Anomalous pressure behavior of tangential modes in single-wall carbon nanotubes

Using the molecular dynamics simulations and the force constant model we have studied the Raman-active tangential modes (TMs) of a (10, 0) single-wall carbon nanotube (SWNT) under hydrostatic pressure. With increasing pressure, the atomic motions in the three TMs present obvious diversities. The pressure derivative of E1g, A1g, and E2g mode frequency shows an increased value (), a constant value (), and a negative value () above 5.3 GPa, respectively. The intrinsic characteristics of TMs consumedly help to understand the essence of the experimental T band of CNT. The anomalous pressure behavior of the TMs frequencies may be originated from the tube symmetry alteration from D10h to D2h then to C2h.Comment: 15 pages, 3 pages, submitted to Phys. Rev.

Numerical simulation of Quasi-Normal Modes in time-dependent background

We study the massless scalar wave propagation in the time-dependent Schwarzschild black hole background. We find that the Kruskal coordinate is an appropriate framework to investigate the time-dependent spacetime. A time-dependent scattering potential is derived by considering dynamical black hole with parameters changing with time. It is shown that in the quasinormal ringing both the decay time-scale and oscillation are modified in the time-dependent background.Comment: 10 pages, 8 figures; reference adde

Thermal Spin Orbit Torque with Dresselhaus Spin Orbit Coupling

Based on the spinor Boltzmann equation, we obtain a temperature dependent thermal spin-orbit torque in terms of the local equilibrium distribution function in a two dimensional ferromagnet with Dresselhaus spin-orbit coupling. We also derive the continuity equation of spin accumulation and spin current, the spin diffusion equation in Dresselhaus ferromagnet, which contains the thermal spin orbit torque under local equilibrium assumption. This temperature dependent thermal spin-orbit torque originates from the temperature gradient applied to the system. it is also sensitive to temperature due to the local equilibrium distribution function therein. In the spin diffusion equation, we can single out the usual spin-orbit torque as well as the spin transfer torque, which is conceded to our previous results. Finally, we illustrate them by an example of spin-polarized transport through a ferromagnet with Dresselhaus spin-orbit coupling driven by temperature gradient, those torques including thermal spin-orbit torque are demonstrated numerically.Comment: 19pages,6figure

Transversus abdominis plane block reduces remifentanil and propofol consumption, evaluated by closed-loop titration guided by bispectral index.

The present prospective, randomized, double-blind study aimed to determine the impact of transversus abdominis plane (TAP) block on propofol and remifentanil consumption, when administered by closed-loop titration guided by processed electroencephalography, i.e., bispectral index (BIS) values. Following institutional review board approval, 60 patients were scheduled for laparoscopic colectomy under general anesthesia. Patients were randomly assigned to receive bilateral TAP block with 20 ml 0.375% ropivacaine (TAP group) or 20 ml 0.9% saline [control (CON) group]. General anesthesia was maintained with propofol and remifentanil administration using closed-loop titration guided by BIS values. The primary outcome was perioperative propofol and remifentanil consumption. The secondary outcomes were hypertensive or hypotensive events requiring treatment, recovery time in PACU and time to first rescue analgesia following surgery. A total of 58 patients participated in the present study. At similar depths of anesthesia, as measured by BIS during the maintenance phase (45-55), patients who received TAP blocks required less propofol (4.2±1.3 vs. 5.5±1.6 mg/kg/h; P<0.001) and remifentanil (0.16±0.05 vs. 0.21±0.05 µg/kg/min; P<0.001). Time to extubation was significantly shorter in the TAP group (9.8±3.2 min) than in the CON group (14.2±4.9 min) (P<0.05). The requirement to treat hemodynamic change was also significantly lower (P<0.05). Pain score at 2 h after surgery was also significantly reduced in the TAP group compared with the CON group (P<0.05), whereas the time to first rescue analgesia was delayed in patients who received TAP block (P<0.05). Postoperative nausea and vomiting occurred at comparable rates in each group (P>0.05). In conclusion, TAP block combined with general anesthesia reduced propofol and remifentanil consumption, shortened time to tracheal extubation and promoted hemodynamic stability in laparoscopic colectomy

