醋酸酯淀粉包膜尿素水中养分溶出特征

以研制的4种醋酸酯淀粉包膜尿素肥料为研究对象,日本70 d聚烯烃包膜尿素肥料为对照,研究醋酸酯淀粉包膜尿素在水中尿素态氮溶出特征,以确定醋酸酯淀粉包膜尿素的控释性能。结果表明,醋酸酯淀粉包膜肥料尿素累积溶出曲线呈倒"L"型,在水中7~13 d达到最大溶出量,尿素态氮累积溶出80%的时间为2~3 d,初期溶出率65.71%~75.79%;养分累积释放率不超过75%的时间为1~2 d;第7 d微分溶出率都显著大于2.5%。聚烯烃包膜肥料尿素态氮累积溶出80%的时间超过40 d,初期溶出率为2.05%;聚烯烃养分累积释放率36 d为73.32%,37 d为75.01%;第7 d微分溶出率1.68%。醋酸酯淀粉包膜尿素缓/控释效果较差,对养分的控释能力明显低于聚烯烃包膜尿素,但对尿素态氮起到了一定的缓/控释作用。醋酸酯淀粉包膜尿素及聚烯烃包膜尿素肥料在水中尿素态氮累积溶出特征曲线符合一元二次方程模型。

低山丘陵半干旱区春小麦田水肥耦合作用的初步研究

在旱棚控制条件下 ,采用 31 2 - D最优饱和设计方案 ,对辽西半干旱区春小麦田水肥耦合作用进行了初步研究。在建立了水肥耦合数学模型基础上 ,分析了各因子的主因素和单因素效应、两因素和三因素间交互耦合效应以及多因子间的耦合和限制作用类型 ,并提出了以水调肥矫正模型 ,为该区水肥耦合作用的充分发挥和互馈作用的人工调控提供了理论依据。

吉林省白城地区干草原栗斑腹的繁殖生态

栗斑腹在吉林省为留鸟 ,一年可繁殖两次 ,其雏鸟为典型的晚成鸟。 4月末开始有求偶追逐和争雌行为 ,5月中旬产卵。雌雄鸟筑巢时间分别是 43 min/d和 3 6min/d(筑巢第 4天 )。平均窝卵数为 5 .0 9± 0 .5 8枚 /巢 (n=3 1 ) ,孵卵前、中、后期雌鸟孵卵占白天活动时间的 3 5 %、74.5 %和 67.6% ,孵化期为 1 2 d,孵化率为 3 6.3 % ,2、8日龄喂雏分别为 4.5次 /h和 9.0次 /h。雏鸟的体重及外部器官的发育除嘴峰外 ,生长曲线均符合 Logistic方程 ,而嘴峰长的生长近似直线 ,栗斑腹雏鸟生长发育体重的生长模型为 :W =1 4.95 /1 +(e- 0 .552 ( t- 3.6 3) ) ,雏鸟 1 1日龄后出飞 ,繁殖成活率为 2 7.7%。

长武塬区大气降水中氢氧同位素特征分析

通过测定长武塬区2005年降水水样的氢氧同位素组成,分析了该区降水氢氧同位素组成的基本特征。结果表明,长武塬区大气降水线方程为δD=7.44δ~(18)O+1.69,其斜率和截距与全球以及我国大气降水线相比均偏小,这与研究区地理位置和气候条件有关;降水氘盈余d值4—6月份较大,大于或接近10,7—10月份则小于10;以天为时间单位采集的次降水,其氢氧同位素组成的温度效应和降水量效应均不显著,而连续2 d长历时降水的雨量效应极显著;降水氢氧同位素组成季节变化明显,春季降水的氢氧同位素值较高,夏季同位素值降低,秋季同位素值最小,这在以次降水量为权重的加权平均值中表现得更加明显。

沈阳市排污明渠——细河CH_4的排放

利用封闭箱法测定了沈阳市排污明渠———细河水面CH4 的排放通量 ,结果表明 ,细河是重要的CH4 排放源 ,水面全年有甲烷排放 ,排放通量达到 2 80 .8mg·m-2 ·d-1.且明显受水温和水体污染物影响 ,即夏季高 ,冬季低 ;渠首高 ,渠尾低 ;以细河作为排污明渠处置污水 ,每升污水的甲烷贡献率为 0 .36 6mg ,高于普通二级污水处理厂 .

