Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii

Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels.     

面向草莓抓取的气动四叶片软体抓手研制

农林业中果蔬的自动化采摘需求日趋强烈,末端抓手是实现无损采摘的关键。传统的末端抓手以刚性结构居多,现有的各种柔性抓手也存在抓取力不足、包覆性不佳等缺点。本文以草莓的无损采摘为研究对象,提出将草莓外部轮廓曲线作为设计曲线,设计了一种新型气动四叶片软体抓手。首先,对软体抓手的结构做仿真优化,提出一种安全地附着在目标物表面的设想。然后,在进行草莓表面的最小破坏应力试验的基础上,测试了软体抓手的末端力,验证了其实现无损抓取的可行性。再次,利用动态捕捉技术,研究了软体抓手叶面的弯曲变形规律。最后,选择使用弧线型气体通道的软体抓手进行了草莓抓取测试,结果证明了气动四叶片软体抓手可以实现草莓的无损抓取,抓取成功率达90%,破损率为2%,表明所研制的四叶片软体抓手用于草莓抓取时具有良好的稳定性和实用性,可用于草莓采摘的末端执行器。本研究也可为其他易损果蔬的采摘技术提供理论基础和技术支撑。     

探地雷达在地下管线探测中的应用

探地雷达技术是如今适应快速、准确、无损地探测地下障碍物而迅速发展的电磁技术。文中介绍了探地雷达的工作原理及工作方式，并通过结合工程实例来探讨探地雷达在地下管线探测中的广泛应用。     

Effect of surface waxes on the persistence of chlorpyrifos-methyl in apples, strawberries and grapefruits

The effects of the cuticle and epicuticular waxes of grapefruit, strawberry and apple on the photodegradation and penetration of chlorpyrifos-methyl were studied. Photodegradation experiments were conducted by exposing the insecticide to the light of a xenon lamp in the presence of a film of wax extracted from the fruit surface. The half-life of chlorpyrifos-methyl irradiated in absence of waxes was 9.6 min. The half-lives of pesticide irradiated in the presence of wax extracts of apple, grapefruit and strawberry were 83, 34 and 26 min, respectively. In penetration studies, fruit with and without wax layers were treated with an aqueous suspension of pesticide. The penetration of the pesticide from the cuticle to the pulp was measured after 24 h. Samples without wax contained a higher total amount of insecticide than those with wax. No pesticide was detected in samples of apple and grapefruit pulp. Residues were detected in all fractions of strawberry. The waxes and cuticle appear to have some effect on the photodegradation and penetration of chlorpyrifos-methyl in fruit samples.     

Ammonia-water absorption machines for refrigeration: theoretical and real performances

In principle, absorption chillers of the ammonia-water type could work at temperatures well below the usual air-conditioning temperatures, arriving at the range 250–260 K, which can be useful for refrigeration applications. This possibility is studied for an air-cooled machine, comparing the results with the experimental data supplied by a manufacturer that recently commercialized such a refrigerator. The prediction is fair, and the study allows an insight into the internal parameters and into the possible behaviour for more severe conditions than those studied.     

"彩色番茄"果实质体超微结构的观察

“彩色番茄”果色新颖、风味甜美,是西餐中颇为流行的水果蔬菜之一.具有果汁少、果肉厚、耐贮运等特点,市场前景广阔,但其果色形成原因尚未见报道.本试验应用电子显微镜技术对其果肉质体进行观察,发现彩色番茄果实中有条纹部分和无条纹部分的果肉细胞质体发育不同步.有条纹部分的质体（主要为叶绿体向有色体的转变）在发育时间上迟于无条纹部分的质体.从解剖学角度初步认为这可能是形成彩色番茄条纹的原因,为番茄果色形成机制提供了一定的理论依据.     

大规格圆钢质量分析和控制

针对湘钢棒材厂生产大规格圆钢出现的表面质量问题，重点介绍了在成品轧机后采用U形辊道和立活套替换棍道；冷床输入辊道采用镶WT合金套；增设高压水除鳞装置；中间轧件尺寸精度控制等措施，成功的解决了大规格圆钢表面擦伤、“麻面”、尺寸超差等表面质量问题，产品质量显著提高。     

Antimicrobial activity of dogwood fruits (Cornus drummondii) from winter food caches of eastern woodrats (Neotoma floridana)

Post-harvest loss of resources to microbial competitors affects a number of species of animals, and many of them have evolved behaviors that reduce the likelihood of such loss. We previously described the inhibition ofBacillus psychrophilus by dogwood fruits (Cornus drummondii), which can comprise a significant portion of the winter food cache of the eastern woodrat (Neotoma floridana). The present study is a further investigation of the ability of dogwood fruits to inhibit growth ofB. psychrophilus. Additionally, we tested the antimicrobial activity of dogwood fruits onEscherichia coli andStaphlococcus aureus. Results of our study indicate that fresh fruits inhibit the growth ofB. psychrophilus andS. aureus but notE. coli. However, fruits taken from woodrat dens after four and six months storage inhibited growth of all three species of bacteria. Further, the strength of inhibition increased over the test period. We suggest the presence of an inhibitor allows woodrats to compete effectively for a valuable and limited food resource.     

不锈钢绕带容器环板与绕带端头的焊接

本文通过焊接试验对奥氏体不锈钢绕带容器环板与绕带焊接工艺进行了研究分析,并得出了合理的焊接方法和工艺参数。