Dynamic Characteristics of Growth and Development of Xiangsha Taro in Jingjiang

The growth and development of Jingjiang Taro [Colocasia esculenta（L.） Schott] were observed, laying foundation for highly-yielding cultivation technology system of Xiangsha taro. The results indicate that germination of the second taro happened from 46 d after sprouting （7-8 leaves）; the first taro began to expand, from 125 d after sprouting （12 leaves） when the the second taro was been formed; the third taro began to form from 141 to 150 d after sprouting （15-16 leaves）. The fresh weight of the second and third taros quickly increased from the time of 15 leaves to harvest. Early September is a transformation term of Xiangsha taro from vegetative body dominant to corm growth dominant.

Effects of Cultivation Methods on Yield Formation and Photosynthetic Characteristics of Zhuliangyou 4024 and H You 159 as Doublecropping Rice

To explore the high-yield cultivation methods of Zhuliangyou 4024 and H You 159 when planted as double-cropping rice, the effects of two cultivation meth- ods, i.e., seedling broadcasting and transplanting, were studied on SPAD value, photosynthetic rate, grain yield and yield components. The results showed that the seedling broadcasting cultivation was conducive to Zhuliangyou 4024 and H You 159 to obtain higher yield. The higher chlorophyll content and photosynthetic rate and their slower decrease of flag leaf after full heading of the seedling broadcasting cultivation were thought to be the physiological basis of high yield.

The Impact of Electrode Configuration on Characteristics of Vacuum Discharge Plasma

Generation characteristics of vacuum discharge plasma are very important for the applied research of metal plasma. The vacuum discharge electrode configuration and the cathode material affect the generation characteristics of the metal plasma which consists of metal ions coming from cathode and generated by vacuum discharge. In this research, the generation characteristics of the metal plasma generated by vacuum discharge are discussed for four patterns of electrode configurations, i.e. cone-mesh electrode setup, cone-cross line electrode setup, cone-line electrode setup and cone-ring electrode setup. Characteristics of the metal plasma, such as elec- tron density, electron temperature, space potential, ion energy, are measured by the probe method for discussing the impacts of different electrode configurations on the density of generated metal plasma. Moreover, the diffusion velocities of the metal plasma are measured for cathode materials of Pb, Al, and Cu, respectively. The experimental results indicate that the plasma generated by the discharge of cone-ring electrode configuration possesses the maximum density and the metal plasma generated by the Al cathode possesses the fastest diffusion velocity and the highest kinetic energy.

Characteristic Analysis of AC Plasma Arc in Water

An experimental system of AC arc discharge in water was designed with pole-pole electrodes and a peak voltage of 1500 V and a test circuit was set up using virtual instrument technology. The mechanism of an AC plasma arc generated in water was analyzed. The voltage- current characteristic of the AC plasma are was obtained from the waveform. The temperature characteristic was tested with a spectrum diagnosis system, and the effect of different electrode materials on the striking voltage and peak current was analyzed. The results show that when a power supply of 6 kW is applied on electrodes with a gap of 2 mm in water, the striking voltage is from 900 V to 1300 V, the arc voltage is from 40 V to 100 V, the arc current is from 2 A to 7 A, and the zero rest period is from 1 ms to 2 ms. In addition, the arc voltage and current are different for electrodes in aluminum, copper and stainless steel. The arc voltage is lower and the current is higher for an aluminum electrode than those for copper and stainless steel ones. The highest temperature of the arc is 7643 K.

Analysis on Characters and Growth Factors of academicians of Agriculture Faculty of Chinese Academy of Engineering

The research analyzed birthplace, work site and Work unit, discipline, agri- cultural product variety, current age, and selected age, as well as internal and exter- nal factors for growth, which providers references for exploring development of high- level agricultural S＆T talents and formulation of relevant policies.

聚(3-羟基丁酸酯-co-4-羟基丁酸酯)的扩链改性

采用环氧丙烯酸型扩链剂改性聚(3-羟基丁酸酯-co-4-羟基丁酸酯)[P(3HB-co-4HB)],考察了扩链剂对熔体黏弹性、力学性能和成型发泡的影响。用流变仪测试熔体稳态黏度与剪切速率、动态黏弹模量与角频率、模量与时间的关系,用扫描电子显微镜观察改性前后P(3HB-co-4HB)的断面形貌。结果表明,扩链剂的加入提高了P(3HB-co-4HB)熔体黏弹性和拉伸断裂应变,有利于该材料的发泡成型。

MECHANICAL BEHAVIORS OF SATURATED SAND UNDER COMPLICATED LOADING

The different physical states of saturated sand, including shear elasticity, positive dilatancy, and negative dilatancy (preliminary negative dilatancy, secondary negative dilatancy and reversal negative dilatancy) are revealed based on the pore water pressure response of saturated sand in undrained dynamic torsional tests of thin cylinder samples and also checked by the drained cyclic triaxial tests under a given mean effective normal stress. According to the effective stress path of different physical states under the undrained cyclic torsional tests the physical state transformation surface, stress history boundary and yield surface are determined, and the state boundary surface is also determined by the range of effective frictional stress state movement. Based on the moving yield surface without rotation, and the expanding stress history boundary surface relevant to the stress path variations under different physical states in 3D stress space, a physical state model is proposed to provide a new approach to calculating the transient pore water pressure under the undrained condition, and the volume strain of dilatation under drained condition in this paper.

凝胶注模成型制备Si_3N_4-SiC材料

以SiC颗粒(3.36～0.15 mm)、SiC细粉(≤19μm)、改性Si粉(≤26μm)、改性Al粉、α-Si3N4粉为原料制成固相体积分数为75%的悬浮体,采用凝胶注模成型工艺和氮化烧成工艺制备Si3N4-SiC材料,并研究了SiC系悬浮体的流变特性以及氮化烧成后Si3N4-SiC材料的性能和显微结构。结果表明:1)悬浮体在切变速率10～160 s-1范围内表现出剪切变稀的特征,满足凝胶注模成型的要求;其流变特征符合Sisko模型,流变方程为η=4.625 4+2 172.9γ-0.450 3,拟合流变曲线与试验流变曲线基本吻合。2)脱模后湿坯的抗折强度为16 MPa,体积密度为2.57 g.cm-3;干燥后坯体结构致密,SiC大颗粒被Si粉和SiC粉均匀包裹。3)氮化烧成后试样的Si3N4含量、常温抗折强度和高温抗折强度均高于非凝胶注模成型的工业产品;Si3N4晶体发育完整,形成了Si3N4晶体紧密环绕SiC颗粒的均匀结构。