Critical behavior of brittle-ductile transition of polymers

We report that the brittle-ductile transition of polymers induced by temperature exhibits critical behavior. When t close to 0, the critical surface to surface interparticle distance (IDc) follows the scaling law: IDc proportional to t(-v) where t = 1 - T/T-BD(m) (T and T-BD(m) are the test temperature and brittle-ductile transition temperature of matrix polymer, respectively) and v = 2/D. It is clear that the scaling exponent v only depends on dimension (D). For 2, 3, and 4 dimension, v = 1, 2/3, and 1/2 respectively. The result indicates that the ID, follows the same scaling law as that of the correlation length (xi), when t approach to zero.

齐聚苯胺修饰的三联吡啶铁配合物的合成及其光谱和电化学性质

合成了一系列齐聚苯胺修饰的三联吡啶铁配合物,研究了齐聚苯胺链长、不同取代基等对配合物光谱性质和氧化还原性质的影响。结果表明,相对于配合物[Fe(TPY)2]2+(TPY:三联吡啶),供电子齐聚苯胺单元的引入,使得修饰基团与配合物中心核[Fe(TPY)2]2+之间形成了强的D-A体系,导致配合物1MLCT吸收波长显著红移至594 nm,且摩尔吸光系数增加近5倍。配合物同时具有基于金属中心、三联吡啶配体和齐聚苯胺单元的多个氧化还原过程,强拉电子取代基使齐聚苯胺单元氧化还原峰简并且峰电势明显正移,而正丁基取代基对氧化还原峰电势的影响较小。

Two-Step Spin-Transition Iron(III) Compound with a Wide [High Spin-Low Spin] Plateau

A new iron(III) coordination compound exhibiting a two-step spin-transition behavior with a remarkably wide [HS-LS] plateau of about 45 K has been synthesized from a hydrazino Schiff-base ligand with an N,N,O donor set, namely 2-methoxy-6-(pyridine-2-ylhydrazonomethyl) phenol (Hmph). The single-crystal X-ray structure of the coordination compound {[Fe(mph)(2)](ClO4)(MeOH)(0.5)(H2O)(0.5)}(2) (1) determined at 150 K reveals the presence of two slightly different iron(III) centers in pseudo-octahedral environments generated by two deprotonated tridentate mph ligands. The presence of hydrogen bonding interactions, instigated by the well-designed ligand, may justify the occurrence of the abrupt transitions. 1 has been characterized by temperature-dependent magnetic susceptibility measurements, EPR spectroscopy, differential scanning calorimetry, and Fe-51 Mossbauer spectroscopy, which all confirm the occurrence of a two-step transition. In addition, the iron(III) species in the high-spin state has been trapped and characterized by rapid cooling EPR studies.

Charge disproportionation in CaCu3Fe4O12

First-principles calculations using the APW+lo method, as implemented in the WIEN2K code, have been used to investigate the structural, electronic, and magnetic properties of the perovskite CaCu3Fe4O12, including the high-temperature Im-3 and low-temperature Pn-3 phase. The high-temperature phase presents a homogeneous valence and an orbital degenerate half-metallic behavior, which is consistent with the previous theoretical result. Instead orbital ordering, charge ordering, or disproportionation on Fe sites occur in the low-temperature phase, leading to the insulating character. More importantly, the charge disproportionation is of 2d(5)L -> d(5)L(2) + d(5) type (where L denotes an oxygen hole or a ligand hole), and the origin for the phenomenon is discussed in detail.

Spontaneous formation of two-dimensional gold networks at the air-water interface and their application in surface-enhanced Raman scattering (SERS)

Two-dimensional (2-D) gold networks were spontaneously formed at the air-water interface after HAuCl4 reacted with fructose at 90 degrees C in a sealed vessel, in a reaction in which fructose acted as both a reducing and a protecting agent. Through fine-tuning of the molar ratio of HAuCl4 to fructose, the thus-formed 2-D gold networks can be changed from a coalesced pattern to an interconnected pattern. In the coalesced pattern, some well-defined single-crystalline gold plates at the micrometer-scale could be seen, while in the interconnected pattern, many sub-micrometer particles and some irregular gold plates instead of well-defined gold plates appeared. It is also found that the 2-D gold networks in the form of an interconnected pattern can be used as substrates for surface-enhanced Raman scattering (SERS) because of the strong localized electromagnetic field produced by the gaps between the neighboring particles in the 2-D gold networks.

