低能离子注入过程中真空和注入对小麦过氧化物酶同工酶的影响

本文报道了真空处理和低能离子束注入处理对小麦过氧化物酶同工酶的影响。研究发现,经真空处理后的样品,其酶活随着培养时间的延长呈增加的趋势,与对照样保持一致;而且相同取样时间不同样品之间的酶活性随真空时间的延长呈现略为增加的趋势;各剂量的N^ 注入处理后,种子的发芽率未受影响,而剂量较大时种子的芽长增长速度受到了明显的抑制;低剂量处理能刺激过氧化物酶酶活升高,而较高剂量处理则使酶活降低。     

影响静电加速器高压的因素

研究了机械尺寸,真空,绝缘气体的成份、气压和湿度对静电加速器高压的影响。发现在67～0.1Pa真空下,存在耐压“盲区,”气体的绝缘性能随气压的升高而增强。在0.6MPa以上时,N2和CO2的击穿电压增加趋势逐渐变缓,而混合气体的击穿电压仍呈直线增加。N2和CO2的比例为802∶0时效果最佳,加入SF6可明显提高绝缘性能,湿度对击穿电压影响不大。     

静电加速器高压的产生、提高、测量与稳定

介绍了静电加速器高压的产生、提高、测量与稳定后研究了绝缘气体成份、气压和湿度对击穿电压Ub的影响。发现67~0.1 Pa气压时存在耐压“盲区”;Ub随气压升高而增强,>0.6 MPa后N2、CO2的Ub增加趋势变缓,而混合气体的Ub仍增加较快,N2∶CO2为4∶1时效果最佳;加入SF6可明显提高Ub;湿度对Ub影响不大。     

乳酸菌鉴定方法在食品工业中的应用及研究进展

乳酸菌是食品发酵工业中一类重要的菌种,准确快速的乳酸菌分类鉴定是十分必要的。本文对目前使用的乳酸菌表型特征鉴定和基因型特征鉴定乳酸菌方法及各种方法的优缺点进行了综述。     

Grain refinement effects of Al based alloys with low titanium content produced by electrolysis

A series of Al based alloys with low titanium contents (mass fraction) from 0.178% to 0.526% were directly produced in ordinary industrial electrolyzer,The electrolyzing results show that producing Al based alloys analysis shows that this method has a great refining effect on transiting the coarse columnar grains in pure Al to equiaxed grains.The grain sizes decrease with the increase of titanium content and tend to a low limit at about 130μm .During the solidification,the non-equilibrium distribution of titanium leads to a great growth-restricting effect and a constitutional under-cooling zone in front of the growing liquid /solid interface.     

A Preliminary Study on a Specifically Expressed Arabidopsis Promotor in Vascular Bundle

From a population of about 3500 single plants is Arabidopsis promoter trapping bank,one plant whose GUS-gene had been specifically expressed in vascular bundle,was screened by the method of gus tissue staining.The T-DNA flanking sequence was amplified using TAIL-PCDR.This band will be purified and connected to TA cloning vector.After sequencing and searching in the genebank ,its function will be demonatrated through transformation.     

HT-6B托卡马克装置放电区精细结构研究(英文)

在HT-6B托卡马克装置的不同n_eq(α) 参数条件下,发现五种不同特性的放电区。两种主要的典型放电区为锯齿区(SAWTOOTH)和MHD振荡区。在此二区之间存在一个过渡区。过渡区中可以出现锯齿和MHD振荡两种放电状态。在低密度情况下出现高能电子区和逃逸区。在低q(α)的过渡区及其附近(共振区),外加共振螺旋场(RHF)有强烈地抑制MHD振荡、放大锯齿波形、改善放电等多种作用。     

Effects of Ion Implantation on in Vitro Pollen Germination and Cellular Organization of Pollen Tube in Pinus thunbergii Parl. （Japanese Black Pine）

Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsible for its biological effects at the cellular level. Here we report the biological effects of a nitrogen ion beams of 30 keV on the pollen grains of Pinus thunbergii Parl. In general, ion implantation inhibited pollen germination. The dose-response curve presented a particular saddle-like pattern. Ion implantation also changed the dimension of the elongated tubes and significantly induced tip swelling. Confocal microscopy indicated that the pollen tube tips in P. thunbergii contained an enriched network of microtubules. Ion implantation led to the disruption of microtubules especially in swollen tips. Treatment with colchicine demonstrated that tip swelling was caused by the disruption of microtubules in the tip, indicating a unique role for microtubules in maintaining the tip integrality of the pollen tube in conifer. Our results suggest that ion implantation induce the disruption of microtubule organization in pollen and pollen tubes and subsequently cause morphological abnormalities in the pollen tubes. This study may provide a clue for further investigation on the interaction between low-energy ion beams and pollen tube growth.     

N+辐照非注入因素对微生物存活率的影响

低能N 辐照Escherichia coli LE392前非注入因素如干燥、真空及菌悬液室温静置时间对其存活率的影响在本文中进行了研究.结果表明,样品干燥过程中E.coli存活率并非稳步下降,而存在一个瞬间急剧降低的现象;干燥样品放入真空靶室的瞬间,真空对E.coli的致死作用最大,随真空处理时间的增加E.coli存活率虽有下降但不显著;E.coli菌悬液室温放置过程中随时间延长其真空的耐受力也相应增加,分批培养的方法为研究提供了状态一致的新鲜样品,避免了由于注入样品间状态差异所引起的试验误差.在控制非注入因素的条件下,将N 1×1014 cm-2和3×1015 cm-2注入E.coli后,相同剂量不同批次间E.coli的存活率无显著差异.     

应用02—5—71菌株葡萄糖基转移酶制备β-环糊精的研究

对环糊精葡萄糖基转移酶催化淀粉生成β-环糊精(β-CD)的转化条件进行了研究。结果表明，转化最适pH为6．5～8．5；随底物浓度增加β-CD生成量增多而转化率降低；酶用量在1000U．g^-1淀粉较合适；5％甲苯及2％乙醇能显著提高β-CD的转化率，以14％马铃薯淀粉为底物转化60h转化率较对照分别提高57．18％及28．36％；5％马铃薯淀粉加入10％乙醇转化24hr转化率可达57．97％。