The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improv...The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improved algorithmal expressions for strap down attitude ut ilizing the angular increment output by the laser gyro from the last two and cur rent updating periods according to the number of gyro samples, and analyses the algorithm error in the classical coning motion. Compared with the conventional algorithms, simulational results show that this improved algorithm has higher precision. A new way to improve the rotation vector algorithms is provided.展开更多
An infrared （IR） imaging simulation framework based on the strap-down platform is proposed for midcourse ballistic targets. It overcomes the shortcoming of the existing algorithms, which cannot simulate IR imaging f...An infrared （IR） imaging simulation framework based on the strap-down platform is proposed for midcourse ballistic targets. It overcomes the shortcoming of the existing algorithms, which cannot simulate IR imaging from the entire midcourse process. The proposed framework includes three steps, target characteristic modeling, motion modeling, and imaging modeling. In imaging modeling, the staring focal plane is taken into account due to its wide employment. In order to obtain IR images of high fidelity, especially that the fluctuation of the target signal-to-noise ratio （SNR） is reasonably similar to the actual one, this paper proposes an improved IR imaging simulation method. The proposed method considers two critical factors of the pixel plane, occupy-empty ratio and defect elements, which affect the imaging of targets markedly but are neglected in previous work. Finally, the IR image sequence of high fidelity is obtained. And the correlative parameters of simulation can be set according to the given scene. Thus the generated images can satisfy the needs of algorithms validation for tracking and recognition.展开更多
Attitude pursuit guidance law is suitable for low cost missiles.A strap-down seeker is used to achieve this guidance law.The additional angles of attack or sideslip caused by wind and by control system are considered ...Attitude pursuit guidance law is suitable for low cost missiles.A strap-down seeker is used to achieve this guidance law.The additional angles of attack or sideslip caused by wind and by control system are considered as two disturbing factors which make attitude pursuit law impossible.Therefore,general attitude pursuit guidance law did not account for this two disturbing factors,because with those disturbing factors,it is difficult to apply.To solve the problem,the principle of strap-down seeker detecting target is investigated,the mathematical control model is established,then a modified attitude pursuit guidance law which employs the angular correction for those two disturbing factors is presented.It is proved that the modified attitude pursuit guidance law is appropriated to both in the presence of the additional angle of attack or sideslip via the simulations with the mathematical control model and Monte-Carlo method.展开更多
In the strap-down TV guidance system, the line-of-sight（LOS） rate can not be obtained frora the measured information, the math platform to select missile attitude information must be set up. The LOS rate selecting m...In the strap-down TV guidance system, the line-of-sight（LOS） rate can not be obtained frora the measured information, the math platform to select missile attitude information must be set up. The LOS rate selecting models based on the missile attitude angle and the rate gyro are set up, the influencing factor and the extracting precision of LOS rate are emulated and analyzed.展开更多
Paper products such as corrugated paperboards are the most common green packaging materials, which are renewable, sustainable, recyclable and biodegradable. However, the plastic or metal straps used to secure the cart...Paper products such as corrugated paperboards are the most common green packaging materials, which are renewable, sustainable, recyclable and biodegradable. However, the plastic or metal straps used to secure the carton boxes are not so green. At the end of packaging, the carton boxes can be recycled, but the plastic/metal straps have to be sorted out for disposal separately. This review focuses on: 1) the global trend of green packaging;2) conventional plastic/metal strapping materials for carton boxes;3) conventional market pulp baling with steel wire as the tying materials;4) cellulose fiber-based materials for strapping market pulp bales and carton boxes. New generation of cellulose paper straps are being developed for more challenging applications with superior strength properties and repulpability.展开更多
自经典的QWERTY键盘推出后,有许多设计巧妙的产品不断推出,从看似老式打字机的彩色设备,到可折叠成棍状物的东西。那么有没有可以完全取代键盘的可穿戴设备呢？这又要另当别论了。Tap Systems Inc。的团队发明了一种名为Tap Strap的新...自经典的QWERTY键盘推出后,有许多设计巧妙的产品不断推出,从看似老式打字机的彩色设备,到可折叠成棍状物的东西。那么有没有可以完全取代键盘的可穿戴设备呢？这又要另当别论了。Tap Systems Inc。的团队发明了一种名为Tap Strap的新型可穿戴设备,可以让你将世界变成一个巨大的键盘。该指套有五个放置手指的孔,展开更多
In advanced nuclear fuel design, the outer strap of a spacer grid plays an important role on fuel assembly mechanical and thermal-hydraulic performance, e.g., precluding the risk of hang-up and improvement on the mixi...In advanced nuclear fuel design, the outer strap of a spacer grid plays an important role on fuel assembly mechanical and thermal-hydraulic performance, e.g., precluding the risk of hang-up and improvement on the mixing of the coolant. The communication of the outer strap affects the hydraulic force exerted by the spacer grid of the fuel assembly which could induce fuel assembly bow. In present study, in order to understand the influencing factors of hydraulic force exerted by the spacer grid, outer straps with various flow opening design features, different location and size are investigated by a commercially CFD （computational fluid dynamics） code, ANSYS CFX 12.1. Three dimensional rod bundles including the outer strap without and with different openings are modelled for simulation. The analysis results show that the openings on the spacer grid outer strap can reduce the lateral hydraulic loadings perpendicular to the centerline of the fuel rods exerted by the spacer grids obviously because of the pressures inside and outside the spacer grids being balanced. Besides, influences of the opening design features on the hydraulic force, resistance characteristics and lateral flow factor are investigated in details.展开更多
This article focuses on comparing the internationalstandards of steel strapping,primarily the US Standard (ASTMD3953-02),European Standard (EN 13246) and the Baosteel Standard(Q/BQB908-2006).Based on the analysis of t...This article focuses on comparing the internationalstandards of steel strapping,primarily the US Standard (ASTMD3953-02),European Standard (EN 13246) and the Baosteel Standard(Q/BQB908-2006).Based on the analysis of the realities of manufactur-ing and trade systems in China,the article discusses modifying the Chi-nese Standard of steel strapping,an issue which is very urgent and im-portant to the healthy and rapid development of the steel strapping in-dustry domestically and internationally.展开更多
文摘The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improved algorithmal expressions for strap down attitude ut ilizing the angular increment output by the laser gyro from the last two and cur rent updating periods according to the number of gyro samples, and analyses the algorithm error in the classical coning motion. Compared with the conventional algorithms, simulational results show that this improved algorithm has higher precision. A new way to improve the rotation vector algorithms is provided.
