In order to study the effect of two-stage injection on two-stroke diesel engines, a well characterized research engine equipped with electronically controlled common rail system and scavenging system was constructed. ...In order to study the effect of two-stage injection on two-stroke diesel engines, a well characterized research engine equipped with electronically controlled common rail system and scavenging system was constructed. Through analysis of combustion and emissions, two-stage injection shows its advantages. Compared with the standard injection, it produces less emissions, while compared with single early injection, it expands engine operation range. Further experiments were carried out to study the influence of several injection control parameters on two-stage injection. The fuel in the first injection is used for forming homogeneous mixture. The fuel in the second injection keeps combustion, and it is the main source of smoke emissions. NO_x is formed in both combustion process caused by these two injections, and there is an optimum fuel allocation ration to produce minimum NO_x. The cylinder pressure decreases, and the combustion is depressed with the increasing of scavenging pressure. By optimizing the injection control parameters of two-stage injection, NO_x and smoke can be reduced beyond 30% simultaneously.展开更多
As a traditional writing instrument for calligraphy and painting, the Chinese brush has enjoyed a high reputation over the last 5,000 years due to its ability to controllably handle liquid ink, and has been widely use...As a traditional writing instrument for calligraphy and painting, the Chinese brush has enjoyed a high reputation over the last 5,000 years due to its ability to controllably handle liquid ink, and has been widely used to deposit ink into certain characters or figures as a means of cultural communication. In this mini-review, we first show how the key to the controllable liquid transfer in a Chinese brush lies in the anisotropic multi-scale structural features of the freshly emergent hairs. Then, drawing inspiration from this, applications in controllable liquid pumping, highly efficient liquid transfer and template-free printing microlines are addressed. We envision that the fundamentals of Chinese brushes and their applications in liquid manipulation mentioned in this review may also be extended to other liquid phase functional material systems.展开更多
基金The National Basic Research Program of China(973 Program)(No.2001CB209208)The National Science Foundation of China(No.50136040)
文摘In order to study the effect of two-stage injection on two-stroke diesel engines, a well characterized research engine equipped with electronically controlled common rail system and scavenging system was constructed. Through analysis of combustion and emissions, two-stage injection shows its advantages. Compared with the standard injection, it produces less emissions, while compared with single early injection, it expands engine operation range. Further experiments were carried out to study the influence of several injection control parameters on two-stage injection. The fuel in the first injection is used for forming homogeneous mixture. The fuel in the second injection keeps combustion, and it is the main source of smoke emissions. NO_x is formed in both combustion process caused by these two injections, and there is an optimum fuel allocation ration to produce minimum NO_x. The cylinder pressure decreases, and the combustion is depressed with the increasing of scavenging pressure. By optimizing the injection control parameters of two-stage injection, NO_x and smoke can be reduced beyond 30% simultaneously.
文摘As a traditional writing instrument for calligraphy and painting, the Chinese brush has enjoyed a high reputation over the last 5,000 years due to its ability to controllably handle liquid ink, and has been widely used to deposit ink into certain characters or figures as a means of cultural communication. In this mini-review, we first show how the key to the controllable liquid transfer in a Chinese brush lies in the anisotropic multi-scale structural features of the freshly emergent hairs. Then, drawing inspiration from this, applications in controllable liquid pumping, highly efficient liquid transfer and template-free printing microlines are addressed. We envision that the fundamentals of Chinese brushes and their applications in liquid manipulation mentioned in this review may also be extended to other liquid phase functional material systems.
