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1.
The rapid measurement of static vapour pressures of binary liquid mixtures as a function of composition by a new continuous-dilution apparatus is described. These measurements, together with the computed excess Gibbs free energies, are reported for mixtures of benzene and 1,1,2-trichlorotrifluoroethane at 283.30, 287.83, 293.21, 298.21, 303.06 and 308.15 K over the full composition range, and are compared with the results of Linford and Hildebrand. The excess enthalpies were measured directly at 303.15 K using a batch calorimeter. The equimolar excess enthalpy is + 754 J mol?1, which is close to the value, + 727 J mol?1, calculated from the temperature dependence of the computed equimolar excess Gibbs free energies.  相似文献   
2.
The Clouds and the Earth's Radiant Energy System (CERES) spacecraft scanning thermistor bolometer sensors measure Earth radiances in the broadband shortwave solar (0.3-5.0 μm) and total (0.3->100 μm) spectral bands as well as in the 8-12-μm water vapor window spectral band. On November 27, 1997, the launch of the Tropical Rainfall Measuring Mission (TRMM) spacecraft placed the first set of CERES sensors into orbit, and 30 days later, the sensors initiated operational measurements of the Earth radiance fields. In 1998, the Earth Observing System morning (EOS-AM1) spacecraft will place the second and third sensor sets into orbit. The prelaunch CERES sensors' count conversion coefficients (gains and zero-radiance offsets) were determined in vacuum ground facilities. The gains were tied radiometrically to the International Temperature Scale of 1990 (ITS-90). The gain determinations included the spectral properties (reflectance, transmittance, emittance, etc.) of both the sources and sensors as well as the in-field-of-view (FOV) and out-of-FOV sensor responses. The resulting prelaunch coefficients for the TRMM and EOS-AM1 sensors are presented. Inflight calibration systems and on-orbit calibration approaches are described, which are being used to determine the temporal stabilities of the sensors' gains and offsets from prelaunch calibrations through on-orbit measurements. Analyses of the TRMM prelaunch and on-orbit calibration results indicate that the sensors have retained their ties to ITS-90 at accuracy levels better than ±0.3% between the 1995 prelaunch and 1997 on-orbit calibrations  相似文献   
3.
A process alarm arises when normal operation limits are exceeded and an alarm management system alerts the operator of a process plant. Due to the material, energy and information flow in a plant, single disturbances can cause multiple consequent alarm messages, and the alarm messages may overload the operator by presenting many redundant alarms. This undesired situation is called an ‘alarm flood’. In such situations, the operator might not be able to fulfil his required tasks to keep the plant within safe operation limits and to find the root cause of the disturbance. The aim of the work presented in this paper is to reduce the number of alerts presented to the operator. If alarms are related to one another, those alarms should be grouped and presented as one alarm problem. For the implementation of the concept, a software prototype has been developed to perform this reduction automatically. The analysis process starts with the alarm history which is a log containing all past alarm messages. This is combined with the plant topology of the controlled system and a set of rules. The rules describe typical interrelations between alarm messages which have a common cause. The combination of these three elements yields an effective alarm management strategy that can help plant owners and operators to comply with standards for alarm management such as ANSI/ISA 18.2 (2009) and EEMUA 191 (2007) which set limits on the number of alarms per unit time for an operator. The effectiveness of the approach is illustrated by two industrial examples where a significant reduction of alarms has been achieved.  相似文献   
4.
Accurate knowledge of how applications are performing across a corporate enterprise infrastructure is a key factor in developing strategy for enterprise IT optimisation aligned to business drivers. BT’s applications-assured infrastructure proposition provides the ability for customers to understand where their application bottle-necks are, fix problems, optimise performance and provide long-term enterprise IT health monitoring. This is a big step towards the goal of supporting guaranteed end-to-end applications performance — the next level of quality-of-service-based product requirements.  相似文献   
5.
Results from spectral radiance measurements using optical multi-channel analyzer over the visible and near infrared regime provide estimates of temperature from expansion products resulting from shocked materials. Specifically, we have made spectral radiance measurements over the wavelength regime of 300–1500 nm. Experiments conducted on aluminum, cerium, and Composition-B high explosive span a wide regime of E/Ev, where E is the internal energy increase of the shocked material, and Ev, is the specific energy required to vaporize the material. For the materials investigated, the ratio is ∼1, 3 and 5 for aluminum, cerium, and Composition-B, respectively. The basic assumption made to deduce these temperatures is that the debris cloud is radiating as a blackbody with emissivity of one and independent of the wavelength. We are also assuming that the probe is monitoring the debris, which is at a single temperature and that there is no spatial temperature gradient. Temperatures at or above the boiling point are confirmed for aluminum and cerium, while the results for Composition-B provide the time-dependent temperature expansion history for shocked Composition-B over the stress regime of 28–130 GPa. These are the first measurements of temperature obtained from the expansion products from materials that have been shocked to very high pressures.  相似文献   
6.
