不同类型花生单粒精播生长发育、光合性质的比较研究

大田高产条件下,以大花生花育22号(HY22)和小花生鲁花12号(LH12)为研究材料,采用单粒精播,对其生长发育过程、光合性质进行了对比研究,分析表明:(1)HY22和LH12植株总干物质积累动态均符合S型生长曲线,整个生育期前者干物质积累量均大于后者;前者CGR与NAR峰值出现早于后者,LAI与LAD峰值大于后者。(2)HY22叶绿素含量峰值略小于LH12;后者苗期和饱果期透光性强;二者群体光合强度最大出现在结荚期,饱果期差异最大。

外源压力对甘薯生长和生理特征的影响

采用不同质地的黏土和砂土,利用室内可控压力的盆栽试验,对不同外源压力T_1,T_2,T_3分别为0,10,20kg的条件下,甘薯生长和生理特征的响应进行了研究.结果表明:1)甘薯地上部茎叶生物量随着压力的增大而增加,而黏土中生育后期,T_2最高,其次为T_3,说明适宜的外源压力有助于甘薯茎叶在中后期的生长.甘薯地下部生物量与地上部生物量均呈现出一致的趋势,T_2最高,其次为T_3.2)每个生育期,光合速率和内源激素最高为T_2,其次为T_3.外源压力处理和瞬时水分利用效率(P_n/T_)之间没有显著关系,而生育期和土壤类型对P_n/T_具有显著影响.3)外源压力处理和根长之间没有显著关系,而生育期和土壤类型对根长具有显著影响;生育期、外源压力处理和土壤类型对根平均直径、根表面积和根体积均具有显著影响,根平均直径、根表面积和根体积在T_2处理中最高,其次为T_3.可见,在本盆栽试验处理中,甘薯最适宜的生长条件为土壤压力为T_2,其次为T_3,而T_1处理最不利于甘薯产量的形成.即土壤外源压力对甘薯产量具有很大的影响,压力过大或过小,均不利于甘薯的高产,且黏土压力处理对甘薯根系的影响要高于砂土.

Transition metal coordination polymers with flexible dicarboxylate ligand:Synthesis,characterization,and photoluminescence property

Under solvothermal conditions,six new coordination polymers(CPs)[Mn(L)(phen)(H_(2)O)]_(n)(1),[Co(L)(phen)(H_(2)O)]_(n)(2),[Cu(L)(phen)(H_(2)O)]_(n)(3),[Zn_(2)(L)_(2)(phen)2(H_(2)O)]_(n)(4),[Zn(L)(phen)]_(n)(5),and[Cd(L)(phen)2]_(n)(6)were synthesized by reactions of dicarboxylate ligand 2,2'-(1,2-phenylenebis(methylene))bis(sulfanediyl)dinobutyric acid(H_(2)L)and 1,10-phenanthroline(phen)with the corresponding metal salts.Complexes 1-6 have been structurally characterized by single-crystal X-ray diffraction analyses,elemental analysis,IR,thermogravimetric analysis,and powder X-ray diffraction.The structures of 1-6 are 1D chains,which are further connected by hydrogen bonding interac-tions to form 3D supramolecular structures.Among them,1 and 2 are isomorphic with L2-of syn-conformation,while L2-shows anti-conformation in 3-6.In addition,the solid-state photoluminescence property of 4-6 was investigated.

Spectral Properties and Characterization of the Modified PSⅡ Core Complexes

用组氨酸的特异性修饰剂 (DEPC)对PSⅡ核心复合物进行了化学修饰 ,并对其光谱性质进行了研究。研究结果表明 :修饰后的PSⅡ核心复合物的吸收光谱在红区发生了很大变化 ,随修饰时间的增加 ,6 80nm处的吸收逐渐下降。修饰后的PSⅡ核心复合物的荧光光谱在最初的 1min内出现荧光上升现象 ,然后逐渐下降 ,峰位蓝移。这些研究结果表明 ,组氨酸残基的修饰导致了原初电子供体P6 80结构的破坏 ,并对其功能产生了影响。

Purification and Spectral Characteristics of Cytochrome b-559 from Oxygen-evolving Photosystem Ⅱ Core Complexes of Spinach and Rice

