面向航空发动机的高精高频动应变测量系统

高速高精动应变监测技术是实现航空发动机旋转部件故障早期诊断目标的关键技术。提出了一种基于相位解调技术的光纤法布里-珀罗(Fabry-Pérot,F-P)动应变测量系统,实现了在高频率条件下的高精度动应变测量。实验结果表明:系统中F-P传感器对应变的灵敏度可以达到100.955 pm/με,约为一般光纤FBG应变传感器(应变约1 pm/με)的100倍;测量频率可以达到10 kHz;在对多种不同标准激振频率进行测量时,误差不超过1.1%;另外测量系统探头能耐受1200℃的高温,因而在未来航空发动机旋转部件故障监测、性能测试方面都具有较好的应用前景。

优良恢复系泰恢808的稻瘟病抗性基因型分析

【目的】泰恢808是目前长江流域应用广、市场潜力大的恢复系之一,具有优良的株型、品质和抗性。因此明确泰恢808的抗性基因型,为水稻育种和材料改良提供参考,促进和保障泰恢808在水稻生产中的安全应用。【方法】以泰恢808为研究对象,LTH为阴性对照,含有抗性基因Pikm的单基因系IRBLkm-Ts为阳性对照,通过PCR扩增和分析Pikm位点的基因序列及表达模式,接种38个稻瘟菌单孢菌株分析这些材料的抗病性。【结果】明确泰恢808含有Pikm基因,该基因在泰恢808和单基因系IRBLkm-Ts中有相似的表达模式,均受稻瘟菌诱导,在接种24 h后开始上调表达。但泰恢808的稻瘟病致病菌株仅有5个,明显少于单基因系IRBLkm-Ts。【结论】根据分子标记和测序的检测结果推测,泰恢808除了含有Pikm基因外,可能含有新的抗性基因。但因致病菌株的出现,在泰恢808的生产应用过程中,需对其抗病性进行实时监测。

基于桩侧砂土圆锥型修正应变楔模型的p-y曲线

基于桩侧砂土三维圆锥型应变楔的变形特征,提出砂土中水平受荷桩的非线性p-y曲线。构建圆锥型楔形体前表面应力体系并引入土体应力-应变双曲线模型,进而考虑应变楔的水平受力平衡得到桩侧土反力的表达式。在此基础上,结合弹性地基梁有限差分数值分析,建立了水平受荷桩非线性p-y曲线的理论推导方法。将该理论用于钻孔桩和打入桩模型试验的算例分析,结果表明:相对于API规范的p-y曲线、双曲线型p-y曲线以及传统非圆锥型应变楔模型得到的p-y曲线,本文方法得到的非线性p-y曲线与模型试验结果更为接近。通过比较本文圆锥变形模式与传统非圆锥型应变楔模式的差异以及桩-土参数的影响分析,进一步论证了该方法的优点。

一株多粘类芽孢杆菌的鉴定及对水稻稻瘟病菌的抑菌作用

本研究旨在开发高效的微生物生防制剂,用于防治水稻稻瘟病。本研究从水稻根际土壤筛选到一株具有较好拮抗作用的菌株KH-19,通过形态学观察、生理生化试验和16S rDNA测序对该菌株进行鉴定,用牛津杯法和平板对峙法测定其抑菌活性,针对水稻稻瘟病进行了盆栽防效试验。结果显示:KH-19菌株为多粘类芽孢杆菌Paenibacillus polymyxa,该菌对3株供试菌株大肠杆菌ATCC 25922、铜绿假单胞菌ATCC 27853和白菜软腐病菌BC2均有抑菌作用,对其他6种病原细菌和8种病原真菌也有较好拮抗作用,对水稻稻瘟病菌抑菌率达63.67%。盆栽试验结果显示随着KH-19菌液浓度的提高水稻稻瘟病病情指数随之降低,当菌悬液浓度为106~107 cfu/mL时,对接种第20天的稻瘟病防病指数达78.11%。P.polymyxa KH-19作为具有广谱抑菌活性的生防菌株,在防治水稻稻瘟病方面具有潜在应用价值。

Band Edge Model of (101)-Biaxial Strained Si

A band edge model in （101）-biaxial strained Si on relaxed Si1-x Gex alloy,or monoclinic Si （m-Si）,is presented using the k · p perturbation method coupled with deformation potential theory. Results show that the [001], [001], [100], [100] valleys constitute the conduction band （CB） edge,which moves up in electron energy as the Ge fraction （x） increases. Furthermore,the CB splitting energy is in direct proportion to x and all the valence band （VB） edges move up in electron energy as x increases. In addition, the decrease in the indirect bandgap and the increase in the VB edge splitting energy as x increases are found. The quantitative data from the models supply valuable references for the design of the devices.

