Effect of Low Content Chlorophyll on Distribution Properties of Absorbed Light Energy in Leaves of Mutant Rice

This paper reported the diurnal variations of photochemical efficiency of PSII, thermaldissipation rate and other physiology process in the low content chlorophyll mutant rice andits wild type under field conditions, and analyzed the difference of absorbed light distributionbetween the two rice varieties in a day. The results showed that the mutant had poor absorbedlight because of its little light absorption coefficient, but higher electron transportg ratecould partly reduce the disadvantageous effect of deficient absorbed light in mutant. Comparedwith wild-type rice, the mutant had less excess excitation energy and the fraction of absorbedlight allocated to photochemical process was more.

High speed continuous turning of hardened steel with newly developed low content PCBN

In this study,newly developed low content PCBN was used to evaluate the cutting performance in high speed turning of hardened steel.Using new PCBN and commercially available PCBN tipped inserts under the same cutting condition,cutting performance with variable cutting speed,feed rate and depth of cuts on tools were measured by observation of flank and crater wear.Its microstructures were analyzed through SEM microscope,measurement of surface roughness on workpiece was also performed. According to cutting performance results,it is shown that new PCBN shows much longer tool life in high speed continuous turning than our conventional PCBN tools,with improved wear and chipping resistance.This result on the machinability of new PCBN for hardened steel will provide effective guidelines to manufacturing engineers,also provide useful economic machining solution for high speed continuous turning for hardened steel.

Chemical-Looping Reforming of Methane Using Iron Based Oxygen Carrier Modified with Low Content Nickel

Fe_(2)O_(3)/Al_(2)O_(3) and Fe_(2)O_(3)/Al_(2)O_(3) modified by low content of Ni(below 2%in weight)oxygen carriers were prepared by mechanical mixing and impregnation method.The synthesized oxygen carriers were characterized by means of X-ray diffraction(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM),BET-surface area and temperature programmed reduction(TPR).Besides,redox cyclic reactivity and the performance of chemical looping reforming of methane of the oxygen carriers were studied in a thermal gravimetrical analysis(TGA)and fixed bed at 850℃.It was observed that the redox reactivity of the oxygen carriers is improved by Ni addition because synergic effect may occur between NiO and Fe_(2)O_(3)/Al_(2)O_(3) to form NiFe_(2)O_(4) and NiAl_(2)O_(4) spinel phases.However,the improvement was not apparent as Ni addition reached 1 wt%or more because more nickel loaded resulted in methane decomposition into H2 and carbon leading to carbon deposition.The SEM and BET analysis showed that NiFe_(2)O_(4) and NiAl_(2)O_(4) particles dispersed into the pores of the Fe_(2)O_(3)/Al_(2)O_(3) particles in the course of preparation.In addition,the resistance to sintering of the modified samples increased with the Ni addition increasing.The results of successive redox cycles showed that the Ni modified Fe_(2)O_(3)/Al_(2)O_(3) oxygen carriers have good regenerability.With integration of reactivity and carbon deposition,the content 1.04 wt%of nickel doping was an optimal amount in the three modified samples.

Progresses in Researches of the Application of Low-Amylose Content Rice Gene for Breeding

Amylose content is a key determinant of eating quality of rice. With the characteristics offluffy texture, glossy appearance when cooked, remaining soft when cooled and excellentpuffing ability, the low-amylose rice with amylose content 5-15% could be served as not onlycooked rice directly, but also good material for convenience, mixed rice and puffing foods.Current status on characterization, inheritance, molecular mechanism and breeding of low-amylose content rice was reviewed in this paper, strategy of related researches in the era ofglymics was mainly discussed furthermore. The future research should focus on screening andenhancing the germplasm, further elucidating the molecular mechanism on mutation of lowamylose content, utilizing the genes independent of Wx on low-amylose content rice breedingprogram, and developing high quality functional rice cultivars for special usage throughpyramiding low amylose gene and other special quality genes.

