1,219 research outputs found
Effects of temperature on the tillering and the endogenous cytokinin activities in rice roots
No full text(29(2):115-130)Effects of the application of plant growth regulators on yield components of early maturing rice
No full text以早熟稻品種日本晴（Nipponbare），廣陸矮 4 號（Kwang - lu - ai 4）及本地現行栽培品種臺農 67 號（Tainung 67）為材料，於 1978 年 1、2 期作種植於田間。在分蘗開始期及分蘗盛期施用 Chloroflurenol ( IT3456 , methyl-2-Chloro-9-hydroxy-fluroene -(9)-carbo-xylate ) 1 mM，並於幼穗分化期、孕穗期及乳熟期加施 50 ppm 之 SNA ( sodium naphthal - ene acetic acid) 與 2000 倍稀釋液之 SNP ( sodium nitrophenol) 之混合液，以及 50 ppm 之 GA3 ( gibberellin )，調查其對稻作生育之反應及對產量之影響。試驗結果摘要如下：（1）施用 Chloroflurenol 對分蘗數之增加有顯著之效果（1 期作增加 3~12 % , 2 期作增加 9~19 %），但所增加之分藥大部份為無效分蘗，且由於分蘗數之增加會導致-穗平均粒數及千粒重之降低。（2）生育後期加施 SNA 與 SNP 混合液可使增加之無效分蘗成為有效分蘗，-株穗數、發育穎花數、結實率及千粒重亦增加，因而使產量增加 4 - 11%（1 期作）及 5 – 14%（2 期作）。（3）加施 GA3 對株高、穗長及粒長有顯著影響外，對其他農藝性狀效果不穩定。（4）三供試品種間，以臺農 67 號對不同生長素處理有較好之反應；稉型早熟品種日本晴因施用 Chloroflurenol 而促進之分藥數增加效果最大；秈型早熟品種廣陸矮 4 號對上述生長素處理，則在一株穗數、千粒重及株高方面較其他供試品種增加效果大。
A sudy was carried out to investigate the effects of plant growth regulators, chloroflurenol (IT 3456, methl-2-chloro-9-hydroxy-fluroene-9-carboxylate ; 1 mM), SNA (sodium naphthalene acetic acid; 50 ppm) +SNP (sodium nitrophenol; 2000 X) and gibberellin (GA3 50 ppm) on grain yield and yield components of paddy rice. Two early maturing rice Nipponbare, Kwang-lu-ai 4 and the local cultivar Tainung 67 were used in this experiment. The following results were obtained.
1. The application of chloroflurenol alone increased tiller number per plant by 3-12% in the first rice season and Ly 9-19% in the second season. However, most of the increased tillers did not bear panicles. No striking effect on grain yield was obtained since mean spikelet number per panicle and 1000-grain-weight were reduced by this treatment.
2. SNA and SNP mixture treatment showed the effects of increasing panicle number, particularly by promoting the additional tillers caused by chloroflurenol treatment to bear effective panicles. Number of florets in the secondary branch position, seed-set percentage and 1000-grain-weight were also increased, especially in the second crop season. Grain yield was increased by 4-11% and 5-14% in the first and second rice seasons, respectly.
3. GA3 treatment significantly affected the plant height and length of panicles and spikelets. Most significant effect was found on the semi-dwarf variety Kwang-lu-ai 4, Spikelet number per plant and seed-set percentage also increased slightly, whereas1000-grain-weight dropped. Other agronomic characters showed relatively unstable results. This treatment caused the reduction of grain yield of Kwang-lu-ai 4 in the first and of all cultivars in the second crop season.
