福安地区葡萄大小粒形成原因及预防措施

近年来,葡萄栽培面积逐渐扩大,随之而来的栽培问题逐渐增多,其中果实僵化、大小粒、单性结实等问题成为较为典型和突出的问题。通过对存在问题的果园进行调查发现出现僵果等问题的原因主要有肥水供应不足、中微量元素缺乏、药害、除草剂为害、异常气候影响、植物生长调节剂使用不当等。主要是解决树体生长势问题,保持充足肥水供给、各元素养分供应平衡,药剂使用二次稀释、合理使用植物生长调节剂。总之,提高树体生长势,增强植株抗逆性和适应性,是有效改善僵果、大小粒问题出现的关键。

葡萄果实大小粒的影响因素调查及防治方法试验

大多数葡萄品种都不同程度的存在果实大小粒现象,果实大小粒不仅影响葡萄的外观品质,而且严重影响经济效益。通过调查果粒大小与种子数量间关系以及与枝条粗度的关系得知,葡萄果实大小粒产生的原因主要是花芽分化不良和营养生长与生殖生长不平衡造成的。采用缓和长势的"V"型水平架式能明显减轻果实大小粒的发生程度。对于易发生果实大小粒的品种,见花7 d,用一定浓度的赤霉素处理果穗,可以提高葡萄果粒的均匀度。

48个葡萄品种果实大小粒性状调查及差异分析

以中国农业科学院郑州果树研究所葡萄种质资源圃内果实大小粒现象明显的48个葡萄(Vitis spp.)品种为材料,对各品种的小果率进行了调查,并对各品种大果和小果的生长性状(包括果粒纵径、果粒横径、果形指数、单果粒质量和单果粒种子数)、果实品质(包括果实硬度、可溶性固形物含量、可滴定酸含量和花色苷含量)和横切面解剖结构进行了比较。结果表明:供试所有葡萄品种的小果率为13.9%~87.9%,且在品种间差异较大。供试所有品种大果的果粒纵径、果粒横径和单果粒质量分别为15.35~30.29 mm、16.16~27.98 mm和2.82~14.32 g,显著(P<0.05)高于同一品种小果;47个有核品种的大果均有种子,单果粒种子数为1~6,但除‘高妻’(‘Takatsuma’)和‘熊岳白’(‘White Xiongyue’)外,其余有核品种的小果均未见种子。供试所有品种大果的果实硬度为0.52~1.66 kg·cm^-2,显著高于同一品种小果;多数品种大果的可溶性固形物含量(13.34%~23.08%)、可滴定酸含量(0.32%~0.99%)和花色苷含量(0.22~3.46 mg·g^-1)显著低于同一品种小果。果实横切面解剖结构观察结果表明:同一品种大果和小果间表皮细胞的长度、宽度和面积差异显著;在400倍视野内,同一品种大果和小果间的表皮细胞数也差异显著,且大果的表皮细胞数显著高于小果。总体来看,同一葡萄品种大果和小果间的生长性状、果实品质和解剖结构存在显著差异,推测其大小粒形成主要由果实发育前期的细胞数量决定。

河北保定地区巨峰葡萄大小粒常见原因及改进措施

葡萄大小粒,大粒是指正常粒,小粒指小于正常大小的粒,像花生或黄豆粒大小,一般无种子,而且先着色。该文通过对巨峰葡萄品种、天气因素、缺硼锌钙等元素、树势太过或太弱等方面存在的问题进行分析,并提出合理的解决措施,有效降低大小粒现象发生几率,提升葡萄收益。

屏南县巨峰葡萄大小粒现象发生的原因

为探究福建省屏南县巨峰葡萄大小粒现象的发生原因,以屏南县巨峰种植园区为调查研究对象,采取随机抽样的方法,调查巨峰葡萄大小粒的情况、植株生长状况以及种植园区的管理水平等内容。调查发现,屏南县巨峰葡萄产业4 a以上老树的大小果现象严重,4 a以下小苗的大小果现象较轻。通过调研初步掌握了屏南县巨峰葡萄产业出现大小粒现象的发生原因为上一年冬肥施量过多且修剪过早,导致结果枝生长过旺。调研结果为预防屏南巨峰葡萄产业出现大小粒现象提供了决策依据。

