全文获取类型
收费全文 | 65篇 |
免费 | 0篇 |
专业分类
机械仪表 | 9篇 |
轻工业 | 2篇 |
无线电 | 27篇 |
一般工业技术 | 3篇 |
冶金工业 | 20篇 |
自动化技术 | 4篇 |
出版年
2018年 | 1篇 |
2017年 | 1篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 1篇 |
2007年 | 3篇 |
2003年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有65条查询结果,搜索用时 16 毫秒
1.
Olver Mark E.; Preston Denise L.; Camilleri Joseph A.; Helmus Leslie; Starzomski Andrew 《Canadian Metallurgical Quarterly》2011,52(4):310
Although survey results seem to indicate an abundant interest among Canadian psychology graduate students in pursuing training in criminal justice psychology, the recruitment and retention of psychologists in the Correctional Service of Canada (CSC) has been of some concern. The present study is a 2008 survey of sites within CSC that provide opportunities for clinical psychology training with offender clientele. Survey findings demonstrated that a broad range of clinical psychology training opportunities were available across 16 sites. The most frequently cited barrier to providing training was lack of time by prospective trainers, and sites reported retaining relatively few of their trainees for subsequent psychologist positions. Information was also obtained regarding vacant psychologist positions across CSC regions. In light of survey findings, substantive discussion is devoted toward the issues of psychologist recruitment and retention in Canadian federal corrections, including a discussion of both potential and existing training initiatives. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
2.
Detection and location of different targets buried in ground or constructional walls depends to a great extent on the knowledge of expected target return response. The analysis of the target-radar response for FM-CW ground probing radar is performed with the aid of a signal flow diagram relating the target response and the radar performance. A plane wave model for the radar radiated electromagnetic waves is adopted and the analysis is carried out for two typical targets; a finite thickness slab and a sphere. Computed returns based on this analysis are compared with those obtained experimentally from a 1-2 GHz FM-CW radar scheme and a very close agreement is found. A computational study is conducted on the response of planar target model, and important conclusions are reached upon relevant to ground probing problem. 相似文献
3.
The ultra-thin film interferometric method of measuring the thickness of very thin films in lubricated contacts has been refined so as to be able to measure films down to 0.3nm with a standard deviation of 0.15nm. The main remaining source of measurement variation for films below 3nm thick is the surface roughness of the contacting solids. This modified technique has been applied to study the film-forming properties of three fluids, hexadecane, a dilute solution of surfactant in hexadecane, and cyclohexane. Purified hexadecane shows a very slightly enhanced oil-film thickness below 1nm. The long-chain surfactant forms a boundary film 2nm thick. Cyclohexane behaves as though it forms a surface layer about 1nm thick with viscosity three times the bulk fluid viscosity. 相似文献
4.
The attenuation of the HE11 mode in a brass corrugated circular waveguide of internal diameter 8 cm is measured in the frequency range 8?10 GHz by means of a resonant-cavity technique. Attenuation values of the order of 4 dB/m are observed. The mean attenuation level exceeds the theoretical value for a perfect corrugated waveguide by about 25%, which is within the experimental accuracy. The attenuation measured is substantially less than that predicted for the H11 mode in a smooth-wall waveguide of comparable size and is, in fact, close to that predicted for the H01 mode. 相似文献
5.
Liu J.J. Olver K.A. Monica Taysing-Lara Taylor T. Wayne Chang Horst S. 《Components and Packaging Technologies, IEEE Transactions on》2003,26(3):548-553
Oxide-confined top-emitting 850 nm and bottom-emitting 980 nm vertical-cavity surface-emitting laser (VCSEL) 8/spl times/8 arrays were designed and fabricated for applications of optical interconnects. The arrays were flip-chip bonded onto sapphire substrates that contain complimentary metal-oxide-semiconductor (CMOS) driver and fan-out circuitries. The off-sited bonding contacts and minimized bonding force produced very high yield of the hybridization process without causing damage to the VCSEL mesas. The hybridized devices were further mounted either on printed circuit board (PCB) or in 68-pin pin-grid-array (PGA) packages. The transparent sapphire substrate allowed optical outputs from the top-emitting VCSEL arrays to transmit directly through without additional substrate removal procedure. Lasing thresholds below 250 /spl mu/A for 850 nm VCSELs and 800 /spl mu/A for 980 nm VCSEL were found at room temperature. The oxide confinement apertures of VCSELs were measured to be around 6 /spl mu/m in diameter. High-speed data transmission demonstrated a bandwidth of up to 1 Gbits/s per channel for these hybridized VCSEL transmitters. 相似文献
6.
