Library

Notes: The experiments are performed to study the hardness layer depth at work piece differentsurface zone in grinding. The result is that hardness layer depth is various at work piece differentsurface zone. The hardness layer depth is thinner at cutting-in grinding zone, deeper at middlegrinding zone and deepest at cutting-off grinding zone. In order to analyze the cause of hardness depthvariation, the grinding temperature field is simulated by means of finite element method. From thetemperature field and heat flux simulation, the cause of the hardness depth variation is that thegrinding heat flux is variable at different grinding zone along the work piece surface ingrind-hardening. At cutting-in zone, most of grinding heat flows into the front-below work piece partinverse to table speed, the depth that temperature of surface layer higher than austenite temperature isthin and there is slim martensite transformation layer. At middle zone, the temperature of surfacelayer is higher than austenite temperature because of grinding heat accumulated in the surface layer,and martensite transformation takes place after cooling. At cutting-off zone, most of grinding heatflows into the below work piece part because of work piece boundary, and hardness depth is deeperthan that at middle zone

Notes: A non-destructive technique to image the dislocations and other extended defects in SiCepitaxial layers has been developed. Basal plane dislocations (BPDs) and threading dislocations(TDs) are imaged. Photoluminescence from the dislocations is excited with the 364 and/or 351 nmlines of an argon ion laser and near-infrared light is collected. A computer controlled probe stationtakes multiple images and the mm-sized images are stitched together to form whole-wafer maps.The technique is applied to a set of four n+ wafers from the same boule with 50 um n- epitaxiallayers. The epitaxy was grown with Cree’s low-BPD process. BPDs form as either single, isolateddislocations or as clusters encircling micropipes. The concentration of TDs is on the order 104/cm2and the local concentration varies more than an order of magnitude. The advantages of mappingdislocations by UV-PL imaging compared to other techniques are discussed

Notes: The contact rigidity and damping between joints of machine tools could vary greatlybecause of the difference of static and dynamic loading conditions. The pseudo-random gashingcutting is adopted in this paper, which makes the identification of structure transfer function ofmachine tools close to actual machining condition and improve the identification accuracy. Themain idea of this method is to decouple the transfer function in two directions based on left edgeand right edge cutting. Therefore, the structure transfer function identification of machine tools inactual cutting excitation is implemented. Finally, this method is compared with the traditionaltransfer function identification based on electromagnetism excitation and the qualified error isgiven

Notes: Background Asthma and allergic rhinitis (AR) frequently coexist, but have usually been studied separately in health economic analyses.Objective To determine the incremental effect of documented AR on health care resource use in adults with asthma.〈section xml:id="abs1-2"〉〈title type="main"〉Methods A retrospective cohort study using data from a UK general practice database for the period 1998–2001 enrolled subjects 16–55 years of age, with one or more asthma-related general practitioner (GP) visits during a 12-month follow-up period. The study outcomes were asthma-related hospitalizations, GP visits, and prescription drug costs during the 12-month follow-up period for patients with and without physician-diagnosed AR.Results Concomitant AR was documented in 4611 (16.9%) of the total sample of 27 303 adults with asthma. Compared with those with asthma alone, patients with concomitant AR experienced more GP visits (5.2 vs. 4.2; P〈0.0001) and more of them were hospitalized for asthma (0.76% vs. 0.45%; P〈0.01) during the 12-month follow-up period. In multi-variable regression analyses, AR was predictive of hospitalization for asthma (odds ratio 1.52, 95% confidence interval (CI) 1.03–2.24) and was associated with an increase in the annual number of asthma-related GP visits (mean increase per patient 0.42, 95% CI 0.42–0.43) and annual asthma-related drug costs (mean increase GBP 5.1, 95% CI 5.0–5.3).Conclusion Adults with asthma and documented concomitant AR experienced more asthma-related hospitalizations and GP visits, and incurred higher asthma drug costs than did adults with asthma alone. A unified treatment strategy for asthma and AR might reduce the costs of treating these conditions.

