Distribution and Formation Causes of PM_(2.5) and O_(3) Double High Pollution Events in China during 2013–20

Fine particulate matter(PM_(2.5))and ozone(O_(3))double high pollution(DHP)events have occurred frequently over China in recent years,but their causes are not completely clear.In this study,the spatiotemporal distribution of DHP events in China during 2013–20 is analyzed.The synoptic types affecting DHP events are identified with the Lamb–Jenkinson circulation classification method.The meteorological and chemical causes of DHP events controlled by the main synoptic types are further investigated.Results show that DHP events(1655 in total for China during 2013–20)mainly occur over the North China Plain,Yangtze River Delta,Pearl River Delta,Sichuan Basin,and Central China.The occurrence frequency increases by 5.1%during 2013–15,and then decreases by 56.1%during 2015–20.The main circulation types of DHP events are“cyclone”and“anticyclone”,accounting for over 40%of all DHP events over five main polluted regions in China,followed by southerly or easterly flat airflow types,like“southeast”,“southwest”,and“east”.Compared with non-DHP events,DHP events are characterized by static or weak wind,high temperature(20.9℃ versus 23.1℃)and low humidity(70.0%versus 64.9%).The diurnal cycles of meteorological conditions cause PM_(2.5)(0300–1200 LST,Local Standard Time=UTC+8 hours)and O_(3)(1500–2100 LST)to exceed the national standards at different periods of the DHP day.Three pollutant conversion indices further indicate the rapid secondary conversions during DHP events,and thus the concentrations of NO_(2),SO_(2) and volatile organic compounds decrease by 13.1%,4.7%and 4.4%,respectively.The results of this study can be informative for future decisions on the management of DHP events.

Teaching Reform and Research on Art Design Majors in Higher Vocational Colleges under the Background of “Double High Plan”

Training talents for the society is the responsibility of colleges and universities.The society needs applied and innovative art design majors.In order to cultivate talents needed by society and keep up with the development plan of the Ministry of Education,higher vocational colleges need to reform.This paper adopts the method of theoretical analysis to elaborate from the four aspects of focusing equally on science and education,promote learning by competition;integrating industry and education,nurturing talents together;keeping the mission in mind while serving students;and finding the right positioning,giving full play to the advantages.

Development of Strategic Industrial Clusters in Guangdong Higher Vocational Colleges based on the"Double High Plan"

This article analyzed the ten strategic pillar industry clusters and the ten strategic emerging industry clusters which were confirmed and announced by Guangdong Province in May 2020 in addition to the 14 professional groups of schools in Guangdong Province which were shortlisted in the"Double High Plan."With comparison and analysis,the degree of coincidence between the professional groups of higher vocational colleges and strategic industrial clusters in Guangdong Province which covered most of the industrial clusters was relatively high.The higher vocational colleges that were shortlisted in the"Double High Plan"still required dynamic adjustments in the construction of professional groups to achieve an allrounded integration of the supply of talents and industrial demands.

Research on Innovation of Modern Apprenticeship Talent Training Model for Art and Design Majors in Higher Vocational Education under the Background of "Double High"

In order to cultivate more excellent talents in art and design majors following the requirements of the"13th Five-Year Plan"national education development,this paper analyzes in-depth on the current status of higher vocational education in art design profession under the background of the"Double High"plan and the challenges faced,and proposes the building of school-enterprise"Double Subject"education system and the establishment of a"diversified"evaluation system.Deepening the integration of industry and education,schools and enterprises jointly explore modern apprenticeship talent training models for innovative art and design majors,and provide a strong guarantee for the implementation of the"Double High"plan modern apprenticeship talent training model.

Research on the Optimization of Talent Recruitment Process in Higher Vocational Colleges under the Background of Double High Plan

In order to elucidate the relationship between talent recruitment and teacher allocation management in higher vocational colleges under the background of the"Double High Plan",this paper studies and analyzes the current status of talent recruitment in Chinese higher vocational colleges in conjunction with the characteristics of talent resource allocation in higher vocational colleges and proposes to elucidate the priorities and improve supporting policies with reasonable planning to improve the optimization guideline of talent recruitment efficiency,so as to better accomplish the building of the national"double high plan"and improve the ability of higher vocational colleges to nurture more outstanding talents for the society.

Thoughts on the Management of Personnel Files in Higher Vocational Colleges in the Context of“Double High Plan”

Starting from the background of the"Double High Plan"in conjunction with the role of personnel file management in advancing the"Double High Plan",this paper analyzes the current status of personnel file management in higher vocational colleges and the necessity of personnel management in higher vocational colleges,and explores the effective measures to strengthen the informatization of personnel files management to make it more reasonable,standardized and informatized.

DOUBLE HIGH ORDER S－BREAKING BIFURCATION POINTS AND THEIR NUMERICAL DETERMINATION

We consider double high order S-breaking bifurcation points of two-Parameter dependent nonlinear problems with Z_2×Z_2-symmetry. Because of the underlying symmetry we could propose some regular extended systems to determine double high order S-breaking bifurcation points. and we could also show that there exist two quadratic pitchfork bifurcation point paths passing through the point being considered.

