Separativity and Stable Range for Formal Triangular Matrix Rings

In this paper we study the formal triangular matrix ring T =and give some necessary and sufficient conditions for T to be (strongly) separative, m-fold stable and unit 1-stable. Moreover, a condition for finitely generated projec-tive T-modules to have n in the stable range is given under the assumption that A and B are exchange rings.

Immediate Knee Joint Range of Motion after Stable Fixation of Tibial Plateau Fractures

The purpose of this study was to evaluate factors that affect initiation of early postoperative range of motion (ROM) rehabilitation and to investigate whether the postoperative ROM and clinical outcomes were affected by initiation of early ROM, immobilization and other factors. We conducted a retrospective analysis of tibial plateau fractures treated using stable internal fixation between December 2003 and June 2007. The resulting degree of flexion and Rasmussen Clinical and Radiographic Scores were evaluated. Thirty-nine patients were included, and 23 patients underwent a lateral submeniscal arthrotomy for evaluation of joint surface reduction, with 6 lateral meniscus lesions identified via arthrotomy. Three lateral collateral ligament lesions, 3 medial collateral ligament lesions and 1 anterior cruciate ligament lesion were found. Meniscus and ligament lesions significantly and negatively affected the initiation of knee joint ROM. Early ROM was achieved in 26 cases and 13 patients underwent immobilization for 4 weeks. At the final evaluation, the early ROM group had 130.42° ± 5.50° of flexion, compared with 122.92° ± 5.28° in the immobilization group. Moreover, the final Rasmussen score was 25.69 ± 2.92 in the early motion group, compared with 22.61 ± 3.5 in the immobilization group. There was no difference between radiographic scores of the groups. Although the initiation of early ROM improved the clinical results, soft tissue lesions influenced initiation of early knee joint motion. Therefore, meniscus and ligament injuries should be considered as prognostic factors in similar cases.

Geology, Mineralization, Fluid Inclusion and Stable Isotope of the Early Cretaceous Sn and Associated Metal Deposits in the Southern Great Xing’an Range, NE China: A Review

The Southern Great Xing’an Range(SGXR) hosts a number of Early Cretaceous Sn and associated metal deposits, which can be divided into three principal types according to their geological characteristics: skarn type deposits, porphyry type deposits and hydrothermal vein type deposits. Fluid inclusion assemblages of different types of deposits are quite different, which represent the complexities of metallogenic process and formation mechanism. CH4 and CO2 have been detected in fluid inclusions from some of deposits, indicating that the ore-forming fluids are affected by materials of Permian strata. Hydrogen and oxygen isotope data from ore minerals and associated gangue minerals indicate that the initial ore fluids were dominated by magmatic waters, some of which had clearly exchanged oxygen with wall rocks during their passage through the strata. The narrow range for the δ34S values presumably reflects the corresponding uniformity of the ore forming fluids, and these δ34S values have been interpreted to reflect magmatic sources for the sulfur. The comparation between lead isotope ratios of ore minerals and different geological units’ also reveals that deeply seated magma has been a significant source of lead in the ores.

Stable-range Approach to the （2＋1）-dimensional Breaking Soliton and Kadomtsev-Petviashvili Equations

By using Xu's stable-range method,families of explicit exact solutions with multiple parameter functions for the(2+1)-dimensional breaking soliton and KadomtsevPetviashvili equations.These parameter functions make our solutions more applicable to related practical models and boundary value problems.

Long range migration of rice planthoppers and associated meteorological conditions in Yulin,Ganzhou,and Huangyan

In recent years,it has been demonstrated that thelow-level jet streams(LLJs)developed in thesouth of the Meiyu(Baiu)front play a critical role inthe overseas migrations of the planthoppers intoJapan and Korea. However, the involement of theLLJs during the process of sequential displacements

Impact of Typical Steady-state Conditions and Transient Conditions on Flow Ripple and Its Test Accuracy for Axial Piston Pump

