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31.
Investigations of fuel behavior are carried out in close connection with experimental research, operation feedback and computational analyses. OECD NEA sets up the “International Fuel Performance Experiments (IFPE) database”, a public domain database on nuclear fuel performance experiments with the purpose of model development and code validation. The objective of the activity (performed in the framework of the IAEA CRP FUMEX-III project) is to investigate the pellet-clad interaction mechanism and the capability of TRANSURANUS code in simulating the phenomena, processes occurring in the fuel rod during the power ramps, with focus on the parameters influencing the cladding failures. The experimental database adopted is the Studsvik PWR Super-Ramp subprogram, part of the IFPE database, which consists of 28 pressurized water reactor fuel rods power ramped at burnup from 28 to 45 MWd/kgU. Relevant results by TRANSURANUS are presented in connection with the experimental evidences. Focus is given on the PCI/SCC failure, demonstrating that the failure threshold, available in TRANSURANUS, results conservative both in case of KWU and W rods.  相似文献   
32.
Cerebral small vessel disease (CSVD) is the second most common cause of stroke and a major contributor to dementia. Manifestations of CSVD include cerebral microbleeds, intracerebral hemorrhages (ICH), lacunar infarcts, white matter hyperintensities (WMH) and enlarged perivascular spaces. Chronic hypertensive models have been found to reproduce most key features of the disease. Nevertheless, no animal models have been identified to reflect all different aspects of the human disease. Here, we described a novel model for CSVD using salt-sensitive ‘Sabra’ hypertension-prone rats (SBH/y), which display chronic hypertension and enhanced peripheral oxidative stress. SBH/y rats were either administered deoxycorticosteroid acetate (DOCA) (referred to as SBH/y-DOCA rats) or sham-operated and provided with 1% NaCl in drinking water. Rats underwent neurological assessment and behavioral testing, followed by ex vivo MRI and biochemical and histological analyses. SBH/y-DOCA rats show a neurological decline and cognitive impairment and present multiple cerebrovascular pathologies associated with CSVD, such as ICH, lacunes, enlarged perivascular spaces, blood vessel stenosis, BBB permeability and inflammation. Remarkably, SBH/y-DOCA rats show severe white matter pathology as well as WMH, which are rarely reported in commonly used models. Our model may serve as a novel platform for further understanding the mechanisms underlying CSVD and for testing novel therapeutics.  相似文献   
33.
Acute bleeding after bone marrow transplantation (BMT) was investigated in 1,402 patients receiving transplants at Johns Hopkins Hospital between January 1, 1986 and June 30, 1995. Bleeding categorization was based on daily scores of intensity used by the blood transfusion service. Moderate and severe episodes were analyzed for bleeding sites. Analysis of the cause of death and the interval of the bleeding episode to outcome endpoints was recorded. Survival estimates were computed for 1,353 BMT patients. The overall incidence was 34%. Minor bleeding was seen in 10.6%, moderate bleeding was seen in 11.3%, and severe bleeding was seen in 12% of all patients. Fourteen percent of patients had moderate or severe gastrointestinal hemorrhage, 6.4% had moderate or severe hemorrhagic cystitis, 2.8% had pulmonary hemorrhage, and 2% had intracranial hemorrhage. Sixty-one percent had 1 bleeding site and 34.4% had more than 1 site. Moderate and severe bleeding was more prevalent in allogeneic (31%) and unrelated patients (62.5%) compared with autologous patients (18.5%). Significant distribution of incidence was found among the different diagnoses, but not by disease status in acute myeloid leukemia, acute lymphoblastic leukemia, chronic myelogenous leukemia, Hodgkin's disease, and non-Hodgkin's lymphoma. Bleeding was associated with significantly reduced survival in allogeneic, autologous, and unrelated BMT and in each disease category except multiple myeloma. Survival was correlated with the bleeding intensity, bleeding site, and the number of sites. Although close temporal association was evident to mortality, bleeding was recorded as the cause of death in only the minority of cases compared with other toxicities after BMT (graft-versus-host disease, infections, and preparative regimen toxicity). Acute bleeding is a common complication after BMT that is profoundly associated with morbidity and mortality. Although bleeding was not a direct cause of death in the majority of cases, it has a potential prognostic implication as a predictor of poor outcome in clinical assessment of patients after BMT.  相似文献   
34.