The operation of a corrugated waveguide is described under conditions where the HE11 mode is the only mode of propagation. Its attenuation is then predicted to be significantly less than that of other single-mode waveguides operating at the same frequency. Verification of the theory is provided by resonant-cavity experiments. Results lie within a range which can be accounted for in terms of surface roughness of the cavity irises. 相似文献
7.
Consider the robust network design problem of finding a minimum cost network with enough capacity to route all traffic demand
matrices in a given polytope. We investigate the impact of different routing models in this robust setting: in particular,
we compare oblivious routing, where the routing between each terminal pair must be fixed in advance, to dynamic routing, where routings may depend arbitrarily on the current demand. Our main result is a construction that shows that the
optimal cost of such a network based on oblivious routing (fractional or integral) may be a factor of Ω(log n) more than the cost required when using dynamic routing. This is true even in the important special case of the asymmetric
hose model. This answers a question in (Chekuri, SIGACT News 38(3):106–128, 2007), and is tight up to constant factors. Our proof technique builds on a connection between expander graphs and robust design
for single-sink traffic patterns (Chekuri et al., Networks 50(1):50–54, 2007). 相似文献
8.
E. H. Aifer J. H. Warner C. L. Canedy I. Vurgaftman E. M. Jackson J. G. Tischler J. R. Meyer S. P. Powell K. Olver W. E. Tennant 《Journal of Electronic Materials》2010,39(7):1070-1079
Shallow-etch mesa isolation (SEMI) of graded-bandgap “W”-structured type II superlattice (GGW) infrared photodiodes provides
a powerful means for reducing excess dark currents due to surface and bulk junction related processes, and it is particularly
well suited for focal-plane array fabrication. In the n-on-p GGW photodiode structure the energy gap is increased in a series of steps from that of the lightly p-type infrared-absorbing region to a value typically two to three times larger. The wider gap levels off about 10 nm short
of the doping-defined junction, and continues for another 0.25 μm into the heavily n-doped cathode before the structure is terminated by an n
+-doped InAs top cap layer. The increased bandgap in the high-field region near the junction helps to strongly suppress both
bulk tunneling and generation–recombination (G–R) current by imposing a much larger tunneling barrier and exponentially lowering
the intrinsic carrier concentration. The SEMI approach takes further advantage of the graded structure by exposing only the
widest-gap layers on etched surfaces. This lowers surface recombination and trap-assisted tunneling in much the same way as
the GGW suppresses these processes in the bulk. Using SEMI, individual photodiodes are defined using a shallow etch that typically
terminates only 10 nm to 20 nm past the junction, which is sufficient to isolate neighboring pixels while leaving the narrow-gap
absorber layer buried 100 nm to 200 nm below the surface. This provides for separate optimization of the photodiode’s electrical
and optical area. The area of the junction can be reduced to a fraction of that of the pixel, lowering bulk junction current,
while maintaining 100% optical fill factor with the undisturbed absorber layer. Finally, with the elimination of deep, high-aspect-ratio
trenches, SEMI simplifies array fabrication. We report herein results from SEMI-processed GGW devices, including large-area
discrete photodiodes, mini-arrays, and a focal-plane array. Current–voltage data show strong suppression of side-wall leakage
relative to that for more deeply etched devices, as well as scaling of dark current with junction area without loss of quantum
efficiency. 相似文献
9.
Micropitting was studied using a three-contact disc machine having a central roller in contact with three harder, annular counter-discs (“rings”) of precisely controlled roughness. Roughness, running conditions, base stock and additive concentration were varied. The response of the same lubricants in a reciprocating sliding wear test operating in the boundary regime was also studied.Results of experimental studies of the rolling contact behaviour of carburised steel rollers are reported. All the tests with the additive present led to micropitting. However, severe micropitting wear was only observed when the calculated film thickness exceeded 12% of the centre-line average roughness of the rings.It was found that there was an approximately inverse correlation between the micropitting damage in the disc machine test and the mild wear in the reciprocating sliding test. This was attributed to the tendency of anti-wear additives to prevent running-in of the rough surface. 相似文献
10.
The authors examined the therapeutic responses of psychopathic sex offenders (≥25 Psychopathy Checklist—Revised; PCL–R) in terms of treatment dropout and therapeutic change, as well as sexual and violent recidivism over a 10-year follow-up among 156 federally incarcerated sex offenders treated in a high-intensity inpatient sex offender program. Psychopathy and sex offender risk/treatment change were assessed using the PCL–R and the Violence Risk Scale—Sexual Offender version (VRS–SO), respectively. Although psychopathic participants were more likely than their nonpsychopathic counterparts ( 相似文献