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Promoting the sustainable intensification of cultivated land use (SICL) has become crucial for ensuring a sufficient supply of grain and important agricultural products, as well as for the sustainable use of resources. Taking widely used areas of Shandong Province in China as examples, an analytical scale and level framework for SICL is constructed in this study. It measures the level of SICL through material flow analysis, constructs Tobit models to analyze the influencing factors of SICL at the farming household scale, and analyzes the transition mechanisms of SICL. The results show that the overall level of SICL in Shandong Province is low, and the spatial distribution is uneven. There are relatively more farmers participating in unsustainable intensification than in medium or low levels of SICL, with farmers working at a high level of SICL making up the smallest proportion. The factors that determine the level of SICL at which farmers work vary significantly. More male farmers operate at a low SICL level than female farmers, while females outnumber males at a high SICL level. This is mainly related to the regional distribution of age and population. Meanwhile, with larger cultivated land areas, there is a lower degree of land fragmentation, with a higher level of SICL corresponding to a smaller distance to the nearest town closer within 1–5 km from the town center. We can see the level of SICL and its processes themselves are closely related to time and space scales. Based on the above analysis, it is necessary to clarify the standard processes of SICL to adapt them to local conditions. This includes instructing managers on how to improve resource utilization, increase the sustainable development of cultivated land and establish a comprehensively efficient and functional SICL mechanism. The sustainable intensification of cultivated land use and its specific application in the new era are conducive to enriching the frontier theories and methodology of sustainable development, and are of great significance to the advancement of green agriculture and the decision-making of rural high-quality development.

An analytical investigation is performed to study the secondary instability and dynamic aspects of the mode jumping in hygrothermally buckled cross-ply laminated plates. The governing partial differential equations (PDEs) and constitution relations are derived rigorously from an asymptotically correct, geometrically nonlinear theory. A novel and relatively simpler solution approach is developed to solve the two coupled fourth-order PDEs, namely, the compatibility equation and the dynamic governing equation. The von Kaman plate equation, namely, the coupled nonlinear governing equation, is reduced to a system of nonlinear ordinary differential equations (ODEs) by expressing the transverse deflection as a series of linear buckling modes. The ODEs, combined with the non-linear algebraic constraint equations obtained from in-plane boundary conditions, are then solved numerically under the parametric variation of the temperature and moisture. The comparison between the present method and the FEA shows that the secondary bifurcation point of the hygrothermally loaded plate is far beyond the primary buckling point, and the jump behavior cannot be predicted correctly without sufficient assumed modes, while the present method has the capability of exploring deeply into the post-secondary buckling realm and capturing the mode jumping phenomenon for various combinations of plate configurations boundary conditions. Furthermore, by monitoring free vibration along the stable primary postbuckling and the jumped equilibrium paths, we find that a mode shifting phenomenon (the exchange of vibration modes) exists in the primary post-buckling regime.

A new micromechanics model is developed to predict the effective properties as well as the local fields of heterogeneous magnetostrictive composite materials using the variational asymptotic method for unit cell homogenization (VAMUCH), a recently developed micromechanics modeling technique. Starting from the total magnetic enthalpy of the heterogenous continuum, we formulate the micromechanics model as a constrained minimization problem taking advantage of the fact that the size of the microstructure is small compared to the macroscopic size of the material. To handle realistic microstructures in engineering applications, we implement this new model using the finite element method. A few examples are used to demonstrate the application and accuracy of the proposed theory and the companion computer program-VAMUCH.

Objective: To observe the implementation and effect of intensive community based sexually transmitted Disease (STD) intervention pilot in community. Methods: To adopt epidemiological experimental research method to establish the community experimental intervention group and the blank control group. To compare the intervention level and effect of venereal disease in each group after 1 years' work, and continue to follow up the pilot intervention group for next 2 years, and evaluated the pilot effect of intensive STD intervention. Results: During the first years of intervention, the two groups had no personnel changes, and there was no significant difference in the distribution of the two groups in the community population, the high-risk population and the vulnerable population (c2=1.864, P=0.172). In the first year, 1141 cases of sexually transmitted diseases were screened, including 748 cases of clinical diagnosis and treatment, and 1306 cases of symptomatic treatment, all of which were significantly higher than those of the control group (c2=11.92,211.3,73.64; P=0.001,0,0). In the intervention group of Neisseria gonorrhoeae and Candida, trichomonas, bacterial vaginosis positive screening rate significantly higher than that in control group (c2=4.45134.85,48.7,17.08; P=0.035,0,0,0). Intervention group of mycoplasma infection, condyloma acuminatum, Candida, trichomonas, bacterial vaginosis of 3, diagnosis and treatment effect significantly higher than that in control group (c2=17.6,4.055136.8,48.7,17.08; P=0,0.44,0,0,0). Two groups of pubic lice and scabies screening positive rate and the curative effect was 100%, but the intervention group treatment 14 cases which were higher than the control group of 3 cases. The intervention group of urethral secretions and vaginal secretions of symptomatic management 3 days efficiency is higher than that of the control group (c2=86.377, 37.239; P=0, 0). The number of STD clinics and the growth rate of total out-patient in intervention group were also significantly higher than those in control group (c2=82.87, 7.44; P=0, 0.006). The STD screening, the average etiological treatment, and the average symptomatic management in the next two years was increased compared with the first year, and the differences were statistically significant (c2=49.619, 12.559, 107.437; P=0,0,0) Conclusion: The effect of intensive STD intervention is much better than the current STD intervention service. Intensive STD intervention has good sustainability and is suitable to be popularized in urban community health service.

The mechanical behavior of rock under uniaxial tensile loading is different from that of rock under compressive loads. A micromechanics-based model was proposed for mesoscopic heterogeneous brittle rock undergoing irreversible changes of their microscopic structures due to microcrack growth. The complete stress-strain relation including linear elasticity, nonlinear hardening, rapid stress drop and strain softening was obtained. The influence of all microcracks with different sizes and orientations were introduced into the constitutive relation by using the probability density function describing the distribution of orientations and the probability density function describing the distribution of sizes. The influence of Weibull distribution describing the distribution of orientations and Rayleigh function describing the distribution of sizes on the constitutive relation were researched. Theoretical predictions have shown to be consistent with the experimental results.

A micromechanics-based model is established. The model takes the interaction among sliding cracks into account, and it is able to quantify the effect of various parameters on the localization condition of damage and deformation for brittle rock subjected to compressive loads. The closed-form explicit expression for the complete stress-strain relation of rock containing microcracks subjected to compressive loads was obtained. It is showed that the complete stress-strain relation includes linear elasticity, nonlinear hardening, rapid stress drop and strain softening. The behavior of rapid stress drop and strain softening is due to localization of deformation and damage. Theoretical predictions have shown to be consistent with the experimental results.

By using the scattering-matrix method and the scalar model of elasticity, we investigate the effect of controllable defects on low temperature thermal conductance in a nanowire with a quantum box geometry. It is found that the thermal conductance can be controlled by adjusting the parameters of the defects. The size and the position of the defect can induce the variation in thermal conductance. It is also found that the behavior of the thermal conductance versus temperature is different for different types of defects.

A mode synthesis method used in the dynamic analysis of multi-shaft rotor-bearing system has been developed in this paper. By introducing the idea of connecting springs and dampers, and using gyroscopic modes instead of complex modes in the mode synthesis, this method differs not only from classical component mode synthesis method, but also from complex mode synthesis. Several numerical examples show the advantages of this method.Copyright © 1985 by ASME