Agronomical evaluation of phosphate fertilizer as a nutrient source of phosphorus for crops: Isotopic procedure

The agronomic effectiveness of P fertilizers, as sources of phosphorus for crops, was evaluated using the quantities, P_f, of phosphorus taken up byLolium perenne grown on 14 soils during greenhouse experiments in pot cultures. The P_f quantities were determined using³²P-labelled fertilizers. Data were analysed using a new concept: the Isotopic Relative Agronomic Effectiveness (IRAE). The IRAE value was defined as the ratio of the P_f quantity, taken up by a crop, of a tested fertilizer over the P_f quantity, taken up by a crop, of a fertilizer used as standard. In our experiments diammonium phosphate (DAP) was used as standard P fertilizer and two rock phosphates, the North Carolina rock phosphate (NCPR) and a calcium-iron-aluminium phosphate (Phospal), were tested. As a linear relationship between P_f(NCPR) quantities and P_f(DAP) quantities was obtained, with r² = 0.95, when the application rates increased from 15 mgP (kg soil)^–1 to 200 mgP (kg soil)^–1, it is conciuded that IRAE values for a given fertilizer, other than the standard fertilizer, could be determined with a single rate of application. As regards soil pH in the range 4.7 to 8.2 the IRAE_NCPR is related to soil pH by a curvilinear relationship: log IRAE_NCPR = –(0.44) pH + 4.05 with r² = 0.89. The average of IRAE_phospal values was 0.15 with a standard error = 7% irrespective of soil pH. Then a logarithmic relationship was obtained between IRAE values of the two tested fertilizers and their water P-solubility determined at the soil pH where they were applied.     

采用读卡机芯片FM1715SL设计的RFID读卡机

根据车辆管理系统对身份识别需求,提出基于国产芯片的RFID读卡机方案。数据接口设计为ISO14443TypeB的设备,在满足安全保密前提下,很好地兼顾了使用方便和高效便捷,大规模的车载应用验证了该方案的可靠性。     

中国石化集团公司石油勘探开发国际合作的初步构想

在分析中国石化集团进行国际合作必要性的基础上,提出“引进来”和“走出去”是石化集团公司石油国际合作应采取的两种基本方式,并提出继续加强国内风险勘探和提高采收率的对外合作以及积极稳妥开展国际石油勘探开发合作业务的初步设想。     

Characterization of yam bean (Pachyrhizus spp.) Seeds as potential sources of high palmitic acid oil

Seeds from 22 accessions of the yam bean species Pachyrhizus ahipa (14 accessions), P. erosus (5), and P. tuberosus (3) were investigated for oil and protein contents, fatty acid composition of the seed oil, and the total tocopherol content and composition. Plants from the accessions were grown under greenhouse conditions during one (P. erosus and P. tuberosus) or two years (P. ahipa). The pattern of the investigated seed quality traits was very similar in the three species. Yam bean seeds were characterized by high oil (from about 20 to 28% in one environment) and protein contents (from about 23 to 34%). Seed oil contained high concentrations of palmitic (from about 25 to 30% of the total fatty acids), oleic (21 to 29%), and linoleic acids (35 to 40%). Levels of linolenic acid were very low, from about 1.0 to 2.5%. Total tocopherol content was relatively low in P. erosus (from 249 to 585 mg kg⁻¹ oil) and P. tuberosus (from 260 to 312 mg kg⁻¹ oil) compared with the levels found in P. ahipa grown under identical conditions (508 to 858 mg kg⁻¹ oil). In all the samples, γ-tocopherol was predominant, accounting for more than 90% of the total tocopherol content. The combination of high oil and protein contents, together with high palmitic acid, low linolenic acid, and high γ-tocopherol concentration, makes these crops an interesting alternative as sources of high palmitic acid oil for the food industry.     

高校体育教学中学生创新能力的培养

从创新能力和体育教学的关系、体育教学的特性及创造教育实施原则等方面入手,对高校体育教学中学生创新能力的培养进行分析,并阐述其基本方法和途径。     

基于零知识交互式证明和Bayesian信誉网的小世界P2P模型

针对当前P2P(Peer-to-Peer)系统在网络拓扑和信誉评估机制结合方面的不足,设计一种基于角色和信誉访问控制机制的可信小世界P2P(SW-R2P)模型.模型使用零知识交互式证明(ZKIP)算法,在不传输节点身份相关信息的前提下安全地验证对等节点的组信息,并以此作为构建小世界网络拓扑的基础.通过Bayesian信誉网对节点和组的多方面信誉进行评估,从而影响节点的各种操作和组之间连接的建立.仿真实验结果表明,SW-R2P模型在资源查找成功率、网络聚合度以及节点信誉偏差等方面的性能优于Chord和R2P模型.SW-R2P模型结合了ZKIP算法、Bayesian信誉网和小世界拓扑的优势,实现了一种可信、安全和高效的P2P网络架构.     

