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51.
Several wines were analyzed by high-performance liquid chromatography (HPLC-PDA), inductively coupled plasma mass spectrometry (ICP-MS), and flame atomic absorption spectroscopy (FAAS) in order to associate the concentration levels of the chemical parameters with the geographical origin of wines and wine varieties. Thus, the concentrations of 22 elements (Li, Be, Co, Ni, Cs, U, Pb, V, As, Ba, Cr, Cu, Zn, Al, Mn, Rb, Sr, Fe, Ca, Mg, Na, and K) and seven phenolic compounds (gallic acid, (+)-catechin, (?)-epicatechin, p-coumaric acid, ferulic acid, trans-cinnamic acid, and resveratrol) were analyzed in 22 wines from two different wine-producing areas of Romania. Among the phenolic compounds, (+)-catechin, (?)-epicatechin, p-coumaric acid, ferulic acid, and resveratrol concentrations were the most useful markers for wine differentiation by geographical origin and wine variety, whereas Ba, Be, Cr, Cs, Li, Mg, Na, Ni, Sr, U, and Zn were the main inorganic parameters selected. To explore the distribution pattern of the samples, aimed at differentiating the wine samples by geographical region and wine variety, principal component analysis (PCA) was applied to the obtained data.  相似文献   
52.
Pure bismuth ferrite was successfully obtained through the thermolysis of new bismuth ferrioxalate coordination compound, namely BiFe(C2O4)3·3H2O. The synthesized precursor was characterized by chemical analysis, infrared spectroscopy and thermal analysis. The bismuth ferrite obtained after a heating treatment of the precursor for at 450–800?°C/1?h was investigated by X-ray diffraction, FE-SEM, TEM and HRTEM. The obtained pure bismuth ferrite nanoparticles (480?°C) was tested as photocatalyst towards the degradation of doxorubicin (DOX), a well-known anti-cancer drug commonly used for the treatment of various cancer types, which has been detected in hospital effluent water. The comparative results of DOX degradation through photolysis and photocatalysis under UV irradiation showed a great photocatalytic activity of bismuth ferrite towards DOX degradation and mineralization from water. The kinetics aspects were discussed based on the first-order kinetics model that fitted the best the experimental photocatalysis results.  相似文献   
53.
Digital manufacturing technologies (DMTs) have the potential to transform industry productivity, but their introduction into the workplace is often a complex process, requiring not only technical expertise but also an awareness of ethical and societal challenges surrounding human–system integration. Concerns about the introduction of new technology have been prevalent throughout history, and exploring public perceptions of these technologies can provide insight to help address such cultural anxieties. However, evaluating user perceptions of futuristic technology is difficult, requiring novel approaches to provide context and understanding. To explore users' perceptions of future DMTs, we applied the ContraVision technique in a questionnaire-based study. Participants viewed films, representing fictionalized utopic and dystopic visions of what the future of these DMTs might involve, and a questionnaire probed the perceptions of the technologies afterward. Findings showed that irrespective of the way technology was portrayed, participants had concerns about the ethical and responsible implementation of these tools. Participant responses were analyzed to identify key challenges for policy surrounding DMT implementation in the future of manufacturing.  相似文献   
54.
The output feedback pole placement problem is solved in an input-output algebraic formalism for linear time-varying (LTV) systems. The recent extensions of the notions of transfer matrices and poles of the system to the case of LTV systems are exploited here to provide constructive solutions based, as in the linear time-invariant (LTI) case, on the solutions of diophantine equations. Also, differences with the results known in the LTI case are pointed out, especially concerning the possibilities to assign specific dynamics to the closed-loop system and the conditions for tracking and disturbance rejection. This approach is applied to the control of nonlinear systems by linearization around a given trajectory. Several examples are treated in detail to show the computation and implementation issues.  相似文献   
55.
In this paper we introduce SFSN, an algorithm for self-organization of Very Large Sensor Networks (VLSN). The 106 or more tiny and inexpensive sensors of a VLSN are indistinguishable from one another; they do not have either a physical or a logical address, as required by the traditional communication protocols. The self-organization scheme limits the number of partners each sensor collaborates with, thus, it limits the amount of communication and the complexity of coordination. The system is scalable, the amount of state information each node has to maintain is strictly limited regardless of the total number of sensors in the network. The systems we consider mimic biological systems where individual cells of the same type are indistinguishable.  相似文献   
56.
