Study on the Safety and Prevention Technology of Coal Mining under the River in Xingyuan Coal Mine

Coal mining-induced surface subsidence poses significant ecological and infrastructural challenges, necessitating a comprehensive study to ensure safe mining practices, particularly in underwater conditions. This project aims to address the extensive impact of coal mining on the environment, infrastructure, and overall safety, focusing on the Shigong River area above the working face. The study employs qualitative and quantitative analyses, along with on-site engineering measurements, to gather data on crucial parameters such as coal seam characteristics, roof rock lithology, thickness, water resistance, and structural damage degree. The research encompasses a multidisciplinary approach, involving mining, geology, hydrogeology, geophysical exploration, rock mechanics, mine surveying, and computational mathematics. The importance of effective safety measures and prevention techniques is emphasized, laying the foundation for research focused on the Xingyun coal mine. The brief concludes by highlighting the potential economic and social benefits of this project and its contribution to valuable experience for future subsea coal mining.

The Approach of Compensation of Air Refractive Index in Thermal Expansion Coefficients Measurement Based on Laser Feedback Interferometry

We present the thermal expansion coefficient （TEC） measurement technology of compensating for the effect of variations in the refractive index based on a Nd： YA G laser feedback system, the beam frequency is shifted by a pair of aeousto-optic modulators and then the heterodyne phase measurement technique is used. The sample measured is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams hit perpendicularly and coaxially on each surface of the sample. The reference beams hit on the reference mirror and the high-refiectivity mirror, respectively. By the heterodyne configuration and computing, the influences of the vibration, distortion of the sample supporter and the effect of variations in the refractive index are measured and largely minimized. For validation, the TECs of aluminum samples are determined in the temperature range of 29-748K, confirming not only the precision within 5 × 10-7 K-1 and the accuracy within 0.4% from 298K to 448K but also the high sensitivity non-contact measurement of the lower reflectivity surface induced by the sample oxidization from 448 K to 748 K.

A simplified approach to the basic principle of security measures onboard ships

There are many reasons whymerchant ships make desirable targetsfor pirates and terrorists as well as aconvenient means of transport for thestowaway. Criminal activity in the form ofsuch threats is quickly becoming one ofthe greatest threats to ships and

Large excavations and their effect on displacement of land boundaries

A study to estimate land surface movement caused by large surface excavations in sedimentary strata is presented.In stratified or jointed strata the stress relief driven movement adjacent to large excavations can be significantly larger than expected.High lateral stresses measured in Australia and other places around the world indicate that the ratio of horizontal to vertical stress has been particularly high at shallow depths.The in situ strata is in compression and during excavation,stress is relieved towards the opening causing strata movement.Large excavations such as,open cut mines or highway cuttings,can initiate an extensive horizontal slide of surface layers towards the excavation.These ground movements can be damaging to surface structures such as water storage dams and large buildings.Based on stress measurements at shallow depths in Australian coal mines the study presented here calculates and models the extent of potential ground movement along the bedding surface adjacent to large excavations and provides a new prediction tool of land movement at the excavation boundary that can benefit the geotechnical practitioners in the mining industry.

Recognition and measurement of potential share value of conversion for convertible bonds

To recognize and measure the potential share value of conversion for convertible bonds more accurately, different approaches such as the straight method, the separating method, the expected value approach and the improved approach are comparatively analyzed by taking China Merchants Bank's convertible bonds as an example. There is also a focus on the improved approach that views that convertible bond issue proceeds can be separated into accrual debt value, accrual equity value and accrual option value according to the characteristics of debt, equity and hybrid securities with embedded options of convertible bonds. It is concluded that the improved approach is a more accurate evaluation method of capital structure so that it can fully reflect the economic reality of convertible bonds.