The need for more sustainable printed electronics has emerged in the past years. Due to this, the use of nanocellulose (NC) extracted from cellulose has recently been demonstrated to provide interesting materials such as functional inks and transparent flexible films due to its properties. Its high specific surface area together with the high content of reactive hydroxyl groups provide a highly tailorable surface chemistry with applications in ink formulations as a stabilizing, capping, binding and templating agent. Moreover, NC mechanical, physical and thermal properties (high strength, low porosity and high thermal stability, respectively) provide an excellent alternative for the currently used plastic films. In this work, we present a process for the production of water-based conductive inks that uses NC both as a template for silver nanoparticles (Ag NPs) formation and as an ink additive for ink formulation. The new inks present an electrical conductivity up to 2 × 106 S/m, which is in the range of current commercially available conductive inks. Finally, the new Ag NP/NC-based conductive inks have been tested to fabricate NFC antennas by screen-printing onto NC-coated paper, demonstrating to be operative.  相似文献   
35.
Lansford  J. Stephens  A. Nevo  R. 《IEEE network》2001,15(5):20-27
This article provides an introduction to issues of coexistence between Bluetooth and Wi-FiTM (IEEE 802.11b), with particular attention to scenarios requiring simultaneous operation, or Sim-OPTM, of both systems in very close proximity. The article explains basic interference mechanisms and quantifies their impact through both actual measurements and simulation. We have developed a detailed simulator that fully models behavior of the physical layer (PHY) and media access control (MAC) of both Bluetooth and 802.11b; it is used to expand the analysis and project the mutual impact of collocated Bluetooth and 802.11b systems across a number of geometries, system parameter settings, and design choices, complementing efforts within the IEEE 802.15.2 Task Group, which are also discussed. The article concludes with a discussion of techniques with the potential to greatly improve the performance of collocated Bluetooth and Wi-Fi systems. A key result of this investigation is that while performance of both systems can degrade when they are collocated, a number of techniques can be employed to virtually eliminate the problems  相似文献   
36.
We show here that elevated levels of gonadotropins (luteinizing hormone and follicle stimulating hormone), as found in menopause or after ovariectomy, promote growth of human ovarian carcinoma by induction of tumor angiogenesis. Human epithelial ovarian cancer tumors progressed faster in ovariectomized mice. This induced growth could be attributed to the elevated levels of gonadotropins associated with loss of ovarian function because direct administration of gonadotropins also was effective in promoting tumor progression in vivo. On the other hand, gonadotropins had no direct effect on the proliferation of human ovarian cancer cells in vitro. Using MRI, we demonstrated that ovariectomy significantly (P < 0.02) induces neovascularization of human ovarian carcinoma spheroids implanted in nude mice. Moreover, conditioned medium of gonadotropin-treated human ovarian carcinoma cells showed increased mitogenic activity to bovine endothelial cells, and this activity could be blocked by neutralizing antibodies against luteinizing hormone and against vascular endothelial growth factor. Accordingly, gonadotropin stimulation resulted in a dose-dependent-induced expression of vascular endothelial growth factor in monolayer culture as well as in the outer proliferating cells of human ovarian cancer spheroids. These results demonstrate the significance of the elevated levels of gonadotropins, as found in menopause and in all ovarian cancer patients, on the progression of ovarian cancer and could explain the protective effect of estrogen replacement therapy. Based on these results, we suggest that hormonal therapy aimed at lowering the circulating levels of gonadotropins may possibly prolong remission in ovarian cancer by extending tumor dormancy.  相似文献   
37.
