小议“胸径”

木材的胸径测量标准不统一导致了混乱和纠纷,对胸径不统一的原因进行分析,提出胸径的测量标准应统一,米径不能作为胸径。

金桂容器苗与地栽苗造林的生长差异研究

选用金桂扦插苗,分别采用容器育苗和地栽育苗的方式,在相同土壤和环境下培育3 a,选取生长高度和粗度大小基本一致的苗木各30株,造林5 a后,比较不同方式培育的金桂苗木在地径(树干距地面30 cm高处)、米径(树干距地面100 cm高处)、树高、平均冠径、主枝粗度和长度等生长因子上的差异。结果表明,容器育苗和地栽育苗对金桂的地径影响显著,对其他生长因子的影响均不显著。

The Ways to Improve the Efficiency of Maize Breeding

Referring to corn breeding literature at home and abroad,the possible ways to improve the efficiency of maize breeding were discussed.The results showed that through the summary and reflection on breeding objectives and strategies,and improvement and optimization of breeding techniques and methods,as well as adjustment and simplification of experimental design and implementation,the breeding cost would be greatly reduced,and the breeding efficiency would be improved.

Effects of Controlled Release Fertilizer on Loss of Nitrogen and Phosphorus from Farmland

[Objective] The aim was to study on effects of controlled release fertilizer on loss of nitrogen and phosphorus from farmland. [Method] Experiment was conducted in fields planted with rice and corn around Chao Lake and effects of compound fertilizer, controlled release fertilizer and controlled release fertilizer （reduced by 20%） on loss of nitrogen and phosphorus through runoff and leaching were analyzed. [Result] Loss of nitrogen and phosphorus mainly occurred in early stage of fertilizing; loss caused by runoff accounted for over 98% and caused by leaching was lower than 2%, indicating that nutrients of rice and corn mainly lost through runoff. As for controlled release fertilizers with 20% reduced, total loss of N and P decreased by 60% and 63% in rice field and reduced by 27.8% and 34% in corn field, respectively, indicating that controlled release fertilizer would maintain nutrients in soils high in later period of plant growth, improve use efficiency of N and P, reduce N and P loss in rice and corn fields in rainy season, and decrease non-point pollution. [Conclusion] The research suggested that controlled release fertilizer would slow down the loss of nutrients in farmlands, providing scientific references and technological support for extension of controlled release fertilizer and reduction of agricultural non-point pollution.

茶叶套种银杏技术模式研究

茶叶套种银杏技术模式研究结果表明,银杏新梢生长高度和米径都比未套种茶叶的银杏要好,增加了苗木的经济效益,而茶叶的产量和品质也得到提高。

不同育苗密度对麻楝生长的影响研究

麻楝为楝科麻楝属植物,树形美观,常用于道路两旁绿化行道树以及园林绿化。近年来,园林绿化常种植麻楝绿化大苗,具有一定的市场前景和较高的经济价值。该试验设置5种不同育苗密度,研究其对苗高、米径、冠幅等指标的影响。结果表明,在育苗密度为100cm×100cm的条件下,麻楝生长最佳,适宜苗圃培育苗木。

Synthesis of Nanometer Cobalt Blue Pigment by Microemulsion Method and Control of Diameter of Particle

The nanometer cobalt blue pigments were prepared by microemulsion method. Using dynamic light scattering(DLS) test method, the influences of water content on the size of liquid drop of microemulsion and the liquid drop of microemulsion on the final diameter of nanometer particle were studied in the course of preparation. Accordingly, the method to control the diameter of nanometer particle by changing water content was established. The nanometer cobalt blue particles were confirmed by XRD and TEM. Color parameters of pigments were determined. The quantum size effect of the pigments was discussed.

Effect of second-phase particle size and presence of vibration on AZ91/SiC surface composite layer produced by FSP

An improved method of friction stir processing(FSP)was introduced for the processing of AZ91 magnesium alloy specimens.This novel process was called“friction stir vibration processing(FSVP)”.FSP and FSVP were utilized to develop surface composites on the studied alloy while SiC nanoparticles were applied as second-phase particles.The effect of reinforcing SiC particles with different sizes(30 and 300 nm)on different characteristics of the composite surface was studied.The results indicated that the microstructure was refined and mechanical properties such as hardness,ductility,and strength were enhanced as FSVP was applied.Furthermore,it was concluded that the effect of reinforcing particles with a size of 30 nm on the microstructure and mechanical properties of the surface composite was more obvious than that of particles with a size of 300 nm.It was also found that mechanical properties and microstructure of FSV-processed specimens were improved as vibration frequency increased.The hardness value in the stir zone was about 157 MPa for the FSV-processed specimen at a vibration frequency of 50 Hz,while this value was around 116 MPa for the FSV-processed specimen at a vibration frequency of 25 Hz.