Formation of bulk ferromagnetic nanostructured Fe_(40)Ni_(40)P_(14)B_6 alloys by metastable liquid spinodal decomposition

Nanostructured Fe40Ni40P14B6 alloy ingots of 3―5 mm in diameter could be synthesized by a metastable liquid state spinodal decomposition method. For undercooling T> 260 K, the microstructure of the undercooled specimen had exhibited liquid state spinodal decomposition in the undercooled liquid state. The microstructure could be described as two intertwining networks with small grains dispersed in them. For undercooling T>290 K, the overall microstructure of the specimen changed into a granular morphology. T...     

P2P网络环境下的推荐信任模型方案

P2P网络的匿名性和动态性带来了许多安全问题,传统的信任管理模型并不能很好的适应对等网络环境。提出了一种基于推荐的P2P网络信任模型,将节点提供服务和推荐的能力进行区分,用信誉值表示节点的推荐能力,根据节点的直接信任值、其它节点的推荐信任值和相应的惩罚值来计算节点的信任度,节点依据信任度选择交易对象。仿真实验表明,基于推荐的信任模型能有效的评估节点的信任度,在交易成功率上要优于传统的信任管理模型。     

Evaluation of the agronomic effectiveness of natural and partially acidulated phosphate rocks in several soils using32P isotopic dilution techniques

The agronomic effectiveness of two natural phosphate rocks (PRs) from North Carolina (USA) and Togo and their 50% partially acidulated products (PAPRs) was evaluated in two greenhouse experiments using³²P isotopic dilution techniques, namely L and A_L values.In the first experiment rye grass was grown in a soil from Ghana. While the proportion of P in the plant derived from the P fertilizer (Pdff) ranged on. the average from about 10% for the PRs up to 80% for the PAPRs, the P fertilizer recovery was less than 1% for a 60-day growth period. In the second experiment, average values of P in the maize plants derived from the PAPRs ranged from 35% to 75% in 3 different soils. Both PRs were ineffective with the exception of North Carolina PR in the Seibersdorf soil. The P fertilizer recovery was 0.25% for the North Carolina PR in this soil whereas the recovery values ranged from 1.2% to 1.6% for the PAPRs.Mean values of the relative fertilizer efficiency estimated from the L values of each soil were less than 1% for the PRs whereas the values for the PAPRs which were dependent on soil type ranged from 20% up to 45%. The coefficient of relative effect of partial acidulation, that was calculated from the ratio of A_L values for PR and PAPR in each soil indicated that partial acidulation increased the effectiveness of the natural PRs in all soils under study.This study showed that the use of³²P isotope dilution techniques allows an accurate measurement of the P availability from natural and modified PR products to crops. Another advantage is that quantitative comparison of the P sources under study, PRs and PAPRs in this case, can be made even in soils where there is no response to the applied P sources.     

Phosphate sorption isotherms in relation to P nutrition of wheat (Triticum aestivum)

The phosphate sorption isotherms are needed to explain differential plant responses to P fertilization in soils. Laboratory and greenhouse experiments investigated the use of phosphorus sorption isotherms in relation to P fertilizer requirement of wheat in ten benchmark soils of Punjab, India. The modified Mitscherlich Equation (3) was used to describe plant response observed in different soils. Maximum obtainable yield (MOY) ranged from 11.6 g pot^–1 in Gurdaspur (I) sandy clay loam to 7.0 g pot^–1 in Nabha sandy clay loam. Response to P applied @ 25 mg P kg^–1 soil was maximum (77%) in Bathinda sand and minimum in Chuharpur clay loam (33%). The response curvature varied from 3.74 × 10^–2 in Nabha sandy clay loam to 4.43 × 10^–2 in Kanjli sandy loam. The soil solution P required to produce optimum yield (90% MOY) varied from 1.61 µg ml^–1 in Bathinda sand to 0.10 µg ml^–1 in Sadhugarh clay. Dry matter yield obtained at 0.2 µg ml^–1 solution P concentration ranged from 55% in Bathinda sand to 85% of MOY in Gurdaspur (II) clay loam. At the same solution P concentration (0.1 µg P ml^–1), dry matter yield was 91% in Sadhugarh clay, 80% in Gurdaspur (II) clay loam and, 43% of MOY in Bathinda sand and eventually coincided with the decreasing maximum buffer capacity (MBC) in these soils. At the same level of sorbed P (100 mg P kg^–1 soil) the yield was observed to be inversely proportional to MBC. The study, therefore, concludes that, soils should be grouped according to their P sorption characteristics and MBC before using critical soil solution P as a criterion for obtaining optimum yields.