Inverse problem of pulsed eddy current field of ferromagnetic plates

To determine the wall thickness, conductivity and permeability of a ferromagnetic plate, an inverse problem is established with measured values and calculated values of time-domain induced voltage in pulsed eddy current testing on the plate. From time-domain analytical expressions of the partial derivatives of induced voltage with respect to parameters,it is deduced that the partial derivatives are approximately linearly dependent. Then the constraints of these parameters are obtained by solving a partial linear differential equation. It is indicated that only the product of conductivity and wall thickness, and the product of relative permeability and wall thickness can be determined accurately through the inverse problem with time-domain induced voltage. In the practical testing, supposing the conductivity of the ferromagnetic plate under test is a fixed value, and then the relative variation of wall thickness between two testing points can be calculated via the ratio of the corresponding inversion results of the product of conductivity and wall thickness. Finally, this method for wall thickness measurement is verified by the experiment results of a carbon steel plate.

Current Situation,Problems and Development Strategies of Marine Ecological Civilization Demonstration Areas in China

Based on analysis of current situation of national marine ecological civilization demonstration areas in China, problems were discussed from aspects of shoreline development, marine disaster waming, marine pollution, etc. Afterwards, some development strategies were proposed to provide references for construction of marine ecological civilization demonstration areas in China, thereby promoting overall construction of marine ecological civilization in China.

Current Situations and Problems of Investment in Agricultural Capital Construction from the Perspective of Investment of Different Ministries and Commissions and Recommendations

Investment in agricultural capital construction is an important factor in improving China's agricultural productivity and international competitiveness. In recent years,the attention to the investment in agricultural capital construction has been lifted to a strategic height. However,there is still little research on the investment in agricultural capital construction. From the perspective of investment of different ministries and commissions,this paper systematically analyzed current situations,problems,and came up with recommendations for the investment in the agricultural capital construction. According to the results,( i) from 1983 to the present,China's investment in agricultural capital construction experienced three stages. Especially after 2010,the scale of investment in agricultural capital construction was huge,and it showed a rapid increasing trend;( ii) the investment in agricultural capital construction is characterized by " multi-sector investment,different departments having different investment priorities and investment scale in different periods";( iii) some investment projects are overlapping between departments,local areas are weak in providing support funds,project construction standard is single,and there are problems of attaching importance to the application,belittling the management,stressing the construction,belittling the maintenance,and serious brain drain;( iv) different departments have accumulated certain experience in long-term exploration. For example,they pay more attention to the refinement and differentiation of projects,focus on the development of targeted poverty alleviation,pay more attention to the " quality" of investment,and pay more attention to the transformation of agricultural production methods. Based on current situations and problems,it came up with recommendations including promoting the integration of funds for investment and project integration,strengthening the personnel cultivation,ensuring simultaneous construction and management of projects,stressing the maintenance after project construction,exploring new modes for project design,management,investment,and financing,and enhancing the support for special investment projects.

Current Situation,Problems and Countermeasures of Modern Agricultural Construction in Bijie Experimental Area

Firstly,the current situation and existing problems of modern agricultural construction in Bijie experimental area were analyzed,and then the countermeasures of promoting construction and sustainable development of modern agriculture were proposed according to the reality of agricultural development in the Bijie experimental area.

SOME PROBLEMS CONCERNING THE CURRENT S&T POLICY-MAKING

Ⅰ. RELEVANT CONCEPTS TO BE CLARIFIED When we talk about S&T policies, there are two concepts involved in the policy-making: one is S&T expenditure and the other is R&D input. The implications of the two are quite different. The former refers to all funds spent on S&T activities and the latter means the total expense used for a given project of systematic innovation. According

Stokes First Problem for an Unsteady MHD Third-Grade Fluid in a Non-Porous Half Space with Hall Currents

The well-known problem of unidirectional plane flow of a fluid in a non-porous half-space due to the impulsive motion of the rigid plane wall it rests upon is discussed in the context of an unsteady MHD third-grade fluid in presence of Hall currents. The governing non-linear partial differential equations describing the problem are converted to a system of non-linear ordinary differential equations by using the similarity transformations. The complex analytical solution is found by using the homotopy analysis method (HAM). The existing literature on the topic shows that it is the first study regarding the effects of Hall current on flow of an unsteady MHD third-grade fluid over an impulsively moving plane wall. The convergence of the obtained complex series solutions is carefully analyzed. The effects of dimensionless parameters on the velocity are illustrated through plots and the effects of the pertinent parameters on the local skin friction coefficient at the surface of the wall are presented numerically in tabular form.