Cytochrome b_559 in photosystem Ⅱ reaction center was purified from spinach ( Spinacia oleracea L.) and rice ( Oryza sativa L.) by a rapid and simple procedure. Their low temperature fluorescence emission and excitation spectra, ultraviolet fluorescence spectra and absolute absorption spectra were presented. The author's purification methods, which enhanced the yield of pure protein and shorted the time for isolation, have several advantages: 1. use of oxygen_evolving PSⅡ core complexes as the starting material in order to avoid disturbing from other cytochromes; 2. isocratic elution of cytochrome b_559 from a DEAE_Sephacel column for eliminating the impurity and yielding the protein in pure state; 3. a simple column procedure for removal of excess Triton X_100. Purified cytochromes b_559 from these species have similar optical spectra and mobility during gel electrophoresis under native conditions. From the results of novel electrophoresis (Tricine_SDS_PAGE), cytochrome b_559 from both spinach and rice reveal two polypeptide bands (apparent molecular weight 9 kD and 4 kD, respectively). By measuring of 77 K fluorescence spectra, it was shown that for the purified cytochrome b_559 there were two excitation peaks at 439 nm and 413 nm, and two emission peaks at 563 nm and 668 nm. This is the first indication that Cyt b_559 is able to emit fluorescence and also transfer excited electrons to chlorophyll. By the use of ultraviolet fluorescence spectra, it was demonstrated for the first time that the location of Trp residue could be in the hydrophobic transmembrane region of cytochrome b_559.

Synthesis of CdSe quantum dots via paraffin liquid and oleic acid

This paper reported an efficient and rapid method to produce highly monodispersed CdSe quantum dots (QDs), in which the traditional trioctylphosphine oxide (TOPO) was replaced by paraffin liquid as solvent and oleic acid as the reacting media. The experimental conditions and the properties of QDs had been studied in detail. The resulting samples were confirmed of uniform size distribution with transmission electronic microscopy (TEM), while UV-vis absorption and photoluminescence (PL) spectra clearly indicated that such synthesized QDs had good fluorescence properties.

Synthesis, Crystal Structure and Nonlinear Optical Properties of Nickel(Ⅱ) Complex with Schiff-base Ligand

The nickel(Ⅱ) complex with the new ligand of S-benzyl-b-N-[10-ethyl- phenothiazine-3-methylene]dithiocarbazate(HL) crystallizes in the triclinic system, space group P?with a = 7.516(1), b = 11.322(1), c = 13.366(1) , a = 84.818(1), b = 81.688(1), g = 76.037(1), V = 1090.26(3) 3, Z = 1, Dc = 1.413 g/cm3, F(000) = 482, m(MoKa) = 0.774 mm-1 (l = 0.7103 ?, R = 0.0573 and wR = 0.1375 for 3357 observed reflections with I ≥ 2s(I). The HL has lost a proton from its tautomeric thiol form and acts as a single negatively charged bidentate ligand coordinating to the nickel ion via the mercapto sulfur and b-nitrogen atoms. The geometry around Ni(Ⅱ) is almost square-planar with two equivalent NiN and NiS bonds. The nonlinear absorption of HL and NiL2 solutions (in DMF) was measured by open-aperture Z-scan technique at the wavelength of 532 nm.

Optical Properties of CdS.Nanobelts and Nanosaws Synthesized by Thermal Evaporation Method

By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostruetures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanos-truetures were observed and discussed.

Science Letters; In-situ synthesis and luminescence properties of titanium oxide gels containing 1,10-phenanthroline europium(Ⅲ) complex

It is difficult to directly dope europium complexes in gel because the excessive water or high acidic condition may lead to their decomposition. We prepared a novel homogeneous TiO2 gel containing Eu-phen complexes by using an in-situ synthesis method. The formation of Eu-phen complexes in sol-gel derived TiO2 was confirmed by luminescence excitation spectra. The effects of temperature and aging time on in-situ synthesis are discussed. The luminescence spectra of gel containing europium complexes were also compared with the pure Eu-phen complexes.

Preparation and Photocatalytic Activity of BiOBr/TiO_2 Heterojunction Nanocomposites

An efficient visible-light-responsive BiOBr/TiO2 heterojunction nanocomposite was fabricated successfully using in-situ depositing technique at room temperature by introducing BiOBr onto the surface of TiO2 nano- belts pre-prepared by hydrothermal reaction and etched with H2SO4. The obtained particles were characterized by XRD, SEM, TEM, XPS, UV-Vis DRS and PL techniques. BiOBr/TiO2 heterojunction nanocomposites with different mass ratios of m （BiOBr）/m （TiO2） were discussed in order to get the best photocatalytie activity, and BiOBr/TiO2-1.0 was proved to be the optimal mass ratio. BiOBr/TiO2-1.0 exhibited excellent photocatalytic activity in the degradation of RhB compared with TiO2 nanobelts, pure BiOBr and the mechanical mixture of TiO2 nanobelts and BiOBr. At last, a possible mechanism ofphotocatalytic enhancement was proposed.

