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To integrate the uneven terrain adaptivity of legged robots and the fast capacity of wheeled robots on even terrains, a four wheel-legged robot is addressed and the cooperative control strategy of wheels and legs based on attitude balance is investigated. Firstly, the kinematics of wheel-legged robot is analyzed, which contains the legged and wheeled motion modal. Secondly, the cooperative control strategy of wheel-legged robot based on attitude balance is proposed. The attitude is calculated by using the quaternion method and complementary filtering, and the attitude stability control of the wheel-legged robot is studied. The trajectory planning of leg motion including walk and trot gait is implemented, and the differential control of wheeled motion is deduced. And then, the cooperative motion control of wheels and legs is achieved by keeping the attitude balance of robot body. Finally, a small prototype is set up to validate the feasibility and effectiveness of proposed method. The experimental results show that the established wheel-legged robot can do walk, trot, and wheel-leg compound motion to overcome many complex terrains and environments.
Biochar conversion from corn stover was evaluated under various process conditions, and the absorption capacity of biochar was investigated for the removal of oxytetracycline in wastewater. Biochar was prepared at lower carbonization temperatures (200–500 °C) and was used in three different concentrations of chemical oxygen wastewater. The results showed that the biochar prepared at the temperature range of 200–500 °C had a faster sorption rate and shorter sorption equilibrium time compared to biochar produced at higher temperatures. The longest time to reach sorption equilibrium was 9 h for biochar obtained at 200 °C. However, the biochar prepared at 500 °C required only 0.5 h to reach the sorption equilibrium. The corn stover-biochar had the highest sorption capacity of 246.3 mg/g for oxytetracycline at 30 °C. The adsorption kinetics was consistent with pseudo–second-order kinetics. This study provides a theoretical basis for the conversion of corn stover into biochar as efficient sorbents.
This study provides a snapshot of the current state of primary care workforce (PCW) serving China's grassroots communities and examines the factors associated with their job satisfaction.
Data for the study were from the 2011 China Primary Care Workforce Survey, a nationally representative survey that provides the most current assessment of community-based PCW. Outcome measures included 12 items on job satisfaction. Covariates included intrinsic and extrinsic factors associated with job satisfaction. In addition, PCW type (ie, physicians, nurses, public health, and village doctors) and practice setting (ie, rural versus urban) were included to identify potential differences due to the type of PCW and practice settings.
The overall satisfaction level is rather low with only 47.6% of the Chinese PCW reporting either satisfied or very satisfied with their job. PCW are least satisfied with their income level (only 8.6% are either satisfied or very satisfied), benefits (12.8%), and professional development (19.5%). They (particularly village doctors) are also dissatisfied with their workload (37.2%). Lower income and higher workload are the two major contributing factors toward job dissatisfaction.
To improve the general satisfaction level, policymakers must provide better pay and benefits and more opportunities for career development, particularly for village doctors.
Background. Most mental health research tools are developed in Western, urban contexts. Few studies have evaluated the applicability of these research tools in rural populations of non-Western countries. We examined the cultural acceptance and psychometric performance of the 12-item General Health Questionnaire (GHQ) in China's rural villages.
Method. Ethnographic investigations were conducted to assess the cultural applicability of self-report rating scales among villagers. This was followed by a survey of 1401 rural residents, randomly selected from 48 villages of Shandong province using stratified multistage cluster sampling. The respondents were administered the GHQ and the Composite International Diagnostic Interview (CIDI).
Results. The GHQ, when administered by trained interviewers, was culturally acceptable to rural residents. The scale had good psychometric properties in the study population. The area under the curve was 0·86. At a cut-off of 1/2, the sensitivity and specificity were 80·6% and 79·3% respectively.
Conclusions. The ethno-psychometric evaluation showed that the GHQ was both culturally valid and psychometrically sound in the Chinese rural context.
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