Yield response of rubber (Hevea brasiliensis) to fertilizers on an Ultisol in Nigeria

The effect of various combinations of N, P, K and Mg fertilizer on yield of rubber over a 3 year period is discussed.N, K and Mg increased yield consistently over the period. The average annual increase in yield over control as a result of application of N, K and Mg were 11%, 3% and 9% respectively; where the effect of P was positive it was negligible.Combined applications of N, K and Mg produced increases that were higher than when they were applied individually. The N₁ K₂ combination produced a mean annual increase of 18% over N₀ K₀, while N₁ Mg₁ increased yield by an average of 26% annually over N₀ Mg₀.N, K and Mg are thus considered as generally required by the rubber trees.     

Magnesium fertilization has a greater impact on soil and leaf nutrient concentrations than nitrogen or calcium fertilization in Florida orange production

Nutrient Cycling in Agroecosystems - Citrus production has been declining in Florida since 2004, mainly because of Huanglongbing (HLB), a deadly disease that is affecting an increasingly large...     

Catalytic effect of mineral matter constituents in a North Assam coal on hydrogenation

The catalytic effect of the mineral matter constituents as estimated in the ash samples prepared from the various specific gravity fractions of a North Assam coal sample on hydrogenation has been studied. Both iron and titanium present in coal have a catalytic effect on hydrogenation. Pyritic as well as organic sulphur present in the coal appear to be responsible for formation of the catalytically active form of iron sulphide from the iron present in the coal mineral matter. Of the aluminosilicates, kaolinite, which is the major component of coal mineral matter, was found to influence the conversion of coal to gas and benzene-soluble products under the conditions of hydrogenation.     

Direct and residual fertilizer phosphorus effects on yield and phosphorus efficiency of upland rice in an Ultisol

Phosphorus (P) deficiency is one of the major limiting factors for crop production in highly weathered soils in the humid zone of West Africa. Very few studies have evaluated the residual value of fertilizer P to rice in these soils. Field experiments were conducted for three years (1993–1995) to determine the response of four upland rice cultivars to fertilizer P applied at 0, 45, 90, 145 and 180 kg P ha^-1 only once in 1993, and to fertilizer P residues in 1994 and 1995. The soil at the experimental site, in the humid forest zone of Ivory Coast (West Africa), was an Ultisol, low in available P. Grain yields of the rice cultivars were significantly increased by fertilizer P in 1993, and by the fertilizer P residues in 1994 and 1995 although the magnitude of response decreased with time since the fertilizer was applied. The cultivars differed in cumulative agronomic and physiological efficiencies, and the efficiencies were higher at the lower rates of P. The amounts of total P removed in three successive crops were similar for all the four rice cultivars although P harvest index was 10–12% higher in the P efficient than inefficient cultivars. The results suggest that the differences observed in the P efficiency of rice cultivars are due to differences in the internal efficiency of P. This revised version was published online in August 2006 with corrections to the Cover Date.     

Laser-induced copper deposition on the surface of an oxide glass from an electrolyte solution

Continuous copper patterns were grown on the surface of oxide glass substrates through laserinduced chemical liquid-phase deposition (LCLD). The deposition was performed with the use of a continuouswave argon laser operating in a multimode regime. The deposition occurred as a result of the reducing chemical reaction initiated by laser radiation. Continuous metal patterns were produced by scanning focused laser radiation along the substrate-electrolyte interface. The morphology and the chemical composition of the deposited patterns were examined with the use of a CEM-SCAN 4 DV scanning electron microscope equipped with an energy-dispersive spectrometer. The morphology of the deposited patterns was investigated as a function of the laser radiation power and the number of scans. It was demonstrated that high-quality continuous patterns can be fabricated using one scan of the laser beam.     

Cowpea varietal differences in uptake of phosphorus from Gafsa phosphate rock in a low-P Ultisol