Absolutely Direct Frequency Measurement of Two-Photon Transition Using Multi-Peak Fitting Approach

The optical frequency comb has been widely used in precision measurement. In this study, a multi-peak fitting approach is first proposed to fit the two-photon transition spectrum which overlaps with the neighboring transition in Rb-87. The multi-peak fitting approach is used to eliminate the frequency shift affected by the neighboring transition. With locking the carrier envelope offset frequency at 1/4 repetition frequency, the transition frequency is measured to be 770569132739.9 +/- 5.8 kHz, which agrees well with the previous result recommended by Comite International des Poids et Mesures.

Future Knowledge Management Challenges:Digital Twins Approach and Synergy Measurements

We are in the midst of a significant transformation regarding the way we produce products and deliver services thanks to the digitization of manufacturing and new connected supply-chains and co-creation systems.This article elaborates Digital Twins Approach to the current challenges of knowledge management when Industry 4.0 is emerging in industries and manufacturing.Industry 4.0 approach underlines the importance of Internet of Things and interactions between social and physical systems.Internet of Things(and also Internet of Services and Internet of Data)are new Internet infrastructure that marries advanced manufacturing techniques and service architectures with the I-o-T,I-o-S,and I-o-D to create manufacturing systems that are not only interconnected,but communicate,analyze,and use information to drive further intelligent action back in the physical world.This paper identifies four critical domains of synergy challenge:(1)man-to-man interaction;(2)man-to-machine interaction;(3)machine-to-man interaction;and finally(4)machine-to-machine interaction.Key conclusion is that new knowledge management challenges are closely linked to the challenges of synergic interactions between these four key interactions and accurate measurements of synergic interaction.

Inspiration of cognitive approach on foreign language teaching

In recent years, the college English teaching reform has been increasingly deepened. The study of the relationship between cognitive approach and foreign language teaching is undoubtedly instructive not only to guarantee the quality of foreign language teaching but also to improve learners＇ foreign language proficiency. In this essay, the author expounds the development of cognitive approach and some relative teaching principles, on which basis the author puts forward some specific practices in foreign language teaching.

TECHNOLOGY OF QUANTITATIVE ANALYSIS ON VIBRATORY STRESS RELIEF BASED ON ULTRASONIC TIME-OF-ARRIVAL METHOD

The effect of vibratory stress relief （VSR） is usually evaluated with the indirect method of observing the change of amplitude frequency response characteristics of structures. A new kind of evaluating method of VSR based on the ultrasonic time-of-arrival method （UTM）, which can obtain the residual stress directly through measuring the propagation time of ultrasonic wave in the material, is presented. At first, the principle of the measuring method of residual stress based on UTM is analyzed. Then the measuring system of the method is described, which is in virtue of ultrasonic flaw detector and high-sampling-rate digital oscillograph. And a set of calibration system that contains a piece of standard specimen is also introduced. Experimental results prove the relation between the residual stress and the propagation time of ultrasonic in workpieces. Finally, the measuring and calibration systems are applied in evaluating the effect of VSR. The final test results show that the method is effective.

Fault reconstruction observer design for continuous-time systems with measurement disturbances via descriptor system approach

This paper addresses a problem of observer-based sensor fault reconstruction for continuous-time systems subject to sensor faults and measurement disturbances via a descriptor system approach. An augmented descriptor plant is first formulated, by assembling measurement disturbances and sensor faults into an auxiliary state vector. Then a novel descriptor state observer for the augmented plant is constructed such that simultaneous reconstruction of original system states, sensor faults and measurement disturbances are obtained readily. Sufficient conditions for the existence of the proposed observer are explicitly provided, and the application scope of the observer is further discussed. In addition, an extension of the proposed linear approach to a class of nonlinear systems with Lipschitz constraints is investigated. Finally, two numerical examples are simulated to illustrate the effectiveness of the proposed fault-reconstructing approaches.

A new method of phase measurement based on optimization

A new method of phase measurement based on optimization is presented. Simulations were ran with synthesized signals, and comparison was made with some spectral domain methods. The results show that, with a suitable number of samples processed, this method is superior to other methods in terms of accuracy, while the amplitude and phase of distortion component have no effect on accuracy.