OsWRKY03, a rice transcriptional activator that functions in defense signaling pathway upstream of OsNPR1

WRKY family proteins are a class of plant specific transcription factors that involve in many stress response pathways. It has been shown that one Arabidopsis WRKY protein, AtWRKY29/22, is activated by MAP kinase signaling cascade and confers resistance to both bacterial and fungal pathogens. However, little is known about the biological roles of WRKY proteins in rice. In this study, we investigated the expression patterns of rice AtWRKY29/22 homolog, OsWRKY03, under different conditions, and also its possible role involved in plant defense. Our results showed that OsWRKY03 was up-regulated by several defense signaling molecules or different treatments. Further analysis revealed that the expression of OsWRKY03 was light dependent. Transcriptional activation activity of OsWRKY03 was also demonstrated by yeast functional assay. Transient expression of OsWRKY03-GFP fusion protein in onion epidermis cells showed that OsWRKY03 was a nuclear localized protein. OsNPR1 as well as several other pathogenesis-related genes, such as OsPRlb, phenylalanine ammonia-lyase （ZB8） and peroxidase （POX22.3）, were induced in OsWRKYO3-overexpressing transgenic plants. These results indicated that OsWRKY03 is located upstream of OsNPR 1 as a transcriptional activator in salicylic acid （SA）-dependent or jasmonic acid （JA）-dependent defense signaling cascades.

In situ nanobubble sizing by visualization particle tracking and image-based dynamic light scattering

A novel method combining visualization particle tracking with image-based dynamic light scattering was developed to achieve the in situ and real-time size measurement of nanobubbles(NBs).First,the in situ size distribution of NBs was visualized by dark-field microscopy.Then,real-time size during the preparation was measured using image-based dynamic light scattering,and the longitudinal size distribution of NBs in the sample cell was obtained in a steady state.Results show that this strategy can provide a detailed and accurate size of bubbles in the whole sample compared with the commercial ZetaSizer Nano equipment.Therefore,the developed method is a real-time and simple technology with excellent accuracy,providing new insights into the accurate measurement of the size distribution of NBs or nanoparticles in solution.

Study on the thermal decomposition kinetics of nano-sized calcium carbonate

This study of the thermal decomposition kinetics of various average diameter nano-particles of cal-cium carbonate by means of TG-DTA(thermogravimetry and differential thermal analysis) showed that the thermal decomposition kinetic mechanisms of the same crystal type of calcium carbonate samples do not vary with decreasing of their average diameters ; their pseudo-active energy Ea; and that the top-temperature of decom-position Tp decreases gently in the scope of micron-sized diameter, but decreases sharply when the average di-ameter decreases from micron region to nanometer region. The extraordinary properties of nano-particles were explored by comparing the varying regularity of the mechanisms and kinetic parameters of the solid-phase reac-tions as well as their structural characterization with the variation of average diameters of particles. These show that the aggregation, surface effect as well as internal aberrance and stress of the nano-particles are the main reason causing both Ea and Tp to decline sharply with the decrease of the average diameter of nano-particles.

Molecular Dynamics of Nanometric Processing of Ion Implanted Monocrystalline Silicon Surfaces

Three-dimensional molecular dynamics simulations are carried out to study the mechanism of nanometric processing of ion implanted monocrystalline silicon surfaces. Lattice transformation is observed during implantation and nano-indentation using radial distribution function and geometric criterion damage detection. Nano-indentation is simulated to study the changes of mechanical property. Implantation analysis shows the existence of amorphous phase. Indentation process shows the lattice evolution, which is beneficial for reducing fractures during processing. The indentation results reveal the reduction of brittleness and hardness of the implanted surface. The ion fluence is in direct proportion to the damage, and inverse to the hardness of the material. Experiments of ion implar, tation, nanoindentation, nano-scratching and nanometric cutting were carried out to verify the simulation results.

Comparison of the Radial Compliance of Three Kinds of Vascular Prostheses and Pig′s Carotid Based on Dynamic-simulated Condition

There are some problems in the vascular prostheses, which influence the health of the patients. This paper aims to the radial compliance of three kinds of vascular prostheses and the pig＇s carotid based on the dynamic-simulated condition. The radial compliance of knitted structure vascular prostheses with crimps ranged from 2.52% to 0.94%/100 mmHg, which was superior to e-FFFE and woven prostheses＇, ranged from 0.73% to 0.31%/100 mmHg and from 0.81% to 0.22%/100 mmHg. But comparing with the radial compliance of pig＇s carotid, ranged from 7.21% to 10.04% /100 mmHg, there was a big gap between them. And also the trend of the radial compliance of vascular prostheses was different from the real pig＇s carotid. There is a lot of work left to improve the radial compliance, not only to change the vascular prostheses＇ compliance, but also to meet with the real vascular.

Optimal selection of annulus radius ratio to enhance heat transfer with minimum entropy generation in developing laminar forced convection of water-Al2O3 nanofluid flow

Heat transfer and entropy generation of developing laminar forced convection flow of water-Al_2O_3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determine entropy generation of fully developed flow, two approaches are employed and it is shown that only one of these methods can provide appropriate results for flow inside annuli. The effects of concentration of nanoparticles, Reynolds number and thermal boundaries on heat transfer enhancement and entropy generation of developing laminar flow inside annuli with different radius ratios and same cross sectional areas are studied. The results show that radius ratio is a very important decision parameter of an annular heat exchanger such that in each Re, there is an optimum radius ratio to maximize Nu and minimize entropy generation. Moreover, the effect of nanoparticles concentration on heat transfer enhancement and minimizing entropy generation is stronger at higher Reynolds.