Detection of the Quantitative Trait Loci with AFLP and RFLP Markers for Phosphorus Uptake and Use Efficiency in Rice

To identify genetic factors underlying phosphorus (P) uptake and use efficiency under low_P stress in rice (Oryza sativa L.), 84 selected genotypes (recombinant inbred lines) and their parents (which differed in tolerance for low_P stress) “IR20” and IR55178_3B_9_3, were cultured in liquid medium supplemented with adequate and low P levels in a greenhouse. Plants were sampled after 6 weeks in culture for measurements of plant dry weight, P concentration, P uptake and P use efficiency under both P sufficient and stress conditions. A total of 179 molecular markers, including 26 RFLPs and 153 AFLPs, mapped on all 12 chromosomes of rice based on the 84 selected genotypes were used to detect the quantitative trait loci (QTLs) underlying tolerance for low_P stress. Three QTLs were detected on chromosomes 6, 7 and 12, respectively, for relative plant dry weight (RPDW) and relative P uptake (RPUP). One of the QTLs flanked by RG9 and RG241 on chromosome 12 had a major effect which explained about 50% of the variations in the two parameters across the population. The results coincided with the QTLs for low_P stress based on relative tillering ability from the same population from a cross between Nipponbare and Kasalath under soil condition. The identical major QTL for P uptake and plant growth under low_P stress in both liquid medium and soil strongly suggests that the ability of P uptake mainly controls rice tolerance for low_P stress.

基于多组分含量分析和指纹图谱的生稻芽质量评价研究

基于HPLC进行多成分含量测定和指纹图谱技术,结合化学模式识别法对生稻芽的质量水平进行评价,为生稻芽后续深入研究与开发提供依据。采用HPLC法建立18批不同批次生稻芽指纹图谱,通过对照品指认出生稻芽中3种主要酚酸类成分,并测定了样品中3种酚酸的含量。通过中药色谱指纹图谱相似度评价系统(2012版)和IBM SPSS Statistics 23进行相似度评价、聚类分析、主成分分析和因子载荷分析。18批生稻芽指纹图谱共标定了6个共有峰,指认的3个共有峰为香草酸、对香豆酸和阿魏酸,指纹图谱相似度范围为0.868~0.995,具有较好的一致性。样品中香草酸、对香豆酸和阿魏酸含量分别为16.70~54.10μg·g^(-1)、27.00~49.54μg·g^(-1)、23.09~50.81μg·g^(-1)。聚类分析将样品分为3类,18批样品中16批聚为一类,来自浙江杭州(S14)、浙江杭州(S17)的样品分别聚为一类,主成分分析用两个主成分进行综合评价,综合得分大于1的前2位分别为S14、S17,18批样品中3种酚酸成分的总含量与主成分分析综合得分存在明显的相关性。建立的生稻芽质量评价方法操作简便、结果可靠,香草酸、对香豆酸和阿魏酸3个主要酚酸可以作为生稻芽质量评价的指标性成分。

Characteristics and mechanisms of strain waves generated in rock by cylindrical explosive charges

A superposing principle, by suitably adding the strain waves from a number of concentrated explosive charges to approximate the waves generated by a cylindrical charge based on the strain wave of a point or small spherical explosive charge generated in rock, is used to further study the triggering time of strain gauges installed in radial direction at same distances but different positions surrounding a cylindrical explosive charge in rock. The duration of the first compression phase and peak value of strain wave, and furthermore, their differences are analyzed and some explanations are given. Besides that, the gauge orientation in which the maximum peak value occurs is also discussed. At last, the effect of velocity of detonation(V.O.D.) of a cylindrical explosive charge on the strain waves generated in the surrounding rock is taken as key research and the pattern of peak amplitude of a strain wave varies with the V.O.D. is likely to have been found.

STUDIES ON MICROYIELD BEHAVIOR OF A SiCp/2024Al COMPOSITE

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Determination of conduction band edge characteristics of strained Si/Si1-xGex

The feature of conduction band （CB） of Tensile-Strained Si（TS-Si） on a relaxed Si1-xGex substrate is systematically investigated, including the number of equivalent CB edge energy extrema, CB energy minima, the position of the extremal point, and effective mass. Based on an analysis of symmetry under strain, the number of equivalent CB edge energy extrema is presented; Using the K.P method with the help of perturbation theory, dispersion relation near minima of CB bottom energy, derived from the linear deformation potential theory, is determined, from which the parameters, namely, the position of the extremal point, and the longitudinal and transverse masses （m1^＊ and mt^＊）are obtained.