聚丙烯造粒产品大小粒形成的原因及改进措施

从Innovene气相聚丙烯装置造粒过程中经常出现大小粒导致产品不合格入手,全面分析了产生大小粒的原因。并针对原因,详细阐述了造粒系统工艺流程中模板、切刀以及冷却水对大小粒的影响以及解决方案,从而达到减少大小粒数量的目的,使装置能够长期稳定的运行。

葡萄大小粒的发生与防治

葡萄在我国水果中占据较大比例,尤其是在现在经济局势和极端气候控制范畴之下,涉及葡萄的栽培技术受到各个不同区域农业科研机构的高度重视。结合以往调查数据整理显示,葡萄的种植面积随着经济的快速发展而逐渐扩大,随之而来的就是葡萄种植过程中出现的各种技术问题。当前,葡萄的栽培技术中面临着最大的问题就是葡萄大小粒不均匀,如果不及时改善,会严重影响葡萄的产量和在市场中的竞争地位,基于此,本文通过对葡萄大小粒的现状以及发生原因为基础,讨论如何防治葡萄大小粒的措施。

葡萄果粒粒径控制研究进展

在葡萄生产中经常会出现果粒偏小或粒径不均一(大小粒)现象,降低了葡萄的销售价值。对葡萄果粒粒径的测定方法、粒径控制的应用背景及控制方法研究进行了综述,认为在葡萄的生产管理中,应"平衡"栽培管理、合理利用药剂、综合利用各种方法,合理控制葡萄果粒粒径大小,促使葡萄产业健康稳步发展。

Load-bearing characteristics and energy evolution of fractured rock masses after granite and sandstone grouting

Experiments on grouting-reinforced rock mass specimens with different particle sizes and features were carried out in this study to examine the effects of grouting reinforcement on the load-bearing characteristics of fractured rock mass.The strength and deformation features of grouting-reinforced rock mass were analyzed under different loading manners;the energy evolution mechanism of grouting-reinforced rock mass specimens with different particle sizes and features was investigated;the energy dissipation ratio and post-peak stress decreasing rate were employed to evaluate the bearing stability of grouting-reinforced rock mass.The results show that the strength and ductility of granite-reinforced rock mass(GRM)under biaxial loading are higher than that of sandstone-reinforced rock mass(SRM)under uniaxial loading.Besides,the energy evolution characteristics of grouting-reinforced rock mass under uniaxial and biaxial loading mainly could be divided into early,middle,and late stages.In the early stage,total,elastic,and dissipation energies were quite small with flatter curves;in the middle stage,elastic energy increased rapidly,whereas dissipation energy increased slowly;in the late stage,dissipation energy increased sharply.The energy dissipation ratio was used to represent the pre-peak plastic deformation.Under uniaxial loading,this ratio increased as the particle size increased and the pre-peak plastic deformation of grouting-reinforced rock mass became larger;under biaxial loading,it dropped as the particle size increased,and the pre-peak plastic deformation of grouting-reinforced rock mass became smaller.The post-peak stress decline rate A_(v) was used to assess the post-peak bearing performance of grouting-reinforced rock mass.Under uniaxial loading,parameter A_(v) exhibited reduction as the particle size kept increasing,and the ability of post-peak of grouting-reinforced rock mass to allow deformation development was greater,and the bearing capacity was greater;under biaxial loading,A_(v) increased with the particle size,and the ability of post-peak of grouting-reinforced rock mass to allow deformation development was low and the bearing capacity was reduced.The findings are considered instrumental in improving the stability of the roadway-surrounding rock by granite and sandstone grouting.

Molecular Dissection of Relationship Between Seedling Characteristics and Seed Size in Rice

Seedling characteristics such as leaf emergency, chlorophyll content, and height are important for early growth and also associated with seed size. Quantitative trait loci (QTLs) for rice (Oryza sativa L.) seedling characteristics (leaf length, chlorophyll content, seedling height) and seed size were identified with an attempt to explore the relationship between seedling characteristics and seed size, using a recombinant inbred population derived from a cross between Zhenshan 97A and Minghui 63. Two, one, five, four, four, and nine QTLs were detected for chlorophyll a content, total chlorophyll, length of the second seedling leaf, length of the third seedling leaf, seedling height, and seed size, respectively. The results indicated that four QTLs for seed size and four QTLs for seedling characteristics shared several similar regions (G359-RG532, C567-RG236, RZ403-R19, C371-C405a), respectively, suggesting a close association between seedling characteristics and seed size. Several chromosomal regions influencing seed size, however, had no effects on seedling characteristics, suggesting that it was possible to improve seedling vigor without increasing grain size.

