耕地结构性质量变化模式研究

耕地保护是关系到我国经济和社会可持续发展的全局性战略问题 ,在我国 ,由于耕地数量减少而导致的耕地质量损失是十分严重的。以江苏省为例 ,采用耕地产出模型 ,由分区域的耕地基本产量计算得出区域综合平均基本产量 ,从而定量揭示该省 13个城市耕地数量的动态变化所导致的耕地结构性质量变化程度 ,以期为政府部门的决策提供参考。图 1,表 4 ,参 8。

幼儿园结构性质量要素组态对课程质量的作用路径与机制——基于模糊集定性比较分析法的研究

幼儿园课程质量对于儿童的学习与发展至关重要。为突破已有研究在研究视角和数据分析方法上的局限,本研究基于复杂性理论和教育生态学思想,采用模糊集定性比较分析法,探索幼儿园结构性质量要素组态对课程质量的影响,以揭示驱动和阻碍幼儿园课程高质量发展的多元路径及其作用机理。结果发现,结构性质量要素并非各自独立而是以相互链接的组态形式影响课程质量。驱动幼儿园课程高质量发展的路径有3条,分别是“资金投入下师资保障驱动型”“资金投入下环境创设驱动型”与“管理引领下师资建设驱动型”,较高的资金投入或良好的管理是其核心条件。阻碍幼儿园课程质量提升的路径也有3条,由于其核心条件都是不适宜的生师比和欠佳的师资质量,所以可以统称为“高生师比—低师资抑制型”。可见,推动和阻碍幼儿园课程质量发展的结构性质量要素组态之间具有非对称性。学前教育行政决策者和幼儿园管理者应坚持“多元决定论”与“整体论”思想,打好政策“组合拳”,才能有效提高幼儿园课程质量。同时,幼儿园应基于自身的资源条件,选择适宜自己的课程质量提升路径,避免盲目依靠以往经验,坚持辩证思维,通过促成驱动幼儿园课程高质量发展的结构要素组态推动课程走上优质化发展道路。

“双普”背景下幼儿园结构性质量的省际差异研究——基于2013—2020年省级面板数据

结构性质量是幼儿园质量建设的重要内容。以2013—2020年全国面板数据为基础,对幼儿园结构性质量进行分析,研究有三个主要发现。一是幼儿园结构性质量由师资结构、保教空间、办公环境和辅助课室构成。图书是“无言”“无形”的教育者,属于师资结构这一维度。生师比、生均图书册达标率最好,生医比、生保比达标率较差;师均办公室和行政办公用房面积达标率较好;生均睡眠室、洗手间面积达标率较差,生均活动室、绿化场地、运动场地面积达标率均在67%以上;生均保健室面积全部达标,生均图书室面积达标率较差。二是2020年全国幼儿园结构性质量排名。中部的内蒙古、黑龙江分别列第一、三位;文化大省江苏、江西和陕西分别列第二、四、八位;东部的辽宁、海南分别列第五、六位;直辖市上海列第七位。师资结构上,东部地区排名靠前,西部地区排名靠后;保教空间上,西部地区排名靠前,东部地区排名靠后。三是东部地区幼儿园的结构性质量总体上显著优于中、西部。东部生师比、生保比、生医比、师均办公室、行政办公用房、生均睡眠室面积和生均图书册数均高于中、西部;西部生均运动场地、活动室和洗手间面积高于中、东部;中部生均绿化面积高于东、西部;东、西部生均保健室面积高于中部;西部生均图书室面积高于东、中部。

高质量幼儿园的结构性质量、过程性质量和结果性质量探究

开办高质量的幼儿园是办好人民满意的教育的重要组成部分。高质量幼儿园主要体现在高质量的结构性质量、过程性质量和结果性质量三个方面,结构性质量是必要条件,过程性质量是充分条件,结果性质量则是可预见的未来。

