Impact of Tactical Parameters of Aircraft on Jamming Effectiveness of Surface-Source IR Decoy

As the platform for surface-source infrared decoys,the target aircraft is the aim of attacks in air-to-air combat.It can quickly and accurately evaluate the jamming effectiveness of the surface-source IR decoy in various states of motion is important for enhancing the security of the aircraft.This paper proposes a model of surface-source IR decoy,and compares and analyzes simulated and measured infrared images of diffusion.A system to assess the effectiveness of the jamming of the surface-source IR decoy,target aircraft,and infrared guided missile called“Trinity”is established.Simulations were conducted to assess the impact of flight height,flight speed,and the maneuvering of the target aircraft on the jamming effectiveness of the surface-source IR decoy.The results show that with an increase in flight height and speed,the jamming probability of a surface-source IR decoy first increases and then decreases,where evasive maneuvering by the target aircraft can effectively improve this probability.When the radius of the vertical snake maneuver was 125 m,that of the horizontal snake maneuver was 200 m,and the radius of the barrel roll maneuver was 250 m,the jamming probability of the surface-source IR decoy was relatively high.By comparing the simulation results with measured data,the study verified the accuracy of the proposed method.

Experimental study on influence of boundary on location of maximum velocity in open channel flows

The velocity dip phenomenon may occur in a part of or in the whole flow field of open channel flows due to the secondary flow effect. Based on rectangular flume experiments and the laser Doppler velocimetry, the influence of the distance to the sidewall and the aspect ratio on the velocity dip is investigated. Through application of statistical methods to the experimental results, it is proposed that the flow field may be divided into two regions, the relatively strong sidewall region and the relatively weak sidewall region. In the former region, the distance to the sidewall greatly affects the location of maximum velocity, and, in the latter region, both the distance to the sidewall and the aspect ratio influence the location of the maximum velocity.

Doping Copper Ions in a Metal-Organic Framework(UiO-66-NH2):Location Effect Examined by Ultrafast Spectroscopy

We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while in the latter,Cu^2+ions are incorporated to form a bimetal-center MOF,with Zr^4+being partially replaced by Cu2+in the Zr-O oxo-clusters.Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cudoped MOFs relative to undoped one,but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2.Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs.These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system,further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.

Accurate Fault Location Modeling for Parallel Transmission Lines Considering Mutual Effect

:A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system(TPTLS)as influenced by the mutual effect to determine the fault location is discussed in this work.The distance relay measures the impedance to the fault location which is the positive-sequence.The principle of summation the positive-,negative-,and zero-sequence voltages which equal zero is used to determine the fault location on the TPTLS.Also,the impedance of the transmission line to the fault location is determined.These algorithms are applied to single-line-to-ground(SLG)and double-line-to-ground(DLG)faults.To detect the fault location along the transmission line,its impedance as seen by the distance relay is determined to indicate if the fault is within the relay’s reach area.TPTLS under study are fed from one-and both-ends.A schematic diagrams are obtained for the impedance relays to determine the fault location with high accuracy.

Correlation between current intensity and effective duration in the treatment of botulinus toxin for cerebral palsy by myoelectricity locating