4. Highly significant differences in grain yield and yield components were found among the three cultivars tested. Different growth regulator treatments had more favourable influence on Tainung 67 than on other cultivars, particularly in grain yield. The application of chloroflurenol could increase the tiller number of Nipponbare, but not 1000-grain-weight and grain yield. The treatment of chloroflurenol, SNA+SNP, and GA3 had more favorable influence on the panicle number per plant, 1000-grain-weight and plant height for Kwang-lu-ai 4 than for other cultivars, and its grain yield showed a slight increase also
(32(3):201-208)Studies on the Improvement of Blast Disease Resistance of Japonica Rice, Tainung 67
No full text為改良臺農67 號之稻熱病抵抗性，於民國68 年第二期作開始以抗稻熱病品種TKM-6 , Ml-48 , Dawn , Tetep , carreon , Shensho 及Dular 等為父本與臺農67 號雜交，後以臺農67 號為輪迴親本進行一系列之回交，以便將抗病基因導入於臺農67 號。其中Dawn , Tetep 及Carreon 有關三組合之BC1F1乃以磨傷法點接稻熱病菌4 個生理小種ID-14 , IE-2 , IF-3 及IG-2 於葉片上，檢驗其對4 小種之抵抗性。Dawn 組合BC1F1之分離比顯示，對IG-14 及IG-2 之抵抗性似各由一對基因所控制，而對IE-2 則有3 對，IF-3 有2 對基因參與。在Carreon 組合之BCIFI 對ID-14 及IG-2 似各有一對，對IE-2 及IF-3 似各有3 對基因參與。Tetep 組合的BC1F1則似乎比前兩組合有較多的抗病基因參與。對ID-14 及IG-2 之抗病性各有2 對，對IE-2 及IF-3 各有4 對基因參與。又Tetep 組合之BC2F1在病圃有較多的抗病系統出現，顯示Tetep 乃具有多數抗病基因之優良抗病種源。經人工接種選拔及病圃篩選選得之植株繼續回交至第3 、4 次，由其後代系統中，已選得多數抗病且株型優良之系統，其中部分已成立為品系參加產量比較試驗；同時亦進行BC4F1間之複交，再以花藥培養法做配偶子型之選拔，預期將可選育抗病性較廣且又高產之稉稻新品種。
Rice variety Tainung 67 which occupied 454,620 hectares of rice area in 1982 in Taiwan is known to have a lower degree of resistance to blast disease (Pyricularia oryzae Cav. ). In order to correct this defect, Tainung 67 was crossed to varieties, Tetep, Carreon, Dawn, M1-48, TKM-6, Shensho and Dular as the resistance source. The F1’s were then backcrossed to Tainung 67 three or four times.
The BC1F1’s of three crosses, TNG 672 /Dawn, TNG 672 /Carreon and TNG 672/Tetep were inoculated with 4 races of the blast fungus that attacked Tainung 67, namely, ID-14, IE-2, IF-3 and IG-2 in the 2nd crop season, 1980. Based on the segregation patterns of bast disease resistance in the BC1F1’s, it is concluded that the resistance of Dawn to races ID-14 and IG-2 seems to be controlled by a single dominant gene, to race IE-2 by 3 pairs and to race IF-3 by 2 pairs of gene, while the resistance of Carreon to races ID-14 and IG-2 seems to be controlled by a single dominant gene and to IE-2 and IF-3 by 3 pairs of gene. However, Tetep’s resistance to races ID-14 and IG-2 seems to be controlled by 2 pairs of gene and to races IE-2 and IF-3 by 4 pairs of gene.
