where the characteristics of the voice and data traffics may vary dynamically, the issue is the deployment of hybrid multiplexing algorithms (HMAs) which satisfy the constraints imposed by the voice traffic, while they simultaneously attain high channel utilization and induce low implementation overhead. In this paper, we propose, evaluate, and compare two HMAs: a semidynamic and a dynamic. The former induces lower implementation overhead than the latter, but it is applicable only to environments where the rate of the voice traffic may vary relatively slowly and its statistics are parametrically known. The semidynamic HMA induces frame structures, where the capacity allocation per frame, for the voice versus data traffic, is dictated by a superimposed traffic monitoring algorithm. The dynamic HMA, on the other hand, assigns each channel slot to voice versus data packets dynamically; it requires no statistical knowledge about the voice traffic, at the expense of significantly increased implementation overhead.     

Elevated levels of hyaluronic acid in the sera of women with fibromyalgia

OBJECTIVE: To evaluate serum levels of hyaluronic acid (HA) in patients with fibromyalgia (FM). METHODS: HA serum levels were evaluated by a radiometric assay in 42 women with FM (ACR criteria), 27 female patients with rheumatoid arthritis (RA) and 36 healthy female controls matched for age. RESULTS: HA serum levels (mean microg/l +/- SEM) were 41 +/- 8.7 in healthy controls; 113 +/- 15.9 in RA: and 420 +/- 26 in FM. CONCLUSION: HA serum levels in women with FM were significantly elevated compared to healthy controls and patients with RA. This observation suggests that FM is associated with a biochemical abnormality and that serum HA could be a laboratory marker for its diagnosis.     

TARS: traffic-aware route search

In a traffic-aware route search (TARS), the user provides start and target locations and sets of search terms. The goal is to find the fastest route from the start location to the target via geographic entities (points of interest) that correspond to the search terms, while taking into account variations in the travel speed due to changes in traffic conditions, and the possibility that some visited entities will not satisfy the search requirements. A TARS query may include temporal constraints and order constraints that restrict the order by which entities are visited. Since TARS generalizes the Traveling-Salesperson Problem, it is an NP-hard problem. Thus, it is unlikely to find a polynomial-time algorithm for evaluating TARS queries. Hence, we present in this paper three heuristics to answer TARS queries—a local greedy approach, a global greedy approach and an algorithm that computes a linear approximation to the travel speeds, formulates the problem as a Mixed Integer Linear Programming (MILP) problem and uses a solver to find a solution. We provide an experimental evaluation based on actual traffic data and show that using a MILP solver to find a solution is effective and can be done within a limited running time in many real-life scenarios. The local-greedy approach is the least effective in finding a fast route, however, it has the best running time and it is the most scalable.     

Use of green fluorescent protein expressing Salmonella Stanley to investigate survival, spatial location, and control on alfalfa sprouts.

Laser scanning confocal microscopy (LSCM) was used to observe the interaction of Salmonella Stanley with alfalfa sprouts. The green fluorescent protein (gfp) gene was integrated into the chromosome of Salmonella Stanley for constitutive expression, thereby eliminating problems of plasmid stability and loss of signal. Alfalfa seeds were inoculated by immersion in a suspension of Salmonella Stanley (ca. 10(7) CFU/ml) for 5 min at 22 degrees C. Epifluorescence microscopy demonstrated the presence of target bacteria on the surface of sprouts. LSCM demonstrated bacteria present at a depth of 12 microm within intact sprout tissue. An initial population of ca. 10(4) CFU/g seed increased to 7.0 log CFU/g during a 24-h germination period and then decreased to 4.9 log CFU/g during a 144-h sprouting period. Populations of Salmonella Stanley on alfalfa seeds decreased from 5.2 to 4.1 log CFU/g and from 5.2 to 2.8 log CFU/g for seeds stored 60 days at 5 and 22 degrees C, respectively. The efficacy of 100, 200, 500, or 2,000 ppm chlorine in killing Salmonella Stanley associated with sprouts was determined. Treatment of sprouts in 2,000 ppm chlorine for 2 or 5 min caused a significant reduction in populations of Salmonella Stanley. Influence of storage on Salmonella Stanley populations was investigated by storing sprouts 4 days at 4 degrees C. The initial population (7.76 log CFU/g) of Salmonella Stanley on mature sprouts decreased (7.67 log CFU/g) only slightly. Cross-contamination during harvest was investigated by harvesting contaminated sprouts, then directly harvesting noncontaminated sprouts. This process resulted in the transfer of ca. 10(5) CFU/g Salmonella Stanley to the noncontaminated sprouts.     

Extended induction of ovulation by human menopausal gonadotropins and a gonadotropin-releasing hormone analog in high responders for in vitro fertilization and oocyte donation

OBJECTIVE: To examine the efficacy of extending ovulation induction for the in vivo maturation of oocytes. STUDY DESIGN: Fifty-nine high responders underwent 72 in vitro fertilization (IVF) cycles with a conventional protocol of human menopausal gonadotropin and a gonadotropin-releasing hormone analog. These patients donated oocytes to 81 recipients. The same 59 patients underwent 90 subsequent cycles in which the duration of induction was extended by two to three days. The oocytes were also donated to 138 patients. RESULTS: With the extended protocol, significantly more oocytes were retrieved (29.1 vs. 20.6), and a greater proportion of them were mature. Fertilization rates were significantly higher for both donors (67.7% vs. 36.2%) and recipients (67.5% vs. 47.1%). Conception rates were also significantly higher for both donors (24.4% vs. 11.1%) and recipients (38.4% vs. 24.7%). CONCLUSION: Extending the duration of ovulation induction in high responders is associated with in vivo maturation of oocytes and improved success rates in IVF and ovum-donation programs.     

Model Checking at IBM

Over the past nine years, the Formal Methods Group at the IBM Haifa Research Laboratory has made steady progress in developing tools and techniques that make the power of model checking accessible to the community of hardware designers and verification engineers, to the point where it has become an integral part of the design cycle of many teams. We discuss our approach to the problem of integrating formal methods into an industrial design cycle, and point out those techniques which we have found to be especially effective in an industrial setting.     

Effects of tantalum on the partitioning of tungsten between the γ- and γ′-phases in nickel-based superalloys: Linking experimental and computational approaches

Atom probe tomography (APT) and first-principles calculations are implemented to study the partitioning of W to the γ (face-centered cubic)- and γ′ (L1₂)-phases in Ni-based alloys. APT observations indicate that whereas W partitions preferentially to the γ′-phase in a ternary Ni–Al–W alloy, its partitioning behavior is reversed in favor of the γ-phase in multi-component alloys. Furthermore, the degree of W-partitioning to the γ′-phase decreases with the addition of Ta to a Ni–Al–Cr–W alloy, a trend which is consistent with Thermo-Calc simulations. First-principles calculations of the substitutional formation energies of W and Ta at 0 K predict that both elements prefer energetically sharing the Al-sublattice sites of the γ′-phase, whereas Ta has a larger tendency to partition to the γ′-phase than does W. This implies that Ta displaces W from the γ′-phase into the γ-phase in multi-component Ni-based alloys.