Convective heat and mass transfer in MHD mixed convection flow of Jeffrey nanofluid over a radially stretching surface with thermal radiation

Mixed convection flow of magnetohydrodynamic(MHD) Jeffrey nanofluid over a radially stretching surface with radiative surface is studied. Radial sheet is considered to be convectively heated. Convective boundary conditions through heat and mass are employed. The governing boundary layer equations are transformed into ordinary differential equations. Convergent series solutions of the resulting problems are derived. Emphasis has been focused on studying the effects of mixed convection, thermal radiation, magnetic field and nanoparticles on the velocity, temperature and concentration fields. Numerical values of the physical parameters involved in the problem are computed for the local Nusselt and Sherwood numbers are computed.

Chinese Athlete Breaks 110-meter Hurdles World Record

Liu Xiang of China set a world mark in the 110-meter hurdles on July 12, breaking the record he shared with Britain’s Colin Jackson. Liu’s time of 12.88 seconds at the IAAF Super Grand Prix athletics meeting in Laussane, Switzerland was 0.03 better than the record he matched in winning gold at the 2004 Athens Olympics.

Influence of Nonionic Surfactant Addition on Drag Reduction of Water Based Nanofluid in a Small Diameter Pipe

The goal of this research was to determine the impact of nonionic surfactants on drag reduction effect in water and metal oxide nanofluid. Two nonionic surfactants （Rokacet 07 and Rokanol KT） and copper（II） oxide wa- ter-based nanofluid were examined. Friction factors in a 4 mm diameter pipe for the Reynolds number between 8000 and 50000 were determined. Results showed that addition of nonionic surfactants caused the decrease of fric- tion factor in water and nanofluid. The drag reduction effect was similar in both cases. Presence of nanoparticles in the system has no great influence on drag reduction effect.

Effect of Fiber Diameter and Air Gap on Acoustic Performance of Nanofibrous Membrane

The absorption of sound in the low frequency range is problematic with fibrous materials made up of coarser fibers. In that case, highly efficient sound absorption materials from much finer fibers must be developed. Although studies on the acoustic properties of conventional textile materials started in the nineties, analysis of the acoustic properties of the electrospun nanofibrous membranes is a novel subject. Nanofibrous membranes can improve acoustic insulation products by increasing the sound absorption coefficient, reducing material thickness, and decreasing material weight offering a competitive advantage. The purpose of this study is to analyze the effect of fiber diameter on the acoustic behavior of nanofibrous membranes.

Ab Initio Nonadiabatic Dynamics of Semiconductor Materials via Surface Hopping Method

Photoinduced carrier dynamic processes are without doubt the main driving force responsible for the efficient performance of semiconductor nanomaterials in applications like photoconversion and photonics.Nevertheless,establishing theoretical insights into these processes is computationally challenging owing to the multiple factors involved in the processes,namely reaction rate,material surface area,material composition etc.Modelling of photoinduced carrier dynamic processes can be performed via nonadiabatic molecular dynamics(NA-MD)methods,which are methods specifically designed to solve the time-dependent Schrodinger equation with the inclusion of nonadiabatic couplings.Among NA-MD methods,surface hopping methods have been proven to be a mighty tool to mimic the competitive nonadiabatic processes in semiconductor nanomaterials,a worth noticing feature is its exceptional balance between accuracy and computational cost.Consequently,surface hopping is the method of choice for modelling ultrafast dynamics and more complex phenomena like charge separation in Janus transition metal dichalcogenides-based van der Waals heterojunction materials.Covering latest stateof-the-art numerical simulations along with experimental results in the field,this review aims to provide a basic understanding of the tight relation between semiconductor nanomaterials and the proper simulation of their properties via surface hopping methods.Special stress is put on emerging state-ot-the-art techniques.By highlighting the challenge imposed by new materials,we depict emerging creative approaches,including high-level electronic structure methods and NA-MD methods to model nonadiabatic systems with high complexity.

Unexpected luminescence enhancement of upconverting nanocrystals by cation exchange with well retained small particle size

Highly luminescent upconversion nanoparticles （UCNPs） with small sizes are highly desirable for bioapplications. A facile in situ cation exchange strategy has been developed to greatly enhance the UC luminescence of hexagonal phase NaYF4 NPs while maintaining their small particle size and shape. Via a cation exchange treatment by hot-injecting Gd3＋ precursors into the as-prepared NPs solution without pre-separation, the naked-eye visible UC emission of the NPs was enhanced about 29 times under 980 nm near infrared （NIR） excitation with unchanged particle size. The cation exchange process was further demonstrated for the case of NaYF4 nanorods （NRs）. After the cation exchange, the nanorod was broken into two NPs with stronger emission. The cation exchanged hydrophobic UCNPs were further encapSulated with poly（amino acid） and successfully applied for targeted cancer cell UC luminescence imaging.