Fine mapping and marker-assisted selection (MAS) of a low glutelin content gene in rice

Rice with low glutelin content is suitable as functional food for patients affected with diabetes and kidney failure. The fine mapping of the gene(s) responsible for low glutelin content will provide information regarding the distribution of glutelin related genes in rice genome and will generate markers for the selection of low glutelin rice varieties. Following an SDS-PAGE screen of rice germplasm from Taihu Valley of China, Japonica selection W3660 is identified to be a novel mutant characterized with low glutelin content. For fine mapping the mutant gene for low glutelin content, F2 and F3 populations were derived from a cross between W3660 and Jingrennuo. SDS-PAGE analysis of the total endosperm protein showed that the low glutelin content trait was controlled by a single dominant nuclear gene. Genetic mapping, using SSRs, located this gene to chromosome 2, in the region between SSR2-001/SSR2-004 and RM1358. The dis- tances of the two markers to the target gene were 1.1 cM and 3.8 cM respectively. By semi-quantitative RT-PCR analysis, the transcripts of GluB4/GluB5 genes located within the region do not change. However, GluB5 gene located proximal to SSR2-001/SSR2-004 was specifically reduced. SSR profiles of seven Japonica varieties were compared with that of W3660 for loci in the relevant genetic region. The markers SSR2-004 and RM1358 were used for marker- assisted selection. The selection efficiencies of SSR2-004 and RM1358 were 96.8% and 92.7% respectively. This provides a standard starting point for the breeding of low glutelin content rice varieties in China.

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 with titanium contents of less than 0.30% without great loss of electrolysis efficiency is possible. The quantitative 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 130 μm. 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.

Electrochemical investigation of the anode processes in LiF-NdF3 melt with low oxygen content

The oxidation of oxygen ions and the generation of an anode effect at a low oxygen content of 150 mg/kg were discussed in this paper.Cyclic voltammetry and square-wave voltammetry tests were conducted to explore the anodic processes of LiF-NdF_(3)melt after a lengthy period of pre-electrolysis purification at 1000℃(during which the oxygen content reduced from 413 to 150 mg/kg).The oxidation process of oxygen ions was found to have two stages:oxidation product adsorption and CO/CO_(2)gas evolution.The adsorption stage was controlled by diffusion,whereas the gas evolution was controlled by the electrochemical reaction.In comparison with oxygen content of 413 mg/kg,the decrease in the amplitude of the current at low oxygen content of 150 mg/kg was much gentler during the forward scanning process when the anode effect occurred.Fluorine-ion oxidation peaks that occurred at about 4.2 V vs.Li/Li+could be clearly observed in the reverse scanning processes,in which fluorine ions were oxidized and perfluorocarbons were produced,which resulted in an anode effect.

Investigation on Steelmaking with Hot Metal Containing Low Silicon Content in Large Converter

There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.

Hydromechanical Behavior of Low-Swelling Soils Compacted at Low Water Content: Laboratory Study

Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of this paper is to study the influence of hydromechanical stresses on the behavior of low swelling soils compacted at low water content in accordance with the French standard GTR 92 (Guide des Terrassements Routiers). Then, various experimental tests on an oedometer were carried out in the laboratory. Two types of low swelling soil sampled in Nasso on the outskirts of the town of Bobo Dioulasso (Burkina Faso) were used. After shuffling, each sample was moistened to its optimum water content and then compacted to 90% and 95% of its optimum density. Behavior tests show that these soils deform very little when subjected to hydromechanical stresses. However, these deformations are swelling in nature for low mechanical stresses and when the stresses are high, they tend to collapse. When these soils are subjected to a vertical stress of 420 kPa, the primary consolidation time is of the order of one minute for NH2 (a silty soil) and about ten minutes for NH3 (a silty-clayed soil).

