Characterization of cellulose in compression and opposite woods of a Pinus densiflora tree grown under the influence of strong wind     

F. Tanaka  T. Koshijima  K. Okamura 《Wood Science and Technology》1981,15(4):265-273

Summary Structural factors in a Pinus densiflora tree grown under the influence of strong wind were measured. No difference for cellulose molecules was noticed between compression and opposite wood, but the was somewhat lower in the region where the compression wood was concentrated. The degree of crystallinity of cellulose was 45–50% in compression wood, about 50% in normal wood, and 50–60% in opposite wood. The crystallinity decreased with increasing height above the ground. The maximum point of crystallographic b-axis (fiber axis) orientation distribution for cellulose crystallites in compression wood was located at 30°, in normal wood at 25° and in opposite wood at 0°. The cellulose crystallite dimension in the transverse direction was 3.2 nm, corresponding to four cellulose unit cells, a value that was almost constant throughout the wood. In the longitudinal direction, there were large differences in cellulose crystallite dimensions between compression and opposite woods. In compression wood the cellulose crystallite dimensions was 12 nm corresponding to 11–12 cellulose unit cells. In opposite wood it was 17–32.5 nm corresponding to 17–32 cellulose unit cells. These structural factors were apparently affected by the environmental conditions, and the mechanical properties of the wood were influenced by these factors. Opposite wood had longer crystallites, a higher degree of crystallinity and a better orientation distribution of cellulose crystallites in the longitudinal direction. Compression wood, on the other hand, had shorter crystallites, a lower degree of crystallinity and a large angle between the stem and the direction of the crystallites.  相似文献   

Variations in transpiration rate and leaf cell turgor maintenance in saplings of deciduous broad-leaved tree species common in cool temperate forests in Japan     

Saito T  Tanaka T  Tanabe H  Matsumoto Y  Morikawa Y 《Tree physiology》2003,23(1):59-66

To clarify mechanisms underlying variation in transpiration rate among deciduous broad-leaved tree species, we measured diurnal changes in stomatal conductance (gs) and leaf water potential, and calculated the maximum transpiration rate (Emax), leaf-specific hydraulic conductance (K(s-l)) and difference between the soil water potential and the daily minimum leaf water potential (Psis - Psi(l,min)). Pressure-volume (P-V) measurements were made on leaves. Saplings of eight broad-leaved tree species that are common in Japanese cool temperate forests were studied. Maximum transpiration rate varied significantly among species. There was a statistically significant difference in Psis - Psi(l,min), but not in K(s-l). Species with large Emax also had large Psis - Psi(l,min) and gs. The results of the P-V analyses showed that species with a large Psis - Psi(l,min) maintained turgor even at low leaf water potentials. The similar daily minimum leaf pressure potentials (Psip) across all eight species indicate that Psip values below this minimum are critical. Based on these results, we suggest that the leaf cell capacity for turgor maintenance strongly affects Psis - Psi(l,min) and consequently Emax via stomatal regulation.  相似文献   

The method for designing the profile of forest roads supported by genetic algorithm     

Kouichi Ichihara  Tosimi Tanaka  Isao Sawaguchi  Shuji Umeda  Katsumi Toyokawa 《Journal of Forest Research》1996,1(1):45-49

This study examines a method for designing an optimum profile of a forest road in a short matter of time. In this method, a genetic algorithm (GA) searches for points where the gradient changes and dynamic programing (DP) designs the longitudinal slope. This method can be applied to the ground heights of an actual forest road. The evaluation function of the DP assesses the total expenditure. The inverse of this function is the fitness function. Crossover and mutation are operators of an evolution simulation of a GA. They are each repeated 20 times and 420 profiles are designed and assessed, all within about 10 min. A comparison of the profile designed by the GA with that of an actual forest road shows only one section where the formation level differed substantially. Overall, both profiles seem to show a high degree of correspondence. From this result, we believe that the profile designed by the GA is best, or the one of the best. A conventional method takes about 65 h to calculate all changing points of gradients. However, by using the GA, the calculation time was reduced to about 1/389 that of the coventional method, showing that the method which uses the GA through the profile design is very useful.  相似文献   

松香酰胺在中性造纸施胶中的应用   总被引：2，自引：0，他引：2  

吴宗华  田中浩雄 《林产化学与工业》1996,16(3):44-44

利用松香与异腈酸的酰经反应在１００－１５０℃下合成了三个松香酰胺，并应用它们到中性造纸松香乳酸，ＰＨ４－８的抄造试验表明这些松香衍生物在这个ＰＨ范围内具有高的施胶效果。松香酰结构与酰胺化度对施胶效果有很大的影响。  相似文献   

    

Chiba O. und K. Tanaka 《Journal of pest science》1970,43(10):159

Ohne Zusammenfassung  相似文献   

Inoculation of fumigated nursery soil increases nodulation and yield of bare-root red alder (Alnus rubra Bong.)     

