Splitting failure and deformation evolution of the red argillaceous siltstone disc in the high humidity environment

The failure mechanism of weakly cemented soft rock under water-rock coupling effect is extremely complex. To reveal the tensile failure of red argillaceous siltstone in high humidity environment, five kinds of disc samples with different water contents were obtained through maintenance in constant temperature and humidity oven. The Brazilian test was carried out to reveal the variation characteristics of splitting behavior of rock samples in high humidity environment. Detailed analysis was conducted on the evolution law of stress-strain relationship and mechanical parameters under five different water contents. Combined with the DIC (Digital Image Correlation) investigation, the displacement evolution patterns of samples with different water content and loading stages were analyzed. Results show that he macroscopic mechanical parameters such as tensile strength and elastic modulus of weakly cemented red sandstone samples under water environment are negatively parabolic correlated with the increase of water content. The moisture content has an important influence on the disc splitting failure mode, forming the main fracture along the radial direction of loading, and showing a local crushing area in the loading area, and the crushing area increases with the increase of water content. Microstructural variation of red sandstone under a high humidity environment is the main reason for its deterioration of macroscopic mechanical properties

Expression and Significance of MicroRNA-183 in Hepatocellular Carcinoma

Objective. In our previous study, we found that some miRNAs were deregulated in hepatocellular carcinoma (HCC), including miR-183. However, the expression of miR-183 in the progression of benign liver diseases to HCC and its correlation with clinicopathologic factors remain undefined. Methods. MiR-183 expression was measured in normal controls (NC) (n=21), chronic viral hepatitis B or C (CH) tissues (n=10), liver cirrhosis (LC) tissues (n=18), HCC tissues (n=92), and adjacent nontumor tissues (NT) (n=92) by quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR). Results. The expression levels of miR-183 were significantly higher in HCC than in NT, LC, CH, and NL (P=0.001, P<0.001, P=0.011, P<0.001, resp.). The upregulated miR-183 in HCC was correlated with TNM stage (P=0.042) and cirrhosis (P=0.025). The Kaplan-Meier survival analysis showed that miR-183 expression was not associated with the survival of HCC patients. However, miR-183 yielded an area under the curve (AUC) of 0.808 with 59.8% sensitivity and 91.8% specificity in discriminating HCC from benign liver diseases (CH and LC) or NC. Conclusions. The upregulated miR-183 may associate with onset and progression of HCC, but not with the patient survival. A further research is needed to determine the potential of miR-183 as biomarker for HCC

nn-strongly Gorenstein graded modules

summary:Let $R$ be a graded ring and $n\geq 1$ an integer. We introduce and study $n$-strongly Gorenstein gr-projective, gr-injective and gr-flat modules. Some examples are given to show that $n$-strongly Gorenstein gr-injective (gr-projective, gr-flat, respectively) modules need not be $m$-strongly Gorenstein gr-injective (gr-projective, gr-flat, respectively) modules whenever $n>m$. Many properties of the $n$-strongly Gorenstein gr-injective and gr-flat modules are discussed, some known results are generalized. Then we investigate the relations between the graded and the ungraded $n$-strongly Gorenstein injective (or flat) modules. In addition, the connections between the $n$-strongly Gorenstein gr-projective, gr-injective and gr-flat modules are considered