The current research about the flow ripple of axial piston pump mainly focuses on the effect of the structure of parts on the flow ripple. Therein, the structure of parts are usually designed and optimized at rated working conditions. However, the pump usually has to work in large-scale and time-variant working conditions. Therefore, the flow ripple characteristics of pump and analysis for its test accuracy with respect to variant steady-state conditions and transient conditions in a wide range of operating parameters are focused in this paper. First, a simulation model has been constructed, which takes the kinematics of oil film within friction pairs into account for higher accuracy. Afterwards, a test bed which adopts Secondary Source Method is built to verify the model. The simulation and tests results show that the angular position of the piston, corresponding to the position where the peak flow ripple is produced, varies with the different pressure. The pulsating amplitude and pulsation rate of flow ripple increase with the rise of pressure and the variation rate of pressure. For the pump working at a constant speed, the flow pulsation rate decreases dramatically with the increasing speed when the speed is less than 27.78% of the maximum speed, subsequently presents a small decrease tendency with the speed further increasing. With the rise of the variation rate of speed, the pulsating amplitude and pulsation rate of flow ripple increase. As the swash plate angle augments, the pulsating amplitude of flow ripple increases, nevertheless the flow pulsation rate decreases. In contrast with the effect of the variation of pressure, the test accuracy of flow ripple is more sensitive to the variation of speed. It makes the test accuracy above 96.20% available for the pulsating amplitude of pressure deviating within a range of ~6% from the mean pressure. However, with a variation of speed deviating within a range of ±2% from the mean speed, the attainable test accuracy of flow ripple is above 93.07%. The model constructed in this research proposes a method to determine the flow ripple characteristics of pump and its attainable test accuracy under the large-scale and time-variant working conditions. Meanwhile, a discussion about the variation of flow ripple and its obtainable test accuracy with the conditions of the pump working in wide operating ranges is given as well.

On use of the alpha stable self-similar stochastic process to model aggregated VBR video traffic

The alpha stable self-similar stochastic process has been proved an effective model for high variable data traffic. A deep insight into some special issues and considerations on use of the process to model aggregated VBR video traffic is made. Different methods to estimate stability parameter a and self-similar parameter H are compared. Processes to generate the linear fractional stable noise （LFSN） and the alpha stable random variables are provided. Model construction and the quantitative comparisons with fractional Brown motion （FBM） and real traffic are also examined. Open problems and future directions are also given with thoughtful discussions.

Direct and Reverse Carleson Conditions on Generalized Weighted Bergman-Orlicz Spaces

Let D be the open unit disk in the complex plane C. For a〉 -1, let dAa（z）=（1 ＋a） （1 -｜z}^2） ^a da（z）be the weighted Lebesgue measure on ]D. For a positive function ω ∈ L^1（D,dAa）, the generalized weighted Bergman-Orlicz spaceA^ψω（D,dAa）is｜｜f｜｜ω^ψ=∫Dψ｜F（z）｜ω（z）dA^（z） 〈 ∞,where q; is a strictly convex Orlicz function that satisfies other technical hypotheses. Let G be a measurable subset of D, we say G satisfies the reverse Carleson condition for A^ψω （D, dAa） if there exists a positive constant C such that ∫Gψ（f（z））ω（z）dAa（z）≥C∫Dψ（｜f（z）dAa（z）.for all f ∈ .A^ψω （D,dAa）. Let μ be a positive Borel measure, we say μ satisfies the direct Carleson condition if there exists a positive constant M such that for all f∈Aψ^ω （D,dAa）,∫Dψ（｜f（z）｜）dμ（z）≤M∫Dψ（｜f（z）｜）ω（z）dAa（a）.In this paper, we study the direct and reverse Carleson condition on the generalized weighted Bergman-Orlicz space Aω^ψ（D,dAa）.We present conditions on the set G such that＇the reverse Carleson condition＇holds. ＂Moreover, we give a sufficient condition for the finite positive Borel measure μ to satisfy the direct carleson condition on the generalized weighted Bergman-Orlicz spaces.