Simulating Error-Opening of Pressure Relief Valves of a Station on a Continuous Undulating Oil Pipeline with Large Elevation Difference

For oil pipeline in mountain areas,high hydrostatic pressure in the pipeline may cause error-opening of pressure relief valves,and oil is discharged from the pipeline to the pressure relief tanks,bringing spilling-over risk of the pressure relief tanks.Therefore,simulating the error-opening situations of the pressure relief valves and investigating the oil discharge process are necessary for checking the possibility of the spilling-over accident and then proposing measures to improve the pressure relief system.This research focuses on a continuous undulating oil pipeline with large elevation difference and a station along this pipeline,which is named B station in this paper,is studied.By OLGA software,simulation model of the pressure relief system of B station is established,and the accuracy of the model is verified by reconstructing a real accident and making a comparison with the actual accident data.The maximum discharge rate reached 8284 m3/h when the pressure relief valve was opened by mistake in the inlet and outlet of the station.The accumulated filling time of the two pressure relief tanks is 200 s,which is in good agreement with the accident data.On this basis,for error-opening of the pressure relief valves at the inlet and outlet of B station,simulation is performed to investigate variations of the discharge velocity,discharge flow rate,accumulated discharge volume and ventilation volume of the vent valve.The discharge velocity is found to be over the maximum velocity allowed for safety consideration.According to the accumulated discharge volume,it is inferred that spilling over of the pressure relief tanks will be caused once error-opening of the pressure relief valve occurs.Also it is judged that the existing breathing valve can not satisfy the ventilation requirement in case of failure of the pressure relief valves.From these simulation results,it is proposed that increasing the number of vent valves,replacing the manual valves with electrically operated valves,and employing security control interlock protection program are improvement measures to guarantee safe,efficient and reliable operation of the pressure relief system at B station.

The Contradiction between Two Versions of Quantum Theory Could Be Decided by Experiment

The incompatibility of Orthodox Quantum Mechanics with philosophical realism poses a serious challenge to scientists upholding such a philosophical doctrine. The desire to find a solution to this and other conceptual problems that quantum mechanics confronts has motivated many authors to propose alternative versions to Orthodox Quantum Mechanics. One of them is the Spontaneous Projection Approach, a theory grounded on philosophical realism. It has been introduced in previous papers and, with a few exceptions, it yields experimental predictions coincident with those of Orthodox Quantum Mechanics. One of these exceptions is analyzed in detail. The difference in predictions becomes apparent in a suggested experiment which could put both theories to the test.

Representation of residual stress symbol in the technical product documentation

A representation of residual stress graphic symbols in technical product documents is studied.The residual stress state of the product can be annotated in the technical product documents such as design drawings,process documents,test reports,papers and monographs.The composition of residual stress and the design of basic symbols,measurement method symbols,relief method symbols and state symbols of residual stress,and the representation of annotation for residual stress in documents are introduced.Residual stress symbol can be used in the design,manufacturing,inspection and service for the residual stress state requirements of the products in the mechanical manufacturing industry,as well as in light industry,daily necessities and other related industries.

基于修正Landweber迭代的声学温度场重建算法

针对不同温度场分布模型,采用修正Landweber迭代技术对其进行温度场重建,介绍了基于声学方法的烟气测温基本原理以及基于Landweber迭代的声学温度场重建算法.根据实际情况,确定了重建算法中的价值函数和迭代步长,使得收敛速度有明显提高,得到了稳定的重建结果.给出了不同温度场分布模型及其重建图像和重建误差.仿真结果表明,即使在声波发射/接收器数目较少时(如8个),该算法仍具有较高的重建精度和抗干扰能力,具有突出优点.

半监督Relief-F特征选择算法

数据规模的不断增加,使得为数据库中全部样本做标记变得尤为困难,数据集也因此呈现出了明显的弱标记性.为此,针对大规模少数标记数据集的特征选择问题,基于经典的Relief-F算法,通过综合考虑有标记样本与无标记样本对数据样本近邻的影响,重新定义样本近邻的搜索策略,提出了一种面向符号数据的半监督特征选择算法.为进一步分析新算法的有效性,仿真实验中选取了5组UCI数据集,并引入机器学习中3个常用分类器对新算法和对比算法的特征选择结果的分类性能作了分析和比较,实验结果很好地验证了本文中提出的新算法的有效性和可行性.

