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Insect reproduction may be affected by a number of factors including seasonal changes in larval or adult nutrition. The effect
of season on the reproductive potential ofMonochamus galloprovincialis (Olivier) females reared inPinus sylvestris L. (Scots pine) logs was investigated by constructing fertility tables for each log that differed only in the season they
were cut. Population parameters were compared among three seasonal cohorts. The intrinsic rate of increase and most of the
associated population parameters of beetles that emerged from logs cut during spring were higher than for beetles emerged
from summer and autumn logs. Slight differences were found between summer and autumn cohorts. We suggest that seasonal differences
in the nutritional quality of logs caused differences inM. galloprovincialis survival and reproductive potential.
http://www.phytoparasitica.org posting March 16, 2008. 相似文献
3.
Akif Kaynak 《Fibers and Polymers》2009,10(5):590-593
Long term performance of conductivity of p-toluene sulfonic acid (pTSA) doped electrochemically synthesized polypyrrole (PPy) films was estimated from accelerated aging
studies between 80 °C and 120 °C. Conductivity decay experiments indicated that overall aging behavior of PPy films deviated
from first order kinetics at prolonged aging times at elevated temperatures. However, an approximate value for the activation
energy of the conductivity decay of PPy was calculated as E=47.4 kJ/mol, enabling an estimate of a rate constant of k=8.35×10−6/min at 20 °C. The rate of decrease of conductivity was not only temperature dependent but also influenced by the dopant concentration.
A concentration of 0.005 M pTSA in the electrolyte resulted in a conductive film and when this film was exposed to 120 °C
for a period of 40 h, the conductivity decayed to about 1/20 of its original value. The concentration of pTSA was increased
to 0.05 mol/l and when the resulting film was aged in the same way, it showed a decrease in the conductivity to about 1/3
of its original value. Both microwave transmission and dc conductivity data revealed that highly doped films were considerably
more electrically stable than lightly doped films. The dopant had a preserving effect on the electrical properties of PPy. 相似文献
4.
Wool and alpaca fibers were coated with polypyrrole by vapor-phase polymerisation method. The changes in frictional and tensile
properties of the single fibers upon coating with the conductive polymer are presented. Coating a thin layer of polypyrrole
on the alpaca and wool fibers results in a significant reduction in the fiber coefficient of friction, as the conducting polymer
layer smooths the protruding edges of the fiber scales. It also reduces the directional friction effect of the fibers. Depending
on the type of fiber, the coating may slightly enhance the tensile properties of the coated fibers. 相似文献
5.
Einsle O Tezcan FA Andrade SL Schmid B Yoshida M Howard JB Rees DC 《Science (New York, N.Y.)》2002,297(5587):1696-1700
A high-resolution crystallographic analysis of the nitrogenase MoFe-protein reveals a previously unrecognized ligand coordinated to six iron atoms in the center of the catalytically essential FeMo-cofactor. The electron density for this ligand is masked in structures with resolutions lower than 1.55 angstroms, owing to Fourier series termination ripples from the surrounding iron and sulfur atoms in the cofactor. The central atom completes an approximate tetrahedral coordination for the six iron atoms, instead of the trigonal coordination proposed on the basis of lower resolution structures. The crystallographic refinement at 1.16 angstrom resolution is consistent with this newly detected component being a light element, most plausibly nitrogen. The presence of a nitrogen atom in the cofactor would have important implications for the mechanism of dinitrogen reduction by nitrogenase. 相似文献
6.
PET fabric is coated with conducting polypyrrole (PPy) by oxidative polymerization from an aqueous solution of Py using ferric
chloride hexahydrate (FeCl3) as oxidant and p-toluene sulphonate (pTSA) as dopant. The optimum concentrations for Py, FeCl3 and pTSA were found to be 0.11, 0.857 and 0.077 mol/l respectively, which yielded a conductive fabrics with resistivity as
low as 72 Ω/sq. PPy fabric gained resistivity less than one order of magnitude when aged for 18 months at room temperature.
The stabilizing effect of the dopant pTSA against thermal degradation was demonstrated; the undoped samples reached resistivity
of around 40 kΩ, whereas doped samples reached less than 2 kΩ at the same temperature and time. 相似文献
7.
