Submillimeter molecular line observations of cometary Levy (1990c)

Observations of HCN and H2CO in Comet Levy (1990c) obtained at the Caltech Submillimeter Observatory during August 1990 are presented. The HCN J=3-2 rotational line was measured at high spectral resolution (0.1 km/s) and mapped at 13 points over a region of approximately 1.5 arcmin. Analysis of the line profile and the map suggest only slight deviations from the distribution expected for isotropic outgassing of HCN from the nucleus at a velocity of 0.7 plus or minus 0.1 km/s. Observations of the HCN J=4-3 and H2CO5(sub 15)4(sub 14) transitions were obtained simultaneously on two days following the HCN J=3-2 measurements. These transitions are the first submillimeter spectral lines to be detected in a comet. Five point maps of the emission show good consistency between the J=3-2 and J=4-3 HCN observations for an HCN production rate of 2 x 10(exp 26) and a rotational temperature of approximately 30 K. The map of H2CO emission indicates that it is more extended than the prediction of models in which H2CO originates entirely from the nucleus. H2CO may also originate from an extended source in the coma

Incentive Mechanism of Enterprises Energy-saving and Emission Reduction Based on Rank Order Tournaments

AbstractThe article establishes the analytical framework of incentive mechanism and the rank order tournaments model that based on the relative performance for developing energy-saving and emission reduction by using the theory of principle-agent and the Malcomson model. We systematically analyzes the model, and proposes the corresponding policy suggestions

Cometary molecules.

A comprehensive model of the excitation and kinematics of cometary molecules has been developed and used to analyze data obtained on comet Levy (1990c). This work builds on previous studies to develop models of the excitation and distribution of HCN and H\sb2CO in the coma and to apply these models to comet Levy in order to determine the physical parameters of the cometary coma and test models of the possible origin of H\sb2CO in comets. The collisional cross sections as a function of $\Delta$J have been considered in the excitation models for both molecules, based on quantum mechanical calculations. The vectorial model has been adopted for consideration of possible daughter species and a Monte Carlo calculation technique has been applied to develop both parent and daughter molecule models for H\sb2CO so that we can calculate its production rate and discuss its original source. With the high quality of spectra for both HCN and H\sb2CO molecules in comet Levy, we are able to use our models to constrain their abundance and some physical parameters of the coma. These new observational results confirm that microwave spectroscopy is an efficient tool to study cometary parent molecules, and help us understand the formation of our solar system

Research on the Anti-Disturbance Control Method of Brake-by-Wire Unit for Electric Vehicles

In order to improve the braking performance of electric vehicles, a novel brake-by-wire actuator based on an electro-magnetic linear motor was designed and manufactured. For the purpose of braking force regulation accuracy and high robust performance, the state observer and the anti-disturbance controller were designed in this paper after describing the actuator structure, braking principle, and mathematical model. The simulation and experimental results showed that the brake actuator responded rapidly, since its response time was only 15 ms. Compared to traditional PID (Proportion Integration Differentiation) methods, the controller proposed in this paper is able to regulate the braking force more precisely and has better anti-disturbance performance, thus the braking process can be accurately controlled according to the driver&rsquo s demand. The vehicle simulation results showed that the braking distance and braking time were shortened by 12.19% and 15.54%, respectively compared with those of the conventional anti-lock brake system (ABS) in the same braking conditions. Document type: Articl

High-efficiency polarization multiplexing metalenses

The polarization multiplexing technique is a well-established method that improves the communication capacity of an optical system. In this paper, we designed orthogonal linear and circular polarization multiplexing metalens using a library of rectangle TiO2 nanostructures. The former can independently focus x- and y-linearly polarized incident lights to designed positions with a focusing efficiency of 53.81% and 51.56%, respectively, whereas the latter with two preset focal points can independently control left and right circularly polarized incident lights with a focusing efficiency of 42.45% and 42.46%, respectively. We also show that both metalenses can produce diffraction-limited focal spots for four polarization states with no obvious distortion, which opens up new applications in polarization imaging and polarization detection

