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HIGHLIGHTS The mechanism of straw smashing was analyzed. Factors such as the speed of the cutter shaft, the number of blades, the thickness, and the inclination angle had a greater impact on the theoretical length of the straw section after crushing. Based on the straw crushing mechanism, the structure of the crushing chamber was designed. The corn stalk crushing and sending device was trial-produced and field experiments were carried out. ABSTRACT . In order to further improve the crushing quality of corn stalks, this research designs a corn stalk crushing and throwing device. First, it introduced the overall structure and working principle, and analyzed the crushing mechanism of corn stalks to obtain the main factors affecting its crushing performance. Then, the crushing blade in the crushing chamber was designed to determine that the number of crushing blades was 10. Kinematics and dynamic balance analysis, and the establishment of a mathematical model, the speed range of the crushing cutter shaft was 530~900 r/min. On this basis, the ADAMS motion simulation software was used to measure the change curves of the restraint force, runout, and acceleration of the shaft end with different speeds of the crushing cutter shaft. The simulation analysis finally determined that when the speed of the crushing knife shaft was 700 r/min, and the working performance of the device was better and meets the requirements of dynamic balance. Finally, the verification test was carried out, and the result shows: when the speed of the crushing knife shaft was 700 r/min, the qualified rate of corn stalk crushing length was 93.65%. Compared with the original silage corn crushing and throwing device, the performance had increased by 4.78%. It meets the standard of corn stalk crushing operation, which can provide a theoretical basis and scientific basis for the design and optimization of corn stalk crushing and returning equipment. Keywords: Crushing mechanism, Dynamic balance, Motion simulation, Silage corn.

A new process of agile turn with engine reignition is proposed in this paper. Compared with the traditional process, this process includes deceleration phase, larger angle manoeuvre phase, and engine reignition phase. Firstly, the paper describes the new process of agile turn. Then, several constraints in this process are described. Considering all these constraints and assumptions, a new dynamic model including two-stage engine and deceleration parachute is established. Then, the optimal control laws are designed and the timing point determination of the secondary engine ignition is discussed. By using Pontryagin principle, the optimal control laws for each actuator are derived. In terms of determining the optimal timing point of the secondary engine ignition, the paper gives the process of proof. Finally, several numerical simulations are given to demonstrate the effectiveness of the method proposed in this paper. According to all these numerical simulations, it is obvious that the new process of agile turn proposed in this paper is better than traditional process especially in having a smaller turning radius, a shorter turning time, and a high terminal velocity.

Chronic lead exposure is associated with the development of neurodegenerative diseases, characterized by the long-term memory decline. However, whether this pathogenesis could be prevented through adjusting gut microbiota is not yet understood. To address the issue, pregnant rats and their female offspring were treated with lead (125 ppm) or separately the extra probiotics (1010 organisms/rat/day) till adulthood. For results, memory dysfunction was alleviated by the treatment of multispecies probiotics. Meanwhile, the gut microbiota composition was partially normalized against lead-exposed rats, which in turn mediated the memory repairment via fecal transplantation trials. In the molecular aspect, the decreased H3K27me3 (trimethylation of histone H3 Lys 27) in the adult hippocampus was restored with probiotic intervention, an epigenetic event mediated by EZH2 (enhancer of zeste homolog 2) at early developmental stage. In a neural cellular model, EZH2 overexpression showed the similar rescue effect with probiotics, whereas its blockade led to the neural re-damages. Regarding the gut–brain inflammatory mediators, the disrupted IL-6 (interleukin 6) expression was resumed by probiotic treatment. Intraperitoneal injection of tocilizumab, an IL-6 receptor antagonist, upregulated the hippocampal EZH2 level and consequently alleviated the memory injuries. In conclusion, reshaping gut microbiota could mitigate memory dysfunction caused by chronic lead exposure, wherein the inflammation–hippocampal epigenetic pathway of IL-6-EZH2-H3K27me3, was first proposed to mediate the studied gut–brain communication. These findings provided insight with epigenetic mechanisms underlying a unique gut–brain interaction, shedding light on the safe and non-invasive treatment of neurodegenerative disorders with environmental etiology.