Effect of breed on fattening performance, slaughter and meat quality characteristics of Awassi and Morkaraman lambs 总被引:1,自引:0,他引:1
Nurinisa Esenbuga Muhlis Macit Mevlut Karaoglu Vecihi Aksakal Muhammet Irfan Aksu Mehmet Akif Yoruk Mehmet Gul 《Livestock Science》2009,123(2-3):255-260
The influence of breed on fattening performance, slaughter and meat quality traits was studied in Awassi and Morkaraman male lambs at approximately 8 months of age. All of the groups were fed a diet consisting of concentrate mixture offered ad libitum, and 300 g of grass hay per lamb per day during 60-day fattening period. Initial live weight, final live weight, daily weight gain and feed conversion efficiency (concentrate and hay consumption for 1 kg of live weight gain) were 39.63 kg, 55.08 kg, 0.258 kg and 6.37 for Awassi; 40.54 kg, 55.58 kg, 0.234 kg and 6.77 for Morkaraman, respectively. The effect of breed on fattening performance and slaughter traits except for LD area was not significant. In addition, meat colour parameters (L = lightness, a = redness, b = yellowness, H = hue angle and C = chroma), pH values, drip loss and sensory attributes were not affected by breed in present study. A significant muscle effect was observed for instrumental measurements of some meat quality characteristics as meat colour parameters (L, a and C), collagen, drip loss, pH, moisture and protein content, WBS, and for some sensory attributes (tenderness, juiciness, acceptability and number of chewing). Results of this study indicate that fattening performance, slaughter and meat quality traits were similar between Awassi and Morkaraman male lambs. 相似文献
8.
Jenelle Izer Ronald Wilson Krista Hernon Akif Ündar 《Veterinary anaesthesia and analgesia》2017,44(1):133-137
Objective
To describe an ultrasound-guided approach for venous and arterial vascular access and catheterization in anesthetized adult Yorkshire cross-bred pigs.Study design
Prospective experimental study.Animals
Ten adult female Yorkshire cross-bred pigs, weighing 78.4 ± 5.6 kg (mean ± standard deviation).Methods
Using ultrasound guidance and the Seldinger technique, a 7 Fr, 20 cm triple-lumen central venous catheter was placed in the external jugular vein and an 18 gauge, 16 cm catheter was placed in the femoral artery. The success rate of catheterization and the incidence of catheter patency over 24 hours of general anesthesia were recorded.Results
Catheterization of the external jugular vein was successful in 10 out of 10 pigs and catheterization of the femoral artery was successful in eight out of 10 pigs. A surgical dissection technique on the femoral artery was performed in two pigs. Venous and arterial catheter patency was maintained in all pigs over the 24 hour study period.Conclusions and clinical relevance
Ultrasound guidance resulted in success rates of 100% for catheterization of the external jugular vein and 80% for catheterization of the femoral artery in anesthetized adult Yorkshire cross-bred pigs. This technique is a noninvasive, easily performed alternative to surgical exposure of the vessels in large pigs undergoing surgical instrumentation for biomedical device testing. 相似文献9.
Wool yarns were coated with conducting polypyrrole by chemical synthesis methods. Polymerization of pyrrole was carried out
in the presence of wool yarn at various concentrations of the monomer and dopant anion. The changes in tensile, moisture absorption,
and electrical properties of the yarn upon coating with conductive polypyrrole are presented. Coating the wool yarns with
conductive polypyrrole resulted in higher tenacity, higher breaking strain, and lower initial modulus. The changes in tensile
properties are attributed to the changes in surface morphology due to the coating and reinforcing effect of conductive polypyrrole.
The thickness of the coating increased with the concentration of p-toluene sulfonic acid, which in turn caused a reduction
in the moisture regain of the wool yarn. Reducing the synthesis temperature and replacing p-toluenesulfonic acid by anthraquinone
sulfonic acid resulted in a large reduction in the resistance of the yarn. 相似文献
10.
Ahmed Abed Gatea AL-SHAMMARY Abbas Z. KOUZANI Akif KAYNAK Sui Yang KHOO Michael NORTON Will GATES 《土壤圈》2018,28(4):581-596
Measurement of soil bulk density is important for understanding the physical, chemical, and biological properties of soil. Accurate and rapid soil bulk density measurement techniques play a significant role in agricultural experimental research. This review is a comprehensive summary of existing measurement methods and evaluates their advantages, disadvantages, potential sources of error, and directions for future development. These techniques can be broadly categorised as direct and indirect methods. Direct methods include core, clod, and excavation sampling, whereas indirect methods include the radiation and regression approaches. The core method is most widely used, but it is time consuming and difficult to use for sampling multiple soil depths. The size of the coring cylinder used, operator experience, sampling depth, and in-situ soil moisture content significantly affect its accuracy. The clod method is suitable for use with heavy clay soils, and its accuracy is dependent on equipment calibration, drying time, and operator experience, but the process is complicated and time consuming. Excavation techniques are most commonly used to evaluate the bulk density of forest soils, but have major limitations as they cannot be used in soils with large pores and their measurement accuracy is strongly influenced by soil texture and the type of analysis selected. The indirect methods appear to have greater accuracy than direct approaches, but have higher costs, are more complex, and require greater operator experience. One such approach uses gamma radiation, and its accuracy is strongly influenced by soil depth. Regression methods are economical as they can make indirect measurements, but these depend on good, quality data of soil texture and organic matter content and geographical and climatic properties. Also, like most of the other approaches, its accuracy decreases with sampling depth. 相似文献