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21.
The binding of Eu(III) to a biosorbent derived from cultured cells of the plant Datura innoxia, have been investigated through elucidation of apparent affinity constants associated with different chemical environments present on the cell wall. Adsorption isotherms for separate types of binding sites were generated using metal ion luminescence measurements. Application of regularized regression analysis to these isotherm data for four chemically distinguishable sites revealed the presence of sites exhibiting both low (mean log Kapp = ?0.3 to 0.6) and higher (mean log Kapp = 3.2–3.5) apparent affinities for pH conditions of 2.0, 4.0, and 5.0. Low affinity sites were observed for all pH conditions and attributed to non-specific binding of the metal ions to the negatively charged biomaterial. The pH-dependent higher affinity sites are ascribed to specific sites involving either an ion-exchange mechanism or formation of weak surface–metal ion complexes. These results differed significantly from a similar analysis of total metal binding isotherms that indicated mean log Kapp values of ?0.5 to 0.25 (low affinity) and 5.6–6.0 (high affinity).  相似文献   
22.
Automatic extraction of multiword expressions (MWEs) presents a tough challenge for the NLP community and corpus linguistics. Indeed, although numerous knowledge-based symbolic approaches and statistically driven algorithms have been proposed, efficient MWE extraction still remains an unsolved issue. In this paper, we evaluate the Lancaster UCREL Semantic Analysis System (henceforth USAS (Rayson, P., Archer, D., Piao, S., McEnery, T., 2004. The UCREL semantic analysis system. In: Proceedings of the LREC-04 Workshop, Beyond Named Entity Recognition Semantic labelling for NLP tasks, Lisbon, Portugal. pp. 7–12)) for MWE extraction, and explore the possibility of improving USAS by incorporating a statistical algorithm. Developed at Lancaster University, the USAS system automatically annotates English corpora with semantic category information. Employing a large-scale semantically classified multi-word expression template database, the system is also capable of detecting many multiword expressions, as well as assigning semantic field information to the MWEs extracted. Whilst USAS therefore offers a unique tool for MWE extraction, allowing us to both extract and semantically classify MWEs, it can sometimes suffer from low recall. Consequently, we have been comparing USAS, which employs a symbolic approach, to a statistical tool, which is based on collocational information, in order to determine the pros and cons of these different tools, and more importantly, to examine the possibility of improving MWE extraction by combining them. As we report in this paper, we have found a highly complementary relation between the different tools: USAS missed many domain-specific MWEs (law/court terms in this case), and the statistical tool missed many commonly used MWEs that occur in low frequencies (lower than three in this case). Due to their complementary relation, we are proposing that MWE coverage can be significantly increased by combining a lexicon-based symbolic approach and a collocation-based statistical approach.  相似文献   
23.
An on-line detection scheme has been developed for the determination of metal ion affinities for binding to a plant-based substrate. This involves monitoring the effluent of a column packed with cell-wall fragments from the plant Datura innoxia for 27 different elements simultaneously by coupling the column to an ICP emission spectrometer. Previously accepted procedures for removing native metal ions from biological materials by washing the material with a pH 2 solution were found to be insufficient for this material. Measurable amounts of Na, Mg, Al, Ca, Mn, Fe, Ni, Cr, Zn, Cd, Pb, Ba, Sr, and Si were all detected in an effluent from the introduction of 1.0M HCl following washing the material in a pH 2 solution. Metal ion breakthrough curves for Cd(2+), Zn(2+), Ni(2+), Cu(2+), and Pb(2+) were found to exhibit an affinity order of Pb(2+)>Cu(2+)>Zn(2+) congruent with Cd(2+)>Ni(2+) for an equimolar mixture of these metal ions. This configuration also enabled the displacement of metal ions to be detected as the breakthrough curve for a subsequent metal ion was monitored. Comparison of Ni and Zn binding indicates a simple ion exchange model is insufficient to explain sequential binding of these metal ions.  相似文献   
24.
No study has yet evaluated the efficacy of British Army basic training in improving material handling performance. Therefore, the purpose of this study was to evaluate the efficacy of the current British Army basic training in improving material handling performance and physical fitness. Forty-seven males (19.4 (3.2) years of age, 1753 (59) mm in height, 71.0 (9.6) kg in weight) and 10 females (21.5 (3.5) years, 1623 (45) mm, 62.5 (5.2) kg) served as subjects. Testing was carried out in the week prior to, and in the final week of, an 11-week basic training course. Maximal box lifts to two different heights, and repetitive lifting and carrying of a 10 kg load did not improve with training. Static (38 cm upright pull) and dynamic (incremental dynamic lift to 145 cm) lifting strength data concurred with the maximal box lift data in that no improvement was observed. Repetitive lifting and carrying of a 22 kg load improved (29.5%, p < 0.001), as did 3.2 km loaded march performance with 25 kg (15.7%, p < 0.001), but march performance with a 15 kg load did not. Predicted VO2max improved from 48.4 to 51.4 ml.kg-1.min-1, a change of 6.1% (p < 0.05). Fat-free mass increased by 0.9 kg (1.5%, p < 0.01), and body fat reduced by 2.7% of body mass (20.1%, p < 0.001), resulting in a loss of 1.2 kg of body mass (1.7%, p < 0.01). It is concluded that basic training in the British Army produces some favourable adaptations in recruits, especially in terms of aerobic fitness. However, the poor development of strength and material handling ability during training fails to improve the ability of soldiers to perform simulated military tasks, and it does little to reduce future injury risk while performing these tasks.  相似文献   
25.