Photoluminescence behavior and visible light photocatalytic activity of ZnO,ZnO/ZnS and ZnO/ZnS/α-Fe_2O_3 nanocomposites

In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange（MeO）, ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic route in the aqueous medium. Phase, crystallinity, surface structure and surface behavior of the synthesized materials were determined by X-ray diffraction（XRD） and Brunauer-Emmett-Teller analysis（BET） techniques. XRD study established formation of good crystalline ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanomaterials. By using intensity of constituent peaks in the XRD pattern, the compositions of nanocomposites were determined. From the BET analysis, the prepared materials show mesoporous behavior, type Ⅳ curves along with H4 hysteresis. The ZnO/ZnS/α-Fe2O3 composite shows the largest surface area among three materials. From the UV-visible spectra, the band gap energy of the materials was determined. Photoluminescence spectra（PL） were used to determine the emission behavior and surface defects in the materials. In PL spectra, the intensity of UV peak of ZnO/ZnS is lowered than that of ZnO while in case of ZnO/ZnS/α-Fe2O3, the intensity further decreased. The visible emission spectra of ZnO/ZnS increased compared with ZnO while in ZnO/ZnS/α-Fe2O3 it is further increased compared with ZnO/ZnS. The as-synthesized materials were used as photocatalysts for the degradation of dye MeO. The photo-degradation data revealed that the ZnO/ZnS/α-Fe2O3 is the best photocatalyst among three specimens for the degradation of dye MeO. The decrease of intensity of UV emission peak and the increase of intensity of visible emission cause the decrease of recombination of electrons and holes which are ultimately responsible for the highest photocatalytic activity of ZnO/ZnS/α-Fe2O3.

Synthesis, Structure and Fluorescent Property of a Cadmium (II) Polymer

A new cadmium(II) coordination polymer with benzenetricarboxylate{Cd2- (Htma)2(H2O)2}}n 1 (Htma = 1-carboxybenzene-2,4-dicarboxylate) has been synthesized by hydro- thermal reaction. 1 crystallizes in triclinic, space group P?with a = 6.9990(8), b = 7.0564(8), c = 10.096(1) ? = 83.438(1), = 86.357(2), = 69.233(2)? V = 463.02(9) 3, Dc = 2.428 g/cm3, F(000) = 328, Mr = 677.08, m(MoKa) = 2.382 mm-1, Z = 1, the final R = 0.0284 and wR = 0.0772 for 1540 observed reflections (I≥2s(I)). The structure of 1 consists of centrosymmetric dinuclear units with all metal centers being six-coordinated, which adopt a distorted octahedral configuration and lead to the formation of three-dimensional microporous framework with size of about 3 ??8 ? Fluoerescent measurement showed that 1 exhibits intense fluorescent emission.

MXene quantum dots of Ti_(3)C_(2):Properties,synthesis,and energy-related applications

The emerging two-dimensional MXene-derived quantum dots(MQDs)have garnered considerable research interest owing to their abundant active edge atoms,excellent electrical conductivity,and remarkable optical properties.Compared with their two-dimensional(2D)counterpart MXene,MQDs with forceful size and quantum confinement effects exhibit more unparalleled properties and have considerably contributed to the advanced photocatalysis,detection,energy storage,and biomedicine fields.This critical review summarizes the fundamental properties of MQDs in terms of structure,electricity,and optics.The mechanism,characteristics,and comparisons of two typical synthesis strategies(traditional chemical method and novel fluorine-free or chemical-free method)are also presented.Furthermore,the similarities and differences between MQDs and 2D MXenes are introduced in terms of their functional groups,light absorption capacity,energy band structure,and other properties.Moreover,recent advances in the applications of MQD-based materials for energy conversion and storage(ECS)are discussed,including photocatalysis,batteries,and supercapacitors.Finally,current challenges and future opportunities for advancing MQD-based materials in the promising ECS field are presented.

Modifying the acidity of H-MOR and its catalytic carbonylation of dimethyl ether

Among the reactions catalyzed by zeolites there are some that exhibit high selectivity due to the spatial confinement effect of the zeolite framework.Tailoring the acidity,particularly the distribution and location of the Bronsted acid sites in the zeolite is effective for making it a better catalyst for these reactions.We prepared a series of H-mordenite（H-MOR） samples by varying the composition of the sol-gel,using different structure directing agents and post-treatment.NH3-TPD and IR characterization of adsorbed pyridine were employed to determine the amount of Bronsted acid sites in the 8-membered ring and 12-membered ring channels.It was shown that controlled synthesis was a promising approach to improve the concentration of Bronsted acid sites in MOR,even with a low Al content.Using an appropriate composition of Si and Al in the sol-gel favored a higher proportion of Bronsted acid sites in the 8-membered ring channels.HMI as a structure-direct agent gave an obvious enrichment of Bronsted acid sites in the 8-membered ring.Carbonylation of dimethyl ether was used as a probe reaction to examine the modification of the acid properties,especially the Bronsted acid sites in the 8-membered ring channels.There was a linear relationship between methyl acetate formation and the number of Bronsted acid sites in the 8-membered ring channels,demonstrating the successful modification of acid properties.Our results provide information for the rational design and modification of zeolites with spatial constraints.