SOME CHARACTERS OF A CLASS OF ORNSTEIN-UHLENBECK TYPE MARKOV PROCESSES WITH STABLE PROCESSES

This article concerns a class of Ornstein-Uhlenbeck type Markov processes and for which the level sets will be approached. By constructing a new class f processes, we shall obtain an inequality on the Hausdorff dimensions of the level sets for the Ornstein-Uhlenbeck type Markov processes. Based on this result, we finally verify that any two independent O-U.M.P with alpha-stable processes could collide with probability one.

On Second-order Sufficient Conditions in Constrained Nonsmooth Optimization

In this paper, we establish a second-order sufficient condition for constrained optimization problems of a class of so called t-stable functions in terms of the first-order and the second-order Dini type directional derivatives. The result extends the corresponding result of [D. Bednarik and K. Pastor, Math. Program. Ser. A, 113（2008）, 283-298] to constrained optimization problems.

火光烟雾条件下无人机激光探测与跟踪实验研究

高能激光在打击低小慢目标时,目标容易燃烧产生火光烟雾,传统的可见光和红外探测方式对目标的跟踪和瞄准在火光烟雾干扰的情况下易受影响进而导致目标失跟。提出了一种基于主动激光雷达体制的高精度探测和瞄准方法。首先,对火光烟雾条件下无人机表面的激光反射特性进行理论分析和仿真模拟,以此设计了基于APD的单光子激光雷达探测系统,获得了仿真探测概率随激光脉冲能量变化的理论曲线;其次,构建了基于InGaAs-SPAD的光子成像探测系统,进行了无人机室内实验。实验结果表明:在无火光烟雾条件下,基于距离像跟踪的目标质心位置相较于基于可见光图像跟踪的目标质心位置平均角偏差小于0.55 mrad,基于距离像序列的跟踪轨迹与基于可见光图像序列的跟踪轨迹基本一致,证明了Mean-Shift跟踪算法用于距离像的跟踪的可行性。在距离30 m处的模拟烟雾干扰条件下,采用选通延时滤除烟雾干扰能够获得轮廓清晰的目标距离像。在模拟火光干扰条件下,跟踪框中心X、Y坐标偏离目标质心约为0.58 mrad和0.39 mrad。

光储直流微电网多运行工况稳定性分析

直流微电网的结构越来越复杂,运行工况也越来越多,而现有稳定性分析方法主要针对单一工况。因此研究适用于多工况运行系统的通用稳定性分析方法非常必要。首先,依据不同的运行工况建立光储直流微电网各单元的阻抗模型,利用稳态分析法结合劳斯判据推导得出系统稳定时负载功率及母线电容的边界条件;其次,通过重新定义系统环路增益表达式,得到更具通用性的基于母线电压控制变换器(BVCC)和母线电流控制变换器(BCCC)的稳定性判据,并利用该判据对系统多种运行工况进行稳定性分析,借助所得边界条件对稳定裕度较低的工况计算合适的系统参数,保证系统能够处于稳定运行状态;最后,搭建系统的仿真模型,通过对3种典型工况仿真分析,验证边界条件及稳定性分析结论的准确性。

北江中游水库调度对水文情势的影响分析

利用水文变异指数(IHA)和变化范围法(RVA)分析了北江中游横石\飞来峡水文站1954~2022年的水文情势变化,并重点分析了飞来峡水库调度对北江低枯水的影响。结果表明:飞来峡水库的库容系数较小,对于较长时间尺度的径流过程无影响,但对于较短时间尺度径流过程有明显影响,流量过程变得“碎片化”,陡涨陡落,切换频繁,枯水期的影响更为显著。

增程式电动汽车发动机的多工作点控制策略

为了研究不同的发动机多工作点控制策略对整车燃油经济性的影响,以某增程式电动汽车为研究对象,在满足整车动力性前提下,设计了发动机三工作点和五工作点控制策略。在不同循环工况下,对比分析了2种控制策略。仿真结果表明,三工作点和五工作点控制策略能够满足整车动力性要求,且三工作点控制策略的燃油经济性更优。

