浙江竹材制板的现状分析

竹材通过加工制成的竹质人造板,不仅大量用作代木材料,而且有的竹质板力学强度很大,非木材所能比拟,是良好的工程结构材料。发展竹质板生产是克服木材短缺的切实有效途径。目前浙江竹质人造板主要种类有:竹材胶合板、竹编胶合板、竹篾胶合板、竹丝胶合板和竹材旋切片(板)五种。文章介绍了上述五种板的工艺流程、板的物理力学性质、主要用途,生产中存在的问题以及可供借鉴的国内外先进技术。     

Study of long-distance movement of Plum pox virus (Sharka) as an alternative resistance-evaluation method in Prunus

During the breeding programs for Plum pox virus (PPV, Sharka) resistance in Prunus, the evaluation of the new releases through symptoms observation on leaves has been contradictory and represents one of the main handicaps in these programs. In order to increase the accuracy of this traditional evaluation method, we here analyze an alternative method based on the study of the ability of a genotype to allow the long-distance movement of the virus through its vascular vessels. Two different plant models have been assayed: (a) in Model I, the inoculation was performed in the ‘GF305’ rootstock with a later grafting of the genotype under evaluation and a scion of healthy control ‘GF305’, to evaluate the long-distance movement through the studied genotype from the rootstock to the scion (xylem transport), and (b) in Model II, the inoculation with ‘GF305’ diseased scions was performed by grafting these diseased scions onto the studied genotypes, which were grafted onto healthy ‘GF305’ peach seedlings, to evaluate the long-distance movement through the studied genotype from the scion to the rootstock (phloem transport). The results show that, regardless of the presence of symptoms, susceptible genotypes allowed the movement of the virus through their vascular vessels in both directions studied. However, the resistant apricot ‘Stark Early Orange’ did not allow this movement. We propose the study of the ability of a genotype to allow the long-distance movement of the virus as an alternative and more accurate method for the evaluation of PPV resistance. However, this protocol is much more tedious than the traditional one and could be used mainly in the evaluation of a reduced number of more interesting genotypes.     

基于双正则化的图像超分辨率盲重建

图像超分辨率重建是利用数字信号处理技术由一系列低分辨率观测图像得到高分辨率图像。大多数重建算法假设成像系统的模糊特性也即点扩散函数(PSF)已知,然而实际的应用环境下PSF事先不知道或部分知道。为此,将未知PSF模型化,提出基于双正则化的图像超分辨率盲重建算法,并且正则化作用的强度随重建图像局部光滑程度的变化而自适应地改变,以便能保护图像细节同时抑制平滑区域的噪声。求解过程中采用交替最小化方法估计PSF参数和高分辨率图像,并随着迭代次数的增加逐步提高每次寻优的精度以节省计算开销。实验结果表明,该算法能够比较准确地估计出PSF参数并取得较好的图像重建效果。     

接装纸涂胶量对卷烟滤嘴通风率的影响

为使接装纸透气度及滤嘴通风率在指标范围内保持稳定,采用单因素试验法,研究接装纸涂胶量对接装纸透气度及滤嘴通风率的影响,以及接装纸涂胶量随接装机运转速度和接装纸包角的变化关系。结果表明,1接装纸涂胶量对接装纸透气度及滤嘴通风率的影响显著;2接装纸涂胶量随接装机运转速度的提高而减少;3接装纸涂胶量随接装纸包角的增大而增加。并建立了接装纸涂胶量与接装机运转速度和接装纸涂胶量与接装纸包角之间的函数关系,经过分析计算得到了接装纸包角与接装机运行速度的数学模型。当接装机运转速度发生变化时,该模型可通过调节接装纸包角使接装纸涂胶量保持稳定,进而使接装纸透气度及滤嘴通风率保持稳定。     

Ready-to-Serve Crab Sandwich Spread in Retort Pouch: Product Development and Process Optimization

A ready-to-serve sandwich spread was developed from the meat of mud crab, Scylla serrata, by thermal processing in retortable pouches in an overpressure retort at temperatures 111.1, 116.1, and 121.1°C; and F₀ values 5, 6, and 7 min. Process optimization was done by evaluating the samples for texture, color, commercial sterility, thiobarbituric acid (TBA) value, and sensory evaluation. All samples were found to be acceptable based on these quality evaluations, and together with principal component analysis (PCA), the sample processed at 116.1°C, 6 min was found to be the best, with cook value of 84.29 and total process time of 42.59 min.     

