344 research outputs found
On the sum of reciprocal generalized Fibonacci numbers
In this paper, we consider infinite sums derived from the reciprocals of the
generalized Fibonacci numbers. We obtain some new and interesting identities
for the generalized Fibonacci numbers
A Review Research on the correlations among Carbon Emissions, Industrial Structure, and Economic Growth
The current situation of industrial structure and economic growth in China is analyzed first, and then collects, sorts, classifies and summarizes relevant studies on the correlations among economic growth, industrial structure, and carbon emissions, and reviews and summarizes the research methods
The thermal and electrical properties of the promising semiconductor MXene Hf2CO2
In this work, we investigate the thermal and electrical properties of
oxygen-functionalized M2CO2 (M = Ti, Zr, Hf) MXenes using first-principles
calculations. Hf2CO2 is found to exhibit a thermal conductivity better than
MoS2 and phosphorene. The room temperature thermal conductivity along the
armchair direction is determined to be 86.25-131.2 Wm-1K-1 with a flake length
of 5-100 um, and the corresponding value in the zigzag direction is
approximately 42% of that in the armchair direction. Other important thermal
properties of M2CO2 are also considered, including their specific heat and
thermal expansion coefficients. The theoretical room temperature thermal
expansion coefficient of Hf2CO2 is 6.094x10-6 K-1, which is lower than that of
most metals. Moreover, Hf2CO2 is determined to be a semiconductor with a band
gap of 1.657 eV and to have high and anisotropic carrier mobility. At room
temperature, the Hf2CO2 hole mobility in the armchair direction (in the zigzag
direction) is determined to be as high as 13.5x103 cm2V-1s-1 (17.6x103
cm2V-1s-1), which is comparable to that of phosphorene. Broader utilization of
Hf2CO2 as a material for nanoelectronics is likely because of its moderate band
gap, satisfactory thermal conductivity, low thermal expansion coefficient, and
excellent carrier mobility. The corresponding thermal and electrical properties
of Ti2CO2 and Zr2CO2 are also provided here for comparison. Notably, Ti2CO2
presents relatively low thermal conductivity and much higher carrier mobility
than Hf2CO2, which is an indication that Ti2CO2 may be used as an efficient
thermoelectric material.Comment: 26 pages, 5 figures, 2 table
Research on Degree Program Construction Platform Scheme Based on Data Fusion Thinking
The article analyzes the existing system for evaluating the construction of degree programs, sorts out the requirements for various work tasks such as application, assessment, evaluation, and inspection, and extracts various data information related to the direction, teachers, students, teaching and research, process, quality, and other aspects of degree program construction. On this basis, a degree program construction platform scheme was designed using data fusion thinking, taking into account all relevant work related to degree program construction, and unifying the management of data related to degree program construction. This has a positive promoting effect on the long-term construction and efficient management of degree programs, and is also a beneficial attempt to modernize the governance system and governance capabilities of the degree programs
Estimation of Total Body Skeletal Muscle Mass in Chinese Adults: Prediction Model by Dual-Energy X-Ray Absorptiometry
Background: There are few reports on total body skeletal muscle mass (SM) in Chinese. The objective of this study is to establish a prediction model of SM for Chinese adults.
Methodology: Appendicular lean soft tissue (ALST) was measured by dual energy X-ray absorptiometry (DXA) and SM by magnetic resonance image (MRI) in 66 Chinese adults (52 men and 14 women). Images of MRI were segmented into compartments including intermuscular adipose tissue (IMAT) and IMAT-free SM. Regression was used to fit the prediction model SM = c + k × ALST. Age and gender were adjusted in the fitted model. The piece-wise linear function was performed to further explore the effect of age on SM. ‘Leave-One-Out Cross Validation’ was utilized to evaluate the prediction performance. The significance of observed differences between predicted and actual SM was tested by t test and the level of agreement was assessed by the method of Bland and Altman.
Results: Men had greater ALST and IMAT-free SM than women. ALST was the primary predictor and highly correlated with IMAT-free SM (R2 = 0.94, SEE = 1.11 kg, P<0.001). Age was an additional predictor (SM prediction model with age adjusted R2 = 0.95, SEE = 1.05 kg, P<0.001). There was a piece-wise linear relationship between age and IMAT-free SM: IMAT-free SM = 1.21×ALST−0.98, (Age <45 years) and IMAT-free SM = 1.21×ALST−0.98−0.04× (Age−45), (Age ≥45years). The prediction performance of this age-adjusted model was good due to ‘Leave-One-Out Cross Validation’. No significant difference between measured and predicted IMAT-free SM was detected.
Conclusion: Previous SM prediction model developed in multi-ethnic groups underestimated SM by 2.3% and 3.4% for Chinese men and women. A new prediction model by DXA has been established to predict SM in Chinese adults
Image-based Visual Servo Control for Aerial Manipulation Using a Fully-Actuated UAV
Using Unmanned Aerial Vehicles (UAVs) to perform high-altitude manipulation
tasks beyond just passive visual application can reduce the time, cost, and
risk of human workers. Prior research on aerial manipulation has relied on
either ground truth state estimate or GPS/total station with some Simultaneous
Localization and Mapping (SLAM) algorithms, which may not be practical for many
applications close to infrastructure with degraded GPS signal or featureless
environments. Visual servo can avoid the need to estimate robot pose. Existing
works on visual servo for aerial manipulation either address solely
end-effector position control or rely on precise velocity measurement and
pre-defined visual visual marker with known pattern. Furthermore, most of
previous work used under-actuated UAVs, resulting in complicated mechanical and
hence control design for the end-effector. This paper develops an image-based
visual servo control strategy for bridge maintenance using a fully-actuated
UAV. The main components are (1) a visual line detection and tracking system,
(2) a hybrid impedance force and motion control system. Our approach does not
rely on either robot pose/velocity estimation from an external localization
system or pre-defined visual markers. The complexity of the mechanical system
and controller architecture is also minimized due to the fully-actuated nature.
Experiments show that the system can effectively execute motion tracking and
force holding using only the visual guidance for the bridge painting. To the
best of our knowledge, this is one of the first studies on aerial manipulation
using visual servo that is capable of achieving both motion and force control
without the need of external pose/velocity information or pre-defined visual
guidance.Comment: Accepted by 2023 IEEE/RSJ International Conference on Intelligent
Robots and Systems (IROS
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