Sleep deprivation (SD) is a common feature in modern society. Prolonged sleep deprivation causes cognition deficits and depression-like behavior in the model of animal experiments. Endocannabinoid system are key modulators of synaptic function, which were related to memory and mood. Although the underlying mechanism remains unknown, several studies indicated the benefits of polyunsaturated fatty acids (PUFAs, linolenic acid, 39.7 %; linoleic acid, 28 %; and oleic acid, 22 %) on brain function through the endocannabinoid system. The present study aimed to evaluate the influence of dietary PUFAs on cognition deficits induced by sleep deprivation in Sprague Dawley rats. The rats were sleep deprivation continuously for 7 days and fed with PUFAs at three different dosages (2, 4 and 8 μl/g body weight) at the meantime. The effect of PUFAs on cognition was investigated by object recognition test while depressive-like behavior were detected using sucrose preference test and forced swim test. The mechanism of PUFAs was elucidated by hippocampal synaptic transmission analyses. The resluts revealed that SD led to the disorder of cognition and mood which was improved by the supplement of PUFAs. SD significantly increased the mEPSC frequency, and decreased the protein level of cannabinoid type-1 receptors (CB1R). These changes were restored by supplement of PUFAs, which showed a similar level to the control group. Behaviour tests showed that the positive effects on repairing cognition and anxiety disorders were almost completely abolished when the CB1R receptor antagonist rimonabant was applied to the SD rats. These findings indicated that PUFAs are a factor regulating cognition deficits and depression induced by SD via cannabinoid type-1 receptors.

Tillage depth measuring is essential in modernization of agricultural production, including tillage depth, seed germination, plant growth and soil conservation. At present, there are no reliable measuring method or equipment for on-line tillage depth data acquisition. To solve this problem, equipment for real-time measuring tillage depth was designed based on ultrasonic sensing technology. This system comprises mainly mechanical constructions, hardware structure, software, specific measurement process and data processing technology. To improve the measuring accuracy, Kalman filter method is used to reduce the influence of uneven surface, weed, and stubble in field. This device was installed on subsoiler, and a field test was conducted. The test results show that: The accuracy of the ultrasonic measuring depth is comparable with the manual measuring method in the field condition of ploughed field, bare field and stubble field.

The non-cooperative target pose measurement has become an essential key technology for the space manipulation activities such as capture of the fault spacecrafts, on-orbit debris removal and so on. A new pose measurement of non-cooperative target based on point cloud is proposed in this paper, including preprocess of point cloud data, recognition of solar panels, position and attitude measurement based on identified solar panels. The simulation experiments are carried out on several different types of spacecraft and the results show that the method is reasonable and feasible. Compared with the traditional overall pose measurement, our method has better speed and accuracy. Compared with the traditional method using two-dimensional image, our method is less affected by illumination and robust. Our method of pose measurement meets the requirement of on-orbit service and has great reference value for the engineering application.

Planet gear mechanism can transform rotary motion into reciprocating linear motion with high efficiency, high accuracy, stability, and reliability. Its application in combine harvester cutter can improve cutting performance significantly and reduce harvest losses of the cutting process. This paper builds the parametric 3D model of the planet gear mechanism for realizing automatism modeling of variable basic parameters with Creo software. Using virtual prototype technology, this paper imports the model into ADAMS software and implements kinematic simulation analysis, getting the characteristic curve of key moving components displacement, velocity, and acceleration. The results can provide effective parameters and helps for design of the planet gear mechanism and its application on the combine harvester cutter.

Ring-type yield loss at wafer edge has been observed during flip-chip packaging process. The failure mechanism is attributed to the scrubber clean process step which generates a lot of charges. This in turn behaves like an electrostatic discharge (ESD) event and damages gate oxide of internal circuits. An equivalent circuit is proposed to analyze such a kind of ESD event and proves the importance of the parasitic capacitance of the interconnect metal.

In this paper, the impact of ball bonding (BB) induced voltage transient on the reliability test including electro-migration (EM), time dependent dielectric breakdown (TDDB), negative bias temperature instability (NBTI) and electro-static discharge (ESD) are investigated. During the electronic flame-off (EFO) of ball bonding process, a spark discharge current, which applies a high electric field between the wire and wand, is used to melt the wire to form a free air ball (FAB). In the mean time, however, the spark may generate ions in the air and some of them may charge to die for package. After free air ball was bonded to pad, a BB-induced voltage transient can be measured and may impose an electrical stress to devices, then to degrade the device lifetime if without suitable I/O protection circuits. The degradation mechanism can be considered as charge device model (CDM) electrostatic-discharge (ESD) event. To remove or reduce this package-induced damage, ionizers had been put closely to the bonding tool and showed very good package yield, compared to those without ionizer.