Adaptive Sliding Mode Control of Permanent Magnet Direct-Drive Wind Turbine

The damping coefficient of permanent magnet direct-drive (PMDD) wind turbine is unmeasurable. To solve the problem, this paper attempts to design a sliding mode control (SMC) strategy that adapts to the speed of PMDD wind turbine. Firstly, the authors analyzed the features of wind turbines, and the nonlinear dynamic structural features of permanent magnet synchronous machine (PMSM). Next, the parameter adaptive law was designed based on Lyapunov stability theory, and backstepping control was combined with SMC into a comprehensive control strategy that regulates the speed of wind turbines. Simulation results show that the proposed strategy can compensate for the disturbance of uncertain parameters, and ensure the frequency stability of the wind turbine

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

A New Allele of the SPIKE1 Locus Reveals Distinct Regulation of Trichome and Pavement Cell Development and Plant Growth

The single-celled trichomes of Arabidopsis thaliana have long served as an elegant model for elucidating the mechanisms of cell differentiation and morphogenesis due to their unique growth patterns. To identify new components in the genetic network that governs trichome development, we carried out exhaustive screens for additional Arabidopsis mutants with altered trichome morphology. Here, we report one mutant, aberrantly branched trichome1-1 (abt1-1), with a reduced trichome branching phenotype. After positional cloning, a point mutation in the SPIKE1 (SPK1) gene was identified in abt1-1. Further genetic complementation experiments confirmed that abt1-1 is a new allele of SPK1, so abt1-1 was renamed as spk1-7 according to the literatures. spk1-7 and two other spk1 mutant alleles, covering a spectrum of phenotypic severity, highlighted the distinct responses of developmental programs to different SPK1 mutations. Although null spk1 mutants are lethal and show defects in plant stature, trichome and epidermal pavement cell development, only trichome branching is affected in spk1-7. Surprisingly, we found that SPK1 is involved in the positioning of nuclei in the trichome cells. Lastly, through double mutant analysis, we found the coordinated regulation of trichome branching between SPK1 and two other trichome branching regulators, ANGUSTIFOLIA (AN) and ZWICHEL (ZWI). SPK1 might serve for the precise positioning of trichome nuclei, while AN and ZWI contribute to the formation of branch points through governing the cMTs dynamics. In summary, this study presented a fully viable new mutant allele of SPK1 and shed new light on the regulation of trichome branching and other developmental processes by SPK1

A High-Performance Mid-infrared Optical Switch Enabled by Bulk Dirac Fermions in Cd3As2

Pulsed lasers operating in the 2-5 {\mu}m band are important for a wide range of applications in sensing, spectroscopy, imaging and communications. Despite recent advances with mid-infrared gain media, the lack of a capable pulse generation mechanism, i.e. a passive optical switch, remains a significant technological challenge. Here we show that mid-infrared optical response of Dirac states in crystalline Cd3As2, a three-dimensional topological Dirac semimetal (TDS), constitutes an ideal ultrafast optical switching mechanism for the 2-5 {\mu}m range. Significantly, fundamental aspects of the photocarrier processes, such as relaxation time scales, are found to be flexibly controlled through element doping, a feature crucial for the development of convenient mid-infrared ultrafast sources. Although various exotic physical phenomena have been uncovered in three-dimensional TDS systems, our findings show for the first time that this emerging class of quantum materials can be harnessed to fill a long known gap in the field of photonics.Comment: 17 pages, 3 figure

Influence of body composition assessment with bioelectrical impedance vector analysis in cancer patients undergoing surgery

BackgroundMalnutrition is common in patients undergoing surgery for cancers and is a risk factor for postoperative outcomes. Body composition provides information for precise nutrition intervention in perioperative period for improving patients’ postoperative outcomes.ObjectionThe aim was to determine changes in parameters of body composition and nutritional status of cancer patients during perioperative period.MethodsA total of 92 patients diagnosed with cancer were divided into gastrointestinal and non-gastrointestinal cancer group according to different cancer types. The patients body composition assessed by bioelectrical impedance vector analysis (BIVA) on the day before surgery, postoperative day 1 and 1 day before discharge. The changes between two groups were compared and the correlation between body composition and preoperative serum nutritional indexes was analyzed.ResultsThe nutritional status of all patients become worse after surgery, and phase angle (PA) continued to decrease in the perioperative period. Fat-free mass (FFM), fat-free mass index (FFMI), skeletal muscle mass (SMM), extracellular water (ECW), total body water (TBW), hydration, and body cell mass (BCM) rise slightly and then fall in the postoperative period in patients with gastrointestinal cancer, and had a sustained increase in non-gastrointestinal patients, respectively (P<0.05). Postoperative body composition changes in patients with gastrointestinal cancer are related to preoperative albumin, pre-albumin, hemoglobin, and C-reactive protein (P<0.05), whereas postoperative body composition changes in patients with non-gastrointestinal cancer are related to age (P<0.05).ConclusionsSignificant changes in body composition both in patients with gastrointestinal cancer and non-gastrointestinal cancer during perioperative period are observed. Changes in body composition for the cancer patients who undergoing surgery are related to age and preoperative serum nutrition index

Generation of cardiomyocytes from human-induced pluripotent stem cells resembling atrial cells with ability to respond to adrenoceptor agonists

Atrial fibrillation (AF) is the most common chronic arrhythmia presenting a heavy disease burden. We report a new approach for generating cardiomyocytes (CMs) resembling atrial cells from human-induced pluripotent stem cells (hiPSCs) using a combination of Gremlin 2 and retinoic acid treatment. More than 40% of myocytes showed rod-shaped morphology, expression of CM proteins (including ryanodine receptor 2, α-actinin-2 and F-actin) and striated appearance, all of which were broadly similar to the characteristics of adult atrial myocytes (AMs). Isolated myocytes were electrically quiescent until stimulated to fire action potentials with an AM profile and an amplitude of approximately 100 mV, arising from a resting potential of approximately −70 mV. Single-cell RNA sequence analysis showed a high level of expression of several atrial-specific transcripts including NPPA, MYL7, HOXA3, SLN, KCNJ4, KCNJ5 and KCNA5. Amplitudes of calcium transients recorded from spontaneously beating cultures were increased by the stimulation of α-adrenoceptors (activated by phenylephrine and blocked by prazosin) or β-adrenoceptors (activated by isoproterenol and blocked by CGP20712A). Our new approach provides human AMs with mature characteristics from hiPSCs which will facilitate drug discovery by enabling the study of human atrial cell signalling pathways and AF

Review of solid–liquid phase change materials and their encapsulation technologies

Various types of solid–liquid phase change materials (PCMs) have been reviewed for thermal energy storage applications. The review has shown that organic solid–liquid PCMs have much more advantages and capabilities than inorganic PCMs but do possess low thermal conductivity and density as well as being flammable. Inorganic PCMs possess higher heat storage capacities and conductivities, cheaper and readily available as well as being non-flammable, but do experience supercooling and phase segregation problems during phase change process. The review has also shown that eutectic PCMs have unique advantage since their melting points can be adjusted. In addition, they have relatively high thermal conductivity and density but they possess low latent and specific heat capacities. Encapsulation technologies and shell materials have also been examined and limitations established. The morphology of particles was identified as a key influencing factor on the thermal and chemical stability and the mechanical strength of encapsulated PCMs. In general, in-situ polymerization method appears to offer the best technological approach in terms of encapsulation efficiency and structural integrity of core material. There is however the need for the development of enhancement methods and standardization of testing procedures for microencapsulated PCMs