A Widely Applicable Method for Plant Genomic DNA Extraction

[Objective] This study aimed to explore a method for plant genomic DNA extraction, to provide guidance for rapid extraction of genomic DNA from plant tissues. [ Method] Based on the published genomic DNA extraction methods, operation steps, reagent amount and processing time of SDS extraction method were optimized. [Result] A widely applicable method was established initially for genomic DNA extraction from various varieties of plants and various kinds of plant tissues. Quality of the extracted genomic DNA was relatively good, which meets the requirements for further operation. [ Conclusion] This study provided guidance for rapid plant genomic DNA extraction.

Research on the Perception of Green Visual Exposure Space Based on SD Method:Taking Saishang Old Street Cultural Area in Hohhot as an Example

With the rapid development and improvement of urban construction,the influence of green environmental exposure on mental health has attracted increasing attention,but the relationship between the psychological perception and the object index has been less explored.From the perspective of the individual and environmental perception,space optimization of cultural blocks was discussed to provide a reference for the development of other old streets.

Research on Spatial Optimization Level Strategy of Beijing Historical Blocks Based on Tourists’Cognitive Evaluation

Tourists,as the main beneficiary of historical block protection and tourism development,are considered qualified to speak on the matter of the preservation of space quality and regional characteristics.The study established a questionnaire using semantic analysis to investigate and evaluate tourists’ perspective of various spatial elements in Beijing’s three historical blocks.Factor analysis and IPA method was introduced to explore how various spatial elements affected the overall environmental perception of tourists.Based on the relative importance of spatial elements,suggestions for optimizing the space of historical blocks were proposed.The study found that:①The overall evaluation of various spatial elements of the historical block was relatively positive,and only the "environmental atmosphere" was closer to the negative evaluation,indicating that most tourists think the environment was too noisy;②All spatial elements can be classified into three indicators:"visual experience","street form" and "perception of regional characteristics";③Landscape planting and space interface needed to be improved first,followed by ground pavement,traffic organization,and advertisement signboard.The research provides a theoretical foundation for reducing the damage caused by improper tourism development behaviors,further improving the spatial quality of historical blocks,and enhancing tourists’ satisfaction of the historical environment.

Analysis of the periodic solutions of a smooth and discontinuous oscillator

In this paper, the periodic solutions of the smooth and discontinuous （SD） oscillator, which is a strongly irra- tional nonlinear system are discussed for the system having a viscous damping and an external harmonic excitation. A four dimensional averaging method is employed by using the complete Jacobian elliptic integrals directly to obtain the perturbed primary responses which bifurcate from both the hyperbolic saddle and the non-hyperbolic centres of the un- perturbed system. The stability of these periodic solutions is analysed by examining the four dimensional averaged equa- tion using Lyapunov method. The results presented herein this paper are valid for both smooth （e 〉 0） and discontin- uous （ce = 0） stages providing the answer to the question why the averaging theorem spectacularly fails for the case of medium strength of external forcing in the Duffing system analysed by Holmes. Numerical calculations show a good agreement with the theoretical predictions and an excellent efficiency of the analysis for this particular system, which also suggests the analysis is applicable to strongly nonlinear systems.

Integrating eye-movement analysis and the semantic differential method to analyze the visual effect of a traditional commercial block in Hefei, China

Eye-movement analysis was adopted to evaluate the visual perception of Chinese traditional commercial blocks,and the Chenghuangmiao block in Hefei,China,was selected as a typical case.Eye-movement data from 40 respondents viewing 14 sample pictures were recorded.The spatial elements of the sample pictures,including landmarks and commercial brands,were further extracted to analyze the visual characteristics of spatial elements and the factors that affect the respondents’perceptions of those elements.Then,the semantic differential method was used to analyze the relationship between visual preferences and psychological perceptions of spatial elements.Seventeen pairs of opposing adjectives were selected to score the intrinsic properties and visitors,feelings of spaces.The software SPSS 22.0 was used to analyze these data.Results showed that distinctive spatial elements,such as street corridors,Ma Tau Walls,and various landmarks,were the most visually attractive.In addition,the location of a given element within a picture was an important factor affecting eye movements.On this basis,strategies for improving spatial-visual effects are proposed.The strategies include emphasizing the visual characteristics of different spatial elements,considering the overall layout of spatial elements,and creating diversified spaces based on different spatial categories.