BACKGROUND： Researches prove that the treatment of cerebral palsy by botulinus toxin （BTX-A） can improve effect and prolong effective duration. Current intensity is the important factor during injection. OBJECTIVE： To observe the changes of motor function and muscular intensity of children with spastic cerebral palsy after injecting BTX-A and analyze correlation between current intensity and effective duration. DESIGN： Cases control trial before and after nerves block SETTING： Capital University of Medical Sciences, China Rehabilitation Research Center PARTICIPANTS： From June 2002 to November 2004, 14 children with spastic cerebral palsy were treated by BTX-A block. All children were hospitalized in the Children Rehabilitation Department of China Rehabilitation Research Center. The children included 9 male and 5 female, and ranged from 4 to 13 years old, and average age was （6±2） years. Muscular tension ranged from grade 1 to grade 3. The diagnosis and the tape of cerebral palsy based on standard of the Fist Nationwide Cerebral Palsy Symposium, and all children were diagnosed with electroencephalogram （EEG）, CT and MRI, and permitted by their guardians. METHODS： （1） Locating and calculation： To locate block points by G6805-2A electro-therapeutic apparatus （Shanghai Huayi Electronic Instrument Plant） at the least stimulating current （continuous wave; impulse frequency; 2.667-83.333 Hz; current intensity： 0-6 mA; voltage： 6 V） to touch off muscles contraction. The current intensity of each point was recorded, and the average current intensity of each patient was calculated at the same time. （2） Dose of BTX-A： Basing upon the spastic degree and weight of patients, the dose was made certain： dose （IU）=（scores of Modified Ashworth Scale ＋2.5） xweight （kg）. The number of the block points was in all 4. The dose of injection ranged from 50 IU to 160 IU with the average of （73.6＋25.8） IU. The BTX-A was made by Lanzhou Institute of Biological Products, and each bottle contains 100 IU BTX-A. Muscular tension was evaluated by Modified Ashworth Scale. The scale ranged from grade 0 to grade 4, and the scores were from 0 to 4. The higher the scores were, the higher the muscular tension was. （3） Effect： Changes of muscular tension were evaluated by modified Ashworth Scale before and after block. Motor function was evaluated by Physician Rating Scale （PRS） before and after treatment. It contained Gait pattern, Hindfoot （ankle） position （stance-floor contact）, Hindfoot position （foot strike）, Knee position （degree of recurvation）, Crouch and Speed of gait. The scores ranged from 0 to 14. The higher the points were, the better the motor function was. （4） Effective duration： The duration was definited by the recovering of the Modified Ashworth Scale. （5） Statistic analysis： Firstly, the current intensity and the effect duration were analyzed by One-Sample Kolmogorov-Smirnov Test, the current intensity： Z= 0.456, P= 0.985, the effective duration： Z= 0.557, P= 0.915. Both data were normal distribution. Secondly, both data were analyzed by Linear Regression. The efficiency of the BTX-A block was analyzed by paired-samples t test. MAIN OUTCOME MEASURES： （1） Changes of motor function of muscular tension; （2） correlation between current intensity and effective duration. RESULTS： Fourteen children with spastic cerebral palsy were all involved in the final analysis. （1） Therapeutic effect： The average score of Ashworth scale after block was lower than that before block [（1.02±0.34） points vs. （2.12±0.48） points, t= 3.644, P〈 0.01]. The average score of RPS after block was higherthan that before block [（9.75±2.78） points vs. （6.16±0.58） points, t =13.222, P〈 0.01]. （2） Relation between the current intensity and the effective duration： The current intensity was （0.1857±0.0506） mA, and the effective duration was （26.36±4.48） weeks. The current intensity was negative correlation with effective duration （r = -0.775, P = 0.01 ）. CONCLUSION： （1） BTX-A occlusion can decrease muscular tension and improve motor function of lower limbs of children with spastic cerebral palsy. （2） The lower the current intensity is, the longer the effective duration is.

A Class of Chaotic Sequences with Gauss Probability Distribution for Radar Mask Jamming

A simple generation approach for chaotic sequences with Gauss probability distribution is proposed. Theoretical analysis and simulation based on Logistic chaotic model show that the approach is feasible and effective. The distribution characteristics of the novel chaotic sequence are comparable to that of the standard normal distribution. Its mean and variance can be changed to the desired values. The novel sequences have also good randomness. The applications for radar mask jamming are analyzed.

