油管油压信号的载荷识别

在高速柴油发动机喷油系统性能检测中,一般以燃油压力信号作为喷油系统性能检测参量。通过对油压波形进行分析来判断喷油系统的工作状况,阐述了采用载荷识别技术识别油压信号的频谱特性,进而得到其时域波形的理论与方法,并在模拟试验中获得了识别结果。     

Dynamic institutionalization: the foundations of Japan’s radioactive problem

Many have suggested that the true purpose behind Japan’s development of a closed nuclear-fuel cycle is to maintain the technical potential to develop nuclear weapons. However, closer examination of the development of Japan’s nuclear industry shows that, although Japan possesses advanced nuclear technologies, there has been no deliberate strategy to create a nuclear-weapon option. There is no “nuclear hedge.” To illustrate this point, this article presents a framework called “dynamic institutionalization” to explain the origins of Japan’s nuclear policies and the different sets of institutionalized pressures and constraints that have perpetuated these policies over time. Japan’s continued development of closed fuel-cycle technologies is primarily driven by domestic politics and the lack of a permanent spent-fuel management solution. On the other hand, Japan’s institutionalized nuclear forbearance is driven by the calculation that, as long as US extended deterrence remains credible, Japan’s security is best guaranteed through reliance on the US nuclear umbrella. By analytically untangling the policy of closed fuel-cycle development from the rationale for nuclear forbearance, this article provides a more nuanced view of the relationships between the domestic and international variables shaping Japan’s nuclear policies.     

航空自导深弹攻潜命中概率分析

以航空自导深弹为研究对象,在分析反潜直升机攻潜过程的基础上,依据某型航空自导深弹的有关技术参数,首先建立了反潜直升机使用航空自导深弹攻潜模型,然后详尽分析了航空自导深弹攻潜作战中的各种源误差,采用解析法计算了反潜直升机在不同条件下投放航空自导深弹攻击潜艇时的单发命中概率,得出了反潜直升机空投航空自导深弹攻潜的使用方法.这对于部队使用航空自导深弹反潜有较高的参考价值.     

均匀设计在柴油无灰节能降污添加剂配方研制中的应用

基于低压氧弹燃烧法研究了充氧压力分别为0．6MPa和0．9MPa时两种无灰型柴油添加剂不同配比对助燃性能的影响。采用均匀实验设计和Matlab回归优化的方法,得到复配体系的最优配方,并对其进行了验证。结果表明,由Matlab回归分析得到的完全二次回归模型最理想,0．6MPa时由该模型得到的最优配方为：添加剂A和B的质量分数分别是0．300‰和0．700‰,并通过实验验证得到的发热量达到最大,变化率为8．697％。0．9MPa时,结合直观分析和回归分析,得到与实际相符的最优配方：添加剂A和B的质量分数分别是0．600‰和0．900‰,此时发热量皮化率为4．453％。     

A generic model of motor‐carrier fuel optimization

Fuel optimizers are decision models (software products) that are increasingly recognized as effective fuel management tools by U.S. truckload carriers. Using the latest price data of every truck stop, these models calculate the optimal fueling schedule for each route that indicates: (i) which truck stop(s) to use, and (ii) how much fuel to buy at the chosen truck stop(s) to minimize the refueling cost. In the current form, however, these models minimize only the fuel cost, and ignore or underestimate other costs that are affected by the models' decision variables. On the basis of the interviews with carrier managers, truck drivers, and fuel‐optimizer vendors, this article proposes a comprehensive model of motor‐carrier fuel optimization that considers all of the costs that are affected by the model's decision variables. Simulation results imply that the proposed model not only attains lower vehicle operating costs than the commercial fuel optimizers, but also gives solutions that are more desirable from the drivers' viewpoint. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

靴形喷油速率耦合预喷射对超高压共轨柴油机性能的影响

在介绍超高压共轨系统工作原理的基础上,基于GT-Power软件建立单缸超高压共轨柴油机的仿真模型,并利用试验验证模型的准确性,而后通过模型分析不同喷油速率、靴形喷油速率耦合不同预喷油量和靴形喷油速率耦合不同预喷提前角对超高压共轨柴油机动力性、经济性以及燃烧排放特性的影响。结果表明:通过调整超高压共轨系统中电控增压器电磁阀和喷油器电磁阀的开启时间,能够实现喷油速率的柔性可调。随着喷油速率从矩形变化到靴形,柴油机缸内压力、温度以及NO_x排放量均逐渐降低,而soot排放量逐渐升高,且靴形喷油速率可使柴油机获得最大的功率(扭矩)和最低的油耗率。靴形喷油速率耦合较小的预喷油量可以使柴油机获得更好的动力性、经济性和燃烧特性,但同时也会导致NO_x排放量的升高。靴形喷油速率耦合较大的预喷提前角有助于改善柴油机排放特性,但受到预喷油量的限制,效果并不明显。     

浅析储油罐安全容量的确定计算

由于油料具有热膨胀性,在运输和储存期间,如果油罐装油超过安全容量,当温度升高时,罐内油料体积膨胀,就可能导致溢油事故的发生,不仅造成油料数量的损失,甚至会引发火灾事故。正确确定不同油罐的安全容量,对油料的安全具有重要意义。文章阐述了油罐安全容量的概念,分析了安全容量计算不准确可能造成的危害,提出了油罐安全容量的计算方法。     

一种RetinaNet与SE融合的航空取证目标检测算法

针对在开展航空侦察取证时缺乏自动化、智能化取证手段的情况,提出了一种基于Reti-naNet与SE融合的航空取证目标检测算法,解决目标尺度变化大、数据集中类别不均衡的问题,并通过SE (squeeze-excitations)模块引入注意力机制进一步改进性能.该改进算法中的特征金字塔网络FPN可有效应对目标尺寸变化较大...     

基于响应面与遗传算法的柴油机喷射参数优化

为解决燃油喷射系统参数优化中高效寻求全局最优解问题,综合响应面设计和遗传算法的优点和不足,采用多项式响应面模型代替原始遗传算法中计算量庞大的目标特性分析模型,建立了多项式响应面模型和遗传算法相结合的参数优化方法。结合非线性规划的凸性分析证明了遗传算法在预定优化区间内全局最优解的唯一性。对优化匹配后的喷射参数进行了模拟计算,结果表明:优化后柴油机油耗降低了1.96g/(kW·h),功率上升了0.99%,排气温度降低了21.86℃。表明该方法具有简单可靠、优化效率高等特点。     

PDSC评定柴油氧化安定性

为研究一种操作简便、检测快速的柴油氧化安定性评定方法,采用高压差示扫描量热法(PDSC)对柴油氧化安定性进行评定,通过单因素变量法分析了升温速率、恒容氧压、试样量对柴油氧化安定性的影响,确定了3种因素水平分别为8~12℃/min,2.5~4.5 MPa,2.5~3.5 mg。通过正交试验法得出升温速率对柴油氧化安定性的影响最大,恒容氧压的影响最小。方差分析表明在升温速率为8℃/min,恒容氧压为3.5 MPa,试样量为3.0 mg时,试验方法的区分性最佳。在该试验条件下,考察了5种油样的重复性,结果表明PDSC法的重复性满足标准要求。