A. B. Hilger  Y. Tanaka  D. D. Myrold 《New Forests》1991,5(1):35-42

To determine if inoculation increases nodulation and yield of bare-root red alder (Alnus rubra Bong.), fumigated nursery plots were treated with inoculum and ammonium sulfate (28 kg N ha^–1) in a factorial experiment. Inoculum was alder soil with 100 infective units of Frankia g^–1. Seedlings were evaluated for nodulation at age 10 wk and when lifted, at age 9 mo. Inoculation produced earlier and more extensive nodulation and increased seedling root collar diameter, height, and dry weight. Fertilization decreased seedling height, but did not decrease nodulation. No interaction of fertilization with inoculation was found. Inoculated unfertilized plots had the highest yield of packable seedlings (257 m^–2), and uninoculated fertilized seedlings had the lowest yield (126 m^–2).  相似文献   

Automatic detection of washboarding in bandsaws     

Nanfeng Zhu  Chiaki Tanaka  Tadashi Ohtani  Hiroshi Usuki 《Journal of Wood Science》2001,47(2):102-108

This paper presents an on-line method for detecting washboarding generated in bandsaws. It uses a parameter based on the shape of sawing force amplitude distributions. The curve of the probability density function of the parallel sawing force amplitude obeyed a normal distribution for the normal sawn surface, but it changed to an M-shaped distribution when washboarding appeared on the sawn surface of the workpiece. The curve of probability density function of the normal sawing force amplitude obeyed the normal distribution for any sawn surface investigated. The workpiece including a knot did not influence use of the parameter for detecting the appearance of washboarding.  相似文献   

Vertical profiles of environmental factors within tropical rainforest, Lambir Hills National Park, Sarawak, Malaysia     

Tomo’omi Kumagai  Koichiro Kuraji  Hironori Noguchi  Yuri Tanaka  Katsunori Tanaka  Masakazu Suzuki 《Journal of Forest Research》2001,6(4):257-264

Environmental factors, such as global solar radiation, wind speed, air temperature, humidity, and CO₂ concentration, were measured above and within the canopy of a tropical rainforest in Lambir Hills National Park, Sarawak, Malaysia. Few data concerning the environment of this forest have been reported. Intensive observations were carried out in 1998, 1999, and 2000 with the following results: (1) The fraction of global solar radiation reaching the upper layer of the canopy varied with global solar radiation above the canopy. Even though the global solar radiation above the canopy fluctuated, the fraction of that reaching the lower canopy and the ground was constantly approximately 5%. (2) The fraction of wind speed reaching each layer of the canopy increased with wind speed above the canopy. Little wind was usually present at the lower canopy. (3) The daytime air temperature at the canopy top was higher than that near the ground. The maximum difference between the air temperature at the canopy top and that at the ground was about 5°C, and the diurnal temperature ranges at the canopy top and those at the ground were about 8°C and about 5°C, respectively. The highest daytime water vapor pressure occurred within the canopy and particularly near the ground. Vertical gradients of water vapor pressure during the day were steep, probably because of high transpiration. (4) In the 1998 observation the minimum and the maximum CO₂ concentrations were 360 ppm in the day and 450 ppm at night, while in the 2000 observation the minimum and the maximum CO₂ concentrations were 350 ppm in the day and 540 ppm at night. The higher CO₂ concentration in the daytime and the lower concentration at night observed during the 1998 observation period were probably due to reduced photosynthesis and soil respiration caused by exceptional dry conditions during the observation period.  相似文献   

High-speed steel tool wear during wood cutting in the presence of high-temperature corrosion and mineral contamination     

Bolesław Porankiewicz  Piotr Iskra  Jakub Sandak  Chiaki Tanaka  Karol Jóźwiak 《Wood Science and Technology》2006,40(8):673-682

Dulling of high-speed steel (HSS) cutting tools after milling five wood species has been analyzed. The wood investigated varied in mineral contamination, high-temperature corrosivity (HTC) and density (D). Experiments performed proved that up to date methods for evaluation of mineral contamination in wood should be improved. A new pipe-like form of mineral contamination particles was evidenced. The correlation between the presence of 3D aggregates of silica in wood and high content of K and Ca in the ash was established. Employing multivariable theoretical simulation method, the combined effect of mineral contamination, HTC and wood density on the tool dullness appeared to be a reasonable explanation of the results obtained.  相似文献   

Simple method for synthesizing phenolicβ-O-4 dilignols     

Shingo Kawai  Kyoko Okita  Kazuhiro Sugishita  Ai Tanaka  Hideo Ohash 《Journal of Wood Science》1999,45(5):440-443

A modified synthetic method for phenolic-O-4 lignin substructure model dimers was developed involving protection of the phenolic hydroxyl group of acetophenons with benzoyl chloride, bromination with 4-dimethylaminopyridiniumbromide perbromide, condensation with phenols in the presence of 18-crown-6-ether, condensation with paraformaldehyde, reduction with NaBH₄ and debenzoylation. This method results in shorter reaction times and increasing yields without the application of strict anhydrous and drastic conditions or chloric solvents. This alternative route could be applied to the-O-4 dilignol syntheses of four combinations of guaiacyl and syringyl derivatives.  相似文献