Effect of biodiesel on polyamide‐6‐based polymers

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149752/1/pen25131.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149752/2/pen25131_am.pd

The Relationships Between the Level of Lignin, a Secondary Metabolite in Soybean Plant, and Aphid Resistance in Soybeans

In the present report, the relationship was discussed between the level of lignin-one of the secondary metabolites in soybean plant and the chemical defense reaction of soybean to the soybean aphid (Aphis glycines Muts). Experimental results indicated that the cultivars with higher level of lignin are more resistant to the damage of aphids than those with lower level of lignin. Lignin is one of the compounds that are responsible to the chemical defense reaction of soybean. This finding laid a foundation for the elucidation of the mechanism of aphid resistance in plants and its biochemical basis.Originating text in Chinese.Citation: Hu, Qi, Zhao, Jianwei, Cui, Jianwen. (1993). The Relationships Between the Level of Lignin, a Secondary Metabolite in Soybean Plant, and Aphid Resistance in Soybeans. Plant Protection (Institute of Plant Protection, CAAS, China), 19(1), 8-9

Delay Sensitive Communications over Cognitive Radio Networks

Supporting the quality of service of unlicensed users in cognitive radio networks is very challenging, mainly due to dynamic resource availability because of the licensed users' activities. In this paper, we study the optimal admission control and channel allocation decisions in cognitive overlay networks in order to support delay sensitive communications of unlicensed users. We formulate it as a Markov decision process problem, and solve it by transforming the original formulation into a stochastic shortest path problem. We then propose a simple heuristic control policy, which includes a threshold-based admission control scheme and and a largest-delay-first channel allocation scheme, and prove the optimality of the largest-delay-first channel allocation scheme. We further propose an improved policy using the rollout algorithm. By comparing the performance of both proposed policies with the upper-bound of the maximum revenue, we show that our policies achieve close-to-optimal performance with low complexities.Comment: 11 pages, 8 figure

Metal adsorption by quasi cellulose xanthogenates derived from aquatic and terrestrial plant materials

The FTIR spectra, SEM-EDXA and copper adsorption capacities of the raw plant materials, alkali treated straws and cellulose xanthogenate derivatives of Eichhornia crassipes shoot, rape straw and corn stalk were investigated. FTIR spectra indicated that of the three plant materials, the aquatic biomass of Eichhornia crassipes shoot contained more O-H and C=O groups which accounted for the higher Cu²⁺ adsorption capacities of the raw and alkali treated plant material. SEM-EDXA indicated the incorporation of sulphur and magnesium in the cellulose xanthogenate. The Cu²⁺ adsorption capacities of the xanthogenates increased with their magnesium and sulphur contents. However more copper was adsorbed than that can be explained by exchange of copper with magnesium. Precipitation may contribute to the enhanced uptake of copper by the cellulose xanthogenate

Spatially resolved pump-probe study of single-layer graphene produced by chemical vapor deposition

Carrier dynamics in single-layer graphene grown by chemical vapor deposition (CVD) is studied using spatially and temporally resolved pump-probe spectroscopy by measuring both differential transmission and differential reflection. By studying the expansion of a Gaussian spatial profile of carriers excited by a 1500-nm pump pulse with a 1761-nm probe pulse, we observe a diffusion of hot carriers of 5500 square centimeter per second. We also observe that the expansion of the carrier density profile decreases to a slow rate within 1 ps, which is unexpected. Furthermore, by using an 810-nm probe pulse we observe that both the differential transmission and reflection change signs, but also that this sign change can be permanently removed by exposure of the graphene to femtosecond laser pulses of relatively high fluence. This indicates that the differential transmission and reflection at later times may not be directly caused by carriers, but may be from some residue material from the sample fabrication or transfer process.Comment: 9 pages, 3 figure