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金刚石中氮存在状态的转变

中国科学(B辑化学生物学农学医学地学) 1985年第4期 295-305页

作者：亓曾笃 t.evans 中国科学院上海硅酸盐研究所英国Reading大学

I_b型人造金刚石在温度为1500—2500℃和压力为6.5—9.5 GPa条件下经过处理,形成了天然金刚石中存在的所有氮的聚集体:A中心,B中心,N3中心和片状体。在红外吸收谱线中出现了与片状体有关的7.3μm吸收峰。I_b型金刚石经过超高压和2000℃... 详细信息

I_b型人造金刚石在温度为1500—2500℃和压力为6.5—9.5 GPa条件下经过处理,形成了天然金刚石中存在的所有氮的聚集体:A中心,B中心,N3中心和片状体。在红外吸收谱线中出现了与片状体有关的7.3μm吸收峰。I_b型金刚石经过超高压和2000℃以上温度的处理变得特别耐磨。I_aA型天然金刚石经压力为9.5 GPa左右和高达2700℃的处理,其红外吸收谱线中的7.3,7.8,8.5,9.1,9.9μm等吸收峰发生了改变;A中心转变成了B中心,部分A中心分解成了单个状态的氮原子;并形成了N3中心。

关键词：金刚石晶体氮原子天然经过人造金刚石磨料片状体存在状态

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新西兰钢铁公司的SL/RN法的发展

钢铁钒钛 1983年第1期 93-99页

作者： Nigel t.evans ,陈夏尔

前言新西兰钢铁公司的SL/RN回转窑法的发展,清楚地表明了把使用煤的直接还原法扩大到工业规模时所遇到的各种问题。因为是固态还原,所以应当避免反应物和产物的熔融。但是由于矿石中的氧化铁、脉石和还原剂中的灰份能形成低熔点的物质... 详细信息

前言新西兰钢铁公司的SL/RN回转窑法的发展,清楚地表明了把使用煤的直接还原法扩大到工业规模时所遇到的各种问题。因为是固态还原,所以应当避免反应物和产物的熔融。但是由于矿石中的氧化铁、脉石和还原剂中的灰份能形成低熔点的物质,常常粘结在耐火炉衬上或者在反应料层里产生结块。这就是用煤直接还原法在大设备操作中所要克服的主要困难。

关键词：海绵铁回转窑空气管还原带地球化学分带 SL/RN 新西兰大洋洲钢铁公司

苯丙氨酸解氨酶(PAL)的生产:适用于L-苯丙氨酸商品化生产的酵母菌株的分离与评价

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氨基酸和生物资源 1988年第1期16卷 44-53页

作者： christopher t.evans Kim Hanna 李广武

含有苯丙氨酸解氨酶的微生物已从各种自然环境中分离得到,以L—苯丙氨酸和t—苯丙烯酸盐为底物对丙氨酸解氨酸双向酶活性初步筛选出最好的21株,其中的12株对细胞总产量和来丙氨酸解氨酶活性进行了比较,并选出7株来作了在各种培养基中的... 详细信息

含有苯丙氨酸解氨酶的微生物已从各种自然环境中分离得到,以L—苯丙氨酸和t—苯丙烯酸盐为底物对丙氨酸解氨酸双向酶活性初步筛选出最好的21株,其中的12株对细胞总产量和来丙氨酸解氨酶活性进行了比较,并选出7株来作了在各种培养基中的PAL诱导程度的试验.根据上述的筛选,对分离株SPA10(已鉴定为Rh-odotorula rudra)的最适条件进行了筛选,在28℃和pH5.0是最适的生长条件,但细胞的苯丙氨酸解氨酶活性已表明在亚适生长温度(36℃)和pH(8.0)时较高。当机体在有各种糖和铵离子的条件下生长时,苯丙氨酸解氨酶的合成受到抑制,控制发酵条件能使苯丙氨酸解氨酶的合成发生在最大生物量水平,在糖耗尽时出现.到达最大合成之后,短时间内细胞内苯丙氨酸解氨酶迅速失活,若补充D.L—异亮氨酸和低浓度D.L—本丙氨酸,改变发酵温度,能使酶催化发酵稳定在100小时以上.上述结果证明了SPA10分离株从反式来丙烯酸生产L—苯丙氨酸进行商业化生产是可行的.

关键词： PAL 商品化生产分离菌分离株酵母菌株丙氛酸异亮氨酸苯丙烯酸酶活性酵母菌发酵

苯丙氨酸解氨酶在催化反式苯丙烯酸向L-苯丙氨酸转化中新的稳定作用

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氨基酸和生物资源 1988年第2期16卷 36-42页

作者： Christopher t.evans Dayle Canrad Kin Hanna 李广武武汉大学生物系

用分离株SPA1O从反式苯丙烯酸生产的L-辈丙氨酸产量减少到起初观测的26%,起初的实验是生产菌与新鲜底物二次作用而进行的。含苯丙氨酸解氨酶细胞的稳定性(再用可能性)明显地受反式苯丙烯酸盐的浓度和最初反应pH的影响。使用2%的反式苯... 详细信息

