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排序方式: 共有333条查询结果,搜索用时 14 毫秒
61.
This article is based on experiences with data and text mining to gain information for strategic business decisions, using host-based analysis and visualisation (A/V), primarily in the field of patents. The potential advantages of host-based A/V are pointed out and the features of the first such A/V software, STN®AnaVist™, are described in detail. Areas covered include the user interfaces, initial set of documents for A/V, data mining, text mining, reporting, and suggestions for further development. 相似文献
62.
Stuart C. Burgess David F. Moore David E. Newland Heather L. Klaubert 《Research in Engineering Design》1997,9(1):46-60
This paper shows that there are three main categories of factors that make the optimum mechanical design of micro-systems different from macro-systems: scale effects, a limited range of materials, and a limited range of production processes. The combined effect of these factors can make the optimum configuration of a micro-system potentially very different from that of the same system on a macro-scale. In particular, the use of flexible elements for hinges is much more feasible and desirable on a micro-scale.Notation
a
acceleration (m/s2)
-
A
cross-sectional area (m2)
-
B
magnetic flux [wb/m2]
-
b
width [m]
-
C
constant
-
d
depth [m]
-
D
drag [N]
-
E
Young's modulus [N/m2]
-
E*=
-
f
resonant frequency [Hz]
-
F
D
drive force [N]
-
F
E
electrostatic pulling force [N]
-
F
emmisivity function
-
F
G
geometric view factor
-
g
gravitational constant [m/s2]
-
h
c
convention heat transfer coefficient [W/m2K]
-
h
height [m]
-
i
current [A]
-
I
A
second moment of area [m4]
-
I
I
moment of inertia [kg m2]
-
J
polar second moment of area [m4]
-
k
stiffness [N/m]
-
K
thermal conductivity [W/m K]
-
l
length [m]
-
m
mass [kg]
-
M
moment [N m]
-
P
load [N]
-
P
H
Hertz contact pressure [N/m2]
-
P
C
cylinder pressure [N/m2]
-
q
heat transfer rate [W]
-
R, r
radius [m]
-
Re
Reynolds number
-
T, t
temperature [K]
-
T
A
atomic friction torque [N m]
-
T
D
drive torque [N m]
-
T
F
Coulomb friction torque [N m]
-
T
I
inertial resistive torque [N m]
-
u
velocity [m/s]
-
mean velocity [m/s]
-
V
volume [m3]
-
V
e
voltage [V]
-
x
distance between electrodes [m]
-
y
maximum distance to neutral axis [m]
-
angular acceleration [rad/s2]
-
d
thermal diffusivity [1/K]
-
rolling friction factor
- P
pressure difference [N/m2]
-
0
dialectric constant [F/m]
-
strain
-
dynamic viscosity [Pa s]
-
scale factor
-
S
coefficient of sliding friction
-
R
coefficient of rolling friction
-
1, 2
Poisson's ratio
-
density (kg/m3)
-
temperature rise [°C]
-
B
bending stress [N/m2]
-
y
yield strength [N/m2]
-
shear stress [N/m2]
-
reliability constant 相似文献
63.
64.
The evolution of macro inclusions during continuous casting was investigated by large-area inclusion characterization using ASPEX and analysis of nozzle blockage deposits. Six kinds of inclusions over 5?μm were observed in samples taken from the tundish and the slabs: single alumina particles, alumina dendrites, refractory-related alumina, alumina associated with bubbles, alumina clusters and Al–Ti complex oxides. By examining the morphology of the nozzle blockage deposit, it was concluded that the refractory-related alumina in the slabs came from the decarburization layer washed away by the steel stream. Some of the alumina clusters that came from the nozzle blockage deposit dislodged by the steel flow, were formed by the agglomeration and sintering of 5–20?μm inclusions that were carried over from the tundish. Two kinds of Al–Ti oxides were found in the tundish, and their evolution mechanisms during the casting process were proposed. 相似文献
65.
用金相、低倍和化学检验方法,对3.5mm厚的热轧卷板严重纵裂和折皱废品进行检验分析,认为纵裂和折皱废品是由于板坯加热过程中局部过烧所致,并提出整改措施。 相似文献
66.
67.
采用扫描电子显微分析方法对我国市售四钼酸铵及其衍生物钼粉进行了结构研究。结果发现,四钼酸铵和钼粉的微观结构可分为规则型和无规则型;其宏观结构则可分为团聚型和非团聚型。四钼酸铵的微观和宏观结构的不同支配着钼系产品的结构和性能。因此,建议四钼酸铵的质量标准应根据其微观和宏观结构来确定,用以代替或补充传统的质量标准。 相似文献
68.
69.
加工孔口倒圆角时,通常可以用成型刀来加工。但是当倒角半径比较特殊时用传统的方法加工就比较困难。文章通过举例的方式介绍了如何用普通立铣刀、球头刀,借助宏程序完成孔口倒圆角几种方法,并对加工效果进行比较。 相似文献
70.
In this paper we elaborate and articulate the need for what has been termed ‘mesoergonomics’. In particular, we argue that the concept has the potential to bridge the gap between, and integrate, established work within the domains of micro- and macroergonomics. Mesoergonomics is defined as an open systems approach to human factors and ergonomics (HFE) theory and research whereby the relationship between variables in at least two different system levels or echelons is studied, and where the dependent variables are human factors and ergonomic constructs. We present a framework which can be used to structure a set of questions for future work and prompt further empirical and conceptual inquiry. The framework consists of four steps: (1) establishing the purpose of the mesoergonomic investigation; (2) selecting human factors and ergonomics variables; (3) selecting a specific type of mesoergonomic investigation; and (4) establishing relationships between system levels. In addition, we describe two case studies which illustrate the workings of the framework and the value of adopting a mesoergonomic perspective within HFE. The paper concludes with a set of issues which could form part of a future agenda for research within systems ergonomics. 相似文献