Molecular imprinted polymer with positively charged assistant recognition polymer chains for adsorption/enrichment of low content target protein

Here, we introduce a new type of molecular imprinted polymer (MIP) with immobilized assistant recognition polymer chains (ARPCs) to create effective recognition sites and with bacterial cloned protein as template for adsorbing the low content target protein from cell extract. In this work, cloned pig cyclophilin 18 (pCyP18), a peptidyl-prolyl cis/trans-isomerase, was used as template. The template protein was selectively assembled with ARPCs from their library, which consists of numerous limited length polymer chains with randomly distributed recognition sites of positively charged amino groups and immobilizing sites. These assemblies were adsorbed by porous microsphers and immobilized on them. After removing the template, binding sites complementary to the target protein in size, shape and the position of recognition groups were exposed, and their confirmation was preserved by the cross-linked structure. The synthesized MIP was used to adsorb the cellular pCyP18, and its proportional content was enriched more than hundred times. The extended experiment on imprinting bovine serum albumin (BSA) with ARPCs shows that this method is also suitable for large protein.

用于MTO装置中的乙炔选择加氢催化剂研究

在MTO工艺装置生产乙烯的过程中,乙烯中常含有50~200μL/L左右的微量乙炔,现有的石油烃蒸汽裂解制乙烯装置中常用的碳二加氢催化剂或适用于微量乙炔选择加氢的乙烯精制催化剂并不是MTO工艺中乙炔选择加氢的最好选择。通过研究Pd含量变化对催化剂性能的影响,发现降低Pd含量能够提高催化剂的乙烯选择性,降低催化剂的乙炔合格温度,在保证乙炔加氢合格的情况下,通过控制较低的氢炔比还能获得更好的乙烯选择性。通过添加适当的助剂,控制助剂的用量也能够提高催化剂的乙烯选择性。和商业碳二加氢催化剂BC2相比,采用浸渍法制备的BC2-MTO催化剂活性组分Pd含量降低了50%以上,活性金属Pd的分散度提高了69%,能够在较低的反应温度和氢炔比条件下使用,具有更好的催化活性和乙烯选择性。

Effect of Low Temperature on Chlorophyll and Carotenoid Content on the Seedlings of Some Selected Boro Rice Varieties

A study was conducted to screen out the low-temperature tolerant Boro rice seedlings from November 2012 to January 2013 for facing the upcoming rice production challenge in Northwest Bangladesh. The experimental time was characterized by a prevailing low environmental temperature of below 15°C. Five rice cultivars (V1: BR-2;V2: BR-16;V3: Pariza;V4: Minicate;V5: BRRI dhan 50) were selected for the study. The leaf proline, chlorophyll content and total carotenoid content were investigated. The V2 (BR-16) seedling synthesized the higher leaf proline (1.228 g·g-1) at a low temperature than those of other tested cultivars. Again, the highest amount of chlorophyll-a (3.957 g·g-1), chlorophyll-b (2.118 g·g-1), chlorophyll-a/b ratio (3.6754 mg·g-1) and total chlorophyll (5.051 g·g-1) was measured in V2 (BR-16). The maximum total carotenoid (1.213 g·g-1) was also observed in V2. In this experiment, the V2 (BR-16) showed comparatively better potentiality to survive at low temperatures (below 15°C) than other varieties.

SPA-H钢低氧出钢的生产技术实践

针对生产SPA-H钢冶炼中低氧控制出钢技术开展研究,分析了相关热力学理论及低氧出钢必要性,确定了SPA-H钢合理低氧范围应为(198~333)×10^(-6)。为实现低氧控制开展了技术改进,合理控制转炉终渣成分,合理排产,实行灵活的溅渣护炉措施;改进冶炼制度,采用“一批料”模式或留少量料模式,改进氧枪工作参数,降低平均枪位,优化枪位控制,保证低枪位拉碳时间,终点温度按照1680℃控制,碳按照0.06%~0.11%控制;采用碳—氧修正模型、转炉质谱仪等辅助手段。改进后,平均终点氧含量降低,氧含量80%控制在选定合理范围,磷、硫、碳及锰含量控制水平均有提升。

Bifunctionality of Cu/ZnO catalysts for alcohol-assisted low-temperature methanol synthesis from syngas:Effect of copper content

Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.