危废综合焚烧回转窑经济高效运行的技术难点及对策

随着国内危险废物处理产业化快速发展,回转窑综合焚烧技术得到了广泛应用,但其工业化应用存在回转窑工况不稳定、焚烧性能差、灰渣率高等问题,严重影响焚烧效率和运行成本。以危废综合焚烧的灰渣率为切入点,从回转窑焚烧机理、工艺设计、工艺控制、工艺运行等方面分析了灰渣率高的原因,并提出了相应的解决对策和建议,为危废综合焚烧回转窑经济高效运行和产业高质量发展提供参考和借鉴。

基于RBF神经网络的油气悬架平顺性研究

目的 提高整车的行驶性能,使车辆可以自主调节,以适应各种不同的路面,从而达到良好的缓冲效果。方法 以双气室油气弹簧为研究对象,对其组成和工作原理进行详细分析,推导出油气弹簧的阻尼力和刚度等非线性特性与车身位移的关系。根据RBF神经网络控制原理,设计RBF-PID控制器,依靠神经网络自学习性对PID参数动态整定,使整个车身振动衰减,快速达到稳定状态,并基于Matlab/Simulink平台建立仿真模型,在B级和C级不平路面输入的情况下,重点对轮胎动载荷、车身质心加速度以及油气悬挂动挠度等3项性能进行仿真和分析。结果 同普通PID控制相比,RBF-PID控制下,车身3项性能的RMS分别降低26%、54%、0.1%。结论 RBF-PID控制能够克服环境影响,实现油气弹簧特性的可靠控制,提高了车辆行驶的平顺性以及稳定性。

一般复合均匀凸优化的强和稳定对偶

在广义凸共轭理论的基础和可分离的局部凸空间的条件下,利用扰动方法和c—共轭方法得到一般复合均匀凸优化问题的对偶问题,并在原问题的基础上再扰动一个连续线性泛函得到其稳定对偶问题.进而在一定的假设条件下,结合函数的均匀凸性,给出保证强对偶和稳定强对偶成立的正则条件.

增程式动力系统发动机运行策略优化研究

为进一步明晰自由度高的增程器系统中发动机运行策略对增程式电动汽车经济性的影响,明确发动机性能优化对整车性能提升的潜力,基于GT-SUITE仿真平台,结合能量流详细分析了发动机线工况和点工况运行策略对整车经济性的影响,并对比分析了发动机性能优化前后的整车性能。结果表明,发动机以点工况运行得到的整车基于中国轻型汽车行驶工况(China light vehicle test cycle, CLTC)油耗更优,相比于线工况下整车CLTC油耗,基于点工况整车CLTC油耗可降低至0.038 24 L/km。以增程器系统最优效率点作为发动机工作点的策略相对单一,不利于整车油耗的改善,相比于最佳值恶化0.81%。性能优化后的发动机在高效区可实现更大的功率输出,整车CLTC油耗均得到改善,最佳值从0.038 24 L/km降低至0.036 64 L/km。

便携式XRF能谱仪中锂离子电池恒压转换器的研究

便携式XRF能谱仪采用锂离子电池供电,锂离子电池放电过程中,输出电压随时间逐渐减小,影响能谱仪检测结果。为消除该不利影响,采用Buck-Boost拓扑结构,基于LTC3789设计宽输入范围、高转换效率的恒压转换器,将锂离子电池转换为恒电压输出。详细介绍了恒压转换器的设计过程,并对其功能和效率进行实验,结果表明:该恒压转换器输出电压稳定,转换效率高,满足使用要求。

自平衡策略的电流互感器取能调速风冷装置设计

随着我国电力系统输电量逐年上升,输电网络中的换流变压器阀侧套管等关键设备部件热功率也随之增大,因此有必要设计开发散热风机等设备,实现过热故障多发点的主动散热。设计研发一种电流互感器(CT)取能调速风冷装置,利用CT从输电线路上获取能量为散热风机供能,以解决输电线路现场常规电源无法使用的难题。针对CT的取能能力随着输电线路电流不断变化且不受控的问题,设计一种功率主动自平衡新策略,通过利用负载的控制自由度来适应CT二次侧电流的宽变化范围,从而扩展装置的稳定运行区间,提升电源的取能能力。将装置套装在交流输电母排上进行实验验证,母排电流的有效值在上千安培范围内变化,装置始终稳定且保持60%以上的功率容量利用率。