The Status Quo and Problems of Red Cultural Sites in the New Era and Their Exploration Paths: Taking the Luxi Region as an Example

Red cultural site is the carrier of red culture,containing profound revolutionary history and value of the times,we should deeply excavate the intrinsic potential of red cultural sites,pay attention to the ontological protection of red cultural sites,develop and improve the red cultural innovation projects,and strengthen the red culture itself and supporting the construction.This paper takes the old revolutionary area of Luxi as an example,conducts field investigation and visits based on the local county records and party history materials,and investigates a total of five red cultural sites and memorial halls in Luxi,focusing on the actual achievements and problems exposed in the protection and development of the current red cultural sites,to provide references and thinking for the protection,development,and innovative utilization of red cultural sites in the new era of our country.

The Forward and Inverse Problem Based on Magneto-Acoustic Tomography with Current Injection

The Magneto-acoustic Tomography with Current Injection (MAT-CI) is a new biological electrical impedance imaging technique that combines Electrical Impedance Tomography (EIT) with Ultrasonic Imaging (UI), which possesses the non-invasive and high-contrast of the EIT and the high-resolution of the UI. The MAT-CI is expected to acquire high quality image and embraces a wide application. Its principle is to put the conductive sample in the Static Magnetic Field(SMF) and inject a time-varying current, during which the SMF and the current interact and generate the Lorentz Force that inspire ultrasonic signal received by the ultrasonic transducers positioned around the sample. And then according to related reconstruction algorithm and ultrasonic signal, electrical conductivity image is obtained. In this paper, a forward problem mathematical model of the MAT-CI has been set up to deduce the theoretical equation of the electromagnetic field and solve the sound source distribution by Green’s function. Secondly, a sound field restoration by Wiener filtering and reconstruction of current density by time-rotating method have deduced the Laplace’s equation that caters to the current density to further acquire the electrical conductivity distribution image of the sample through iteration method. In the end, double-loop coils experiments have been conducted to verify its feasibility.

On the Problems and Strategies in Trademark Translation

Trademark,which is commonly known as brand,is the logo of commodity produced by manufacturer or operator of goods.Such kind of logo is usually composed of words or graphs,or by the combination of them.The trademarks of this paper refer to the trademark words,or brand names. This paper starts with the characteristics of English and Chinese trademarks,and then exhibits the current situation and problems in trademark translation;puts forward some basic strategies and methods of translation.Finally,some principles are provided to make translation of trademarks much more vivid and more expressive.All the above is to arouse consumers’ desire to buy,which will make the products more competitive.

Problems of Spaces in Urban Villages and Optimization Strategies Based on the Concept of Healthy City:A Case Study of Luotuo Lane in Lanzhou City,Gansu Province

Urban villages are closely related to residents’health as the built-up areas for their living activities.Taking Luotuo Lane in Qilihe District,Lanzhou City,Gansu Province for example,this paper based on the concept of healthy city analyzed the study area mainly from the perspectives of fundamental research,influence factors,status quo investigation,and problem analysis,so as to put forward the optimization strategies.

Problems and Countermeasures of Green Logistics Development in China

Green logistics represents direction and trend of future logistics development, and is a kind of new mode of the logistics industry under the guidance of strategic guidance of scientific development concept and construction guideline of ecological civilization. Various countries in the world gradually make green logistics activity as the focus of logistics industry development and actively study special technology of green logistics, thereby laying foundation for green and sustainable development of logistics. In China, green logistics starts later, and awareness on green logistics is very limited, We study current situation of green logistics development in China, analyze many problems at concept, regulations and policies, in- frastructure, technical information and logistics personnel of green logistics, and put forward specific suggestions for improving green logistics devel- opment in China.

Existing Problems and Recommendations for Cultivation of Agricultural Science and Technology Talents in China

China is a large agricultural country. Healthy and rapid development of agriculture plays an important role in overall socialist construction of China. To realize sustainable agricultural development,cultivation of agricultural science and technology innovation talents should be strengthened. Through analyzing existing problems in cultivation of agricultural science and technology innovation talents and combining actual situation of China's agricultural development,this paper came up with pertinent recommendations for strengthening China's agricultural science and technology talent cultivation,including improving agricultural science and technology innovation talent cultivation system,implementing " government- industry- university- institute" talent cultivation mode,speeding up construction of experimental teaching demonstration center,and applying human resource theories.