文摘An infrared （IR） imaging simulation framework based on the strap-down platform is proposed for midcourse ballistic targets. It overcomes the shortcoming of the existing algorithms, which cannot simulate IR imaging from the entire midcourse process. The proposed framework includes three steps, target characteristic modeling, motion modeling, and imaging modeling. In imaging modeling, the staring focal plane is taken into account due to its wide employment. In order to obtain IR images of high fidelity, especially that the fluctuation of the target signal-to-noise ratio （SNR） is reasonably similar to the actual one, this paper proposes an improved IR imaging simulation method. The proposed method considers two critical factors of the pixel plane, occupy-empty ratio and defect elements, which affect the imaging of targets markedly but are neglected in previous work. Finally, the IR image sequence of high fidelity is obtained. And the correlative parameters of simulation can be set according to the given scene. Thus the generated images can satisfy the needs of algorithms validation for tracking and recognition.
文摘Attitude pursuit guidance law is suitable for low cost missiles.A strap-down seeker is used to achieve this guidance law.The additional angles of attack or sideslip caused by wind and by control system are considered as two disturbing factors which make attitude pursuit law impossible.Therefore,general attitude pursuit guidance law did not account for this two disturbing factors,because with those disturbing factors,it is difficult to apply.To solve the problem,the principle of strap-down seeker detecting target is investigated,the mathematical control model is established,then a modified attitude pursuit guidance law which employs the angular correction for those two disturbing factors is presented.It is proved that the modified attitude pursuit guidance law is appropriated to both in the presence of the additional angle of attack or sideslip via the simulations with the mathematical control model and Monte-Carlo method.
文摘In the strap-down TV guidance system, the line-of-sight（LOS） rate can not be obtained frora the measured information, the math platform to select missile attitude information must be set up. The LOS rate selecting models based on the missile attitude angle and the rate gyro are set up, the influencing factor and the extracting precision of LOS rate are emulated and analyzed.
文摘Paper products such as corrugated paperboards are the most common green packaging materials, which are renewable, sustainable, recyclable and biodegradable. However, the plastic or metal straps used to secure the carton boxes are not so green. At the end of packaging, the carton boxes can be recycled, but the plastic/metal straps have to be sorted out for disposal separately. This review focuses on: 1) the global trend of green packaging;2) conventional plastic/metal strapping materials for carton boxes;3) conventional market pulp baling with steel wire as the tying materials;4) cellulose fiber-based materials for strapping market pulp bales and carton boxes. New generation of cellulose paper straps are being developed for more challenging applications with superior strength properties and repulpability.
文摘自经典的QWERTY键盘推出后,有许多设计巧妙的产品不断推出,从看似老式打字机的彩色设备,到可折叠成棍状物的东西。那么有没有可以完全取代键盘的可穿戴设备呢？这又要另当别论了。Tap Systems Inc。的团队发明了一种名为Tap Strap的新型可穿戴设备,可以让你将世界变成一个巨大的键盘。该指套有五个放置手指的孔,
文摘In advanced nuclear fuel design, the outer strap of a spacer grid plays an important role on fuel assembly mechanical and thermal-hydraulic performance, e.g., precluding the risk of hang-up and improvement on the mixing of the coolant. The communication of the outer strap affects the hydraulic force exerted by the spacer grid of the fuel assembly which could induce fuel assembly bow. In present study, in order to understand the influencing factors of hydraulic force exerted by the spacer grid, outer straps with various flow opening design features, different location and size are investigated by a commercially CFD （computational fluid dynamics） code, ANSYS CFX 12.1. Three dimensional rod bundles including the outer strap without and with different openings are modelled for simulation. The analysis results show that the openings on the spacer grid outer strap can reduce the lateral hydraulic loadings perpendicular to the centerline of the fuel rods exerted by the spacer grids obviously because of the pressures inside and outside the spacer grids being balanced. Besides, influences of the opening design features on the hydraulic force, resistance characteristics and lateral flow factor are investigated in details.
文摘This article focuses on comparing the internationalstandards of steel strapping,primarily the US Standard (ASTMD3953-02),European Standard (EN 13246) and the Baosteel Standard(Q/BQB908-2006).Based on the analysis of the realities of manufactur-ing and trade systems in China,the article discusses modifying the Chi-nese Standard of steel strapping,an issue which is very urgent and im-portant to the healthy and rapid development of the steel strapping in-dustry domestically and internationally.