Lung alveolar proteomics of bronchoalveolar lavage from a pulmonary alveolar proteinosis patient using high-resolution FTICR mass spectrometry

High-resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometry was developed and applied to the proteome analysis of bronchoalveolar lavage fluid (BALF) from a patient with pulmonary alveolar proteinosis. With use of 1-D and 2-D gel electrophoresis, surfactant protein A (SP-A) and other surfactant-related lung alveolar proteins were efficiently separated and identified by matrix-assisted laser desorption/ionization FTICR mass spectrometry . Low molecular mass BALF proteins were separated using a gradient 2-D gel. An efficient extraction/precipitation system was developed and used for the enrichment of surfactant proteins. The result of the BALF proteome analysis show the presence of several isoforms of SP-A, in which an N-non-glycosylierte form and several proline hydroxylations were identified. Furthermore, a number of protein spots were found to contain a mixture of proteins unresolved by 2-D gel electrophoresis, illustrating the feasibility of high-resolution mass spectrometry to provide identifications of proteins that remain unseparated in 2-D gels even upon extended pH gradients.

Comparison for DNA primary sequence

In this article, two schemes are suggested based on three exons of beta-globin gene belonging to 10 species for comparison of DNA primary sequences. At first, the positions of four nucleic acid bases were extracted, and then based on the information, as the numerical characterization of DNA sequences, the sequence invariants were derived. Sequences comparisons of 10 species selected in this work by using these invariants were performed. The results, especially with scheme 2, are quite satisfactory.

A novel invariant and sequence comparison for DNA

We consider numerical characterization of DNA primary sequence based on the positions of bases (a, t, c, g) and the pairs of bases X, Y in DNA (X, Y=a, t, c, g). This leads to a representation of DNA by a numerical sequence. Then, we extract a novel invariant (molecular connectivity index) from the derived numerical sequences. The suitable invariant can offer a characterization of DNA primary sequence. Finally, we provide an illustration of its utility by making a comparison between ten DNA sequences belonging to beta-globin gene in different species. The evolutionary relationships of ten species we have revealed in this contribution accord with phylogenetic tree properly.

Interdigited phospholipid/alkanethiol bilayers assembled on APTMS-supported gold colloid electrodes

The preparative procedure of a kind of phospholipid/alkanethiol bilayers on a planar macroelectrode was copied to the as-prepared gold colloid electrodes. The electrochemical and spectral results show that the bilayers on colloid electrodes are interdigited, which are different from their 2-D counterparts on a planar macroelectrode.

New high-dimensional networks based on polyoxometalate and crown ether building blocks

Three novel supramolecular assemblies constructed from polyoxometalate and crown ether building blocks, [(DB18C6)Na(H2O)(1.5)](2)Mo6O19.CH3CN, 1, and [{Na(DB18C6)(H2O)(2)}(3)(H2O)(2)]XMo12O40.6DMF.CH3CN (X = P, 2, and As, 3; DB18C6 = dibenzo-18-crown-6; DMF = N,N-dimethylfomamide), have been synthesized and characterized by elemental analyses, IR, UV-vis, EPR, TG, and single crystal X-ray diffraction. Compound 1 crystallizes in the tetragonal space group P4/mbm with a = 16.9701(6) Angstrom, c = 14.2676(4) Angstrom, and Z = 2. Compound 2 crystallizes in the hexagonal space group P6(3)/m with a = 15,7435(17) Angstrom, c = 30.042(7) Angstrom, gamma = 120degrees, and Z = 2. Compound 3 crystallizes in the hexagonal space group P6(3)/m with a = 15.6882(5) Angstrom, c = 29.9778(18) Angstrom, gamma = 120degrees, and Z = 2. Compound 1 exhibits an unusual three-dimensional network with one-dimensional sandglasslike channels based on the extensive weak forces between the oxygen atoms on the [Mo6O19](2-) polyoxoanions and the CH2 groups of crown ether molecules, Compounds 2 and 3 are isostructural, and both contain a novel semiopen cagelike trimeric cation [{Na(DB18C6)(H2O)(2)}(3)(H2O)(2)](3+). In their packing arrangement, an interesting 2-D "honeycomblike" "host" network is formed, in which the [XMo12O40](3-) (X = As and P) polyoxoanion "guests" resided.