Problems and Solutions about Land Use of Different Karst Environments in Southern China

This paper is aimed to analyze the current situation and problems about land use of various karst environments via field survey,documentation and comparison methods,and to make reasonable recommendations about land use and management for different karst types in a bid to provide theoretical and practical basis for optimization of karst land use and the comprehensive control of karst rock desertification.The results show that,①as the bare karst areas are lack of water and soil and highly vulnerable to droughts and floods,land utilization in such areas should follow the principles of soil and water conservation and ecological restoration,emphasize both the ecological benefit and the economic benefits and reasonably configure the land resources to achieve virtuous circle;②in covered karst areas,the most important task is to take measures to prevent the appearance of secondary karst rock desertification,water exhaustion and karst collapse;③the buried karst areas shall mainly focus on prevention of overlaying sand shale collapse,and possible pollution of deep karst water and the surface land resulted from exploration and exploitation of oil and gas and geothermal water.④The final conclusion is that features and problems of land utilization of the three karst types are different from each other,and that the general principle for land use in karst regions shall be based on the local conditions.

Current Situations of Edible Fungus Production in Lianyungang City and Development Countermeasures

On the basis of characteristics of edible fungus production in Lianyungang City, we analyzed its advantages and disadvantages and put forward suggestions and countermeasures for development of edible fungus industry, mainly including strengthening guidance and leadership of government, introducing professional personnel, and developing the edible fungus industry through science and technology.

Reconstruction of Current Density Distribution in Weld Area During Resistance Spot Welding of Aluminum Alloy Based on Magnetic Field

Magnetic flux density around the weld area was used to reconstruct the current density distribution during resistance spot welding(RSW) of aluminum alloy according to inverse problem theory. A current-magnetic field model was established and the conjugate gradient method was used to solve this model. The results showed that the current density was low at the center of nugget while high on the edge of nugget. Moreover, the welding time of 30ms—60 ms is a key period for nucleation. The current density distribution can reflect whether the weld nugget is formed or splashed, therefore it has the potential to monitor the weld quality of RSW.

“双一流”高校图书馆纸质资源政府采购合同的现状、问题与优化--基于中国政府采购网合同公告信息的分析

从中国政府采购网“政府采购合同公告系统”收集整理“双一流”高校图书馆纸质资源政府采购合同公告479份、合同原始文本402份。通过统计和文本分析,展示“双一流”高校图书馆纸质资源政府采购合同的整体情况和核心条款,梳理“双一流”高校图书馆纸质资源政府采购合同存在的问题,并结合最新法律法规及业务实践,从规范合同信息的签订和公告流程、避免盲目套用合同示范文本、加强合同金额/价款条款的合规性审查、细化产品质量服务标准及违约责任条款、明确约定结算与支付条款、将履约验收要求纳入合同条款并加以细化等方面提出优化建议,以期为我国高校图书馆纸质资源政府采购合同的规范管理提供有益参考。

地方高职院校产业学院现状、问题及策略探析——以阜新高等专科学校为例

地方高职院校现代产业学院建设已取得一定成绩,但也存在着政策供给不足、建设现代产业学院意识不强、多元主体协同机制有待完善、区域产业布局不完全合理以及地方高职院校受到自身存在主观问题的制约等客观问题。因此,政府、企业、院校应各自从自身角度做出改变,并同步实施,动态完善,以推进校企深度融合,完善地方高职院校产业学院建设。

全球地热发电现状与研究进展

地热发电作为地热资源开发利用的主要方式之一,其发展对于促进能源结构低碳清洁、推动“双碳”目标的实现意义重大。在明确世界及中国地热能发电发展历程,以及干蒸汽发电技术、闪蒸式发电技术、双循环(双工质)发电技术、全流发电技术等主要地热发电技术概况的基础上,详细阐述了干热岩发电技术、热伏发电技术、超临界CO_(2)循环发电技术、联合发电技术,以及地热-太阳能、地热-风能、地热-生物质能、地热-海洋能等多能互补发电技术等新兴地热发电技术及其研究进展,结合我国地热发电现状及存在问题,提出了我国地热发电发展的建议,以期对我国地热发电的未来发展提供参考借鉴。