Production of Indigo by Immobilization of E. coli BL21 （DE3） Cells in Calcium-Alginate Gel Capsules

The ability of catalyzing indole into indigo of gene engineering strain expressing P450 BM3 immobi- lized by entrapment in calcium-alginate gel capsules was examined,and various characteristics of immobilized cells were assessed.Optimum conditions for cells activity were not affected after immobilization,and pH and tempera- ture for both free and immobilized cells were found to be pH 7.5 and 35℃,respectively.The immobilized cells ex- hibited a markedly improved thermal stability than free cells.After five repeated experiments,the yield of indigo with the immobilized cells retained over 94%of their original activity,which indicated that the operational stability for recycling in batch processes was improved.

FINITE ELEMENT ANALYSIS ABOUT STRESS AND STRAIN OF SURFACE PEELING IN Cu-Fe-P SHEET

The microstructure of surface peeling in finish rolled Cu-0.1Fe-0.03P sheetis analyzed by scanning electron microscope and energy dispersive spectroscope. Fe-rich areas ofdifferent contents are observed in the matrix. The stress distributions and strain characteristicsat the interface between Cu matrix and Fe particle are studied by elastic-plastic finite elementplane strain model. Larger Fe particles and higher deforming extent of finish rolling are attributedto the intense stress gradient and significant non-homogeneity equivalent strain at the interfaceand accelerate surface peeling of Cu-0.1Fe-0.03P lead frame sheet.

Induced Effects of Exogenous Phenolic Acids on Allelopathy of a Wild Rice Accession(Oryza longistaminata,S37)

Four exogenous phenolic acids, including salicylic acid, fumalic acid, p-coumaric acid and p-hydroxybenzonic acid, were used to investigate the regulatory effects on allelopathy of a wild rice accession of S37 （Oryza Iongistaminata）, which is a known allelopathic rice. The four exogenous phenolic acids induced the enhancement of the allelopathic potential of wild rice S37 in target weeds though the weed-suppressive activities were low, and the inducible effects were dependent on the specific phenolic acid, concentration and treatment time. After foliar application of exogenous phenolic acids, the inhibition rates for plant height, root length and fresh weight of barnyard grass （Echinochioa crus-galli） were significantly higher than those of the control. Especially at the concentration of 100 mg/L, the inhibition rates for plant height and fresh weight of barnyard grass by fumalic acid were 38.12% and 26.31% higher than those of the control, showing that fumalic acid was more effective compared with other phenolic acids in inhibiting monocotyledon weed growth. Furthermore, the weedsuppressive activity of aqueous extract from the leaves of wild rice S37 treated with exogenous phenolic acids was increased, and it peaked at 48 h after the treatment with the aqueous extract, and then gradually declined.

Necking of Q&P Steel during Uniaxial Tensile Test with the Aid of DIC Technique

A lot of research has been focused on the necking process during the plastic deformation of sheet metals, but the localized necking is rarely distinguished form diffused necking by experiments, due to the limit of measurement equipment and method. Quenching and Partitioning (Q&P) steel is a 3rd generation advanced high strength steel (AHSS). Its good combination of high strength and ductility ensures potential application in automobile industry. Uniaxial tensile tests of QP980 steel sheet at five strain rates are performed to investigate the necking process and the effect of strain rate on necking behavior of Q&P steel. Digital image correlation (DIC) method is applied during tensile tests, and evolutions of major strain, minor strain and normal strain distributions along gauge section of the tensile specimens are obtained. The diffused and localized necking strains are determined according to SWIFT necking theory and HILL necking theory respectively. The test results indicate that with the increasing of strain rate in the investigated range, the diffused necking strain decreases from 0.152 to 0.120 and localized necking strain decreases from 0.245 to 0.137. Meanwhile, the difference of the two strains decreases form 0.096 to 0.017. Thus it can be concluded that strain rate has an influence on both necking strains during the deformation of QP980 steel sheet. Diffused and localized necking strains are determined by uniaxial tensile tests with the aid of DIC technique and the effect of strain rate on necking strains is evaluated.

