Operational Problems and Countermeasures of Public Elective Courses in Higher Vocational Colleges and Universities Based on the Perspective of Academic Affairs Management:Taking Guangdong C Vocational College as an Example

With the vigorous development of higher vocational education,public elective courses,as one of the core components of the higher vocational curriculum system,occupy a pivotal position.Based on the perspective of academic affairs management and taking Guangdong C Vocational College as an example,this paper meticulously analyzes the operational problems in the declaration,setting,teaching,and management of public elective courses through questionnaire surveys and other methods.It also puts forward a series of targeted solutions,with a view to continuously improving the teaching quality and management level of public elective courses.

Application of Audio-Magnetotelluric Method for Exploration the Concealed Ore-Bodies in Yuele Lead-Zinc Ore Feild, Daguan County, NE Yunnan Province, China

The results of recent mineral exploration in the Yuele lead-zinc mining area of Daguan County, northeastern Yunnan province, showed that there are much early Paleozoic strata under thick late Paleozoic strata in northeastern Yunnan province, where developed some hidden salt structures (SSs), often with lead-zinc polymetallic mineralization varying degrees along the tension torsional fault (belts) or fracture (joint). The ore-bodies belong to the epigenetic hydrothermal filling vein-type deposit, and the prospecting potential is great. In this area, the superficial mineralization information displayed clear, but the deep mineralization is unknown, so the exploration work is restricted. The audio-megnetotelluric (AMT) surveying is an advantageous method to characterize the size, resistivity and skin depth of the polarizable mineral deposit concealed beneath thick overburden. This paper presents the surveying results using AMT method to evaluate the concealed lead-zinc mineralization in Yuele lead-zinc ore field, Daguancounty, NE Yunnan province, China. After comparing the interpretation result of AMT surveying data with the geological data and the drilling data, it is found that there is some distinct difference in resistivity and polarizable between ore-bodies hosted strata, upper strata and gypsum strata. The results show that AMT method is helpful to identify lead-zinc mineralization under this geological condition.

Reconfigurable logic and in-sensor encryption operations in an asymmetrically tunable van der Waals heterostructure

Reconfigurable devices can be used to achieve multiple logic operation and intelligent optical sensing with low power consumption,which is promising candidates for new generation electronic and optoelectronic integrated circuits.However,the versatility is still limited and need to be extended by the device architectures design.Here,we report an asymmetrically gate two-dimensional(2D)van der Waals heterostructure with hybrid dielectric layer SiO_(2)/hexagonal boron nitride(h-BN),which enable rich function including reconfigurable logic operation and in-sensor information encryption enabled by both volatile and non-volatile optoelectrical modulation.When the partial gate is grounded,the non-volatile light assisted electrostatic doping endowed partially reconfigurable doping between n-type and p-type,which allow the switching of logic XOR and not implication(NIMP).When the global gate is grounded,additionally taking the optical signal as another input signal,logic AND and OR is realized by combined regulation of the light and localized gate voltage.Depending on the high on/off current ratio approaching 105 and reliable&switchable logic gate,in-sensor information encryption and decryption is demonstrated by manipulating the logic output.Hence,these results provide strong extension for current reconfigurable electronic and optoelectronic devices.

Serotypes of human enteroviruses causing pediatric viral encephalitis and meningitis in Hebei province, China, from 2013 to 2015

Importance:Viral encephalitis and meningitis are severe infectious diseases responsible for substantial morbidity and mortality in children.Enteroviruses are typically the most common causative agents of viral encephalitis and meningitis.Objective:This study aimed to investigate the etiology of viral encephalitis and meningitis among children in Hebei province,China.Methods:Cerebrospinal fluid samples from children with viral encephalitis (n=309) and meningitis (n=133) were collected between Nov 2013 and Dec 2015 and viral pathogens were identified by real-time and multiplex PCR.Amplification and sequencing of partial VP1 genes was used to type enteroviruses.Results:The causative pathogen was successfully detected in 176 (57％) patients with viral encephalitis and 82 (61.7％) patients with viral meningitis.The most common causative agents of both viral encephalitis and meningitis were enteroviruses (55.7％ and 64.6％ of cases,respectively).The most common enterovirus serotypes identified were echovirus 18,echovirus 6 and echovirus 30.Echovirus 18 accounted for 74.4％ of all typed enteroviruses and caused a viral encephalitis and meningitis outbreak in Hebei province in 2015.By contrast,the major enterovirus serotypes circulating in 2014 were echovims 6 and echovirus 30.Interpretation:Enteroviruses were the main causative agents of viral encephalitis and meningitis in children in Hebei province from Nov 2013 to Dec 2015.Echovirus 18 became the leading cause of viral encephalitis and meningitis for the first time in Hebei province in 2015.

Synthesis of Substituted Benzoxacycles via a Pd（ll）-Catalyzed Intramolecular Arylation Reaction of Allylic Alcohols

ein a Pd-catalyzed intramolecular allylation reaction of unprotected allylic alcohols was developed,and the reaction proceeded through a Pd（Ⅱ）-mediated allylic carbocation species formation,followed by a Friedel-Crafts type annulation to afford functionalized chromanes.

Inter-textual Vocabulary Growth Patterns for Marine Engineering English

This paper explores two fundamental issues concerning the inter-textual vocabulary growth patterns for Marine Engineering English,viz.vocabulary growth models and newly occurring vocabulary distributions in cumulative texts.On the basis of the DMMEE(Dalian Maritime University Marine Engineering English)corpus,four mathematical models(Brunet's, Guiraud's,Tuldava's,and Herdan's models)are tested against the empirical vocabulary growth curve for Marine Engineering English.A new growth model based on the logarithmic function and the power law is presented.The theoretical mean vocabulary size and the 95% upper and lower bound values are calculated and plotted as functions of the sample size.Being significant in explicit EFL teaching and learning,the new growth model can make accurate estimates not only on the vocabulary size and its intervals for a given textbook but also on the volume of texts that are needed to produce a particular vocabulary size.

Geometric attack resistant image watermarking based on MSER

Geometric distortions are simple and effective at- tacks rendering many watermarking methods useless. They make detection and extraction of the embedded watermark difficult or even impossible by destroying the synchroniza- tion between the watermark reader and the embedded water- mark. In this paper, we propose a blind content-based image watermarking scheme against geometric distortions. Firstly, the MSER detector is adopted to extract a set of maximally stable extremal regions which are affine covariant and robust to geometric distortions and common signal processing. Sec- ondly, every original MSER is fitted into an elliptical region that was proved to be affine invariant. In order to achieve rota- tion invariance, an image normalization process is performed to transform the elliptical regions into circular ones. Finally, watermarks are repeatedly embedded into every circular disk by modifying the wavelet transform coefficients. Experimen- tal results on standard benchmark demonstrate that the pro- posed scheme is robust to geometric distortions as well as common signal processing.

Dynamic room-temperature phosphorescence by reversible transformation of photo-induced free radicals

Room-temperature phosphorescence(RTP)with a dynamic feature endows organic luminescent materials with promising application in optoelectronic fields.However,it remains a formidable challenge to obtain dynamic RTP materials.Herein,we reported a strategy for dynamic RTP via reversible transformation of radicals under external stimuli.RTP gradually disappeared with continuous UV-light irradiation owing to the conversion of NDIA to NDIA^(·-)in NDIA/PVA film,which can be recovered by oxidation with oxygen.Regarding the excellent reversibility and repeatability,the potential applications for round-the-clock anticounterfeiting and tag were first demonstrated.This finding not only outlines a principle to synthesize new RTP materials with dynamic behavior,but also expands the scope of applications of dynamic RTP materials.