Ground state solutions to a coupled nonlinear logarithmic Hartree system

In this paper, we study the following coupled nonlinear logarithmic Hartree system \begin{align*} \left\{ \displaystyle \begin{array}{ll} \displaystyle -\Delta u+ \lambda_1 u =\mu_1\left( -\frac{1}{2\pi}\ln(|x|) \ast u^2 \right)u+\beta \left( -\frac{1}{2\pi}\ln(|x|) \ast v^2 \right)u, & x \in ~ \mathbb R^2, \vspace{.4cm}\\ -\Delta v+ \lambda_2 v =\mu_2\left( -\frac{1}{2\pi}\ln(|x|) \ast v^2 \right)v +\beta\left( -\frac{1}{2\pi}\ln(|x|) \ast u^2 \right)v, & x \in ~ \mathbb R^2, \end{array} \right.\hspace{1cm} \end{align*} where $\beta, \mu_i, \lambda_i \ (i=1,2)$ are positive constants, $\ast$ denotes the convolution in $\mathbb R^2$. By considering the constraint minimum problem on the Nehari manifold, we prove the existence of ground state solutions for $\beta>0$ large enough. Moreover, we also show that every positive solution is radially symmetric and decays exponentially

Controllable radio interference for experimental and testing purposes in wireless sensor networks

Abstract—We address the problem of generating customized, controlled interference for experimental and testing purposes in Wireless Sensor Networks. The known coexistence problems between electronic devices sharing the same ISM radio band drive the design of new solutions to minimize interference. The validation of these techniques and the assessment of protocols under external interference require the creation of reproducible and well-controlled interference patterns on real nodes, a nontrivial and time-consuming task. In this paper, we study methods to generate a precisely adjustable level of interference on a specific channel, with lowcost equipment and rapid calibration. We focus our work on the platforms carrying the CC2420 radio chip and we show that, by setting such transceiver in special mode, we can quickly and easily generate repeatable and precise patterns of interference. We show how this tool can be extremely useful for researchers to quickly investigate the behaviour of sensor network protocols and applications under different patterns of interference, and we further evaluate its performance

A Visualization Investigation on the Influence of the Operating Conditions on the Phase Change in the Primary Convergent-divergent Nozzle of a Transcritical CO2 Ejector

Complex flow processes exist in the primary convergent-divergent nozzle of a transcritical CO2 ejector because of the rapid expansion of the supercritical CO2 flow, which have a significant influence on the performance of a transcritical CO2 ejector expansion refrigeration system. A visualization experiment with the direct photography method was carried out to investigate the phase change phenomena in the primary convergent-divergent nozzle of a transcritical CO2 ejector. The visualization transcritical CO2 ejector was designed as a rectangular cross section to minimize the optical distortion. In order to better interpret the phase change phenomena of CO2 flow, four pressure measurement points were lumped in the convergent-divergent nozzle to get the pressure distribution along the convergent-divergent nozzle for various operating conditions. The results revealed that the phase change position in the convergent-divergent nozzle was closely related to the primary flow inlet conditions and the suction flow inlet pressure. .The results showed that the phase change could start after or before the nozzle throat, and the phase change position moved upstream by decreasing the primary flow inlet pressure and temperature simultaneously. As keeping the primary flow inlet pressure constant, the phase change position also moved upward by decreasing the suction flow inlet pressure. In addition, the measured pressure results indicated that the pressure differences in the convergent section of the primary convergent-divergent nozzle increased as the CO2 suction flow inlet pressure decreased because of more adequate expansion of the primary flow

A bi-directional strategy to detect land use function change using time-series Landsat imagery on Google Earth Engine:A case study of Huangshui River Basin in China

Constructed land, cropland, and ecological land are undergoing intense competition in many rapidly-developing regions. One of the major reasons to cause frequent land use (LU) conversions is the policy dynamics. The detection of such conversions is thus a prerequisite to understanding urban dynamics and how policies shape landscapes. This paper presents a bi-directional strategy to detect the LU change of the Huangshui River Basin of China from 1987 to 2018 using time-series Landsat imagery. We first initialized classification and optimization of remote sensing images using the Random Forest algorithm; We then detected bi-directional spatio-temporal changes based on the distribution probability of land-cover types. Our results reveal complicated dynamics underlying the net increase in urban and built-up land (UB) and the net decrease in cropland. In this area, due to the implementation of ecological compensation projects such as ecological migration and mine restoration, we found that on average 5.52 km2 of UB was converted into ecological land (forest, grassland and shrubland) every year, even though UB has expanded 3.6 times in the last 30 years with multiple conversions for cropland and ecological land. Meanwhile, 60% of lost cropland was converted to shrubland and grassland, and 40% was converted to UB. The accuracy of LU classification increases by 6.03% from 88.17%, and kappa coefficient increases by 2.41% from 85.16, compared to the existing initial results and uni-directional detection method. This study highlights the importance of the use of an effective remote sensing-based strategy for monitoring high-frequency LU changes in watershed areas with complicated human-nature interactions.</p