In a recent work [M.J. Rayson, P.R. Briddon, Phys. Rev. B 80 (2009) 205104] an implementation of filter diagonalisation with localisation constraints was shown to provide an accurate and highly efficient method to solve the Kohn-Sham equations using a primitive Gaussian basis for systems containing several thousand electrons. In this work, an alternative filtration algorithm is proposed, based on a rational approximation to the filtration function, to replace the kernel of this algorithm. This approach is considerably faster than the diagonalisation approach used previously and also its performance is largely independent of the filtration temperature, aiding a more flexible approach to the construction of filtered basis sets.  相似文献   
26.
While terrorism informatics research has examined the technical composition of extremist media, there is less work examining the content and intent behind such media. We propose that the arguments and issues presented in extremist media provide insights into authors’ intent, which in turn may provide an evidence-base for detecting and assessing risk. We explore this possibility by applying two quantitative text-analysis methods to 50 online texts that incite violence as a result of the 2008/2009 Israeli military action in Gaza and the West Bank territories. The first method—a content coding system that identifies the occurrence of persuasive devices—revealed a predominance of moral proof arguments within the texts, and evidence for distinguishable ‘profiles’ of persuasion use across different authors and different group affiliations. The second method—a corpus-linguistic technique that identifies the core concepts and narratives that authors use—confirmed the use of moral proof to create an in-group/out-group divide, while also demonstrating a movement from general expressions of discontent to more direct audience-orientated expressions of violence as conflict heightened. We conclude that multi-method analyses are a valuable approach to building both an evidence-based understanding of terrorist media use and a valid set of applications within terrorist informatics.  相似文献   
27.
Requirements Engineering - We report experience in requirements elicitation of domain knowledge from experts in clinical and cognitive neurosciences. The elicitation target was a causal model for...  相似文献   
28.
Postpartum rats are less anxious than diestrous virgin females, a phenomenon requiring that mothers have recent contact with their infants. Oxytocin (OT) is one of many neurochemicals released intracerebrally while mothers interact with infants, and we investigated whether OT receptor activity in the ventrocaudal periaqueductal gray (cPAGv) contributes to mothers' reduced anxiety. Infusion of the highly specific OT receptor antagonist, desGly-NH?,d(CH?)?[D-Tyr2,Thr?]OVT, into the cPAGv reduced the percentage of time dams spent in the open arms of an elevated plus-maze, but had no effect on the open-arm behavior of diestrous virgins. Conversely, after separating dams from their litters for 4 hr to increase anxiety, a lower (2 ng) but not higher (5 ng) dose of OT infused into each hemisphere of the cPAGv doubled the percentage of time dams spent in open arms, but did not do so in virgins. OTergic manipulations inconsistently affected risk-assessment behaviors (stretch-attend postures, head dips) in both virgins and dams. Therefore, OT receptor activation in the cPAGv is an important consequence of contact with infants that reduces some anxiety-related behaviors in mother rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
29.
This contribution describes the experimental program undertaken to test the performance of a novel firefighting foam against the current Class B foam technology. The novel foam involved the use of a chemical reaction between dissolved species to generate inert nitrogen gas in situ; hence in situ generated nitrogen foams (ISNF). The experimental program encompassed the utilisation of the DEF(AUST)5706 test standard for measuring the suppression and burnback performance of the ISNF as well as that of compressed air foams (CAF). All tests were performed using the same two types of surfactant concentrates (one telomer and one PFOS-based) in order to accurately determine the effect of the generation technology on the foam performance. The three kinds of foams (i.e., aspirated, CAF and ISNF) were characterised in terms of their bubble size distributions and drainage rates. Bubble size analysis placed the size distribution of the ISNF midway between those of aspirated and compressed air foams, whilst drainage performance was found to be only slightly superior to the aspirated foam. The results of the experiments showed that in situ nitrogen foams are able to achieve good performance, similar to that of aspirated and CAF technologies. Further work is needed to optimise foam formulations for ISNF so that surfactants are not affected by the chemistry of nitrogen generation and by the presence of salts formed during chemical reactions.  相似文献   
30.
This study assessed the physical demands of the 24-week Combined Infantryman's Course (CIC) for Parachute Regiment (Para) recruits and developed physical selection standards for applicants. Fifty recruits were monitored over five separate periods (35 d in total during weeks 1-2, 5, 9, 15 and 19-20). Energy expenditure (doubly labelled water), physical activity (accelerometry) and cardiovascular strain (% heart rate reserve) were measured. There was no overall progression in both the levels of physiological stress (physical activity counts and energy expenditure) and resultant cardiovascular strain during the first nine weeks of training. Applicants' 2.4 km run time and static lift strength measured at selection predicted 10 mile loaded march performance at the end of CIC Para. The introduction of job-related selection procedures and a more progressive approach to training has reduced the incidence of medical discharge from 14.4% to 5.1% and increased overall pass rates from 43% to 58%.  相似文献   
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