带邻近作用的高增益率co-location模式挖掘

大多数空间co-location模式挖掘将距离阈值作为衡量不同对象实例间邻近关系的标准,进而挖掘出频繁co-location模式,并没有考虑具有邻近关系的实例间的相互影响和模式的增益率问题。在空间co-location模式挖掘过程中,引入实例间的相互作用率和对象的季均收益,定义了对象作用率、套间总收益和增益率等概念,并提出挖掘高增益率co-location模式的基础算法(NAGA)和有效的剪枝算法(NAGA_JZ)。最后通过大量的实验来验证基础算法的正确性和实用性,并对基础算法和剪枝算法的挖掘效率进行了对比,验证了剪枝算法的高效性。

通信干扰信道和功率智能决策算法

智能干扰是一种利用环境反馈自主学习干扰策略,对敌方通信链路进行有效干扰的技术。然而,现有的智能干扰研究大多假设干扰机能够直接获取通信质量反馈(如误码率或丢包率),这在实际对抗环境中难以实现,限制了智能干扰的应用范围。为了解决这一问题,该文将通信干扰问题建模为马尔科夫决策过程(MDP),综合考虑干扰基本原则和通信目标行为变化制定干扰效能衡量指标,提出了一种改进的策略爬山算法(IPHC)。该算法按照“观察(Observe)-调整(Orient)-决策(Decide)-行动(Act)”的OODA闭环,实时观察通信目标变化,灵活调整干扰策略,运用混合策略决策,实施通信干扰。仿真结果表明,在通信目标采用确定性规避策略时,所提算法能够较快收敛到最优干扰策略,并且其收敛耗时较Q-learning算法至少缩短2/3;当通信目标变换策略时,能够自适应学习,重新调整到最优干扰策略。在通信目标采用混合性规避策略时,所提算法也能够快速收敛,取得较优的干扰效果。

一种基于目标RCS起伏模型的雷达干扰效果评估方法

目前,在雷达干扰效果评估的相关研究中,大多将雷达探测目标的雷达截面积(RCS)设为常数。实际上,目标的RCS是起伏的,会影响干扰效果。基于此,论文中提出了一种基于RCS起伏模型的雷达干扰效果评估方法,通过理论分析得到了目标RCS起伏条件下的干信比概率密度函数模型,进而推导提出了目标RCS起伏条件下的有效干扰概率模型,并运用该模型对不同场景下的干扰效果进行了仿真评估,为干扰策略优化提供了有效支撑。

基于改进混合密度网络的毁伤效应预测方法

提出一种基于改进混合密度神经网络的毁伤效应预测方法,解决了现有智能毁伤效应预测方法中仅能输出点预测结果,但难以量化毁伤效应预测结果的不确定性问题。采用鲁棒性更好的t分布作为混合分量,利用混合密度网络生成概率密度函数,以反映毁伤效应预测中的不确定性,并根据给定置信水平获得区间预测结果。仿真实验表明,获得的概率密度函数可以较为准确地拟合蒙特卡洛仿真模拟结果,与现有的毁伤效应预测方法相比,可以更好地指导作战筹划。

城市市场需求对企业布局的诱致影响研究

随着市场分工的不断深化,城市市场逐渐成为功能完备的独立市场单元。企业布局的区位选择是遵循利润最大化做出微观决策的空间分布结果,在不同城市市场中呈现差异化的布局特征。以2000—2021年304个城市的新注册企业与上市公司为研究对象,考察城市市场需求对企业布局的诱致影响、作用机制及区域异质性,并实证检验需求距离在其中的调节作用。实证结果表明:需求规模大的城市市场更有利于吸引新企业进入布局。机制分析表明,劳动力“蓄水池”、中间品共享和技术溢出效应是城市市场诱致企业布局的三个重要渠道。大规模城市、省会城市、东部城市及高度市场化城市的市场需求对于企业进入布局的诱致作用更强,具有典型的路径依赖性。针对此类城市,除招商优惠政策外,地方政府更需要考虑城市市场正外部性的综合理念提升市场环境,亟须防范新企业因模仿与重复布局导致的市场效率降低。需求距离的调节效应表明,城市市场需求中心对企业的诱致作用在6公里范围内显著。企业邻近城市中心的布局方式有利于要素获取,从而显著提高企业生存概率,但应注意防范城市市场的“拥挤效应”。因此,实施差异化的市场准入政策有利于各地城市市场发展的协调性与均衡性,有利于扩展城市市场需求规模以及推行招商优惠政策。