Prenatal Progestin Exposure Is Associated With Autism Spectrum Disorders

We have previously reported that prenatal progestin exposure induces autism-like behavior in offspring through ERβ (estrogen receptor β) suppression in the brain, indicating that progestin may induce autism spectrum disorders (ASD). In this study, we aim to investigate whether prenatal progestin exposure is associated with ASD. A population-based case-control epidemiology study was conducted in Hainan province of China. The ASD children were first screened with the Autism Behavior Checklist (ABC) questionnaire, and then diagnosed by clinical professionals using the ASD diagnosis criteria found in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V). Eventually, 235 cases were identified as ASD from 37863 children aged 0–6 years old, and 682 matched control subjects with typically developing children were selected for the analysis of potential impact factors on ASD prevalence using multivariate logistic regression. Our data show that the ASD prevalence rate in Hainan was 0.62% with a boy:girl ratio of 5.4:1. Interestingly, we found that the following factors were strongly associated with ASD prevalence: use of progestin to prevent threatened abortion, use of progestin contraceptives at the time of conception, and prenatal consumption of progestin-contaminated seafood during the first trimester of pregnancy. All the above factors were directly or indirectly involved with prenatal progestin exposure. Additionally, we conducted in vivo experiments in rats to further confirm our findings. Either endogenous (progesterone) or synthetic progestin (norethindrone)-treated seafood zebrafish were used to feed pregnant dams, and the subsequent offspring showed autism-like behavior, which further demonstrated that prenatal progestin exposure may induce ASD. We conclude that prenatal progestin exposure may be associated with ASD development

Transcriptome analysis of Hpa1Xoo transformed cotton revealed constitutive expression of genes in multiple signalling pathways related to disease resistance

The transcriptome profile in leaves and roots of the transgenic cotton line T-34 expressing hpa1Xoo from Xanthomonas oryzae pv. oryzae was analysed using a customized 12k cotton cDNA microarray. A total of 530 cDNA transcripts involved in 34 pathways were differentially expressed in the transgenic line T-34, in which 123 differentially expressed genes were related to the cotton defence responses including the hypersensitive reaction, defence responses associated with the recognition of pathogen-derived elicitors, and defence signalling pathways mediated by salicylic acid, jasmonic acid, ethylene, auxin, abscicic acid, and Ca2+. Furthermore, transcripts encoding various leucine-rich protein kinases and mitogen-activated protein kinases were up-regulated in the transgenic line T-34 and expression of transcripts related to the energy producing and consuming pathway was also increased, which suggested that the enhanced metabolism related to the host defence response in the transgenic line T-34 imposed an increased energy demand on the transgenic plant

Review on the Development, Control Method and Application Prospect of Brake-by-Wire Actuator

This paper reviews and summarizes the development, key technologies, and application of brake-by-wire (BBW) actuators. BBW is the technology orientation of future vehicle brake system. The main feature of BBW is to replace some of the mechanical and hydraulic components of traditional brake system with electronic control components, and use cables and wires to transmit energy and signals. BBW actuators have outstanding advantages, such as fast response, accurate control, and compact structure. They are easy to integrate with active safety functions and they are easily matched with the regenerative braking systems of electric vehicle. First, this paper summarizes the classification, characteristics, performance, and architecture of BBW actuators. Subsequently, the braking process regulation of vehicle is considered to be the main target, which is summarized from two aspects of actuator regulation and braking force distribution. The state estimation algorithm and control algorithm applied to these actuators are summarized and analyzed, and the development trend, challenges, and schemes of the braking force distribution are proposed. The development and research trend of braking force match strategies between the regenerative brake system and BBW system are also analyzed and summarized. The further electrification and intelligence of vehicle demand BBW’s braking force control method and distribution method must have higher control accuracy, stronger robustness, and wider adaptability, and the effects on braking comfort and handling stability must be further discussed

Grayscale Image Display Based on Nano-Polarizer Arrays

Optical metasurfaces have shown unprecedented capabilities to control the two-dimensional distributions of phase, polarization, and intensity profiles of optical waves. Here, a TiO2 nanostructure functioning as a nano-polarizer was optimized considering that an anisotropic nanostructure is sensitive to the polarization states of incident light. We demonstrate two metasurfaces consisting of nano-polarizer arrays featured with different orientations, which can continuously manipulate the intensity distribution of the output light cell by cell according to Malus law and clearly display the detailed information of the target image. These metasurfaces have potential application in ultracompact displays, high-density optical information storage, and many other related polarization optics fields