镉低积累水稻品种的筛选及酵素降镉效果研究

为了探究镉污染下水稻的安全生产方式,采用小区试验,比较了50个水稻品种在湖南省镉轻度污染地区的糙米镉积累情况,并研究了喷施植物酵素对不同品种糙米镉积累的影响。结果表明:不同品种水稻对镉的吸收存在显著差异,在考察的50个水稻品种中,泰优390、隆香优310、隆两优1988等品种检测出的镉含量显著低于其他品种,可作为镉轻度污染区域水稻安全生产的应急品种;喷施生物酵素的试验结果表明,生物酵素对不同品种稻米镉累积的影响存在显著差异,施喷酵素可以使某些水稻品种中镉含量降低至国家安全限值以下。

CO优先氧化反应MnCu/Ce催化剂的制备及性能

采用共浸渍法制备较低Cu含量的MnCu/Ce催化剂,通过XRD、BET、H_(2)-TPR、XPS和CO_(2)-TPD等表征手段对催化剂进行表征,考察催化剂焙烧温度对催化剂结构、性质及其在含有CO_(2)的富氢气氛下对CO优先氧化性能的影响。结果表明,MnCu/Ce催化剂均有Cu/Mn-O-Ce固溶体形成,其中,在焙烧温度600℃制备的催化剂中,Mn与Cu、Ce之间相互作用较强,形成较多三元氧化物固溶体,氧空位/Ce^(3+)含量高,具备良好的CO-Prox活性。此外,对反应条件的考察发现,添加不同分压Ar对催化剂的CO-Prox活性影响较小,气体空速和氧过量系数对催化剂活性影响较大,且反应原料气中CO_(2)的存在对CO-Prox反应有负面影响。氧过量系数为1.2、空速范围为20266-30400 mL/(g·h)时,CO转化率最高,达到94.7%。

低温下环丙酸酰胺调控棉花内源激素促进噻苯隆脱叶的机制

脱叶催熟是棉花机械采收的前提,但遇低温可导致噻苯隆(TDZ)脱叶效果下降,不能满足机械化采收的要求,本实验室发现环丙酸酰胺(CYC)可显著提高低温下TDZ的脱叶效果,但CYC促进低温下棉花化学脱叶的机制尚不清楚。为此,以中棉425品种为材料,设置2个温度水平(25℃和15℃),清水(CK)、TDZ单剂(T)和TDZ+CYC复配(TC)3种处理方式,分析棉叶脱落过程中离层中内源激素含量变化及相关基因的表达情况。结果表明:低温(15℃)下处理后240 h,T处理棉花脱叶率仅为53.0%,但TC处理的棉叶脱落开始时间较T处理提前24 h且脱落率升高至79.6%。低温下,相较于T处理,TC处理棉叶离层生长素(IAA)运输相关基因(LAX2、PIN1)、IAA响应基因(IAA9、ARF3)表达量显著下降,离层中IAA含量降低;离层乙烯(ET)合成基因(ACS、ACO)表达量升高,ET合成前体ACC含量增加,ET下游信号基因(ERF1B)显著上调表达;茉莉酸(JA)合成相关基因(AOC4)上调表达,离层中JA含量增加。综上,低温下CYC和TDZ复配抑制棉叶离层中IAA运输与信号传导,促进ET、JA合成与ET信号转导,是CYC提高低温下TDZ脱叶效果的主要原因。

