稀土“农乐”益植素的增产效果

稀土农用是国家经委要求的推广项目之一。石河子地区经过三年的小区试验和大面积示范,说明在春小麦的苗期、棉花的初花期喷施稀土“农乐”益植素可以收到明显的增产效果和经济效益。     

Optical diagnostics on the reactivity controlled compression ignition (RCCI) with micro direct-injection strategy

Micro direct-injection (DI) strategy is often used to extend the operation range of the reactivity controlled compression ignition (RCCI) to high engine load, but its combustion process has not been well understood. In this study, the ignition and flame development of the micro-DI RCCI strategy were investigated on a light-duty optical engine using formaldehyde planar laser-induced fluorescence (PLIF) and high-speed natural flame luminosity imaging techniques. The premixed fuel was iso-octane and an oxygenated fuel of polyoxymethylene dimethyl ethers (PODE) was employed for DI. The fuel-air equivalence ratio of DI was kept at 0.09 and the premixed equivalence ratio was varied from 0 to 1. RCCI strategies with early and late DI timing at –25° and –5° crank angle after top dead center were studied, respectively. Results indicate that the early micro-DI RCCI features a single-stage high-temperature heat release (HTHR). The combustion in the low-reactivity region shows a combination of flame front propagation and auto-ignition. The late micro-DI RCCI presents a two-stage HTHR. The second-stage HTHR is owing to the combustion in the low-reactivity region that is dominated by flame front propagation when the premixed equivalence ratio approaches 1. For both early and late micro-DI RCCI, the intermediate-temperature heat release (ITHR) of iso-octane, indicated by formaldehyde, takes place in the low-reactivity region before the arrival of the flame front. This is quite different from the flame front propagation in spark-ignition (SI) engine that shows no ITHR in the unburned region. The DI fuel mass is a key factor that affects the combustion in the low-reactivity region. If the DI fuel mass is quite low, there is more possibility of flame front propagation; otherwise, sequential auto-ignition dominates. The emergence of the flame front propagation in micro-DI RCCI strategy reduces its combustion rate and peak pressure rise rate.     

Effect of cation and anion defects on the resistive switching polarity of ZnO x thin films

In this paper, we achieve the resistive switching (RS) polarity from unipolar to bipolar in a simple Al/ZnO _x /Al structure by moderating the oxygen content in the ZnO sputtering process. In a pure Ar sputtering, Al/ZnO _x /Al shows unipolar behavior, as oxygen partial pressure increases, the RS polarity changes to bipolar, and the switch current decreases by about five orders of magnitude. The current transport properties of unipolar device show ohmic behavior under both high resistance (HRS) and low resistance states (LRS), but the bipolar device shows Schottky barrier modulated current transport properties. We study the defect types in the unipolar and bipolar devices through photoluminescence (PL) spectra. The PL results show that the interstitial zinc (Zn_i) and interstitial oxygen (O_i) are dominant in unipolar and bipolar devices, respectively. We attribute this phenomenon to Zn_i and O_i playing important role in unipolar (URS) and bipolar resistive switching (BRS), respectively.     

Sesquiterpenes and Monoterpenes from the Leaves and Stems of Illicium simonsii and Their Antibacterial Activity

Two undescribed ether derivatives of sesquiterpenes, 1-ethoxycaryolane-1, 9β-diol (1) and 2-ethoxyclovane-2β, 9α-diol (3), and one new monoterpene glycoside, p-menthane-1α,2α,8-triol-4-O-β-D-glucoside (5), were obtained, together with eight known compounds from the stems and leaves of I. simonsii. Their structures were elucidated by spectroscopic methods. Compounds 1–11 were evaluated for their potency against Staphylococcus aureus and clinical methicillin-resistant S. aureus (MRSA). Among them, compound 3 was weakly active against S. aureus (MIC = 128 μg/mL), and compounds 6 and 7 exhibited good antibacterial activity against S. aureus and MRSA (MICs = 2–8 µg/mL). A primary mechanism study revealed that compounds 6 and 7 could kill bacteria by destroying bacterial cell membranes. Moreover, compounds 6 and 7 were not susceptible to drug resistance development.     

简单共聚模型的分布函数与组成方程推导

针对自由基共聚合反应歧化终止和偶合终止两类机理生成的线型共聚物,应用统计物理的基本原理,对处于最可几分布状态下的线型共聚物分子量分布函数进行了理论推导,并以此分布函数,结合自由基共聚合机理动力学处理和概率计算,从另一种途径得到Mayo-Lowis和Alfrey-Goldfinger简单共聚物组成方程,研究结果有助于进一步理解简单共聚模型组成方程的物理学基础,同时也将为线型自由基共聚合反应机理的研究提供一个新方法.     

Complete convergence of weighted sums for arrays of rowwise φ-mixing random variables

In this paper, we establish the complete convergence and complete moment convergence of weighted sums for arrays of rowwise φ-mixing random variables, and the Baum-Katz-type result for arrays of rowwise φ-mixing random variables. As an application, the Marcinkiewicz-Zygmund type strong law of large numbers for sequences of φ-mixing random variables is obtained. We extend and complement the corresponding results of X. J. Wang, S. H. Hu (2012).     

1,2,5-Oxadiazole-1,2,3,4-tetrazole-based high-energy materials: molecular design and screening

Structural Chemistry - Various 1,2,5-oxadiazole-1,2,3,4-tetrazole-based high-energy materials were designed and their properties investigated. Their heat of formation, detonation properties, and...     

Design and selection of pyrazolo[3,4-d][1,2,3]triazole-based high-energy materials

Structural Chemistry - In this study, we design a series of bridged energetic compounds based on pyrazolo[3,4-d][1,2,3]triazole to screen potential energetic materials with excellent detonation...     

Micro-gated-field emission arrays with single carbon nanotubes grown on Mo tips

Using our approach previously reported, we have fabricated relatively large area micro-gated-field emission arrays with carbon nanotube (CNT) grown on Mo tips. By redesigning the device and fabrication processes, the percentage of single CNTs increased to about 50-70% with a substantial improvement in leakage current between gate and cathode and gate interceptive current. The I-V measurement of a 11000 cell array at a gate to cathode voltage of 92 V showed an anode current of 1.2 mA, corresponding to a current density of 0.57 A/cm², with a gate current only 3.3% of the anode current.     

Fundamental frequency patterns of Chinesein different speech modes

I.IntroductionTheF,patternsofspeechareimportantnotonlyforthcprosodicfeaturesbuta1soforvoicesourcecharactcristics.Nowmoreandmorespeechscientistsrecognizedthatvoiceexcitationsourceintcxt-to-spccchsystemsp1aysanimportantro1elnbothintclligibilityandnaturalnessorsynthcticspcech.Espccially,forChinese,atone1anguagewithmulti-tonesystem,thetonalpatternswhicharcmainlydcmonstratedintheF,con-tourscarry1exicalmeaning.SomecomparativestudiesoftheF,pattcrnsinbetweentonelanguage(Chinese)andstress1anguage(En…