白钨矿浮选药剂研究现状及展望

提高捕收剂的选择性和强化抑制剂的高效性始终是白钨矿浮选研究中的重点.从白钨矿的捕收剂和调整剂的种类、作用机理及研究使用现状等方面进行了分析,提出高选择性捕收剂和针对性强的抑制性是白钨矿浮选急需解决的问题.运用高新技术,结合理论研究,开发高效、经济、环保的浮选药剂已成为白钨浮选药剂的发展趋势.     

参数可调离心级联的静态特征根及扰动传播分析

离心级联水力学特征根表征了级联的重要特性。本文借鉴扩散级联水力学中使用的方法,对参数可调离心级联进行研究,求解各级流体参数完全相同情况下的扰动方程,得到了离心级联各级流体参数完全相同时水力学的静态特征根。由于离心机轻馏分流量与轻馏分出口处压强无关,重馏分处于音速流状态,离心级联只有2个静态特征根,Z1是级联的主静态特征根,Z2是由供取料引起的。供料管道阻力系数、调节装置放大倍数等因素均会影响主静态特征根Z1的数值。Z1小于1时,供料管道阻力系数增大,Z1增大,调节装置放大倍数增大到一定程度后,对Z1的影响已很小。最后,利用解析求解和数值计算两种方法计算了级联出现扰动后的状态参数分布。     

Nanoscale smooth interface maintained metallisation of polyimide using low concentration ozone micro–nano bubbles dispersed in water

In order to induce adhesion of electroless CuNiP deposition to polyimide (PI) film substrate, surface modification of PI film with an aqueous dispersion of ozone micro–nano bubbles was investigated. The treatment resulted in maximum adhesion strength of 1·14 kN m^?1 for a treatment time of 5 min. Structure of the modified PI surface, the PI/plating interface, mechanism for adhesion and laminate properties were analysed. Despite increased adhesion, surface roughness of PI was not notably changed by the ozone induced surface modification. Contact of PI surface with high ozone concentration micro–nano bubbles with sufficient frequency was found to modify the surface with a low total ozone concentration of the aqueous dispersion. Cross-sectional observation of the interface suggested that formation of a thin nanoporous anchor layer on the PI surface was responsible for plating adhesion. This method provides an environment friendly and improved process for plating on PI using low concentration ozone treatment.     

四桥臂电压质量调节器及其在微电网中的应用

低压配电网电压跌落、骤升、不平衡、谐波等扰动影响微电网的正常并网运行,为抑制以上配电网电压扰动影响,采用具有综合补偿电压扰动能力的四桥臂电压质量调节器（VQR）。针对VQR的补偿目标,采用一种基于新型谐振PVPI控制器的电压电流双环控制策略,通过提取跌落后电压基波正序分量,将输出补偿量分为跌落（或骤升）补偿部分和用于抵消负序、零序及谐波电压分量部分,利用PVPI控制实现对两部分补偿指令信号的零稳态误差控制。仿真结果证明所提出的四桥臂电压质量调节器有效地补偿了配电网电压扰动的影响,提高了微电网故障穿越能力。     

A Semiparametric Approach to the One-Way Layout

We consider m distributions in which the first m ? 1 are obtained by multiplicative exponential distortions of the mth distribution, which is a reference. The combined data fromm samples, one from each distribution, are used in the semiparametric large-sample problem of estimating each distortion and the reference distribution and testing the hypothesis that the distributions are identical. The approach generalizes the classical normal-based one-way analysis of variance in the sense that it obviates the need for a completely specified parametric model. An advantage is that the probability density of the reference distribution is estimated from the combined data and not only from the mth sample. A power comparison with the t and F tests and with two nonparametric tests, obtained by means of a simulation, points to the merit of the present approach. The method is applied to rain-rate data from meteorological instruments.     