This paper discusses the application of control loop performance assessment (CLPA) in a refinery setting. The CLPA algorithm has several parameters that have to be adjusted correctly to give the best results. Procedures are described for selecting these parameters which make it feasible to implement the algorithm on a refinery-wide scale. We report practical experiences with the use of the techniques.  相似文献   
7.
Validating genomic prediction equations in independent populations is an important part of evaluating genomic selection. Published genomic predictions from 2 studies on (1) residual feed intake and (2) dry matter intake (DMI) were validated in a cohort of 78 multiparous Holsteins from Australia. The mean realized accuracy of genomic prediction for residual feed intake was 0.27 when the reference population included phenotypes from 939 New Zealand and 843 Australian growing heifers (aged 5–8 mo) genotyped on high density (770k) single nucleotide polymorphism chips. The 90% bootstrapped confidence interval of this estimate was between 0.16 and 0.36. The mean realized accuracy was slightly lower (0.25) when the reference population comprised only Australian growing heifers. Higher realized accuracies were achieved for DMI in the same validation population and using a multicountry model that included 958 lactating cows from the Netherlands and United Kingdom in addition to 843 growing heifers from Australia. The multicountry analysis for DMI generated 3 sets of genomic predictions for validation animals, one on each country scale. The highest mean accuracy (0.72) was obtained when the genomic breeding values were expressed on the Dutch scale. Although the validation population used in this study was small (n = 78), the results illustrate that genomic selection for DMI and residual feed intake is feasible. Multicountry collaboration in the area of dairy cow feed efficiency is the evident pathway to achieving reasonable genomic prediction accuracies for these valuable traits.  相似文献   
8.
Particle launch experiments were performed to study application of the enhanced hypervelocity launcher (EHVL), i.e. the third-stage addition to the two-stage gun, for launching micron to millimeter sized particulates at velocities unobtainable with a standard two-stage light gas gun launch. Three types of particles or fliers were tested along with several barrel designs. For micron scale particles fine-grain polycrystalline ceramics were impacted and fractured, launching particulate clouds at velocities of 15 km/s. Multiple titanium particles 400 μm diameter embedded in plastic were “shotgun” launched to velocities of 10 km/s. Flier plates of 3 mm diameter by 1 mm thick Ti6Al4V were launched to 19 km/s. All experiments used a second-stage projectile with graded density facing impacting a flier in an impact generated acceleration reservoir. This paper describes the modification and adaptation of the Sandia EHVL to provide micrometeoroid simulation capabilities.  相似文献   
9.
The current potency test for pertussis vaccines, the mouse protection test (MPT), has many disadvantages. However, no alternative is yet available. The purpose of this study is to develop a serological alternative for the MPT based on in vitro assessment of the humoral immune response against pertussis in mice. After immunization with pertussis whole cell vaccine, the MPT shows a normal primary and secondary antibody response. Moreover, the i.c. challenge has a distinct booster effect on the pertussis IgG response. The relationship between the concentration of IgG antibodies against the surface-antigens of pertussis bacteria and the survival of mice after the i.c. challenge was demonstrated in a modified MPT (R = 0.91). To this end a protecting antibody level of > or = 45 EU/ml was selected as a level at which concentration most of the mice survived. Survival of mice in the MPT could be predicted, based on the antibody concentration at the day of challenge. Potencies estimated with the predicted and actual survival corresponded well (P = 0.990). This confirmed the essential role of vaccine induced pertussis antibodies in the protection against a lethal i.c. challenge and offered a possibility to develop a pertussis potency test based on serology. We developed a model in which mice (20-24 g) are immunized (i.p.) with graded doses of vaccine and bled after four weeks. Sera are titrated in Bordetella pertussis whole cell ELISA and potency based on vaccine dose dependent antibody response is estimated by means of a parallel line analysis. The potency of vaccines tested in the Pertussis Serological Potency Test (PSPT) and MPT are significantly similar, a P-value of 0.92 was found by means of the chi 2 test. Compared to the MPT, the PSPT is more reproducible as is indicated by its smaller 95% confidence intervals. Moreover, by using the PSPT the animal distress can be reduced to an acceptable level and the PSPT also results in a reduction of more than 25% in use of mice.  相似文献   
10.
This paper reports an application of the Kolmogorov-Smirnov test for the purpose of detecting changes in the distribution of a sequence of measurements. The ‘probability chart’ of the title gave a value reflecting whether the distribution was constant in the neighbourhood of each observation. The chart had the advantage that the threshold for detection of a change was a dimensionless probability value. The non-parametric nature of the test made it suitable for measurements sampled from a non-Gaussian distribution.  相似文献   
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