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排序方式: 共有61条查询结果,搜索用时 15 毫秒
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We develop a theory of communication within branching programs that provides exponential lower bounds on the size of branching programs that are bounded alternating. Our theory is based on the algebraic concept of -branching programs, : , a semiring homomorphism, that generalizes ordinary branching programs, -branching programs [M2] andMOD p-branching programs [DKMW].Due to certain exponential lower and polynomial upper bounds on the size of bounded alternating -branching programs we are able to separate the corresponding complexity classesN ba ,co-N ba ba , andMOD p - ba ,p prime, from each other, and from that classes corresponding to oblivious linear length-bounded branching programs investigated in the past.  相似文献   
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Ordered binary decision diagrams are the state-of-the-art representation of switching functions. In order to keep the sizes of OBDDs tractable, heuristics and dynamic reordering algorithms are applied to optimize the underlying variable order. When finite state machines are represented by OBDDs the state encoding can be used as an additional optimization parameter. In this paper, we analyze local encoding transformations which can be applied dynamically. First, we investigate the potential of re-encoding techniques. We then propose the use of an XOR-transformation and show why this transformation is most suitable among the set of all encoding transformations. The presented theoretical framework establishes a new optimization technique for OBDDs.  相似文献   
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Driving macrophage (M?) polarization into the M2 phenotype provides potential against inflammatory diseases. Interleukin‐4 (IL‐4) promotes polarization into the M2‐M? phenotype, but its systemic use is constrained by dose‐limiting toxicity. Consequently, we developed IL‐4‐decorated surfaces aiming at sustained and localized activity. IL‐4 muteins were generated by genetic code expansion; Lys42 was replaced by unnatural amino acids (uAAs). Both muteins showed cell‐stimulation ability and binding affinity to IL4Rα similar to those of wt‐IL‐4. Copper‐catalyzed (CuAAC) and copper‐free strain‐promoted (SPAAC) 1,3‐dipolar azide–alkyne cycloadditions were used to site‐selectively anchor IL‐4 to agarose surfaces. These surfaces had sustained IL‐4 activity, as demonstrated by TF‐1 cell proliferation and M2, but not M1, polarization of M‐CSF‐generated human M?. The approach provides a blueprint for the engineering of cytokine‐activated surfaces profiled for sustained and spatially controlled activity.  相似文献   
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Meinel AB  Meinel MP 《Applied optics》2001,40(22):3688-3697
Fresnel null correctors are compared with classical Offner and Hindle null correctors for both optical performance and system sensitivities to errors of construction and placement in the test setup. Fresnel null correctors are closely related to circular diffractive null correctors, the main difference being that a Fresnel uses tilted grooves functioning like a blazed diffraction grating. The Fresnel has an advantage in that specific power terms can produce an aspheric wave front directly and not as the byproduct of bending lenses as in the traditional lens null correctors. The parametric relationships are summarized for a range of configurations of lens null correctors and for Fresnel null correctors. The sensitivities to construction and deployment errors are presented for each of these examples. The performance of two Fresnel correctors for an autocollimation test of a full three-mirror Cassegrain configuration is presented.  相似文献   
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Methods for analyzing the fracture behavior of high‐strength steel fiber‐reinforced concretes High‐strength and ultra‐high strength fiber‐reinforced concretes are most suitable for applications with extreme mechanical loads. These extreme conditions require a ductile behavior under tensile loading, which is obtained solely by the addition of steel fibers and their working mechanism. Profound know ledge on the working mechanism of the steel fibers is necessary for optimizing this material. Usually, this knowledge is obtained by means of classical measuring techniques of destructive tests. Adopting measuring techniques from non‐destructive material testing helps to analyze and to identify the different stages of the fracture mechanism of high‐strength and ultra‐high strength fiber‐reinforced concretes in detail. The application of different non‐destructive measuring techniques is shown exemplary on tensile tests conducted on an ultra‐high strength fiber‐reinforced concrete and its applicability for analyzing the fracture behavior is discussed. The main focus is on the characterization of the relevant failure modes under tensile loading by the different measuring techniques and the comparison with classical measuring techniques (e. g. extensometer). The tensile tests have been analyzed by optical deformation measurements using digital image correlation (DIC), acoustic emission analysis (AE), and 3D computed tomography (CT).  相似文献   
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The analytical and monitoring capabilities of central event repositories, such as log servers and intrusion detection systems, are limited by the amount of structured information extracted from the events they receive. Diverse networks and applications log their events in many different formats, and this makes it difficult to identify the type of logs being received by the central repository. The way events are logged by IT systems is problematic for developers of host-based intrusiondetection systems(specifically, host-based systems), developers of security-information systems, and developers of eventmanagement systems. These problems preclude the development of more accurate, intrusive security solutions that obtain results from data included in the logs being processed. We propose a new method for dynamically normalizing events into a unified super- event that is loosely based on the Common Event Expression standard developed by Mitre Corporation.We explain how our solution can normalize seemingly unrelated events into a single, unified format.  相似文献   
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在法兰克福Techtextil’99展览会上 ,德国的belChem纤维材料有限公司展出了一种新型纺织用高性能纤维 -belCoTex。这种纤维的标准形式是由Al2 O3改性硅酸制得的短纤维粗纱。这种粗纱具有类似天然纤维 ,如棉等的优良毛感 ,十分柔软、蓬松。同时 ,它还能较长时间的耐 10 0 0℃以下高温 ,并且可很容易地被织造成各种各样的纺织品。这种粗纱是belChem公司用其开发的材料合成方法———“高级化学纤维精制 (ACFR)”技术的产物。这种新型纤维克服了一般纤维的耐高温性能与纺织加工性能之间存在的矛盾 :纤…  相似文献   
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