Development and evaluation of 4WSS electric-driven chassis for high-clearance sprayer

IntroductionThe high clearance sprayer with conventional steering mechanisms, as an intelligent spraying machine, is frequently stuck or broken in muddy fields due to the excessive torque load.MethodsA Four-Wheel Self-Steering (4WSS) electric-driven chassis with a smaller turning radius and better passability is developed to handle complex agricultural terrains. The 4WSS chassis is mainly composed of two custom-designed steering bridges and four in-wheel drive motors. It can achieve steering and driving forward simultaneously through coordinate differential speed control of drive motors, saving a set of dedicated servo steering systems and requiring less torque during steering compared to conventional structures. A kinematic model depicting the speed relationships between four wheels is established via geometric analysis, and a Speed Distribution Controller (SDC) is designed to accomplish locomotion objectives.ResultsExperimental results demonstrate the effectiveness of the new prototype 4WSS chassis system in tracking speed and steering angle. Compared to conventional agricultural chassis, the 4WSS chassis has a smaller turning radius of 2,877 mm. DiscussionThe 4WSS chassis exhibits superior performance in typical field conditions, including muddy terrain, deep gullies, and ridges

PENGARUH DEWAN KOMISARIS ASING, DEWAN KOMISARIS INDEPENDEN DAN KEPEMILIKAN SAHAM ASING TERHADAP NILAI PERUSAHAAN (STUDI EMPIRIS PADA PERUSAHAAN MANUFAKTUR YANG TERDAFTAR DI BEI TAHUN 2009-2011)

Penelitian ini bertujuan untuk menguji pengaruh dewan komisaris asing, dewan komisaris independen dan kepemilikan saham asing terhadap nilai perusahaan manufaktur yang terdaftar di BEI (Bursa Efek Indonesia) selama periode pengamatan (2009-2011).Penelitian ini merupakan penelitian empiris dengan pendekatan kuantitatif yang melibatkan penggunaan analisa statistik. Penelitian ini menggunakan data sekunder. Alat analisisnyang digunakan dalam penelitian ini adalah regresi linier berganda dengan bantuan sofware SPSS (Statistical Package for Social Scienc) Hasil penelitian menunjukkan bahwa dewan komisaris asing dan kepemilikan saham asing berpengaruh positif dan signifikan terhadap nilai perusahaan, sedangkan variabel dewan komisaris independen tidak mempunyai pengaruh yang signifikan terhadap nilai perusahaan

19 karya seni, artifak dipamer pada NYAWA ‘18

SERDANG, 23 Jan: Sebanyak 19 hasil penyelidikan dan penemuan saintifik yang diolah dalam bentuk karya seni dan artifak dipamerkan pada pameran Nature’s Yield and Wonders of Art (NYAWA) ‘18 di Galeri Serdang, Fakulti Rekabentuk dan Senibina, Universiti Putra Malaysia (UPM)

Study of the correlation between vitamin D level and liver function in children with infectious mononucleosis

Objective To investigate the correlation between the serum level of 25-hydroxyvitamin D （25（OH）D） and liver function in children with infectious mononucleosis （IM）. Methods Ninety children with acute IM were enrolled into the IM group， and 40 healthy children who underwent physical examination during the same period were allocated into the control group. Serum level of 25（OH）D was determined by electrochemiluminescence and the viral load of Epstein-Barr virus DNA （EBV-DNA） in plasma was determined by quantitative fluorescent RT-PCR. Clinical data and serum 25（OH） D levels were compared between two groups. The correlation between 25（OH）D level and atypical lymphocytes， liver function parameters and plasma EBV-DNA in children with IM was analyzed. Results Serum 25（OH）D level in the IM group was significantly lower， whereas the 25（OH）D inadequacy rate was significantly higher than those in the control group （both P &lt; 0.05）. Serum 25（OH）D level was negatively correlated with atypical lymphocytes in the IM group （P &lt; 0.05）. The levels of alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， glutamyl transpeptidase （GGT）， and adenosine deaminase （ADA） in IM children with serum 25（OH）D inadequacy were higher than those in their counterparts with adequate serum 25（OH）D （all P &lt; 0.05）. No significant differences were found in total bilirubin （TBIL）， direct bilirubin （DBIL） and plasma EBV-DNA load between the adequate and inadequate subgroups （all P &gt; 0.05）. In the IM group， serum 25（OH）D level was negatively correlated with ALT， GGT， and ADA （all P &lt; 0.05）， whereas positively correlated with CHE （P &lt; 0.05） and had no correlation with AST， TBIL or DBIL （all P &gt; 0.05）. Conclusions Serum vitamin D insufficiency occurs in children with IM. Vitamin D may be involved in the incidence and development of the course of IM， which is probably associated with liver function impairment