Based on wireless sensor network (WSN) technology and crop growth simulation techniques, this paper shows the design and realization of an automatic monitoring and closed-loop control system in greenhouses. Firstly, a multi-hop network communication method based on clustering and simple medium access control that is suitable for the monitoring of a large-scale greenhouse environment is designed and analysed, and the simulation results show that its lifetime is 10% longer than LEACH (low energy adaptive clustering hierarchy) when 1% and 20% nodes die. Secondly, a physiological development day-based crop growth simulation model will be built to predict the tomato growth and make further decisions in adjusting the greenhouse climate. In order to obtain the model indicators, early experiments were carried out on four kinds of tomato variety, and the experiment results show that the proposed model has a higher accuracy than the effective temperature model on the root mean square error within 1–4 days, and on the mean absolute error within 2–4 days. Finally, according to the proposed methods, a comprehensive greenhouse dynamic monitoring and closed-loop control system with a 60 MC13213 nodes WSN was implemented. The implementation results show that with three AAA Ni–MH (nominal capacity 750 mAh) batteries, 80% nodes maintained a survival time of 45–60 days, and the model prediction compared with the observed value is at a high correlation efficient of 95%.

Pre-and post-selected (PPS) measurement, especially the weak PPS measurement, is a useful protocol for amplifying small physical parameters. However, it is difficult to retain both the attainable highest measurement sensitivity and precision with the increase of the parameter to be measured. Here, a modulated PPS measurement scheme based on coupling-strength-dependent modulation is presented with the highest sensitivity and precision retained for an arbitrary coupling strength. This idea is demonstrated by comparing the modulated PPS measurement scheme with standard PPS measurement scheme, respectively, in the cases of balanced pointer and unbalanced pointer. By using the Fisher information metric, we derive the optimal pre-and post-selected states, as well as the optimal coupling-strength-dependent modulation without any restriction on the coupling strength. We also give the specific strategy of performing the modulated PPS measurement scheme, which may promote practical application of this scheme in precision metrology.

The cubic compressive strength is one of the important mechanical properties of concrete, and the indicator of cubic compressive strength of recycled sand concrete is more important to be promoted. This paper presents the results of the cubic compressive strength tests on concrete specimens using the recycled sand, the replacement ratios of recycled sand by mass to the natural sand are 0, 30%, 50%, 70% and 100% respectively. This could be used as a reference for the applications of the concrete using the recycled sand in engineering.