A greenhouse experiment was conducted to evaluate varietal differences in the uptake and availability of P from Gafsa phosphate rock (PR) to five cowpea cultivars grown in a low-P Paleustult soil from Ghana, using the A value technique. The³²P radioisotope used as a tracer was³²P-labelled triple superphosphate (TSP). Each cultivar received sole or a combined application of the two fertilizers (TSP, PR). From these treatments it was possible to estimate for each cultivar, A_R + A_S, A_S and by difference A_R (A_R and A_S stand for A values for phosphate rock and soil, respectively). Using this approach we measured significant genotypic differences in P uptake from PR and A_R values. The ranking of the cultivars in P uptake from PR was the same as for A_R, i.e. Asontem > Vallenga > Soronko > IT81D-1137 > Amantin. Similarly, ranking for uptake from soil P was the same as A_S, i.e. Vallenga, Soronko, IT81D-1137, Asontem and Amantin. Thus although PR could not be labelled directly, using the A value approach it was possible to distinguish between P availability from PR and soil to the plant. The recoveries of applied TSP ranged from 8.0% to 9.4% and those of PR from 2.3% to 3%.The other advantage of the A value method is that it made it possible for the different genotypes tested to be compared directly in units of a standard fertilizer, TSP in this case. Thus for Vallenga in this soil 3.01 kg of P in Gafsa PR was capable of supplying the same amount of P that could be supplied by 1 kg P of TSP; whereas for Amantin a higher amount i.e. 3.5 kg P as Gafsa PR was needed. This information is useful for adjusting application rates to be recommended for different P fertilizer sources in field trials so as to achieve similar effects.     

Response of upland rice to phosphorus in an Ultisol in the humid forest zone of West Africa

Phosphorus (P) deficiency is one of the major limiting factor for crop production in highly weathered soils in the humid tropics. Field experiments were conducted for two years (1992 and 1993) to determine P response and efficiencies of upland rice cultivars in an Ultisol, low in available P, in the forest zone of Cote d'Ivoire. The rice cultivars tested were selected from a large number of entries tested earlier for acidity tolerance.Grain yields of the cultivars were significantly increased by P application. There was little further response in grain yield at higher rates than 60 kg P ha^–1. The rice cultivars differed in agronomic and physiological P efficiencies and the efficiencies were higher at lower rates of P. The rooting depths of the cultivars were increased by application of P at the lowest application rate (30 kg P ha^–1).The results suggest that P fertilization of soil acidity-tolerant upland rice cultivars can significantly improve the productivity of the Ultisols.     

淫羊藿属植物黄酮类化学成分研究进展

综述了淫羊藿属植物中几乎所有已发现的黄酮类成分,并对其进行系统分类整理,可为该类成分的深入研究与开发提供参考。     

Scattering from a polymer solution at an arbitrary concentration

The elastic coherent scattering intensity for a polymer solution at an arbitrary concentration has been calculated. We introduce an approximate model of contacts between many chains which is a generalization of the well known Zimm single contact model. The results are consistent with the predictions of the random phase approximation^2–4 and can be considered as a direct application of the theory of Ornstein and Zernike⁸. It is shown that the effect of higher order contacts between chains simply reduces to a redefining of an apparent second virial coefficient which would be a function of concentration only. The model is applied to a mixture of deuterated and ordinary homopolymers and the results are not affected by the polydispersity.     

栀子油脂制取亚油酸的研究

用气相色谱法分析了栀子果实油脂中主要脂肪酸的组成 ,软脂酸和亚油酸分别占总脂肪酸的 2 5 .5 %和71.8%。栀子油脂经皂化、酸化、丙酮溶解、冷冻结晶等工艺可制出符合医药标准的亚油酸 ,并对工艺参数进行了研究     

有埋深无体积质量的黏性土地基极限承载力的直接求解

对于有埋深无体积质量黏性土地基极限承载力的求解,目前大多数土力学的书籍中都是先假定滑移面然后用静力平衡的方法求解,这样的求解过程是不精确的.利用Coulomb-Mohr屈服准则,基于R.希尔调和挤出图,采用了塑性力学滑移线的方法求解,得到了相同的结论,但是推导过程却大为简化.     

干姜挥发油成分GC-MS分析

目的:分析和鉴定干姜中的挥发油成分。方法:采用水蒸汽蒸馏法提取干姜中的挥发油,气相色谱-质谱联用分离并鉴定化学成分,各组分的相对含量采用峰面积归一法计算。结果:从干姜挥发油中共鉴定出59个化合物,占挥发油总量的88.238%,其中主要成分为4-甲基-1-(1-甲基乙基)-二环[3.1.0]己-2-烯(9.930%)、桉叶油醇(9.828%)、冰片(9.127%)、莰烯(8.188%)、[S-(R*,S*)]-2-甲基-5-(1,5-二甲基-4-己烯基)-1,3环己二烯(6.279%)、(E)-柠檬醛(3.688%)、α-松油醇(3.489%)、芳樟醇(2.716%)、(1R)-(+)-α蒎烯(2.541%)、Β-倍半水芹烯(2.538%)、1-甲基-4-(1-亚甲基-5-甲基-4-己烯基)环己烯(2.495%)、右旋柠檬烯(2.429%)、A-姜黄烯(2.205%)。结论:本实验方法操作简单、时间短、实验结果准确,可以为干姜的质量分析提供理论依据。     