The synthesis of diaqua(1,10-phenanthroline-N,N')(thiosulfato-O,S)manganese(ll) [Mn(phen)(S(2)O(3))(H(2)O)(2)] was investigated. Its structure was determined by single crystal X-ray diffraction from 2418 reflections (I > 3 sigma(I)) to a final value of R = 0.047 and Rw = 0.054. Crystal data are as follows : space group P(2) (1); a = 10.356(3), b = 7.097(3), c = 20.316(2) A, beta = 94.29(2) degrees , V = 1489.1(8) , A(3), Z = 2. There are two independent title compounds in the asymetric unit. Each manganese atom has a distorted octahedral Mn(SO)N(2)O(2) geometry with the S and O atoms (from two neighbouring thiosulfate ligands) mutually trans, two N atoms from the 1,10-phenanthroline ligand and two water oxygen. The thiosulfate group behaves as a bridging ligand, connecting, through sulfur and oxygen, Mn atoms related by the binary b translation, thus forming infinite chains running parallel to this axis. Infrared and electronic spectra are reported.  相似文献   
57.
A robust predictive control strategy is proposed for the secondary voltage control of large-scale power systems. It is based on the decoupling between control and prediction. The asynchronous part of the input delay is taken into account in the controller synthesis, while the output delay plus the synchronous part of the input delay is handled using an original minimal state Kalman predictor  相似文献   
58.
A key requirement for the make-to-order (MTO) manufacturing companies to remain competitive is the ability to assess incoming orders in terms of performance and to determine the best orders that they should accept. In this paper, we propose a method to control the entire production process, from customer enquiry up to product delivery, for the MTO manufacturing systems. In practice, decisions on order acceptance and on production planning are often made separately. Sales department is responsible for accepting orders, while the production department is in charge of production planning for implementation of accepted orders. The method proposed in this paper aims to facilitate the connection between the two departments by an integrated control based on the earning power evaluation. The main problems for a MTO manufacturing system manager, i.e. those related to order acceptance and machine control, are solved by the new control method. The solutions are highlighted by presenting the conceptual flowchart of the proposed method, followed by a case study, where three time and cost modeling techniques—namely analytical, neural, and k-NN regression techniques—are applied. The models of earning power at operation, job, and order level are further built and analyzed. The results show that the method could lead to a significant increase of the manufacturing system performance.  相似文献   
59.
After sintering advanced ceramics, there are invariably distortions, caused in large part by the heterogeneous distribution of density gradients along the compacted piece. To correct distortions, machining is generally used to manufacture pieces within dimensional and geometric tolerances. Hence, narrow material removal limit conditions are applied, which minimize the generation of damage. Another alternative is machining the compacted piece before sintering, called the green ceramic stage, which allows machining without damage to mechanical strength. Since the greatest concentration of density gradients is located in the outer-most layers of the compacted piece, this study investigated the removal of different allowance values by means of green machining. The output variables are distortion after sintering, tool wear, cutting force, and the surface roughness of the green ceramics and the sintered ones. The following results have been noted: less distortion is verified in the sintered piece after 1 mm allowance removal; and the higher the tool wear the worse the surface roughness of both green and sintered pieces.  相似文献   
60.
Wide use of vitrified bond CBN grinding wheels in today's production grinding is due to their higher grinding efficiency and longer wheel life compared to other types of CBN wheels or conventional wheels. Trueing and dressing, however, strongly affect these advantages, since superabrasive wheels usually act dull after a dressing operation and require an initial break-in period. In this study, a rotary trueing and dressing process was investigated for vitrified bond CBN/ Seeded Gel wheels to determine optimum parameters required to eliminate the initial break-in period and to grind at steady-state right after dressing. This paper describes the effects and importance of dressing factors on wheel grinding performance. A limiting factor for useful wheel life between dresses is also suggested.  相似文献   
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