用分离株SPA1O从反式苯丙烯酸生产的L-辈丙氨酸产量减少到起初观测的26%,起初的实验是生产菌与新鲜底物二次作用而进行的。含苯丙氨酸解氨酶细胞的稳定性(再用可能性)明显地受反式苯丙烯酸盐的浓度和最初反应pH的影响。使用2%的反式苯丙烯酸盐,L-苯丙氨酸的产量在PH9.0连续培养3次后比在最适pH10.2时的产量大7倍。细胞在存在有5%的反式苯丙烯酸盐时的作用相当不稳定。渗透因子,如甲苯、二甲苯能促进L-本丙氨酸的合成量,但同时也会增加苯丙氨酸解氨酶的不稳定性。有几种效应物表明对苯丙氨酸解氨酶的起始转化速率起促进作用,但只有山梨醇,藻酸盐,戌二醛,聚乙二醇和甘油使其具一定程度的稳定性。用不同的气体对培养物和生物反应器进行通气搅动,表明氧气促进苯丙氨酸解氨酶失活,二氧化碳有少的影响,而氮气使苯丙氨酸解氨酶活性在培养基中几个星期都具明显的稳定性。氯离子的存在(来自HCl)以及底物的通气搅动降低酶的再用可能性,用硫酸取代盐酸,并用氮气进行通气搅动,在26℃时,导致极好的最初转化速率,并且酶活相当稳定,但在30℃时效果差些,反应物中含有1.5M山梨醇使苯丙氨酸解氨酶活性稳定连续维持几个培养周期。

关键词：苯丙烯酸 L-苯丙氨酸苯丙氨酸解氨酶转化速率生物反应器细胞转化分离株藻酸盐氯离子培养物

Case study of a driven pile foundation in diatomaceous soil.I:Site characterization and engineering properties

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 431-445页

作者： Jiayao Wang Ehsan Yazdani t.Matthew evans School of Civil and Construction Engineering Oregon State UniversityCorvallisOR97331USA

Diatomaceous soils are comprised of the silica frustules of diatom microalgae that are present in marine and lacustrine environments throughout the *** to their unique origin,diatomaceous soils are typically characterized by high intraparticle porosity,complex particle shapes,and uniform mineralogy,causing them to exhibit atypical physical and engineering behaviors.A substantial deposit of diatomaceous silt was observed during site exploration for construction of the Buck Creek Bridge on OR140 near Klamath Falls,OR,USA.A comprehensive laboratory and in situ testing program indicated that the diatomaceous soil possessed“non-textbook”engineering ***,tested samples had high liquid limits(≈100%-140%)with natural water contents at or near the liquid ***,the soil is expected to be normally consolidated,yet high apparent overconsolidation ratios(OCR)(≈15-40)were observed both in oedometric consolidation tests and through cone penetration test(CPt)*** penetration test(SPt)results show a corrected standard penetration resistance consistent with a medium-dense sand(i.e.(N1)_(60)≈25).CPt results include corrected tip resistances(qt)of approximately 7-10 MPa and excess pore pressures(u_(2))of up to 4 *** CPt dissipation tests,pore water pressures(PWPs)returned to hydrostatic pressure in less than 1 *** this work,we synthesize these seemingly disparate material properties in an attempt to infer appropriate engineering properties for the diatomaceous deposit at the Buck Creek Bridge and attempt to provide insight into the underlying reasons for the observed behavior.

关键词： Diatomaceous soil Problematic soil Site characterization Laboratory testing

Case study of a driven pile foundation in diatomaceous ***:Pile installation,dynamic analysis,and pore pressure generation

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 446-456页

作者： Ehsan Yazdani Jiayao Wang t.Matthew evans School of Civil and Construction Engineering Oregon State UniversityCorvallisOR97331USA

this paper presents the results from a case study highlighting the difficulties of pile driving in diatomaceous *** the companion(first)paper to this article,results of an extensive laboratory and in situ testing program were presented while the results from pile driving and further analysis of field observations were presented *** high pile rebound(HPR)was observed during driving of a closed-end pipe pile,with refusal occurring at a depth of less than 5 *** open-ended piles were thus *** and case pile wave analysis program(CAPWAP)data were collected during driving of both closed-and open-end *** data indicated that negative pore water pressures(PWPs)were generated while the closed-ended pile exhibited high *** from in situ tests indicated change in material stiffness and strong dilative tendencies near the depth of refusal.A hypothesis for observed behavior was proposed that considers the soil beneath the pile as a medium with an effectively infinite bulk modulus.