Inoculation of Loquat Endophytic Trichoderma Strain P3.9 into Loquat Rhizosphere Soil and Its Effect on Quantity of Indigenous Fungi

In order to explore whether the endophytic Trichoderma strain P3.9 of loquat has an adverse effect on indigenous fungi in loquat rhizosphere soil, the quantitative change of aboriginal fungi is determined by dish dilution and plate colony-counting method with time changing in one season. The results showed that after the inoculation of endophytic Trichoderma strain P3.9, the total number of indigenous fungi in loquat rhizosphere soil had an obviously downward trend in contrast with the control which was without inoculation. For treatment groups, 5~60 d after inoculation, the number of indigenous fungi showed a cyclic upward-downward trend at a 10-d interval except for the insignificant changes from 35 to 40 d;60~90 d after inoculation, the upward-downward trend repeated at a 30-d interval. For the control group, the number of indigenous fungi first presented a downward-upward trend every 15 d during the period of 5~50 d, and then an upward-downward trend from the period of 50~70 d and the 75~85 d, and lastly continuous growth from 85 to 90 d;particularly, it did not vary greatly from 70 to 75 d. In general, the quantity of indigenous fungi is unstable in the control group which fluctuates more significantly than in the treatment group. The number of indigenous fungi in the treatment group was significantly lower than that in the control group. The Trichoderma strain P3.9 can inhibit indigenous fungi in loquat rhizosphere soil effectively.

Plastic deformation behavior of Fe_(40)Ni_(40)P_(14)B_6 bulk metallic glass investigated by nanoindentation

Fe40Ni40P14B6 bulk metallic glass rods have been prepared by water quenching the fluxed alloy. The deformation behavior was investigated by nanoindentation tests and compressing tests. The average hardness and elastic modulus of the as-prepared Fe40Ni40P14B6 BMG (bulk metallic glass) measured by nanoindentation tests are 8.347 and 176.61 GPa respectively. The displace- ment-load curve shows “pop-in” characteristics which correspond to the loading rate bursts. Many shear bands around the indent were observed. The as-prepared Fe-based BMG exhibits a compressive plastic strain of 5.21%, which is much larger than that of other Fe-based glassy alloys and most of other BMGs.

Effect of Fe Particle on the Surface Peeling in Cu-Fe-P Lead Frame

Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame aUoy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress coacentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of intefrace make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.

Valence band structure and density of states effective mass model of biaxial tensile strained silicon based on k·p theory

After constructing a stress and strain model, the valence bands of in-plane biaxial tensile strained Si is calculated by k·p method. In the paper we calculate the accurate anisotropy valance bands and the splitting energy between light and heavy hole bands. The results show that the valance bands are highly distorted, and the anisotropy is more obvious. To obtain the density of states （DOS） effective mass, which is a very important parameter for device modeling, a DOS effective mass model of biaxial tensile strained Si is constructed based on the valance band calculation. This model can be directly used in the device model of metal-oxide semiconductor field effect transistor （MOSFET）. It also a provides valuable reference for biaxial tensile strained silicon MOSFET design.

The strain seismograms of P- and S-waves of a local event recorded by four-gauge borehole strainmeter

At a sampling rate of 100 samples per second,the YRY-4 four-gauge borehole strainmeters（FGBS） are capable of recording transient strains caused by seismic waves such as P and S waves or strain seismograms. At such a high sampling rate, data from the YRY-4 strainmeters demonstrate fairly satisfactory self-consistency. The strain tensor seismograms demonstrate the senses of motion of P waves, that is, the type of seismic wave travels in the direction of the maximum normal strain change. The observed strain patterns of S waves significantly differ from those of P waves and should contain information about the source mechanism. Spectrum analysis shows that the strain seismograms are consistent with conventional broadband seismograms from the same site.

A k·p analytical model for valence band of biaxial strained Ge on(001) Si_(1-x)Ge_x

In this paper,the dispersion relationship is derived by using the k·p method with the help of the perturbation theory,and we obtain the analytical expression in connection with the deformation potential.The calculation of the valence band of the biaxial strained Ge/（001）Si1-xGex is then performed.The results show that the first valence band edge moves up as Ge fraction x decreases,while the second valence band edge moves down.The band structures in the strained Ge/（001）Si 0.4 Ge 0.6 exhibit significant changes with x decreasing in the relaxed Ge along the [0,0,k] and the [k,0,0] directions.Furthermore,we employ a pseudo-potential total energy package（CASTEP） approach to calculate the band structure with the Ge fraction ranging from x = 0.6 to 1.Our analytical results of the splitting energy accord with the CASTEP-extracted results.The quantitative results obtained in this work can provide some theoretical references to the understanding of the strained Ge materials and the conduction channel design related to stress and orientation in the strained Ge pMOSFET.