The application of advanced technologies for engine efficiency improvement and emissions reduction also increase the occurrence possibility of abnormal combustions such as incomplete combustion, misfire, knock or pre-ignition. Novel promising combustion modes, which are basically dominated by chemical reaction kinetics show a major difficulty in combustion control. The challenge in precise combustion control is hard to overcome by the traditional engine map-based control method because it cannot monitor the combustion state of each cycle, hence, real-time cycle-resolved in-cylinder combustion diagnosis and control are required. In the past, cylinder pressure and ion current sensors, as the two most commonly used sensors for in-cylinder combustion diagnosis and control, have enjoyed a seemingly competitive relationship, so all related researches only use one of the sensors. However, these two sensors have their own unique features. In this study, the idea is to combine the information obtained from both sensors. At first, two kinds of ion current detection system are comprehensively introduced and compared at the hardware level and signal level. The most promising variant (the DC-Power ion current detection system) is selected for the subsequent experiments. Then, the concept of ion current/cylinder pressure cooperative combustion diagnosis and control system is illustrated and implemented on the engine prototyping control unit. One application case of employing this system for homogenous charge compression ignition abnormal combustion control and its stability improvement is introduced. The results show that a combination of ion current and cylinder pressure signals can provide richer and also necessary information for combustion control. Finally, ion current and cylinder pressure signals are employed as inputs of artificial neural network (ANN) models for combustion prediction. The results show that the combustion prediction performance is better when the inputs are a combination of both signals, instead of using only one of them. This offline analysis proves the feasibility of using an ANN-based model whose inputs are a combination of ion current and pressure signals for better prediction accuracy.
Fuzzy weighting technique is carried out and applied to motion control of an amphibious hovercraft to resolve the motion control problem with navigation characteristic change greatly. Multiple models are constituted to cover the navigation characteristic variety bring by ship speed change. Controllers are designed for every speed point respectively, and fuzzy rules figure out controller weight to realize smooth switch between these controllers. Simulation tests show that, when speed of amphibious hovercraft changes in wide range, the controller designed based on fuzzy weighting has good performance in motion control. And the method will not bring controller's output jump, which is exist in general switch control.
During the COVID-19 pandemic, organizations need to effectively manage changes, and employees need to proactively adapt to these changes. The present research investigated when and how individual employees' narcissism was related to their change-oriented organizational citizenship behavior. Specifically, based on a trait activation perspective, this research proposed the hypotheses that individual employees' narcissism and environmental uncertainty would interactively influence employees' change-oriented organizational citizenship behavior via felt responsibility for constructive change; furthermore, the effect of narcissism on change-oriented organizational citizenship behavior via felt responsibility for constructive change would be stronger when the environmental uncertainty prompted by the COVID-19 pandemic was high rather than low. Two studies were conducted to test these hypotheses: an online survey of 180 employees in mainland China (Study 1) and a field study of 167 leader-follower dyads at two Chinese companies (Study 2). The current research reveals a bright side of narcissism, which has typically been recognized as a dark personality trait, and enriches the understanding of the antecedents of change-oriented organizational citizenship behavior. This research can also guide organizations that wish to stimulate employee proactivity.
Because private equity investment is characterized by non-public and non-transparent, it has many risks in its operation. The article focuses on reviewing the investment risk management of private equity funds, pointing out that phased investment and contractual investment can reduce the moral risk in investment to a certain extent. This article categorizes the common risks of private equity fund investment in China, then discusses the main risks, and puts forward corresponding preventive and management measures for these problems, which aims to further promote the benign development of the private investment industry.
To investigate the airborne pollen concentration in Beijing city during autumn and to grade the Artemisia pollen concentration.Burkard volumetric trap was used to sample the airborne pollen in Beijing city from August 1st 2007 to October 10th 2007. Patients only allergic to mugwort pollen were followed up, and their symptom scores and the mugwort pollen concentration were analyzed statistically.1) Mugwort and Humulus (including Cannabis Sativa L) were the main airborne pollen during August and September in Beijing city, accounting for 31% and 51%, respectively; 2) Mugwort pollen season was from 8th August to 8th October; 3) The daily peak concentration of Mugwort pollen was 267 g/m3, with an average of 71 g/m3, the daily peak concentration of Humulus pollen was 672 g/m3, with an average of 124 g/m3; 4) 88.5% out-patients suffering from hay fever or asthma during Autumn were allergic to mugwort, 28.2% allergic to Humulus; 5) the grading of airborne Mugwort pollen concentration: 0-14 g/m3 as grade 0, 15-40 g/m3 as grade I, 41-116 g/m3 as grade II, more than 117 g/m3 as grade III.It was the first time that Burkard volumetric sampler was employed in monitoring Mugwort and Humulus concentration in Beijing city. Average concentration of mugwort pollen was about 100 g/m3, and concentration grade III of mugwort pollen was distributed during the last ten days of August and the beginning of September.
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