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排序方式: 共有65条查询结果,搜索用时 578 毫秒
1.
Electroinitiated cationic copolymerisation of indene and styrene was investigated by constant potential electrolysis. Effects of copolymerisation potential and temperature on the copolymer composition and the reactivity ratios are discussed. The reactivity ratios of the monomers were calculated according to the integrated Lewis-Mayo equation. 相似文献
2.
Reflex sympathetic dystrophy is one of the important complications effecting the rehabilitation programmes of hemiplegic patients in a negative manner by causing pain and function loss. In this study, the aim was to investigate the effects of salmon calcitonin treatment in reflex sympathetic dystrophy that develops in hemiplegia. Forty-one patients with hemiplegia resulting from cerebrovascular events and stage 1-2 reflex sympathetic dystrophy were included in the study. Salmon calcitonin, 1 x 100 IU/day intramuscularly for 4 weeks, was administered to 25 of these patients (calcitonin group) to the other 16 patients physiological saline, 1 ml/day intramuscularly for 4 weeks, was administered (control group). At the end of the fourth week of treatment the pain score of the calcitonin group was significantly lower than that of the control group. Shoulder abduction and external rotation, wrist flexion and metacarpophalangeal extension of the calcitonin group were found to be significantly better than those of the control group. In the calcitonin group the significant decrease in pain and tenderness resulted in improvement of range of motion and motor functions. 相似文献
3.
Evran E. Ural Victoria Toomajian Ehsanul Hoque Apu Mladen Veletic Ilangko Balasingham Nureddin Ashammakhi Masamitsu Kanada Christopher H. Contag 《International journal of molecular sciences》2021,22(9)
Extracellular vesicles (EVs) are cell-derived nanostructures that mediate intercellular communication by delivering complex signals in normal tissues and cancer. The cellular coordination required for tumor development and maintenance is mediated, in part, through EV transport of molecular cargo to resident and distant cells. Most studies on EV-mediated signaling have been performed in two-dimensional (2D) monolayer cell cultures, largely because of their simplicity and high-throughput screening capacity. Three-dimensional (3D) cell cultures can be used to study cell-to-cell and cell-to-matrix interactions, enabling the study of EV-mediated cellular communication. 3D cultures may best model the role of EVs in formation of the tumor microenvironment (TME) and cancer cell-stromal interactions that sustain tumor growth. In this review, we discuss EV biology in 3D culture correlates of the TME. This includes EV communication between cell types of the TME, differences in EV biogenesis and signaling associated with differing scaffold choices and in scaffold-free 3D cultures and cultivation of the premetastatic niche. An understanding of EV biogenesis and signaling within a 3D TME will improve culture correlates of oncogenesis, enable molecular control of the TME and aid development of drug delivery tools based on EV-mediated signaling. 相似文献
4.
Loss mechanisms and high power piezoelectrics 总被引:1,自引:0,他引:1
K. Uchino J. H. Zheng Y. H. Chen X. H. Du J. Ryu Y. Gao S. Ural S. Priya S. Hirose 《Journal of Materials Science》2006,41(1):217-228
Heat generation is one of the significant problems in piezoelectrics for high power density applications. In this paper, we
review the loss mechanisms in piezoelectrics first, followed by the heat generation processes for various drive conditions.
Heat generation at off-resonance is caused mainly by dielectric loss tan δ′ (i.e., P-E hysteresis loss), not by mechanical
loss, while the heat generation at resonance is mainly attributed to mechanical loss tan φ′. Then, practical high power materials
developed at Penn State is introduced, which exhibit the vibration velocity more than 1 m/s, leading to the power density
capability 10 times of the commercially available “hard” PZTs. We propose a internal bias field model to explain the low loss
and high power origin of these materials. Finally, using a low temperature sinterable “hard” PZT, we demonstrated a high power
multilayer piezoelectric transformers. 相似文献
5.
A. Ngamjarurojana S. Ural S.H. Park S. Ananta R. Yimnirun K. Uchino 《Ceramics International》2008,34(4):705-708
In this study, in order to develop low-temperature sintering ceramics for a multilayer piezoelectric transformer application, we explored CuO and Bi2O3 as sintering aids at low temperature (900 °C) sintering condition for Sb, Li and Mn-substituted 0.8Pb(Zr0.48Ti0.52)O3–0.16Pb(Zn1/3Nb2/3)O3–0.04Pb(Ni1/3Nb2/3)O3 ceramics. These substituted ceramics have excellent piezoelectric and dielectric properties such as d33 347 pC/N, kp 0.57 and Qm 1469 when sintered at 1200 °C. The addition of CuO decreased the sintering temperature through the formation of a liquid phase. However, the piezoelectric properties of the CuO-added ceramics sintered below 900 °C were lower than the desired values. The additional Bi2O3 resulted in a significant improvement in the piezoelectric properties. The composition Sb, Li and Mn-substituted 0.8Pb(Zr0.48Ti0.52)O3–0.16Pb(Zn1/3Nb2/3)O3–0.04Pb(Ni1/3Nb2/3)O3 + 0.5 wt% CuO + 0.5 wt% Bi2O3 showed the value of kp = 0.56, Qm = 1042 (planar mode), d33 = 350 pC/N, when it was sintered at 900 °C for 2 h. These values indicated that the newly developed composition might be suitable for multilayer piezoelectric transformer application. 相似文献
6.
