Using specific secondary metabolites as markers to evaluate allelopathic potentials of rice varieties and individual plants

It is a key of the breeding of allelopathic rice cultivars to evaluate and screen few accessions with allelopathic traits from numerous rice accessions and individual plants. Rice varieties and individual plants with allelopathic traits demonstrated their allelopathic effects by producing and releasing specific secondary metabolites into environment. Therefore, using specific secondary metabolites as markers, the allelopathic potentials of rice varieties and individual plants could be evaluated by HPLC. The allelopathic potentials of 3000 rice accessions and some individual plants of F3 and F4 were evaluated by this method in 1 a. If these accessions and plants were evaluated by the traditional method in the field, it would take more than 10 a, furthermore, the breeding process of allelopathic rice cultivars would be directed and monitored by this method. Isolation and structural identification of specific secondary metabolites was done by LC/MS coupling ¹H and ¹³C NMR. It revealed that allelochemicals of rice tissue were glucosides of resorcinol, flavone and hydroxamic acid, and were not well-known phenolic and fatty acids in previous studies. However, these glucosides could degrade immediately into sugar, phenolic and fatty acids under microbial and acidic medium when they released into the environment.     

Dissociation of methanol in intense femtosecond laser field

Methanol was irradiated by 80 fs laser pulse, intensity range of 10¹³–10¹⁴ W/cm². A TOF-mass spectrometer was coupled to the laser system and used to detect the ions produced. The parent ions CH₃OH⁺ appeared firstly at the laser intensity of 1.4×10¹³ W/cm². While the laser intensity was gradually increased, the parent ions were dissociated and the primary ions CH₂OH⁺ were given as verified from the irradiation of deuterated methanol (CH₃OD) showing the C—H bond cracking firstly. While the laser intensity was further increased to 2.0 × 10¹³ W/cm², the C—O bonds of the parent ions also broke to give CH₃ ⁺. When the laser intensity was higher, smaller fragment ions like CH⁺, C⁺, OH⁺ and O⁺ also appeared. Among the fragment ions, only H⁺ ion yield had anisotropic angular distribution dependence on the laser polarization vector in the dissociation of methanol. All the experimental observations show that the dissociation of methanol proceeds through stepwise mechanism but not Coulomb explosion.     

Gene expression profiling related to powdery mildew resistance in wheat with the method of suppression subtractive hybridization

“Bainong 3217 × Mardler” BC₅F₄ wheat line at the initial stage of inoculation with powdery mildew pathogen (Erysiphe graminis DC) was used to construct a suppression subtractive hybridization (SSH) cDNA library. Totally 760 ESTs were obtained through sequencing. Similarity analysis of ESTs based on BLASTn and BLASTx with the sequences in GenBank, in combination with macroarray differential screening, revealed that 199 ESTs of 65 kinds were known to be functionally disease resistance related. Based on the gene expression profiling in the present study, it is postulated that salicylic acid (SA) and MAP-related signal transduction pathways were involved in powdery mildew resistance in wheat. System acquired resistance genes were predominant in terms of kinds and quantity. With the initiation of cell defense reaction, the genes conferring anti-oxidation substances were largely expressed and thus cell protection mechanism was activated. Much evidence revealed that phenylpropanes metabolic pathway was involved in phytoalexin synthesis in wheat powdery mildew resistance. Genes conferring some enzymes of structural modification of cell walls and proteinase inhibitors inhibiting pathogen growth were also detected. The genes controlling a few proteinases (mainly cysteine proteinase) had a considerable redundancy of expression.     

岩体工程系统失稳的能量突变判断准则及其应用

在明确区分岩石材料的破坏与岩石工程系统失稳破坏不同含义的基础上，提出了在用有发元计算模拟地下岩石开挖工程和实际工程设计中，不应简单地将岩石材料的破坏与岩石工程系统的破坏用同样的破坏准则加以判断的观点，运用系统能量的原理，借助突变理论的方法，导出央体工程开挖系统失稳破坏的能量突变准则，并将其引入了有限元程序中，用以判断岩体工程系统失稳的可能性，通过对金川二矿区大面积无矿柱胶结充填采场稳定性的有限元模     

用 MOS-DYL 电路实现逻辑推理神经元

介绍神经网络的电子学实现方法并分析了用ＭＯＳ－ＤＹＬ电路实现神经网络的优越性。提出了用ＭＯＳ－ＤＹＬ电路实现基本神经元模型的方法，并证明应用其有可能实现逻辑推理功能，最后用专用软件在微机上对上述电路结构进行了仿真，说明设计的可行性。     

动量守恒定律和动量矩守恒定律的正确表述

现行力学教材和普通物理教材大都把动量守恒定律和动量矩守恒定律视为质点组动量定理和动量矩定理的推论，忽视了守恒星的本质意义，是不正确的．本文绘出正确表述．     

N-酰基-(R)-四氢噻唑-2-硫酮-4-羧酸乙酯与外消旋氨基酸的反应

N-乙酰基-（R）-四氢噻唑2-硫酮-4-羧酸乙酯及N-苯甲酰-（R）－四氢噻唑-2-硫酮-4-羧酸乙酯同外消旋的两氨酸、蛋氨酸、本现氨酸、亮氨酸反应，得到光学活性N-酰基氨基酸2a～f及光学活性氨基酸3a～f。     

小白菜中超氧化物歧化酶的提取及稳定性

对从小白菜中提取超氧化物歧化酶（ＳＯＤ）进行了探索性实验。用盐析法提取粗品，然后经过透析，层析后制取了具有较高活性的ＳＯＤ，并对其在温度、时间、ｐＨ、紫外光条件下，稳定性的影响上进行研究。     

陶瓷基复合材料微观应力分析与调控

初步分析了陶瓷基复合材料内部的微观应力及其影响因素，并结合具体的陶瓷基颗粒复合材料，阐明微观应力对材料力学性能的重要作用，并提出了通过调控材料内部的微观应力以改善材料力学性能．还研究了采用高频微波处理St3N4／TiC（P）陶瓷复合材料，利用Si3N4和TiC对微波能的不同吸收特性，调整材料内部的微观应力，提高材料的力学性能．     

NonlinearV-I property of Ag/BaTiO3 composite materials

Conclusion There is no chemical reaction between Ag and BaTiO₃ in the Ag/BaTiO₃ composite materials prepared by the ceramic process in this study. The composite with 10% Ag shows nonlinearV-I character. The tunneling effect of separated Ag particles and electrostrain effect of BaTiO₃ grains can be used to interpret the electrical phenomena.