城乡儿童发展与幼儿园质量差距:以华北某县为例

在全球范围内,缩小儿童早期发展的不平等是政府发展学前教育的重要目标之一。本文以华北某县为例,分析了县域内儿童发展、幼儿园质量城乡差距及其随时间变化的趋势。结果发现:(1)县镇儿童总体发展水平及多个发展领域显著高于乡村儿童。(2)总体而言,在儿童发展的大多数领域,没有证据显示城乡差距有显著扩大的趋势。(3)尽管幼儿园班级规模和幼师比等结构性质量指标及大多数过程性质量指标似乎都有显著改善,但县镇园在大多数两类指标上都显著高于农村园,同时没有证据显示幼儿园过程性质量城乡差距鸿沟有显著扩大趋势。在初步解释城乡儿童发展差距鸿沟持续存在的结构性和体制性根源后,本文提出了促进城乡儿童发展公平性的公共政策建议及研究展望。

不同轻基质和施肥处理对白桦苗木养分承载的影响

通过不同轻基质及施肥处理对白桦苗木质量指数、苗木养分承载量,以及非结构性碳(NSC)质量进行研究与分析,目的是为培育优质白桦苗木提供理论依据。结果表明:①不同轻基质处理中随施肥量增加白桦苗木质量指数呈增加的趋势,但2.5、3.0kg·m^-3施肥处理间无显著差异;随施肥量增加,轻基质处理对白桦苗木质量指数的影响逐渐减弱。②红松腐殖质结合3.0kg·m^-3施肥处理,苗木N、P、K质量达到最大,分别为42.35、4.54、27.80mg·株^-1;红松腐殖质结合2.5kg·m^-3施肥处理,苗木可溶性糖、淀粉、NSC质量均达到最大,分别为89.32、85.11、174.43mg·株^-1;2.5kg·m^-3与3.0kg·m^-3施肥处理间无显著差异。③不同处理间苗木NSC、可溶性糖、淀粉质量与N、P、K质量具有极显著相关关系(P<0.01)。可溶性糖质量与N、P、K质量相关性系数较高,K质量与NSC、可溶性糖、淀粉质量相关性系数较高。综上所述,红松腐殖质轻基质材料培育白桦苗木更有利于苗木生长及养分承载量积累,且最适施肥量为2.5kg·m^-3。NSC中可溶性糖是促进养分吸收的主要能量来源,而苗木K质量积累更有利于NSC的合成。

China’s 13th and 14th Five-Year Plans:Review and Advice

The 13th Five-year Plan period ushered in a new era of socialism with Chinese characteristics.During this period,China’s economy transitioned from rapid to high-quality growth and weathered the storms of the trade war with the United States and the COVID-19 outbreak.Chinese policymakers embraced new development concepts,and fought to cut overcapacity and excess inventory,deleverage,lower costs,and bolster weak areas under the theme of supply-side structural reforms.In fighting the three tough battles of major risk prevention,targeted poverty reduction and pollution abatement,China has largely resolved myriad structural contradictions and maintained rapid domestic economic growth and stability.Most targets for the 13th Five-year Plan period have been achieved ahead of time or are near completion on time.Institutional sophistication has bolstered high-quality development.

Natural ventilation performance of single room building with fluctuating wind speed and thermal mass

Natural ventilation is driven by either buoyancy forces or wind pressure forces or their combinations that inherit stochastic variation into ventilation rates. Since the ventilation rate is a nonlinear function of multiple variable factors including wind speed, wind direction, internal heat source and building structural thermal mass, the conventional methods for quantifying ventilation rate simply using dominant wind direction and average wind speed may not accurately describe the characteristic performance of natural ventilation. From a new point of view, the natural ventilation performance of a single room building under fluctuating wind speed condition using the Monte-Carlo simulation approach was investigated by incorporating building facade thermal mass effect. Given a same hourly turbulence intensity distribution, the wind speeds with 1 rain frequency fluctuations were generated using a stochastic model, the modified GARCH model. Comparisons of natural ventilation profiles, effective ventilation rates, and air conditioning electricity use for a three-month period show statistically significant differences （for 80% confidence interval） between the new calculations and the traditional methods based on hourly average wind speed.