Correlation between H-ZSM-5 crystal size and catalytic performance in the methanol-to-aromatics reaction

The porosity of H‐ZSM‐5zeolite is known to facilitate the diffusion of molecules in the methanol‐to‐aromatics(MTA)reaction.The activity and selectivity of the H‐ZSM‐5catalyst in the MTAreaction has been studied as a function of crystal size.ZSM‐5zeolites with different crystal sizeswere successfully synthesized by conventional hydrothermal methods.Tailoring ZSM‐5particle sizewas easily controlled by changes to the sol‐gel composition,and in particular,the deionized waterto tetrapropylammonium hydroxide ratio,and crystallization time.The structure of the H‐ZSM‐5zeolites were characterized by X‐ray diffraction and the morphology of the zeolite particles wasdetermined by scanning electron microscopy.N2adsorption‐desorption measurements establishedchanges to the textural properties,and compositional properties were characterized by X‐ray fluorescencespectroscopy.Acidity measurements of the catalysts were measured by pyridine‐adsorbedFourier transform infrared spectroscopy and the temperature‐programmed desorption of ammonia.After subjecting the catalysts to the MTA reaction,the total amount of coke formed on the spentdeactivated catalysts was determined by thermal gravimetric analysis.The results show that theSiO2/Al2O3molar ratios and acidic properties of the H‐ZSM‐5samples are similar,however,thenano‐sized hierarchical ZSM‐5zeolite with an additional level of auxiliary pores possesses a higher

Recent advances in naphtha catalytic cracking by nano ZSM-5:A review

This review discussed the use of nano ZSM‐5 in naphtha catalytic cracking. The impact of nano ZSM‐5 on product selectivity, reaction conversion and catalyst lifetime were compared with micro‐sized ZSM‐5. The application of nano ZSM‐5 not only increased the catalyst lifetime, but also gave more stability for light olefins selectivity. The effects of the reaction parameters of temperature and feedstock on the performance of nano ZSM‐5 were investigated, and showed that high temperature and linear alkanes as feedstock improved light olefin selectivity and conversion.

Difference in Organic Carbon Contents and Distributions in Particle-size Fractions between Soil and Sediment on the Southern Loess Plateau, China

The purpose of this study was to assess the effect of long-term cultivation and water erosion on the soil organic carbon （OC） in particle-size fractions. The study site is located at Nihegou Watershed in the Southern Loess Plateau, China. The soil at this site is loess with loose and silty structure, and contains macropores. The results showed that the OC concentrations in sediments and in the particle-size fractions of sediments were higher than those in soils and in the particle-size fractions of soils. The OC concentration was highest in the clay particles and was lowest in the sand particles. Clay particles possessed higher OC enrichment ability than silt and sand particles. The proportions of OC in the silt fractions of soil and sediment were the highest （mean value of 53.87% and 58.48%, respectively）, and the total proportion of OC in the clay and silt fractions accounted for 96% and 98% of the total OC in the soil and sediment, respectively. The loss of OC was highest in silt particles, with an average value of 0.16 Mg ha^-1 y^-1, and was lowest in the sand （0.003 Mg ha^-1 y^-l）. This result suggests that the fine particle-size fraction in the removed sediment may be an important indicator to assess soil OC losses.

Periodical attenuation of Al(OH)_3 particles from seed precipitation in seeded sodium aluminate solution

Periodical attenuation of particles,which interferes seriously the normal alumina production,exists in Bayer process.In order to solve this problem,the rule of periodical attenuation of Al(OH) 3 particles was investigated by laboratory experiments under simulated industrial conditions.The results show that at higher temperature the variation period of particle size is shortened,while prolongs with more solid content.Particle size fluctuation amplitude reduces with the temperature rising but increases with the solid content increasing.Particle size distribution becomes more uniform by replenishing fine seeds,enabling the periodical fluctuation of Al(OH)3 particle size to be attenuated.Combining properly the additives with controlling the seed size is able to reduce the amplitude of periodical fluctuation and shorten the attenuation time.With unbalance of particle size distribution,the particles gradually become bigger,even inducing the decrease of the specific surface area of seeds,which is the major reason causing explosive attenuation of Al(OH)3 particles in seed precipitation process.