气室加载式先导减压阀动态特性分析与参数影响研究

针对在航空航天领域广泛应用的气室加载式先导减压阀,建立了能够模拟其动态工作过程的数学模型。在模型有效性校验的基础上,对该类型减压阀在不同使用场景、不同结构参数下的动态输出特性进行了计算仿真。根据已有使用经验,结合仿真计算结果表明:采用“分级加载”模式能够提升气室加载式减压阀使用寿命,长时间大流量的连续供应将使阀出口压力逐步抬升,阀座处密封填料倒角将显著影响阀门输出特性。此外,对于既定结构减压阀,可通过优化弹簧腔及控制腔阻尼孔直径来快速调节其动态特性。     

Integrated mixed signal control IC for 500-kHz switching frequency buck regulator

The main purpose for this work is to study the challenges of designing a digital buck regulator using pipelined analog to digital converter (ADC). Although pipelined ADC can achieve high sampling speed, it will introduce additional phase lag to the buck circuit. Along with the latency brought by processing time of additional digital circuits, as well as the time delay associated with the switching frequency, the closed loop will be unstable; moreover, raw ADC outputs have low signal-to-noise ratio, which usually need back-end calibration. In order to compensate these phase lag and make control loop unconditional stable, as well as boost up signal-to-noise ratio of the ADC block with cost-efficient design, a finite impulse response filter followed by digital proportional-integral-derivative blocks were designed. All these digital function blocks were optimised with processing speed. In the system simulation, it can be found that this controller achieved output regulation within 10% of nominal 5 V output voltage under 1 A/µs load transient condition; moreover, with the soft-start method, there is no turn-on overshooting. The die size of this controller is controlled within 3 mm² by using 180 nm CMOS technology.     

植物生长调节剂对大豆子粒超微结构的影响

本研究以东农46为试验材料,在大豆生长发育期对其叶面喷施4种植物生长调节剂：三碘苯甲酸（TIBA）、硝酸稀土（RE）、亚硫酸氢钠（SBS）、2-N,N-二乙氨基乙基乙酸酯（DTA-6）.通过对大豆贮藏细胞亚显微结构观察发现,在鼓粒期TIBA对蛋白质体聚集起到了一定的作用,SBS使蛋白质体形状不规则,贮藏细胞中淀粉粒较多.RE和DTA-6对增加蛋白质体和脂体的数量效果显著.在生理成熟期,TIBA对蛋白质体聚集作用效果不明显,而使脂体数量增加,排列更紧密.RE处理样贮藏细胞蛋白质体和脂体仍较多.SBS处理样贮藏细胞淀粉粒蛋白质体较多.DTA-6使蛋白质体增多、形状大小不均一,蛋白质体的平均直径大于对照.在成熟期,贮藏细胞的物质丰富,蛋白质体较大.RE、SBS和DTA-6处理样的贮藏细胞中蛋白质体多,其中RE使蛋白质体排列更紧密.DTA-6使蛋白质个体增大,但贮藏细胞中仍有一些淀粉粒没有转化,说明DTA-6减缓了淀粉粒的降解及转化速度.SBS处理样的贮藏细胞脂体排列疏松,RE和TIBA处理样的贮藏细胞中脂体排列紧密,而且饱满.实验表明,植物生长调节剂对大豆子粒贮藏细胞的生长发育有显著影响.在大豆生长的某些特定阶段（从苗期到盛花期、鼓粒始期）,喷施本实验选定的4种植物生长调节剂,均可实现增加产量、提高品质的目的.其中RE、DTA-6增产可达17.00％、21.83％,增产效果十分显著.喷施TIBA的大豆植株矮化、壮杆效果明显,株高降低了28％ ～ 30％,抗倒伏能力显著提高.     

基于降阶谐振调节器的正负序分量检测方法

在电网不平衡下并网逆变器的控制策略中需对电网电压进行正负序分量准确检测,还需要对电流的正负序分量进行控制。研究了一种谐振调节器,该调节器是由传统的二阶谐振（SOGI）调节器降阶得到,称之为降阶谐振（ROR）调节器,理论分析表明,其能在特定频率下对交流量的正序或负序分量实现独立的无静差调节。将其应用在电网电压和电流的正负序检测中,提出一种新的电网电压和电流正负序检测方法,该方法加入了调节器的积分系数,角频率由锁相环反馈得到,实现自适应调节。仿真和实验验证了所提方法动态响应快,能在静止坐标系下分别对电网基波正