Mapping the risk of establishment and spread of sudden oak death in California

Sudden oak death, caused by the recently described pathogen Phytophthora ramorum, is an emerging forest disease that has reached epidemic levels in coastal forests of central California. We present a rule-based model of P. ramorum establishment and spread risk in California plant communities. The model, which is being used as a management tool to target threatened forests for early-detection monitoring and protection, incorporates the effects of spatial and temporal variability of multiple variables on pathogen persistence. Model predictions are based on current knowledge of host susceptibility, pathogen reproduction, and pathogen transmission with particular regard to host species distribution and climate suitability. Maps of host species distributions and monthly weather conditions were spatially analyzed in a GIS and parameterized to encode the magnitude and direction of each variable's effect on disease establishment and spread. Spread risk predictions were computed for each month of the pathogen's general reproductive season and averaged to generate a cumulative risk map (Fig. 6a and b). The model identifies an alarming number of uninfected forest ecosystems in California at considerable risk of infection by Phytophthora ramorum. This includes, in particular, a broad band of high risk north of Sonoma County to the Oregon border, a narrow band of high risk south of central Monterey County south to central San Luis Obispo County, and scattered areas of moderate and high risk in the Sierra Nevada foothills in Butte and Yuba counties. Model performance was evaluated by comparing spread risk predictions to field observations of disease presence and absence. Model predictions of spread risk were consistent with disease severity observed in the field, with modeled risk significantly higher at currently infested locations than at uninfested locations (P < 0.01, n = 323). Based on what is known about the ecology and epidemiology of sudden oak death, this model provides a simple and effective management tool for identifying emergent infections before they become established.     

进境原木上截获的落叶松大小蠹及其扩散风险浅析

2006年,莆田口岸先后几次从美国阿拉斯加进口原木中截获到一种大小蠹,经鉴定复核,确定为落叶松大小蠹(Den-droctonus simplexLeconte)。该种在国内未见分布和相关研究报道。本文详细描述了落叶松大小蠹的形态特征、地理分布、寄主植物、生物学特性及危害等,并对其检疫重要性进行了分析。     

Role of asymptomatic carrier trees in epidemic spread of pine wilt disease

To determine why pine wilt disease caused by the pinewood nematode (Bursaphelenchus xylophilus) recurs in the same pine stand even after thorough eradication of dead pine trees, the amount of oleoresin exudation from artificial wounds was measured from 72 Pinus koraiensis trees, highly susceptible to this disease, for 4 years. The amount of exuded oleoresin was rated from 0 to 4. All values obtained for each tree were summed at each measurement; thereby a cumulative curve was drawn to monitor the physiological condition of each test tree. Cumulative curves suggest that some pine trees that died had already been infected in the previous year or earlier and then had survived without any visible symptoms. If cessation of oleoresin exudation delays, and overlaps with activity of Monochamus alternatus, the vector beetle of pinewood nematodes, in the following season, such trees can be referred to as latent carriers or asymptomatic carriers. They could play a significant role as attractants for M. alternatus that could then transmit B. xylophilus to neighboring trees. Behavior of M. alternatus caged with several pine seedlings, only one of which acted as an asymptomatic carrier of B. xylophilus, confirmed this idea. The presence of asymptomatic pine trees, which harbored B. xylophilus nematodes or had reduced annual elongation, near stumps of newly dead trees in the study stand also substantiated this hypothesis.     

Development and Prospects of the Anti-jamming Communications

An overview of the developments of some key technics such as spread frequency communication, adaptive anti-interference and comprehensive anti-jamming technology in anti-jamming communications over the world is shown and discussed. Some suggestions to develop anti-jamming communications are also given in the paper.     

Intraspecific variation in host susceptibility and climatic factors mediate epidemics of sudden oak death in western US forests

Umbellularia californica is one of the key infectious hosts of the exotic Phytophthora ramorum, which causes sudden oak death (SOD) in California and Oregon forests. This study provides a comprehensive analysis of the epidemiologically relevant parameters for SOD in California and southern Oregon, including potential differences between the two states. Experimental infection of U. californica leaves was optimal when leaves were wet for 6–12 h, temperature was approximately 19°C and pathogen concentration was approximately 2·7 × 10⁴ zoospores mL^?1. Seasonal variation in host susceptibility and disease incidence was examined for two populations by inoculating detached leaves at 12 dates and by monitoring naturally infected leaves, respectively. Susceptibility of U. californica and disease incidence varied significantly in time and the variation was highest for both in spring. Susceptibility of trees from 17 natural populations from California and southern Oregon was assessed in detached leaf inoculations. One California and three southern Oregon populations had significantly and repeatable lower average susceptibility in artificial inoculations, but differences among three selected California and Oregon populations were not significant in inoculations of seedlings grown from seed in a common garden. This study concludes that U. californica susceptibility has a large environmental component, yet still predicts potential disease severity in different sites especially where infestations are young or the pathogen has not yet arrived. The accuracy and utility of predictive risk models for P. ramorum will be enhanced by the inclusion of both the environmental and host susceptibility components.