Notes on Quantitative Structure-Properties Relationships （QSPR） Part Four： Quantum Multimolecular Polyhedra, Collective Vectors, Quantum Similarity, and Quantum QSPR Fundamental Equation

The nature and origin of a fundamental quantum QSPR （QQSPR） equation are discussed. In principle, as any molecular structure can be associated to quantum mechanical density functions （DF）, a molecular set can be reconstructed as a quantum multimolecular polyhedron （QMP）, whose vertices are formed by each molecular DF. According to QQSPR theory, complicated kinds of molecular properties, like biological activity or toxicity, of molecular sets can be calculated via the quantum expectation value of an approximate Hermitian operator, which can be evaluated with the geometrical information contained in the attached QMP via quantum similarity matrices. Practical ways of solving the QQSPR problem from the point of view of QMP geometrical structure are provided. Such a development results into a powerful algorithm, which can be implemented within molecular design as an alternative to the current classical QSPR procedures.

Microstructure and optical properties of TiO_2 thin films deposited at different oxygen flow rates

To research the influence of oxygen flow rate on the structural and optical properties of TiO2 thin film,TiO2 films on glass were deposited by reactive magnetron sputtering.The microstructure and optical properties were measured by X-ray diffractometry,AFM and UV-VIS transmittance spectroscopy,respectively.The results show that the films deposited at oxygen flow rate of 10 mL/min has the lowest roughness and the highest transmittance.The absorption angle shifts to longer wavelengths as oxygen flow rates increase from 5 to 10 mL/min,then to shorter ones as the oxygen flow rate increase from 10 to 30 mL/min.The band gap is 3.38 eV,which is nearly constant in the experiment.For the TiO2 thin films deposited at 10 mL/min of oxyge flow rate,there are nano-crystalline structures,which are suitable for anti-reflection(AR) coating in the solar cells structure system.

Estimation of surface tension of organic compounds using quantitative structure-property relationship

A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.

Structure characteristics and adhesive property of humic substances extracted with different methods

The structure characteristics and adhesive property of humic substance(HS) extracted with different methods were mainly studied by terms of elementary analysis,visible spectrum,FT-IR spectroscopy,viscosity,adsorption and pelletizing experiments.The results show that HSs extracted with new method(HS-a) own higher degree of aromatization and polymerization,larger relative molecular mass and more polar functional groups than HS extracted with usual method(HS-b).The viscosity of HS-b is about 30-40 mPa·s lower than that of HS-a.The maximum adsorption amounts of HS-a and HS-b onto iron concentrates are 9.11 mg/g and 8.08 mg/g,respectively.Meanwhile,HS-a has a better performance than HS-b in the practical application for pelletizing of iron concentrates.The difference in agglomeration behaviors with iron concentrates lies in the differences of the structure characteristics of HSs.With higher content of polar functional groups,larger relative molecular mass and viscosity of HSs,the agglomeration behavior is improved.

Estimation of half-wave potential of anabolic androgenic steroids by means of QSER Approach

The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors were calculated by semi-empirical calculations. Models were established using partial least square(PLS) regression and back-propagation artificial neural network(BP-ANN). The QSPR results indicate that the descriptors of these derivatives have significant relationship with half-wave reduction potential. The stability and prediction ability of these models were validated using leave-one-out cross-validation and external test set.