Research on the Stationarity of Hexapod Robot Posture Adjustment

This paper proposes a smooth adjustment method for the instability problem that occurs during the start and stop of a multi-footed robot during attitude change. First, kinematics analysis is used to establish the mapping relationship between the joint angles of the robot support legs and the body posture. The leg joint angle is a known quantity that can be measured accurately and in real time. Therefore, when the position of the foot end of the support leg is unchanged, a unique set of joint angles can be obtained with the change of body posture at a certain moment. Based on the designed mapping model, the smooth adjustment of the posture can be achieved by the smooth adjustment of the support legs. Second, a constraint index that satisfies the requirements of the robot&rsquo;s steady adjustment of the robot is given. The S-curve acceleration/deceleration method is used to plan the body&rsquo;s attitude angle transformation curve, and then the mapping control relationship is used to obtain the control trajectory requirements of the joint to achieve smooth adjustment. In addition, this paper also gives a simple choice and motion control method for the redundancy problem caused by the number of support legs of a multi-footed robot when the attitude is changed. The simulation and prototype experiments verify and analyze the proposed method. The results of comparative experiments show that the posture adjustment method proposed in this paper has continuous acceleration without breakpoints, the speed changes gently during the start and stop phases of the attitude transformation, and there is no sudden change in the entire process, which improves the consistency of the actual values of the attitude planning curve with the target values. The physical prototype experiment shows that the maximum deviation between the actual value of the attitude angular velocity and the target value changes from 62.5% to 5.5%, and the degree of fit increases by 57.0%. Therefore, this study solves the problem of the instability of the fuselage when the robot changes its attitude, and it provides an important reference for the multi-footed robot to improve the terrain adaptability

Group Heterogeneity of Rural Households’ Satisfaction with Good Life from the Perspective of Rural Revitalization—A Case Study from Zhejiang Province of China

In the context of rural revitalization, this article explores the group heterogeneity and influencing factors of the satisfaction of rural households’ good life in five dimensions, including industry and economy, living environment, rural culture, rural governance, and material life, and provides micro evidence and policy suggestions for the specific strategies of deepening rural revitalization and improving the satisfaction level of rural households’ good life. Based on the field survey data in rural areas of Zhejiang Province, this article analyzes the group heterogeneity of rural households’ satisfaction with a good life through latent profile analysis and further reveals the influencing factors through multinomial logistic regression. The results indicate that most dimensions of rural households’ satisfaction with good life, except rural culture in Zhejiang, are higher than average. The rural households’ satisfaction with good life presents obvious group differences, which are aggregated into three latent classes: very-satisfied class, medium-satisfied class, and low-satisfied class. The results of multinomial logistic regression analysis showed that subjective psychological evaluation, such as communication, self-confidence, and village status evaluation, had significant positive effects on the group category of good life satisfaction. The proportion of non-agricultural income and the level of per-capita family income have a significant negative influence on the group category of good life satisfaction, and the condition of public service at the village level has a significant positive influence on the group category of good life satisfaction. The satisfaction of rural households on sanitary toilet environment, New Year celebration, cultural activities in the countryside, work of village committee, fair treatment of village affairs, and soliciting opinions of village affairs were not high. Lack of self-confidence in communication and other subjective psychological factors and poor public service conditions at the village level are the important reasons for this. Therefore, measures should be taken to deepen the construction of rural civilization, build a multi-path and long-term mechanism to increase farmers’ income, and make up for the shortage of rural infrastructure and public services

The Capability Approach to Adolescent Poverty in China: Application of a Latent Class Model

After 2020, poverty alleviation in China will shift from eliminating absolute poverty to alleviating unbalanced and insufficient relative poverty. Based on Amartya Sen&rsquo;s capability approach, this article aimed to realize the freedom of &ldquo;capability&rdquo; of children and ensure the well-being and development of Chinese adolescents, who are often ignored in child poverty research. The study sought to estimate the 10&ndash;15-year-olds in a multidimensional capabilities poverty group. Our analysis was based on the adolescent capability methodology framework, using data from the 2018 China Family Panel Studies (CFPS) to investigate the types and influencing factors of adolescent capability poverty in China. The result of latent class analysis showed that there are four types of capability poverty among the Chinese adolescents, namely, Extreme Capability Poverty Class, Goal Capability Poverty Class, Opportunity Capability Poverty Class, and Capability Non-Poverty Class. Multinomial logistic regression showed that the personal factors of gender, ethnic minority, hukou, and pocket money; the family factors of parents&rsquo; marital status, parents&rsquo; education level, and region of residence; and the family economic factor of per capita family income had a significant impact on the types of China&rsquo;s adolescent capability poverty. The article provides empirical and quantitative evidence for the adolescent (ages 10&ndash;15) class of capability poverty. The findings provide a reference for policy makers to target poverty-alleviation efforts according to different types of poverty and to interrupt the intergenerational transmission of poverty