Used personal data gathered by the Israeli Biographical Information Inventory to predict military success for 390 men and 524 women, aged 20-26. Each sex group was randomly divided into equal keying and replication samples. In the keying samples, correlations between biographical item responses and the criterion of military rank (when released from compulsory service) were examined. 13 items, scored on the basis of these correlations, were summed. These total scores were then correlated with the criterion. Significant positive correlations were found for both sex groups in both the keying and replication samples, although correlations for men were always significantly (p  相似文献   
38.
This study was designed to evaluate the conventional techniques of assessing sleep, nursing and patient report, of inpatients on a clinical psychiatric unit. Nurses assessed sleep/wake status at hourly checks and patients completed a sleep diary. For three nights patients wore a wrist actigraph, a portable instrument which provides objective data about sleep/wake activity. The nursing and patient data obtained were compared with actigraphy data. Nursing staff evaluated sleep with satisfactory agreement (76.5% night 1 and 81.6% night 3) that improved over the first three nights of hospitalization (p < 0.03). When the nurses' report did not agree with the actigraph, they tended to overestimate sleep. Patients tended to underestimate their total sleep time and total time awake after sleep onset. Time in bed and initial sleep latency were overestimated. There was great intersubject variability, making determination of agreement impossible. This data suggest that treatment teams on psychiatric units should in general consider nursing reports of sleep more accurate than patient self-report. However, since nursing staff and patients observe different aspects of sleep, both sources of data are important to inpatient treatment teams on clinical units.  相似文献   
39.
While the business value of IT (BVIT) is central to the IS discipline, only recently a possible chain of causation from IT assets (i.e., fungible, widely available, commodity-like, technology-based products) to firm performance has been conceptually specified. Furthermore, little empirical evidence exists regarding IT assets’ business value. In light of this paucity, this paper makes several contributions to IS research and practice. First, it advances the BVIT literature by empirically testing a model that traces a path from IT assets through IT-enabled resources to firm performance. Second, it extends the BVIT and resource-based view (RBV) literatures by explicating and testing the impact of a firm’s external environment on its IT-enabled resources. Third, it builds on recent literature to argue for, and test, two distinct forms of firm-level outcome: operational and strategic benefits. Finally, the paper contributes to managers’ and IS practitioners’ knowledge by demonstrating the transformative capacity of IT assets on the strategic potential of organizational resources. Empirically, the paper develops and employs valid and reliable scales to test the research model using survey data on IT-enabled customer service departments. The findings demonstrate that when an IT asset is combined with an organizational resource, the extent of synergy borne out of the resulting relationship can positively impact the strategic potential of the ensuing IT-enabled resource. This IT-enabled resource, in turn, is positively associated with firm-level benefits. Further, the external environment is shown to exert a positive effect on the strategic potential of outside-in IT-enabled resources. In sum, this paper offers several important conceptual and empirical contributions to a stream of research that is at the core of the IS discipline.  相似文献   
40.
1D core–shell heterojunction nanostructures have great potential for high‐performance, compact optoelectronic devices owing to their high interface area to volume ratio, yet their bottom‐up assembly toward scalable fabrication remains a challenge. Here the site‐controlled growth of aligned CdS–CdSe core–shell nanowalls is reported by a combination of surface‐guided vapor–liquid–solid horizontal growth and selective‐area vapor–solid epitaxial growth, and their integration into photodetectors at wafer‐scale without postgrowth transfer, alignment, or selective shell‐etching steps. The photocurrent response of these nanowalls is reduced to 200 ns with a gain of up to 3.8 × 103 and a photoresponsivity of 1.2 × 103 A W?1, the fastest response at such a high gain ever reported for photodetectors based on compound semiconductor nanostructures. The simultaneous achievement of sub‐microsecond response and high‐gain photocurrent is attributed to the virtues of both the epitaxial CdS–CdSe heterojunction and the enhanced charge‐separation efficiency of the core–shell nanowall geometry. Surface‐guided nanostructures are promising templates for wafer‐scale fabrication of self‐aligned core–shell nanostructures toward scalable fabrication of high‐performance compact photodetectors from the bottom‐up.  相似文献   
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