Suphi S. Oncel Esra Imamoglu Emre Gunerken Fazilet Vardar Sukan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(3):414-420
BACKGROUND: Recent studies indicate that microalgal cultivation using organic carbon sources has the potential to provide high yields. Haematococcus pluvialis and Chlorella zofingiensis, two important carotenoid producers, were selected for co‐culture cultivations to utilize the unique advantages of both organisms. A co‐culture production process was investigated in terms of the effects of organic carbon source, co‐cultivation method, and light intensity on carotenoid production. RESULTS: The addition of 5 g L?1 glucose resulted in a growth rate of 0.60 day?1 for H. pluvialis and 0.59 day?1 for C. zofingiensis, which were higher than those for other carbon sources tested and the control group. Incremental increase of light intensity instead of direct increase to 170 µE m?2s? prevented cell loss in both cultures. Co‐cultivation based on cell numbers (60% H. pluvialis and 40% C. zofingiensis) prevented population domination of one microalgae over the other. The biomass production rate of the co‐culture was higher (0.61 g L?1 day?1) in glucose‐enriched medium. The total carotenoid content of the co‐culture in the control culture was higher (0.83 mg total carotenoids g?1 cell) than that obtained in glucose‐enriched medium (0.54 mg total carotenoids g?1 cell) but not as high as the amounts reached in mono‐cultures. CONCLUSION: Total carotenoid content of the mono‐cultures gave higher yields in standard bold basal medium (BBM). Preliminary high performance liquid chromatography (HPLC) studies indicated a variation in the amounts of astaxanthin isomers produced. Further studies are in progress to determine the effects of carbon‐enriched media and co‐cultivation on the type of isomers and caretenoids produced. Copyright © 2010 Society of Chemical Industry 相似文献
7.
The objective of testing is to determine whether an implementation under test conforms to its specification. In distributed
test architectures involving multiple remote testers, this objective can be complicated by the fact that testers may encounter
coordination problems relating to controllability (synchronization) and observability during the application of tests. Based
on a finite state machine (FSM) specification of the externally observable behaviour of a distributed system and a distinguishing
sequence, this paper proposes a method for constructing a checking sequence where there is no potential controllability or
observability problems, and where the use of external coordination message exchanges among testers is minimized. The proposed
method does not assume a reliable reset feature in the implementations of the given FSM to be tested by the resulting checking
sequence.
phone: 613-562-5800(Extn)6684
Received May 2004
Revised March 2005
Accepted April 2005 by J. Derrick, M. Harman and R. M. Herons 相似文献
8.
This study explores the effects of chroma on participants' performance and environmental appraisal of an office. The research was conducted in a full‐scale experimental room designed as a private office where achromatic and chromatic color schemes with coequal values were applied. Sixty participants were assigned tasks and given a questionnaire to appraise the spatial color schemes. The findings show that chroma significantly affects performance and space appraisal. In terms of accuracy and time spent performance scores measured significantly better in the room with the chromatic scheme than those in the room with the achromatic scheme. The office with the chromatic scheme was found to be more pleasant, attractive, satisfying and dynamic than the one with the achromatic scheme, whereas the achromatic scheme was thought to be more formal and harmonious. Categorization of pleasantness, harmony, dynamism and spaciousness by factor analysis also showed differences between the achromatic and chromatic schemes. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2012 相似文献
9.
Hydrogenated amorphous silicon oxygen alloy thin films (a-SiOx:H) were prepared on glass and crystalline silicon substrates, with two different oxygen contents: x = 0.15 and x = 0.32. The deposition was realized in an RF-PECVD reactor by using the plasma of the gas mixture SiH4 and CO2 with tunable flow rates. The optical characterization data of the single layers were received from the optical transmittance experiments. Multilayered samples were designed upon the results of the single layers. In depositing the multilayers the repetition of the a-SiO0.15:H/a-SiO0.32:H kernel-pair was used. The samples were prepared as 25-pair of λ/4 layers, 3-pair of λ/4 layers and 3-pair of λ/2 layers. The inner morphologies and nanostructural contents of the films were investigated by Small-Angle X-ray Scattering (SAXS) method. 相似文献
10.
S Kü?üko?lu E Ural H Mutlu D Ural B S?nmez S Uner 《Canadian Metallurgical Quarterly》1997,10(8):862-865
This report describes a case of right coronary sinus of Valsalva aneurysm which ruptured into the left ventricle. The diagnosis was made with two-dimensional transthoracic echocardiography which showed an abnormal structure extending from the aortic root into the left ventricle adjacent to the interventricular septum. Subsequent examinations with transesophageal echocardiography and aortic root angiography and surgical findings confirmed the diagnosis of transthoracic echocardiography. The patient underwent aortic valve replacement. At follow-up 12 months later, the patient was without symptoms and repeated echocardiographic examinations showed no recurrence. 相似文献