Analysis of Vegetation Coverage Dynamics of YongDeng County Using Normalized Difference Vegetation Index (NDVI) and Pixel Binary Model

The research is supported by the fundamental research funds of Gansu provincial natural science fund of “Research on Land use and Ecological Security in Ecologically Vulnerable Areas” (project No. GSAN-ZL-2015-045) and “Research on the Coordination Relationship between Land Urbanization and Population Urbanization” (project No. GSAU-ZL-2015-046) Abstract Under the current background of global climate change, it is very important to study the temporal and spatial characteristics of vegetation cover which will provide a scientific basis for ecosystem management decisions that will protect the integrity of biodiversity and ensure a continuous supply of valuable ecological services. The objective of this study was to use the normalized difference vegetation index and the pixel binary model in ENVI to analyze the vegetation cover dynamics of YongDeng County using 1993, 2001, 2009, and 2017 satellite images. Satellite images were obtained from the Geospatial Data Cloud (Http/westdc.westgis.ac.cn). Combined with the vegetation coverage information and unique ecological characteristics of the study area, the vegetation coverage types were classified into four grades as Grade I (Bare land, water, and built-up environment), grade II (Low yield grassland and sparse vegetation classified), grade III (Middle grassland and vegetation of cultivated land) and grade IV (Dense woodland and shrubs). The results showed a dynamic trend in the different grades of vegetation cover in the study area from 1993 to 2017. Grade I vegetation-covered an area of 1208.72 km² and 1098.09 km² in 1993 and 2001 respectively but decreased to 375.99 km² in 2009 and finally increased slightly to 398.88 km² in 2017. Grade II vegetation cover did not show significant changes over the years considered for this study. It covered an area of 3821.2 km² and 3803.1 km² in 1993 and 2001 respectively. In 2009 and 2017 it covered approximately 3769.2 km² and 3787.82 km² respectively. Grade III vegetation cover showed an increasing trend from 1993 to 2017. From 334.76 km² in 1993, it increased to 468.28 km² and 980.39 km² in 2001 and 2009 respectively, and finally increased further to 1008.5 km² in 2017. Grade IV vegetation-covered an area of 4552.62 km², 442.6 km², and 667.52 km² in 1993, 2001, and 2009 respectively and finally reduced slightly to 596.64 km² in 2017. Economic development in areas such as mining, construction, and urbanization played a major role in reducing Grade I vegetation cover. Grade II did not show any significant change because of fewer disturbances as a result of their inaccessible nature to humans. Expansion and Continues farming throughout the year as a result of the presence of an irrigation system in the area accounted for the increasing trend of Grade III vegetation cover. This study reveals there is an urgent need for measures to be put in place to mitigate activities that lead to the removal of vegetation cover as this may have serious implications on the supply of important ecological services. Keywords: Vegetation coverage, YongDeng, NDVI, Pixel Binary model, dynamic analysis DOI: 10.7176/JEES/10-9-09 Publication date:September 30th 202

Implementation of a Social Network Information Dissemination Model Incorporating Negative Relationships

For the study of information dissemination in online social networks, most existing information dissemination models include only positive relationships, ignoring the existence and importance of negative relationships, and do not consider the influence of inter-individual relationship polarity on dissemination. To solve these problems, we propose a social network information dissemination model incorporating negative relationships in this paper. Drawing on the state concept of the SIR (Susceptible Infected Recovered) model, the three types of SIR states are subdivided into five sub-states. Combining the advantages of the viewpoint evolution model, the influence of relational polarity on node attitudes is added to the modeling of the propagation process. The experiment proves that the method proposed in this paper can show more specifically the changing trend in the number of propagation nodes with different attitudes and portray the process of information propagation in online social networks