Notes: Background Inadequately controlled allergic rhinitis (AR) in asthmatic patients can contribute towards increased asthma exacerbations and poorer symptom control, which may increase medical resource use. We assessed asthma-related medical resource use and attacks in asthmatic patients who did and did not have concomitant AR and were adding montelukast or salmeterol to baseline treatment with inhaled fluticasone.Methods A post hoc resource use analysis of a 52-week, double-blind multicentre clinical trial (IMPACT: IMProving Asthma Control Trial) including 1490 adults with chronic asthma, aged 15–72 years, with FEV1 50–90% of predicted and 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:09547894:CEA2251:ges" location="ges.gif"/〉12% increase in FEV1 after salbutamol administration, treated with either montelukast 10 mg daily or salmeterol 50 μg twice daily in addition to fluticasone 200 μg, was undertaken. Asthma-related medical resource use included medical visits (defined as either an unscheduled visit [to a general practitioner, a specialist or a non-medical provider] or a specialist visit), emergency room visits and hospitalizations during follow-up. Asthma attacks were defined as the worsening of asthma requiring unscheduled visit, emergency visit, hospitalization or oral/intravenous/intramuscular corticosteroids.Results A self-reported history of concomitant AR was identified in 60% of the patients (n=893). Univariate analysis suggests that significantly more patients with concomitant AR experienced emergency room visits (3.6% vs. 1.7%, P=0.029) and asthma attacks (21.3% vs. 17.1%, P=0.046). Multivariate analysis adjusting for treatment group, age and baseline asthma severity confirmed these results since the presence of concomitant AR in patients with asthma increases the likelihood of emergency room visit (odds ratio (OR)=2.35, 95% confidence interval (CI)=1.12–4.80) and asthma attack (OR=1.35, 95% CI=1.03–1.77). Patients with asthma alone compared with patients with both conditions did not differ in terms of unscheduled or specialist visits and hospitalizations.Conclusions Presence of self-reported concomitant AR in patients with asthma resulted in a higher rate of asthma attacks and more emergency room visits compared with asthma patients without concomitant AR.

Notes: Genetic variation within and between 34 populations of Eichhornia crassipes (water hyacinth) in China was surveyed using random amplified polymorphic DNA (RAPD) markers. A total of 1009 individuals were analysed, for which 12 RAPD primers amplified 69 reproducible bands, with 22 (32%) being polymorphic. The percentage of polymorphic loci (p) within a population ranged from 4.4% to 17.4%, and the mean Nei's gene diversity (He) was 0.046 ± 0.0145, indicating a low genetic diversity of E. crassipes in China. Each population contained at least four RAPD phenotypes (genotypes), and the same particular genotype was invariably dominant in all the populations sampled. The mean proportion of distinguishable genotypes was 0.29. Analysis of molecular variance revealed a large proportion of genetic variation (83.9%) residing within populations and a slightly larger proportion (88.1%) within localities, indicating a low genetic differentiation of E. crassipes populations, both locally and regionally. Human-mediated dispersal, vigorous clonal growth, and a generally low level of sexual reproduction were thought to be responsible for such a pattern of genetic structure.

Notes: For the purpose of electronic packaging applications, a homogenous and void free 4032Al (Al-12wt.%Si) matrix composite with 70vol.% SiC particles was fabricated by squeeze casting technology. TEM observations indicated that SiC particles acted as heterogeneous nucleation sites for Si phases in the matrix and the SiC-Al interfaces were clean and free from any interfacial reaction products. The composite possessed lower coefficients of thermal expansion (CTEs) and excellent thermal conduction properties, and the CTEs could be further reduced by annealing treatment because of the alteration of original thermal residual stresses within the specimens. The incorporation of high volume fraction of SiC particles also induced enhanced mechanical properties for the composite, and its moduli even exceeded 200GPa. Some diodes were finally produced with nickel plated SiCp/Albaseplates and the results of thermal cycling tests between -55ı and 150ıfor these diodes were presented

Notes: In this study, X-ray detectors with coplanar metal-semiconductor-metal structure, were fabricated employing high quality chemical vapour deposited (CVD) diamond film grown by a direct current arc jet plasma system. In which the electrical contacts with dimension of 25 µm in width with a 25 µm inter-electrode spacing, were patterned on the growth side of the diamond film using lift-off technology. The performance of the fabricated detectors was evaluated by steady-stateX-ray illumination. The photoconductivity of the diamond detectors was found to linearly increase with increase in the X-ray photon flux. This demonstrates that high quality CVD diamond can be used for X-ray detectors

Notes: This paper puts forward a damage-fracture mechanical model and adamage-rheology mechanical model for the jointed rock mass of the high slopes in the ship lock area of Three Gorges Project. These two models are used to analyze the slopes’ stability. A comparison of the computed displacements at numbers of points on the slope surfaces with the results from 3-D analysis is also made. In addition, some computing results are compared with the in-situ measured ones, showing that the model proposed is basically reliable

Notes: Ultra-precision positioning technique has become one of the important parts in thedevelopment of precision machines. Flexure stage driven by piezoelectric actuator (PZT) has beenused widely as micro-feed installation because they have many advantages, such as: driving directly,fine displacement resolution, no friction or spacing. This paper designed a micro-feed stage driven byPZT using clinograph mechanism, analyzed the influence of flexure hinges on the static and dynamicperformance of micro-feed stage based on finite element analysis. The design procedure waspresented by which we can determine the geometrical dimensions of flexure hinge easily and achievedesired performance parameters of the stage, and the effectiveness of the design method was validatedby experiment