A Cadmium(II) Coordination Polymer: Crystal Structure and Fluorescent Property of [CdCl_2(4,4'-bipyridine)]_ ∞

The reaction of L-histidine, CdCl22.5H2O and 4,4-bipyridine in methane/water gave rise to a two-dimensional coordination polymer [CdCl2(4,4-bipyridine)] which has been characterized by single-crystal X-ray diffraction. The polymer crystallizes in the orthorhombic sys- tem, space group Cmmm with a = 12.083(7), b = 11.771(7), c = 3.781(2) ? V = 537.8(6) ?, Z = 2, C10H8N2CdCl2, Mr = 339.48, Dc = 2.097 g/cm3, F(000) = 328 and (MoK? = 2.490 mm-1. The final R = 0.0658 and wR = 0.1398 for 257 observed reflections with I≥2(I).

Synthesis and photophysical and electrochemical properties of new cyclometalated platinum complex containing oxadiazole ligand

A new cyclometalated platinum complex containing 2, 5-bis(naphthalene-1-yl)-1,3,4-oxadiazole ligand was synthesized and characterized. The UV-Vis absorptions and photoluminescent properties of the ligand and its platinum complex were investigated. A characteristic metal-ligand charge transfer absorption peak at 439 nm in the UV spectrum and a strong emission peak at 625 nm in the photoluminescence spectrum were observed for this complex in dichloromethane. Cyclic voltammtry (CV) analysis shows that the EHOMO (energy level of the highest occupied molecular orbital) and ELUMO (energy level of the lowest unoccupied molecular orbital) of the platinum complex are about 、5.69 and 、3.25 eV, respectively, indicating that the oxadiazole-based platinum complex has a potential application in electrophosphorescent devices used as a red-emitting material.

Synthesis and spectroscopic properties of N^2, 3-ethenoguanosine

The synthetic route of N^2, 3-ethenoguanosine （ε-G） was described. Its ultraviolet and fluorescent properties at various pH were studied. These results indicate that ε-G dissociates a hydrogen ion to give the anion ε-G and associates a hydrogen ion to give a the cation ε-GH~. The neutral specie ε-G is the origin of fluorescence. The fluorescent properties in different media were studied and there was most strong fluorescence in water. Based on fluorescencc quenching of ε-G on BSA, the binding constant and the number of binding sites between ε-G and BSA were determined, which were 1.78x10^3 L/mol and I, respectively. The quenching mechanism was discussed. It indicates that the powerful interaction exists between ε-G and BSA.

Circuit-level simulation of the hysteresis inversion frequency of the ferroelectric liquid crystals

The V-shaped electro-optical properties control is investigated by an equivalent circuit model.Simu-lation results show that genuine V-shaped form is only observed at hysteresis inversion frequency,and be-low and above this frequency an anomalous and normal hysteresis are observed.And the inversion fre-quency decreases with the resistance of ferroelectric liquid crystal(FLC)layer following logf_i=-alogR_(LC)+b .The results are in good accordance with the reported experimental results.

Facile Synthesis of Coronene Dimers Having Unique Optical Properties

The authors synthesized very pure dimer phase of coroneae by simple heat-treatment and subsequent sublimation purification. It was confirmed by laser desorption/ionization mass spectroscopy measurements that pure dimer phase of coronenes can be obtained by controlling the fusing and sublimation temperatures. The crystal structure of the dimer phase was analyzed by synchrotron XRD （X-ray diffraction） experiments. It was also found that very bright red light is emitted by irradiating ultra violet light （λ = 350 nm） to the dimer phase. The external and internal quantum yields were determined to be 5.56% and 6.95%, respectively.

Enhancement effect of terbium complex luminescence by binding to silver nanoparticles in the solution

The luminescent properties of terbium complex (terbium citrate) by binding to silver nanopartilces in the solution have been reported in this paper.The enhanced luminescence of the complex containing silver nanoparticles was observed at a limited particle concentration region.The nanoparticle concentration dependence of the luminescent intensity was regarded as the result of a delicate balance between an enhancing and a quenching effect of the silver nanoparticles.Furthermore,silver nanoparticles also affected the asymmetric ratio (AS) value of terbium luminescence.We discuss the luminescent properties of the terbium complex in terms of the local electromagnetic field,refractive index,and the ligand field around terbium ion.