Private Topic or Public One： On Topic Sentence Quality

Topic effect on L2 writing has long been an issue of controversy. This study was carried out to investigate the influence of topic type on the quality of topic sentence. The participants, 150 college students at three different proficiency levels, were asked to write both on a private topic and a public topic. The results show that the participants on the whole wrote better on the public topic, and their proficiencies can be differentiated by the quality of their topic sentences. The public topic was conducive to the production of complete English discourse structures, as well as the generation of informative and predictive topic sentences. Moreover, the results also reveal the dynamic nature of contrastive rhetoric

Landslide Susceptibility Mapping by Using Landslide RatioBased Logistic Regression:A Case Study in the Southern Taiwan

The object of the research is to compare the model performance and explain the error source of original logistic regression landslide susceptibility model(abbreviated as or-LRLSM) and landslide ratio-based logistic regression landslide susceptibility model(abbreviated as lr-LRLSM) in the Chishan watershed with a serious landslide disaster after 2009 Typhoon Morakot. The landslide inventory induced by 2009 Typhoon Morakot in South Taiwan is the main research material, while the Chishan watershed is the research area. Six variables, including elevation, slope, aspect, geological formation, accumulated rainfall, and bank erosion, were included in the two models. The performance of lr-LRLSM is better than that of or-LRLSM. The Cox & Snell R2, Nagelkerke R2 value, and the area under the relative operating characteristic curve(abbreviated as AUC) of lrLRLSM is larger than those of or-LRLSM, and the average correct ratio for the lr-LRLSM to predict landslide or non-landslide is larger than that of orLRLSM by 5.0%. The increase of the average correct ratio(abbreviated as ACR) difference from or-LRLSM to lr-LRLSM shows in slope, revised accumulated rainfall, aspect, geological formation and bank erosion variables, and only light decreases in elevation variable. The error sources of continuous variables in building the or-LRLSM is the dissimilarity between the distribution of landslide ratio and production of coefficient and characteristic values, while those of categorical variables is due to low correlation of landslide ratio and the coefficient value of each parameter. Using the classification of landslide ratio as the database to build logistic regression landslide susceptibility model(abbreviated as LRLSM) can revise the errors. The comparison of or-LRLSM and lr-LRLSM in the Chishan watershed also shows that building the landslide susceptibility model(abbreviated as LSM) by using lr-LRLSM is practical and of better performance than that by using the or-LRLSM.

Effects of TiO_2 volume fraction on the microstructure and magnetic properties of CoPt-TiO_2 nanocomposite films

CoPt-TiO2 nanocomposite films were synthesized by rapid thermal annealing of CoPt/TiO2 multilayers.The effects of TiO2 volume fraction on the microstructure and magnetic properties of the nanocomposite films were studied.Results showed that the ordering and texture of the L10-CoPt particles did not change with TiO2 content up to 76 vol.% of TiO2.However,the volume of the L10-CoPt particles in the film decreased with an increase in TiO2 content.Increasing TiO2 content effectively reduced the coalescence of magnetic grains when TiO2 content was larger than 56 vol.%.Both the out-of-plane coercivity and remanence ratio of the film decreased slightly with TiO2 content,but the in-plane coercivity and remanence ratio of the film decreased firstly and then increased after TiO2 content was larger than 56 vol.%.The reduction in the coercivity of the film should be due to the reduction in the size of the L10-CoPt particles.The reduction in remanence ratio might be due to the weakening of the exchange coupling strength between the magnetic grains when TiO2 content was increased,as indicated by the MFM images.

Hydrographic field investigations in the Northern South China Sea by open cruises during 2004-2013

In the past 10 years （2004-2013）, annual open cruise during late summer provided new opportunities for comprehensive studies in the Northern South China Sea （NSCS）. The 10-year field investigation program was carried out by the South China Sea Institute of Oceanology, Chinese Academy of Sciences （SCSIO, CAS）. Measurements inclu- ded water mass property, ocean circulation, atmospheric structure, and chemical and biological elements. The observation data collected during these open cruises have been intensively used in the studies of marine oceanographic, meteorological, chemical, and biological processes in the NSCS. In this study, comprehensive assessment of data application in oceanographic and meteorological studies is provided： （1） the property and variability of water masses in different layers; （2） the distribution of main currents and three-dimensional structure of mesoscale eddies; and （3） atmospheric structure and its feedback to the ocean. With the continuance of open cruises, it is feasible to construct high- quality, gridded climatological marine meteorological datasets in the NSCS in the near future.