基于主动探测原理的直流配电线路短路故障测距

为克服对端系统助增作用的影响,实现直流配电线路短路故障的准确测距,提出一种主动探测式的故障测距原理。故障发生后,设计限流策略限制短路电流,进而切换至主动探测控制策略下,向直流线路注入特征频率探测信号。根据特征频率下故障等效电路的激励与响应特性,构建故障测距方程,实现了基于故障分析法的单端量故障测距。基于PSCAD电磁暂态仿真软件搭建了对应模型,仿真验证了不同故障位置和故障过渡电阻情况下测距原理的性能,采用特征频率探测信号构建测距方程,克服了对端电源助增作用的影响,测距结果的相对误差在0.5%以内。

乳腺组织定位标记夹在乳腺癌新辅助化疗中的应用效果

目的探讨乳腺组织定位标记夹在乳腺癌新辅助化疗中的应用效果。方法选取2020年8月至2022年8月九江市第一人民医院乳腺科收治的60例乳腺癌新辅助化疗患者作为研究对象,按照随机数字表法将患者分为对照组(30例)与试验组(30例),其中对照组在新辅助化疗后行术前导丝定位乳腺病灶,试验组则在新辅助化疗前放置乳腺组织定位标记夹,完成病灶定位后由同一治疗组医师进行手术治疗。对两组保乳手术率、保乳切缘阴性率、前哨淋巴结活检率、病理评估准确率进行比较,同时比较两组引流管留置时间、住院时间和住院费用。结果试验组保乳手术率、保乳切缘阴性率、前哨淋巴结活检率、病理评估准确率均高于对照组,差异有统计学意义(P<0.05);试验组手术时间、引流管留置时间和住院时间短于对照组,住院费用低于对照组,差异有统计学意义(P<0.05)。结论乳腺组织定位标记夹应用在乳腺癌新辅助化疗中,能精准定位乳腺原发灶及腋窝转移淋巴结,改善乳腺癌患者预后,可获得较好的社会和经济效益,在临床上值得应用和推广。

高重频激光对测距机干扰试验研究

高重频激光干扰是对脉冲式激光测距机的一种有效干扰手段,为探究高重频激光对测距机干扰效能的影响因素及规律,开展相关的理论分析与试验研究。试验研究了干扰激光的功率、重复频率及干扰距离对测距机干扰效能的影响。结果表明:存在一个与干扰激光频率相关的最小干扰距离,干扰激光的重复频率越高,最小干扰距离越小,有效干扰距离范围越大。当实际干扰距离大于最小干扰距离时,若干扰激光的功率不足,则无干扰效果;干扰成功后继续增大干扰激光功率,则被干扰后测距结果会趋于正态分布,且干扰激光功率越高,测距结果正态分布中心越趋近于最小干扰距离,但受干扰的测距结果最小值会始终分布于测距机盲区附近。

为什么大量高效率企业留在中小城市?——基于位置效应与异质性企业生产率的一个解释

针对现实中大量高效率企业留在中小城市这一与异质性区位理论预测明显矛盾的现象,本文提出位置效应假说,即高效率企业之所以留在中小城市是因为其在当地的经济地位排序更靠前,而靠前的位置排序在信号机制的作用下,使其能在融资、用工、上下游供应链中获得优势。本文基于中国工业企业数据的检验结果表明,以企业销售额为指标对城市内企业进行位置排序,排序靠前能显著提高企业的生产率。在控制企业规模、行业和城市自身特征等诸多因素,并通过构造复合工具变量控制内生性之后,结论仍然成立。本文结论为地区差别化优惠政策提供了理论支持,即在相对落后地区重点补贴位置排序靠前的企业,可以进一步增强该“位置”对高效率企业的吸引力,比均等补贴所有企业更有利于促进该地区的发展。