不同施氮水平下低烟碱烟草品种烟碱累积和成熟落黄特性

为研究低烟碱烟草的烟碱累积和成熟落黄特性,解析烟碱含量与烟草成熟落黄特性的相关性,以NC95背景低烟碱烟草品种MAFC5、MLAFC34和LAFC53,K326背景低烟碱烟草品种CD01为材料,并以NC95和K326作对照,分析了不同施氮水平对供试烟草材料不同时期、不同叶位叶片烟碱含量的影响,并进行了成熟落黄特性比较。结果表明:随着烟株的生长,低烟碱烟草的烟碱含量逐渐增高;供试低烟碱烟草品种的烟碱含量均低于对照NC95和K326,表现为MAFC5>MLAFC34>LAFC53>CD01,分别较对照降低39%、43%、79%、96%;MAFC5、MLAFC34、LAFC53不同叶位叶片的烟碱含量由下至上逐渐升高,而CD01不同叶位叶片的烟碱含量则由下至上依次降低;施氮量增加,各品种烟草烟碱含量均增加,从低施氮量到高施氮量,MAFC5、MLAFC34和LAFC53的叶片的烟碱含量分别增加24.3%、26.1%、19.6%,而CD01仅增加9.9%左右,影响较小;MLAFC34和LAFC53的成熟落黄特性较差,CD01和MAFC5的成熟落黄特性和对照烟草接近。本研究发现低烟碱烟草品种叶片的烟碱含量均低于对照品种,施氮量增加对各品种烟碱含量有不同程度的提升作用,叶片烟碱含量与成熟落黄特性无必然关联。

花期低温对草莓叶片光系统荧光特性及保护酶活性的影响

以草莓品种“赛娃”(Fragaria ananassa cv.Selva)为试材,于2022年11-12月在南京信息工程大学开展人工环境控制试验。11月中旬草莓苗进入开花期,挑选长势一致的草莓苗放入人工气候室进行低温处理。温度设置3个水平,即5℃(日最低气温)/15℃(日最高气温)、10℃/20℃和15℃/25℃(CK),处理持续时间为3d、6d和9d。测定不同低温持续天数下草莓叶片光系统荧光诱导动力学参数和保护酶活性等指标,以期了解低温对草莓叶片光系统荧光特性及保护酶活性的影响。结果表明:(1)在日最低温5~15℃范围内,随着温度的降低,持续时间的延长,草莓叶片单位反应中心吸收的光能(ABS/RC)、单位反应中心耗散掉的能量(DIo/RC)和单位反应中心捕获的用于还原QA的能量(TRo/RC)均有所升高,但单位反应中心捕获的用于电子传递的能量(ETo/RC)下降。日最低温5℃持续9d处理的ABS/RC、DIo/RC分别为CK的1.367倍和1.718倍。日最低温10℃持续3d、6d、9d和日最低温5℃持续9d的TRo/RC分别较CK增加了7.42%、14.66%、25.27%和30.48%,而ETo/RC分别较CK下降了1.71%、20.39%、26.65%和28.32%。用于热耗散的量子比率(φDo)随着低温持续时间的延长而显著增大,日最低温5℃持续3d和9d时分别较CK升高了12.34%和25.32%。然而用于电子传递的量子产额(φEo)随低温持续时间的延长而降低,日最低温5℃持续3d和9d分别较CK下降了27.92%和43.02%。(2)随着温度的降低和低温持续时间的延长,草莓叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性和丙二醛(MDA)含量逐渐增加。日最低温5℃持续6d时SOD和POD的活性达到最大,分别为CK的1.39倍和2.03倍,CAT受低温影响变化幅度较小。日最低气温5℃持续9d的MDA含量最高,为CK的2.10倍。研究显示低温会破坏草莓叶片光系统的结构和功能,光化学效率下降,以热量散失的能量增加,导致PSⅡ供体侧提供电子的能力下降,电子传递效率降低,草莓叶片会激发体内的抗氧化系统,对环境产生一定的抵抗能力,表现为SOD、POD、CAT的活性较CK相比均有不同程度的升高,但细胞膜结构仍有一定损伤,膜透性增加。