关键词： Diatomaceous soil Problematic soil Site characterization Laboratory testing

Effect of baffles on performance of fluid catalytic cracking riser

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Particuology 2018年第3期16卷 18-30页

作者： Milinkumar t. Shah Vishnu K. Pareek Geoffrey M. evans Ranjeet P. Utikar Department of Chemical Engineering Curtin University Western Australia Australia Department of Chemical Engineering University of Newcastle New South Wales Australia

Increasing demand of automobile fuel and a need to process heavier crude oil makes it imperative to find improvements to the design of existing fluid catalytic cracking （FCC） units. Several modifications to the design of the riser section of FCC units have been suggested in previous studies including： improved feed nozzle designs, multiple nozzle configurations, internal baffles, and novel two-stage-riser systems. In this study, we investigate the effects of baffles on the performance of FCC risers using computational fluid dynamics simulations. In this study, predictions from a basis model （without baffles） are compared with those from four different configurations including：（i） 5-cm baffles at 5-m spacing, （ii） 7.5-cm baffles at 5- m spacing, （iii） 10-cm baffles with 5-m spacing, （iv） lO-cm baffles at 2.5-m spacing, and （v） lO-cm baffles at 1-m spacing. the baffles force the catalyst away from wails toward the center of the riser, enhancing the radial dispersion of the catalyst and the heat transfer inside the riser. the use of longer baffles and smaller spacings further increases the dispersion, yielding more homogeneous radial profiles. the changes in the radial dispersion result in variations in the conversion, yields, and pressure drops. the baffles increase conversion of vacuum gas oil （VGO） and the yield of gasoline. However, the simulations showed that longer baffles and a larger number of baffles did not always give a higher yield or higher conversion. Among the simulated configurations, the 5-cm baffles at 5-m spacing gave the highest conversion of VGO, whereas the 10-cm baffles at 1 -m spacing resulted in the highest yield of the gasoline. thus, rational optimization of baffle configurations is required to achieve optimal performance.

关键词： Fluid catalytic cracking Riser Baffles Computational fluid dynamics

Selective Deactivation of Gibberellins below the Shoot Apex is Critical to Flowering but Not to Stem Elongation of Lolium

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Molecular Plant 2008年第2期1卷 295-307页

作者： Rod W. King Lewis N. Mander torben Asp Colleen R MacMillan Cheryl A. Blundell Lloyd t. evans CSIRO Plant Industry Canberra ACT 2600 Australia Research School of Chemistry Australian National University Canberra ACT 0200 Australia Department of Genetics and-Biotechnology University of Aarhus 4200 Slagelse Denmark Present Address: ENSIS PO Box E 4008 Kingston ACT 2604 Australia

Gibberellins （GAs） cause dramatic increases in plant height and a genetic block in the synthesis of GA1 explains the dwarfing of Mendel＇s pea. For flowering, it is GAs which is important in the long-day （LD） responsive grass, Loliurn. As we show here, GA1 and GA4 are restricted in their effectiveness for flowering because they are deactivated by C-2 hydroxylation below the shoot apex. In contrast, GAs is effective because of its structural protection at C-2. Excised vegetative shoot tips rapidly degrade [14C]GA1, [14C]GA4, and [14C]GA20 （〉80% in 6 h）, but not [14C]GAs. CoincidentaUy, genes encoding two 2β-oxidases and a putative 16-17-epoxidase were most expressed just below the shoot apex （〈3 mm）. Further down the immature stem （〉4 mm）, expression of these GA deactivation genes is reduced, so allowing GA1 and GA4 to promote sub-apical stem elongation. Subsequently, GA degradation declines in florally induced shoot tips and these GAs can become active for floral development. Structural changes which stabilize GA4 confirm the link between florigenicity and restricted GA 2β-hydroxylation （e.g. 2α-hydroxylation and C-2 di-methylation）. Additionally, a 2-oxidase inhibitor （trinexapac Ethyl） enhanced the activity of applied GA4, as did limiting C-16,17 epoxidation in 16,17-dihydro GAs or after C-13 hydroxylation. Overall, deactivation of GA1 and GA4 just below the shoot apex effectively restricts their florigenicity in Loliurn and, conversely, with GAs, C-2 and C-13 protection against deactivation allows its high florigenicity. Speculatively, such differences in GA access to the shoot apex of grasses may be important for separating floral induction from inflorescence emergence and thus could influence their survival under conditions of herbivore predation.

关键词： flowering shoot apices Shoots Gallium Lolium plant height Deactivation G(A1) ganglioside Apex APEX1 protein, human Gibberellins stem elongation

Ultrasound-assisted microfeeding of fine powders

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Particuology 2008年第1期6卷 2-8页

作者： Xuesong Lu Shoufeng Yang Julian R.G. evans Department of Materials Queen Mary University of London Mile End Road London E1 4NS UK

Ultrasonic microfeeding of powders is a new and promising method for use in solid freeforming and pharmaceutical dosing. In this work, computer-controlled microfeeding systems using ultrasonic vibration of a capillary were built. A wide range of controlled, stable rates of flow and switching control were achieved in the acoustic vibration system and uniform powder doses were obtained in the ultrasonic system. Experimental results show that nozzle diameter, transmission fluid depth, waveform, voltage amplitude, frequency and oscillation duration all influence the dose mass. Among these factors, nozzle diameter, voltage amplitude and oscillation duration can be best used to control the dose mass. An artificial neural network （ANN） technique was applied to predict the dose mass. Based on these research results, four types of microfeeding were proposed.

关键词： Microfeeding Ultrasound Fine powders