Approaching strain limit of two-dimensional MoS_(2) via chalcogenide substitution

Strain engineering is a promising method for tuning the electronic properties of two-dimensional(2 D)materials,which are capable of sustaining enormous strain thanks to their atomic thinness.However,applying a large and homogeneous strain on these 2D materials,including the typical semiconductor MoS_(2),remains cumbersome.Here we report a facile strategy for the fabrication of highly strained MoS_(2) via chalcogenide substitution reaction(CSR)of MoTe_(2) with lattice inheritance.The MoS_(2)resulting from the sulfurized MoTe_(2) sustains ultra large in-plane strain(approaching its strength limit~10%)with great homogeneity.Furthermore,the strain can be deterministically and continuously tuned to~1.5%by simply varying the processing temperature.Thanks to the fine control of our CSR process,we demonstrate a heterostructure of strained MoS_(2)/MoTe_(2)with abrupt interface.Finally,we verify that such a large strain potentially allows the modulation of MoS_(2) bandgap over an ultra-broad range(~1 e V).Our controllable CSR strategy paves the way for the fabrication of highly strained 2D materials for applications in devices.

Influence of Organic Matter Content on Hydro-Structural Properties of Constructed Technosols

Constructed Technosols may be an alternative for creating urban green spaces. However, the hydro-structural properties emer- ging from the assembly of artefacts have never been documented. The soil shrinkage curve （SSC） could provide relevant structural information about constructed Technosols, such as the water holding capacity of each pore system （macropores and micropores）. The objectives of this study were （i） to evaluate the SSC and water retention curve （WRC） to describe the structure of constructed Tech- nosols and （ii） to understand the influence of organic matter content on soil hydro-structural properties. In this study, Technosols were obtained by mixing green waste compost （GWC） with the material excavated from deep horizons of soil （EDH）. The CWC was mixed with EDH in six different volumetric percentages from 0% to 50% （GWC/total）. The GWC and EDH exhibited highly divergent hydro-structural properties： the SSC was hyperbolic for GWC and sigmoid for EDH. All six mixture treatments （0%, 10%, 20%, 30%, 40% and 50% GWC） exhibited the classical sigmoid shape, revealing two embedded levels of pore systems. The 20% GWC treatment was hydro-structurally similar to the 30% and 40% GWC treatments; so, a large quantity of expansive GWC is unnecessary. The relation with the GWC percentage was a second-degree equation for volumetric available water in micropores, but was linear for volumetric available water in macropores and total volumetric available water. Total volumetric available water in the 50% GWC treatment was twice as high as that in the 0% GWC treatment. By combining SSCs and WRCs, increasing the GWC percentage increased water holding capacity by decreasing the maximum equivalent size of water-saturated micropores at the shrinkage limit and increasing the maximum equivalent size of water-saturated macropores, resulting in an increased range of pore diameter able to retain available water.

A video structural similarity quality metric based on a joint spatial-temporal visual attention model

Objective video quality assessment plays a very important role in multimedia signal processing. Several extensions of the structural similarity （SSIM） index could not predict the quality of the video sequence effectively. In this paper we propose a structural similarity quality metric for videos based on a spatial-temporal visual attention model. This model acquires the motion attended region and the distortion attended region by computing the motion features and the distortion contrast. It mimics the visual attention shifting between the two attended regions and takes the burst of error into account by introducing the non-linear weighting fimctions to give a much higher weighting factor to the extremely damaged frames. The proposed metric based on the model renders the final object quality rating of the whole video sequence and is validated using the 50 Hz video sequences of Video Quality Experts Group Phase I test database.