Double North Pacific High in Summer

An example of sea level pressure (SLP) and sea surface temperature (SST) is displayed for a summer month based on historical monthly mean data for the North Pacific. A double North Pacific High (NPH) co-occurred with a double large-scale SST maximum along 40 N. Centers of the two NPHs had very nearly the same longitudes as did the SST maxima. Seven similar coincidences happened within the 30-year records. These particular associations between extrema of SLPs and SSTs enhance a previously published conjecture that single and double NPHs are caused by heat transfer from the sea surface to the atmosphere. The eastern SST maximum is the signature of a permanent wide warm surface current flowing northeast off California. To the west of it in the summer is a transient wide warm surge of surface water flowing north as it crosses mid-latitudes. These are the heat sources that generate the single and double NPHs.

Enhancement of Breakdown Voltage in AlGaN/GaN High Electron Mobility Transistors Using Double Buried p-Type Layers

A novel A1GaN/GaN high electron mobility transistor （HEMT） with double buried p-type layers （DBPLs） in the GaN buffer layer and its mechanism are studied. The DBPL A1GaN/GaN HEMT is characterized by two equi-long p-type GaN layers which are buried in the GaN buffer layer under the source side. Under the condition of high-voltage blocking state, two reverse p-n junctions introduced by the buried p-type layers will effectively modulate the surface and bulk electric fields. Meanwhile, the buffer leakage is well suppressed in this structure and both lead to a high breakdown voltage. The simulations show that the breakdown voltage of the DBPL structure can reach above 2000 V from 467 V of the conventional structure with the same gate-drain length of 8μm.

Extreme Light Concentration and High Absorption of the Double Cylindrical Microcavities

We numerically study the enhancement factor of energy density and absorption efficiency inside the double cylindrical microcavities based on a triple-band metamaterial absorber. The compact single unit cell consists of concentric gold rings with a gold disk in the center and a metallic ground plane separated by a dielectric layer. We demonstrate that the multilayer structure with subwavelength electromagnetic confinement allows 104-105-fold enhancement of the electromagnetic energy density inside the double cavities and contains the most energy of the incoming light. Particularly, the enhancement factor of energy density G shows strong ability of localizing light and some regularity as the change of the thickness of the dielectric slab and dielectric constant. At the normal incidence of electromagnetic radiation, the obtained reflection spectra show that the resonance frequencies of the double microcavities operate in the range of 10-30μm. We also calculate the absorption efficiency C, which can reach 95%, 97% and 95% at corresponding frequency by optimizing the structure＇s geometry parameters. Moreover, the proposed structure will be insensitive to the polarization of the incident wave due to the symmetry of the double cylindrical microcavities. The proposed optical metamaterial is a promising candidate as absorbing elements in scientific and technical applications due to its extreme confinement, multiband absorption and polarization insensitivity.

LD Pumped High Efficient Intracavity Frequency-Doubled Green Laser

A laser diode (LD) pumped Q switched high efficient intracavity frequency doubled Nd ∶YAG laser is reported here. The authors have designed an optical coupler and pointed out that the key to increasing harmonic conversion efficiency is to decrease the loss of fundamental wave. In the experiments, a fundamental mode output laser was acquired. When the pumping power was 12 W, 2.6 W average output power at 1 064 nm with AO Q switch was obtained. 2.1 W average output power at 532 nm was obtained with intracavity frequency doubling, and the highest second harmonic conversion efficiency was 82 0 0.

Effects of High Temperature and Strong Light Combine Stress on Yield and Quality of Early Indica Rice with Different Amylose Content during Grout Filling

High temperature(HT)accompanied with strong light(SL)often occurs in early indica rice production during grout filling stage in Southern China,which accelerates grain ripening.Two indica rice cultivars with different amylose content(Zhongjiazao17,ZJZ17,high amylose content;Xiangzaoxian45,XZX45,low amylose content)were grown under control(CK),HT,and HT+SL conditions during grout filling to determine the effects on grain yield and quality of rice.The results showed that compared with CK,HT and HT+SL significantly reduced the 1000-grain weight and filled grain rate whether in high or low amylose content early indica rice cultivars during grout filling,resulting in a significantly lower grain yield.Meanwhile,HT and HT+SL significantly decreased the milled rice rate,brown rice rate and head rice rate,whereas significantly increased chalky rate and chalky degree;and breakdown decreased and setback,pasting temperature increased in the cultivars,leading to the poor processing,appearance and cooking and eating quality of early indica rice cultivars.Compared with HT,the yield of ZJZ17 was significantly decreased under HT+SL,due to the lower 1000-grain weight.However,the effect of HT+SL on rice quality varied in the cultivars.In general,the yield and rice quality of ZJZ17 were relatively poor under HT+SL.Our results suggested that HT and HT+SL during grout filling had significant damage to the yield and quality of early indica rice cultivars,especially HT+SL,while the high amylose cultivar ZJZ17 showed a higher negative effect under HT+SL.

High χ polystyrene-b-polycarbonate for next generation lithography

Over the past half century,the semiconductor chips have deeply influenced our everyday life through increasingly sophisticated electronic products.The central driving force underlying the remarkable evolution in semiconductor industry is Moore’s Law,nowadays referring to a doubling of transistor counts per chip every 18 months.Sustaining Moore’s Law is economically beneficial;while the manufacturing cost per chip has been held constant,