Estimation of coal particle size distribution by image segmentation

Several industrial coal processes are largely determined by the distribution of particle sizes in their feed.Currently these parameters are measured by manual sampling,which is time consuming and cannot provide real time feedback for automatic control purposes.In this paper,an approach using image segmentation on images of overlapped coal particles is described.The estimation of the particle size distribution by number is also described.The particle overlap problem was solved using image enhancement algorithms that converted those image parts representing material in lower layers to black.Exponential high-pass filter(EHPF) algorithms were used to remove the texture from particles on the surface.Finally,the edges of the surface particles were identified by morphological edge detection.These algorithms are described in detail as is the method of extracting the coal particle size.Tests indicate that using more coal images gives a higher accuracy estimate.The positive absolute error of 50 random tests was consistently less than 2.5% and the errors were reduced as the size of the fraction increased.

Separation and Manipulation of Rare-earth Oxide Particles by Dielectrophoresis

A challenge in chemical engineering is the separation and purification of rare-earth elements and their compounds. We report the design and manufacture of a dielectrophoresis(DEP) microchip of microelectrode arrays. This microchip device is constructed in order to use DEP to capture micro-particles of rare-earth oxides in petro-leum. Dielectrophoretic behavior of micro-particles of rare-earth oxides in oil media is explored. The dielectropho-retic effects of particles under different conditions are investigated. It is showed that the prepared microchip is suit-able for use in the investigation of dielectrophoretic responses of the rare-earth oxides in oil media. The factors such as frequency,particle size and valence of rare-earth metal are discussed. When the frequency is fixed,the transla-tion voltage decreases as particle size increases. Lower frequencies are more effective for manipulation of inorganic particles in oil media. Particles of the same rare-earth oxide with different size,as well as particles of different rare-earth oxides,are captured in different regions of the field by regulating DEP conditions. This may be a new method for separation and purification of particles of different rare-earth oxides,as well as classification of particles with different size.

Effect of Additive EDTA on Crystallization Process of Magnesium Hydroxide Precipitation

The effects of additive ethylenediaminetetraacetic acid (EDTA) on crystallization process were investigated by the induction time of MgSO 4-NaOH system. Nucleation and growth rates, growth mechanism and particle size distribution of magnesium hydroxide precipitation were involved with. The induction time in unseeded and seeded precipitation of magnesium hydroxide with and without additive EDTA was measured. The conductivity method was used to determine the induction period. Theoretical relations of the induction time and supersaturation ratio for different growth mechanisms and a combined analysis on the induction time were applied to determine nucleation and growth rates. The growth mechanism of magnesium hydroxide precipitation was disclosed by analyzing the experimental data with and without additive. The analysis on induction time indicated that additive EDTA had a significant influence on both nucleation and growth of magnesium hydroxide precipitation. The mechanism underlying the effect of EDTA on crystal growth was 2-dimension nucleation-mediated growth model.

Thermal properties of open-celled aluminum foams prepared by two infiltration casting methods

Contrastive research was carried out to study the thermal properties of open-celled aluminum foams prepared by counter-gravity infiltration casting system and the traditional process respectively.The experimental results show that the thermal conductivity coefficients of aluminum foams prepared by two different infiltration methods have similar increasing trend with the increase of particle size;along with the reducing porosity,the thermal conductivity coefficients will be enhanced oppositely.However,with the same particle size,the open-celled aluminum foam prepared by the former method has a higher thermal conductivity coefficient obviously.It is largely because that the sample prepared by counter-gravity infiltration casting has a lower void content and better dense crystallization of metal-matrix after the constant pressure process.

Removal of Nitrophenols by Adsorption Using β-Cyclodextrin Modified Zeolites

Removal of nitrophenols （NPs） from aqueous solutions through the adsorption process by using cationic β-cyclodextrin （CCD） modified zeolite （CCDMZ） was investigated. The effects of particle size, contact time, solution pH values and sodium chloride content in the aqueous on adsorption capacity were evaluated through a series of batch experiments. The results showed that CCDMZ had a higher adsorption capacity for removing NPs at a size fraction of 0.45-0.9 mm while adsorption of NPs on CCDMZ reached equilibrium within 60 min. The adsorption process was apparently influenced by pH values and sodium chloride content in aqueous solution. To ascertain the mechanisms of sorption, the experimental data were modeled by using the pseudo-first and pseudo-second order kinetic equations, and the results indicated that the adsorption kinetics of NPs on CCDMZ well-matched with the pseudo-second order rate expression.