Five heavy metals in propagules of ten mangrove species of China

Five heavy metals in the propagules of 10 mangrove species in China have been investigated. The results revealed that the levels of five heavy metals in most of the propagules were lower than the background levels of the soil. The levels of copper, manganese, zinc, cadmium, and lead in the propagules varied at about 2.1–7.8 g/g, 3.9–28.0 g/g, 5.7–60.0 g/g, 0.014–0.057 g/g, and 0.018–0.038 g/g, respectively. On average, the levels of five heavy metals were in the order Zn > Mn > Cu > Cd > Pb. The biological absorption coefficients were 0.02–1.30 for copper, manganese, zinc, and cadmium and about 0.0007–0.0020 for lead in propagules, showing the following order: Zn > Cd > Cu > Mn > Pb. The above results indicate that the five heavy metals have low accumulation in most of the propagules of 10 mangrove species and are at safe levels for the effective utilization of mangrove resources.     

辊压处理大青杨木材的密度和干缩系数变异

对大青杨辊压处理材(压缩率10%～50% )的密度和干缩系数进行测试和研究.结果表明,与素材相比,辊压处理材的全干、气干和基本密度均有所增加,密度变化率＜5%,其中气干密度增幅最大,密度变异与压缩方向无明显相关;气干和全干干缩系数随压缩率增大而变大,变动范围-3.448%～23.678%;弦向干缩系数变化大于径向.     

Double-Face Dynamic Balance Method of Spot Rotator without Removing the Test Weights

Site dynamic balance is a important element in installation and maintenance of heavy rotary mechanism. It's hard to discharge testing weights, and the remanent weights will effect the result of balance test. The paper presents a kind of dynamic balance algorithm which need not to discharge the test weights, basing on influence coefficient. The principle of the algorithm is to balance the sum of original unbalance weights and testing weights by the result balance weights. In the algorithm , the influence coefficient of last time can be used optionally for the same rotor. Then developing a dynamic balance system building on it. The site experimental results indicates that this algorithm has a high balance precision, predigests the steps and reduces the operation time.     

Discussion of the Negative Thermal Expansion Coefficient of the Laminar Crystal

The variation of the thermal expansion coefficient of the graphite crystal is derived. According to the theory of temperature with the thermodynamic and statistical physical, the free energy of the graphite crystals is given with the De-Bye Model, and relationship between the thermal expansion coefficient of the graphite crystal and the temperature range is probed. The results are showed: the thermal expansion coefficient is equal to zero if T =0 K or T is on the verge of the 15 K or 42 K; negative if the temperature is in the range of 15 to 42 K; constant if the temperature is higher. The theoretical calculations accord with the experimental results. From this, In the layered crystals the reason that there is the negative expansion is that the statistical weight of the transverse acoustic vibration for the atoms in the plane layer is very large. In some temperature ranges, the variation of distance between atoms in the direction perpendicular to the plane layer with the temperature resulted in by the transverse acoustic vibration reverses with that in the plane layer. Then the film effect is resulted in.     

THE STRAIN OF THE BARS IN THE STRUCTURAL COLUMNS OF THE PRESTRESSED EARTHQUAKE-RESISTANT BRICK-WALLS

Through the comparative tests of prestressed and non-prestressed brick-walls un-der the repeated lateral loading,the effect of the prestress-force to the strain distribution in the non-prestressed bars of the structural columns has been investigated.This effect is beneficial:the pre-stress-force will reduce the value of strain in the bars of the lower part in the columns and uniformize the strain distribution along the whole height of the columns.Furthermore,instead of a strainreduction,the strain of prestressed be will increase along with the increasing of the lateral load.Thus,the coefficient of prestress-force-increase could be calculated in the tWo stages of the crack-resistance and ultimate bearing capacity.As a result,both the prestressed and non-prestressed barsare able to give the potential of their bearing capacity a full play,and improve the earthquake-resis-tant property.     

Noise-reduction of Digital Video Image Based on Time-recursive Filtering

With the analysis of the principle of time-recursive filter, the authors find that the nature of time-recursive filter is Weighted Mean Low-Pass filter and the relationship between filter coefficients and SNR and the artifact arising from the area where motion can not be tracked. One approach based on Automatic Control Method is proposed to solve the artifacts problem during the process of filtering and the authors designed the corresponding hardware based on FPGA and software respectively. The experimental results show that the time-recursive filtering is good at digital video image denoising and reduces the random noise of digital camera system.     

孔隙分形修正的混凝土中氯离子扩散系数

在已有的氯离子扩散理论和孔隙分形理论的基础上,提出小孔的孔轴线分形维数表征氯离子扩散的曲折度、大孔的孔表面分形维数修正孔隙率,并推导得到基于孔隙分形修正的氯离子扩散系数模型。通过分析龄期为14 d和28 d不同配比混凝土的基于孔隙分形的氯离子扩散系数模型的计算结果和快速氯离子扩散试验(ASTM C1202)电通量,发现两者之间有良好的线性关系。采用基于孔隙分形修正的氯离子扩散系数代入Fick第二定律的解析解,对试验后各组混凝土中不同扩散深度的氯离子浓度进行拟合,计算结果与实测值吻合情况较好。     

部分水稻品种对稻瘟病菌群体的抗病性分析

利用生物间遗传学关于毒力频率和联合抗病性分析的方法，分析了16个品种对稻瘟病菌群体的抗瘟性。结果表明，参试病菌群体对各个品种的毒力以及不同稻区的病菌群体对同一品种的毒力均存在明显差异，筛选出毒力频率较低的4个品种：汕优多系1号、Ⅱ优多系1号、金优431和金优多系1号。用联合致病性系数和联合抗病性系数分析了品种搭配在生产上的应用前景。     

The role of sensitivity to abscisic acid and gibberellin in pre-maturity α-amylase formation in wheat grains

To study the role of abscisic acid (ABA) and gibberellin (GA) sensitivity in regulating pre-maturity α-amylase (PMA) in wheat grains, plants were grown in a glasshouse under cold-shock and ambient conditions. α-amylase activity in response to applied ABA and GA was measured in detached-grains with the embryo removed (in vitro) and in intact-grains attached to the plant (in situ). The in vitro experiment was conducted using Spark (low PMA-susceptible genotype) and Rialto (highly PMA-susceptible genotype), with the aim of defining the time point for GA-sensitivity. The results showed an increase in GA-sensitivity at about 640 degree days after anthesis (DAA) in Rialto. There was no evidence for a change in ABA-sensitivity in either variety. The in situ experiments were conducted using genotypes from a Spark × Rialto doubled haploid population segregating for the Rht-D1a (tall) or Rht-D1b allele and for the presence or absence of 1BS/1RS. For Rht-D1a (tall) or Rht-D1b genotypes with or without 1BS/1RS, the cold-shock significantly increased GA-sensitivity, whereas there was no significant change in ABA-sensitivity. These results show PMA is related to an increase in GA-sensitivity that occurs in the aleurone at around 640 degree DAA, and can be enhanced by environmental factors (e.g. cold-shock).