Design for a Crane Metallic Structure Based on Imperialist Competitive Algorithm and Inverse Reliability Strategy

Uncertainties in parameters such as materials, loading, and geometry are inevitable in designing metallic structures for cranes. When considering these uncertainty factors, reliability-based design optimization （RBDO） offers a more reasonable design approach. However, existing RBDO methods for crane metallic structures are prone to low convergence speed and high computational cost. A unilevel RBDO method, combining a discrete imperialist competitive algorithm with an inverse reliabil- ity strategy based on the performance measure approach, is developed. Application of the imperialist competitive algorithm at the optimization level significantly improves the convergence speed of this RBDO method. At the reli- ability analysis level, the inverse reliability strategy is used to determine the feasibility of each probabilistic constraint at each design point by calculating its a-percentile per- formance, thereby avoiding convergence failure, calcula- tion error, and disproportionate computational effort encountered using conventional moment and simulation methods. Application of the RBDO method to an actual crane structure shows that the developed RBDO realizes a design with the best tradeoff between economy and safety together with about one-third of the convergence speed and the computational cost of the existing method. This paper provides a scientific and effective design approach for the design of metallic structures of cranes.

Principle of in-situ 3D rock stress measurement with borehole wall stress relief method and its preliminary applications to determination of in-situ rock stress orientation and magnitude in Jinping hydropower station

As a main constituent of geological body, the rock masses have distinct differences from other materials, one of which is that rock masses are initially stressed in their natural states. Hence, it is an extremely challenging and significant research project to know the present residual stress of the rock masses in the earth's crust. Although some regularities of distribution of in-situ rock stresses can be deduced, the basic means to study the state of rock stress is in-situ stress measurement. After a brief review of several measuring methods of in-situ 3D rock stress, a new one, borehole wall stress relief method (BWSRM) to determine the in-situ 3D rock stress tensor in a single drilled borehole was proposed. Based on the principle of in-situ rock stress measurement with BWSRM, an original geostress measuring instrument was designed and manufactured. Preliminary experiments for determination of in-situ stress orientation and magnitude were carried out at an experimental tunnel in Jinping Ⅱ hydropower station in China, where the buried depth of overburden was about 2430 m. The results showed that it was feasible to measure the in-situ 3D rock stresses with BWSRM presented in this paper. The BWSRM has a broad prospect for in-situ 3D rock stress measurements in practical rock engineering.

Exploring the spatial pattern of historic Chinese towns and cities:A syntactical approach

This study explores the spatial pattern of Historic Chinese Towns and Cities(HCTC)by using a syntactic approach.The HCTC is an important element of the built environment and exhibits a variety of unique spatial characteristics.Although previous research has been focused on qualitative analysis,a quantitative approach to exploring this issue is scarce,leading to insufficient understanding of the spatial characteristics of HCTC.This study presents a quantitative approach to analyzing the spatial pattern of HCTC by utilizing the space syntax method.Four well-preserved historic towns were selected as case studies,each representing a typical spatial type of historic town in China.A series of mathematical measures from space syntax were used to explore the spatial characteristics of HCTC,facilitating expanded interpretation of traditional Chinese ideologies.Results contribute to a more critical understanding of the spatial pattern of HCTC.

Feature Selection Based on Distance Measurement

Every day we receive a large amount of information through different social media and software,and this data and information can be realized with the advent of data mining methods.In the process of data mining,to solve some high-dimensional problems,feature selection is carried out in limited training samples,and effective features are selected.This paper focuses on two Relief feature selection algorithms:Relief and ReliefF algorithm.The differences between them and their respective applicable scopes are analyzed.Based on Relief algorithm,the high weight feature subset is obtained,and the correlation between features is calculated according to the mutual information distance measure,and the high redundant features are removed to obtain the feature subset with higher quality.Experimental results on six datasets show the effectiveness of our method.