Research on dynamic measurement method of speckle in laser display

Laser display technology is the most promising display technology in the market and is widely used in many fields. However, laser speckle has been troubling the application and expansion of this technology in some fields. In order to better evaluate the speckle, speckle measurement methods must be studied. In this study, a dynamic measurement method for laser speckles is proposed according to the optical superposition characteristics of speckle, which can reduce the influence of non-coherent factors on the speckle measurement results. The feasibility of the dynamic speckle measurement method is verified by designing an experimental scheme.

A Novel Method for Resolving and Completing Authors' Country Affiliation Data in Bibliographic Records

Purpose: Our work seeks to overcome data quality issues related to incomplete author affiliation data in bibliographic records in order to support accurate and reliable measurement of international research collaboration(IRC).Design/methodology/approch: We propose, implement, and evaluate a method that leverages the Web-based knowledge graph Wikidata to resolve publication affiliation data to particular countries. The method is tested with general and domain-specific data sets.Findings: Our evaluation covers the magnitude of improvement, accuracy, and consistency. Results suggest the method is beneficial, reliable, and consistent, and thus a viable and improved approach to measuring IRC.Research limitations: Though our evaluation suggests the method works with both general and domain-specific bibliographic data sets, it may perform differently with data sets not tested here. Further limitations stem from the use of the R programming language and R libraries for country identification as well as imbalanced data coverage and quality in Wikidata that may also change over time.Practical implications: The new method helps to increase the accuracy in IRC studies and provides a basis for further development into a general tool that enriches bibliographic data using the Wikidata knowledge graph.Originality: This is the first attempt to enrich bibliographic data using a peer-produced, Webbased knowledge graph like Wikidata.

Analytical investigation for stress measurement with the rheological stress recovery method in deep soft rock

Due to the difficulty and weakness of current stress measurement methods in deep soft rock, a new rheological stress recovery method of the determination of the three-dimensional(3D) stress tensor is proposed. It is supposed that rock stresses will recovery gradually with time and can be measured by embedding transducers into the borehole. In order to explore the applicability and accuracy of this method, analytical solutions are developed for stress measurement with the rheological stress recovery method in a viscoelastic surrounding rock, the rheological properties of which are depicted as both the Burger's model and a 3-parameter solid model. In such conditions, explicit analytical expressions for predicting time-dependent pressures on the transducer are derived. A parametric analysis is then adopted to investigate the influences of the grout solidification time and the mechanical properties of the grout layer. The results indicate that this method is suitable for stress measurement in deep soft rock, the characteristics of which are soft, fractured and subjected to high geo-stress.

Research on sound velocity measurement in a laboratory for large elastic materials

A measurement scheme carried out in a tank is designed to obtain the compressionaland shear-wave velocities of a large elastic material.A hydrophone is used to receive the high frequency acoustic signals which penetrate the tested material,in order to determine the transmission time from the source to the hydrophone,the transmission time is also calculated according to the ray acoustic theory in layered media.A cost function is built based on the measured and the calculated transmission time,then the compressional- and shear-wave velocities can be obtained using the optimization algorithm.Compared with the traditional measurement scheme,this approach can not only get the 2 kinds of sound velocities in the tested material at the same time,but also keep the integrality of the tested material.With the proposed measurement system,the uncertainty of measurement results is less than 3.5%.

Research on Evaluation of Forest Ecological Benefit

Forests create three major benefits, i.e. economic, ecological and social benefits. Evaluation onforest ecological benefits is an important issue to study nowadays, which can provide the scientific basis forreasonable allocation of resources and realization of forestry compensation. This paper is focused on theconception of forest ecological benefits, the current research on evaluation of forest ecological benefits athome and abroad, and research methods adopted and theoretical basis with the following 7 aspects involved:water head protection, soil and water conservation, wind prevention and sand fixing, carbon fixing and oxygenproduction, atmosphere purification, forest recreation and biodiversity conservation. Problems existing incurrent studies are also presented, such as rationality of replacement, compatibility of the outcomes, repetitionof calculation, comprehensiveness of evaluation and affection of subjective factors, and so on. In the end,suggestions for future studies on evaluation of forest ecological benefits are offered.

Limitations of citation analysis on the measurement of research impact:A summary

Although citation analysis is broadly used to design and develop bibliometric indicators or methods measuring the research impact,some limitations of citation analysis regarding citing motivation and behavior,database coverage and bias,as well as the analytical methods may threaten the validity and reliability of the measurement.This paper reviews the literature on the limitations of citation analysis in the measurement of research impact,which is not addressed by many bibliometric studies introducing new indicators or methods for research evaluation,to remind researchers of the possible inappropriate use of citation-based indicators or methods on research evaluation.