大青叶挥发油成分GC-MS分析

目的:分析和鉴定大青叶中的挥发油成分。方法:采用水蒸气蒸馏法提取大青叶中的挥发油,气相色谱-质谱联用分离并鉴定化学成分。结果:从大青叶中鉴定出30种成分,相对含量占挥发油总量的90.207%。主要成分为正二十九烷(34.195%)、棕榈酸(17.012%)、植酮(10.036%)、11-戊烷-3-基二十一烷(5.843%)、植物醇(2.275%)、邻苯二甲酸二丁酯(2.107%)。结论:首次对大青叶中的挥发油成分进行分析鉴定,为其进一步开发并合理利用提供理论依据。     

Preparation of amino-functionalized silica for copper removal from an aqueous solution

In the present research, amino-functionalized silica materials were synthesized to develop absorbents for removing copper (II) ions from water. Three kinds of silica with various BET surface areas and pore volumes (331.4 m²/g, 460.1 m²/g, 717.7 m²/g and 1.38 cm³/g, 1.06 cm³/g, 0.57 cm³/g, respectively) were used to determine an optimum material. 3-Aminopropyltrimethoxysilane (3-APTMS) and N-[3-(trimethoxysilyl)propyl]-ethylenediamine (MSDA) are two amino-functional moieties grafted onto silica surfaces. A maximum copper absorption of 33.45 mg/g was confirmed using the amino-functionalized material at an initial 3-APTMS concentration of 2.52 mmol/g. Silica with a BET surface of 331 m²/g and a pore volume of 1.38 cm³/g demonstrated a good copper absorption capacity. Interference species such as pH, NH₃ and EDTA were also studied in this work.     

Adsorption characteristics of sericite for cesium ions from an aqueous solution

To efficiently remove cesium ions from aqueous solution, sericite was used as a novel adsorbent. The silanol (SiO₂) and aluminol (Al₂O₃) groups in sericite are likely to play an important role in adsorption process. The maximum adsorption capacity (q_m) and adsorption constant (K_L) for cesium ions obtained from the Langmuir isotherm model were 6.68 mg/g and 0.227 L/mg, respectively and regression curve fit well with the experimental data as the 0.965 of correlation coefficients (r²). However, when the Freundlich isotherm model was used correlation coefficient (r²) was 0.973. Therefore, it was concluded that Freundlich model fits equilibrium data better than Langmuir model. When the 6.0 g/L of sericie concentration was added to aqueous solution, cesium ions were removed by about 80% and the increase was not happened above 6.0 g/L of sericite concentration any more. The process was determined as exothermic reaction because the removal efficiency of cesium ions decreased as temperature increased. Furthermore, all adsorption was completed in 120 min and comparing the pseudo first and second-order kinetic models indicates that the adsorption of cesium ions using sericite follows well the pseudo-second-order kinetics.     

Impact of a single crystal in solution, on an immersed target, in conditions which simulate impact attrition in crystallizers

In industrial crystallization, attrition due to particle–crystallizer contacts is a primary source of generation of fragments, which greatly affects operating conditions, and the resulting size-distribution and morphology. The objective of this work is to contribute to the understanding of the attrition propensity of crystals in suspension, under conditions of impact at velocities which typically occur in crystallizers. Two types of parameters were studied: those related to the operating conditions (impact velocity, number of impacts, type of target) and those related to the properties of the crystals and of the solution which they are in. The rate of attrition increases with the velocity of impact and depends on the orientation and on the material of the target. An attempt to correlate the data to the impact energy is made.     

Initiation of combustion of exothermic mixtures by a flash from an impact

Kuibyshev. Translated from Fizika Goreniya i Vzryva, Vol. 28, No. 3, pp. 26–29, May–June, 1992.     

蒜头果挥发油化学成分研究

采用同时蒸馏萃取及水蒸气蒸馏方法分别提取新鲜蒜头果果皮中的挥发性成分,挥发油通过气相色谱-质谱联用法进行分离和鉴定,采用峰面积归一化法确定百分含量。从水蒸气蒸馏中分别鉴定出9种成分,分别占总量的96.62%和99.80%,这些成分主要是为苯甲醛、α-羟基-苯乙腈、苯甲醇、4-羟甲基苯甲酸甲酯和2-羟基-丙烷腈等成分。结果表明,采用同时蒸馏萃取法得到的挥发油得率(为1.23%)较水蒸气蒸馏方法 (为0.92%)高,所鉴定出来的挥发性成分含量占总量的比例较水蒸气蒸馏方法高,因此采用同时蒸馏萃取方法更适用于蒜头果果皮精油的提取。