基于SDAE-SVM算法的雷达干扰方案在线决策方法

面向主动雷达型末制导干扰场景,提出了一种基于SDAE-SVM算法的雷达干扰方案在线决策方法。基于认知电子战机理构建在线干扰方案决策原理模型,包括雷达状态在线评估模块和干扰效果在线评估模块;区分有源压制干扰和有源欺骗干扰,分别构建雷达状态在线评估指标和干扰效果在线评估指标;建立雷达状态和干扰效果自适应评估流程,融合SDAE算法和SVM算法构建SDAE-SVM算法,用于干扰方案在线决策模型求解。通过仿真案例分析得出以下结论:本研究提出的雷达干扰方案在线决策方法准确率达到96.02%,同时与单独使用SDAE算法和SVM算法进行求解相比,采用SDAE-SVM算法求取的决策方案准确率最高,证明本研究方案可行。

基于复合导引头态势的抗干扰评估方法

针对雷达抗干扰效果评估中,抗干扰方获取评估信息困难、主观性强等问题,以主/被动复合导引头的态势变化为主线,基于主动导引头感知的位置态势和导引头本身的态势、主/被动导引头侦察到敌方有源干扰信号的态势信息,建立抗干扰评估指标体系。基于态势的麻雀搜索算法优化卷积神经网络(Sparrow Search Algorithm-Convolutional Neural Network, SSA-CNN)方法开展导引头抗干扰效果评估。在态势信息存在缺失时,采用卷积自编码器(Convolutional Auto-Encoder, CAE)完成非完备信息下的导引头抗干扰效果评估。仿真结果表明,在复杂干扰环境下的2种人工智能算法对导引头抗干扰评估均具有优秀的有效性和准确性。

基于概率推理的舷外有源诱饵干扰评估方法研究

针对电子对抗的非合作性和传统干扰效能评估方法的主观性,围绕舷外有源诱饵,提出了一种基于概率推理的干扰有效性评估方法。首先,由导弹末段制导动态过程推导干扰有效性判据,从信号层面与态势层面分析非合作参数作用。然后,基于概率推理原理,构建干扰有效性推理模型,阐述了干扰有效性评估内容。最后,通过数值仿真分析了正向推理和反向推理结果,并对不同诱饵干扰策略进行评估。仿真结果表明,利用概率推理可从未知参数中得到干扰有效性判据的概率分布,为舷外有源诱饵提供了量化且可扩展的干扰评估框架。

大倾角煤层中煤层气井压降传播规律

新疆局部地区煤层倾角可达50°,与水平煤层不同,大倾角煤层中流体受重力影响较大,且煤层气井压力传播规律具有特殊性,最佳排采井位有待优化。考虑地层水重力效应,建立了大倾角煤层单相排水阶段的压力传播模型,并验证了模型的正确性;计算了倾斜煤层中裂缝井在稳定渗流状态下的产水量,并优化了最佳排采井位;采用数值模拟方法,分别研究了单井和井组在非均质有界倾斜储层中的压力传播规律。结果表明,在倾角为45°的大倾角煤层中,排采井与上边界和下边界的距离之比为3∶1的位置为最佳排采井位;在定压排采模式下,下倾方向和上倾方向的压力下降幅度差别不大;在恒速降压排采模式下,上倾方向的压力下降幅度远远大于下倾方向的压力下降幅度。

余甘果酱的研制及其体外降脂功效研究

以余甘果、山楂为原料,辅以一定的荷叶、葛根、薏苡仁浸提液,研制一种具有降脂功效的余甘果酱。以感官评价、黏度、色差为评价指标,采用单因素及正交试验,确定余甘果酱的最佳配方,并研究其体外降脂功效。结果表明:以余甘果和山楂总质量为基准,余甘果酱最佳参数为余甘果和山楂质量比97∶3、木糖醇添加量30%、蜂蜜添加量22%、黄原胶添加量0.4%。体外降脂功效表明:余甘果酱对花生油的吸附量为9.82 mg/g,对胰脂肪酶能起一定的抑制作用,且随着浓度的增加抑制效果显著增大;余甘果酱在pH 7.0条件下对胆固醇的吸附量达176.08 mg/g。余甘果酱酸甜可口,有较好的降脂功效。