Research on Low Energy Consumption Static Postures of Bionic Feet

By studying the relation of the robot&rsquo;s postures and its energy consumption, a static analysis-based method to obtain the low-energy postures of the robot is proposed. This method decreases the energy consumption and increases the battery life by adjusting the postures in the horizontal environment. The method takes the low-speed hexapod bionic robot as the research object. First, we obtain the output torque of each joint of the leg through static analysis and establish the energy consumption model of the robot. Considering the flexibility of the robot, we then introduce the performance index of the maximum step length and establish an equilibrium solution based on energy consumption and maximum step size. Finally, we derive the low-energy postures of the robot using MATLAB (MATLAB 2014a, The MathWorks, Natick, Massachusetts State, USA, 2014) simulations. An energy consumption experiment is carried out with a physical prototype to verify the validity of the method

Group Heterogeneity of Rural Households&rsquo; Satisfaction with Good Life from the Perspective of Rural Revitalization&mdash;A Case Study from Zhejiang Province of China

In the context of rural revitalization, this article explores the group heterogeneity and influencing factors of the satisfaction of rural households&rsquo; good life in five dimensions, including industry and economy, living environment, rural culture, rural governance, and material life, and provides micro evidence and policy suggestions for the specific strategies of deepening rural revitalization and improving the satisfaction level of rural households&rsquo; good life. Based on the field survey data in rural areas of Zhejiang Province, this article analyzes the group heterogeneity of rural households&rsquo; satisfaction with a good life through latent profile analysis and further reveals the influencing factors through multinomial logistic regression. The results indicate that most dimensions of rural households&rsquo; satisfaction with good life, except rural culture in Zhejiang, are higher than average. The rural households&rsquo; satisfaction with good life presents obvious group differences, which are aggregated into three latent classes: very-satisfied class, medium-satisfied class, and low-satisfied class. The results of multinomial logistic regression analysis showed that subjective psychological evaluation, such as communication, self-confidence, and village status evaluation, had significant positive effects on the group category of good life satisfaction. The proportion of non-agricultural income and the level of per-capita family income have a significant negative influence on the group category of good life satisfaction, and the condition of public service at the village level has a significant positive influence on the group category of good life satisfaction. The satisfaction of rural households on sanitary toilet environment, New Year celebration, cultural activities in the countryside, work of village committee, fair treatment of village affairs, and soliciting opinions of village affairs were not high. Lack of self-confidence in communication and other subjective psychological factors and poor public service conditions at the village level are the important reasons for this. Therefore, measures should be taken to deepen the construction of rural civilization, build a multi-path and long-term mechanism to increase farmers&rsquo; income, and make up for the shortage of rural infrastructure and public services

2D Semimodel of Full-Section Anchorage in Thick Soft Rock Roadway

This paper focuses on the reinforcement effect of full-face anchorage in thick soft rock roadway. A 2D semimodel of full-face anchorage in roadway with thick surrounding soft rock was proposed firstly by transforming the confinement effect of the excavation face in the longitudinal direction as the virtual internal support force at the circumferential surface. Then, based on the theory of elasticity, the theoretical model of the coupling effect between surrounding rock and anchoring system was established, and the analytical solutions of stress and displacement were obtained employing superposition principle. Finally, the theoretical solution was verified by numerical simulation, and the distribution laws of stress release-anchor stock-surrounding rock coupling were analyzed in detail considering stress release. Results demonstrated that the stress field of the surrounding rock diverse widely with different stress release coefficients. With the increasing of stress release coefficient, the radial stress of the surrounding rock decreases, while the tangential stress increases. The supporting role of the bolt is mainly reflected in improving the radial stress of the anchorage zone. However, it has little effect on the tangential stress. What is more, the anchoring effect is more significant to soft rock stress than hard rock. In addition, the prestress of rock bolt has a certain matching relation with the bolt parameters, the surrounding rock parameters, and the initial stress. This study laid a theoretical foundation for further analysis of the interaction between surrounding rock and bolt supporting in plastic zone