The main purpose of this experiment was to introduce resisatnce genes of Tetep, Carreon, etc. into Tainung 67. To understand the mode inheritance of resistance in the early segregating generations of these crosses will facilitate our further efforts. The resistant BC1F1 plants selected from the above-mentioned test were again backcrossed to Tainung 67 three or four times and the BC2F1’s and BC4F1’s were grown in a blast disease nursery for continuous selection
(27(2):169-174)EFFECTS OF SUCROSE APPLICATION ON GRAIN YIELD IN MEIOSIS AND MATURING STAGES OF THE RICE PLANT
No full text本省位於亞熱帶地區，連綿陰雨天往往持續至二個星期甚且更長，尤其在二期作更甚，其間之日照亦常低於150克卡／平方公分／天（氣象中心年報1975），因此影響水稻之正常生育而導致產量減產。本試驗乃針對影響水稻光合作用最大之減數分裂期及成熟期，將稻株人工遮陰(90%)，以蔗糖噴施稻葉，及以蔗糖溶液灌施，以探討直接施用蔗糖能否補救因光照不足所引起產量減少之部份原因。
供試材料臺農育A6號（蓬萊稻），由Pot試驗結果，由於本試驗於第二期作執行，於生育後期遭遇低溫及寡日照之影響，結果遮陰並未使退化穎百分比顯著提高，但其結實率，千粒重，登熟率及每欉谷粒產量却大幅降低，因此，蔗糖處理仍未顯出明顯之反應。但嘉農秈8號却有良好之結果，遮陰使退化穎花數增加約54%，蔗糖處理亦有使退化穎花百分比降低之趨勢。
經田間試驗結果顯示：蔗糖葉面噴施及灌溉水施用，對產量構成因素沒有明顯之效果，其小區產量經變方分析結果亦未達顯著之差異。
1. Prolonged rainy weather or low solar radiation is considered one of the causes of low yields of the second crop rice in Taiwan. The total solar radiation during such period commonly falls down to 150 gr. cal/cm2/day or less. Attempts were made to find out whether sucrose application in meiosis and maturing stages corrects the effect of low solar radiation on rice plants.
2. In a pot experiment, about 90% shading by a piece of black cloth for ten days was made during meiosis stage, and the plants were applied with 0, 0.3, 0.6, 0.9 g/hill sucrose through foliage spraying and irrigation water. Inaddition, two field experiments were conducted, one by application of sucrose by foliage spraying and the other in irrigation water through roots. Dssiolve sucrose 50, 100, 150 kg/ha in 20 c.c/hill water, and apply them during meiosis stage, after heading stage and both stages.
3. In the pot experiment an indica rice variety, Chianung Sen 8 showed 54% of degenerated spikelet by the shading treatment. However, sucrose application tended to prevent the spikelets from degeneration. The shading did not cause significant degree of spikelet degeneration in Tainung Yuh A6. Hence the difference in the percentage of degenerated spikelets among the sucrose treatments was not significant. But 1,000 grain weight, percentages of seedset and matured grain and grain yield perhill were reduced appreciably.
4. In both fild experimeits, the analysis of variance of grain yield per plot showed non-significant differences in grain yield among sucrose treatments in meiosis, mat uring stages and both stages
(34(2):125-134)Development of Rice Variety Tainung 69
No full text水稻品種臺農69 號是由F3 （臺農6lM510 -14 / Oryza rufipogon） //臺農62 號之雜交後代選出。第一期作比臺農67 號低產4 %-5%，第二期作高產8 %-19.3%。在全省性區域試驗比臺農67 號減產4 %-7%。本品種有相當廣幅又穩定的稻熱病抵抗性，同時亦抗細菌性白葉枯病，並具有臺農67 號相似之紋枯病忍耐性。臺農69 號不但抗褐飛蝨1 、2 、3 生理型、也抗白背飛蝨並受斑飛蝨之害亦較緩慢。本品種的米質、株高、抽穗期等特性與臺農67 號相似，但稻稈稍軟不如臺農67 號耐倒伏，故其肥料反應也稍差。
Rice variety Tainung 69 is a selection from the progenies of a cross between F3 (Tainung 61 M510 -14 / Oryza rufipogon) and Tainung 62. It yielded lower than Tainung 67 by 4%-5% in the first crop but outyielded it by 8%-19.3% in the second crop. In regional tests, Tainung 69 gave an yield of 4%-7% lower than Tainung 67 in average. It is resistant to a wide range of blast pathogen including that at IRRI, Philippines and is also resistant to bacterial leaf blight disease. It exhibited a tolerance to sheath blight disease similar to Tainung 67. Tainung 69 was found resistant in the tests to brown planthopper biotypes 1, 2 and 3, and also to the white-backed planthopper. It showed a slower progress in the damage caused by small brown planthopper. The plant height, days to mature and rice quality of Tainung 69 are similar to those of Tainung 67, but its straw is not as stiff as that of Tainung 67, hence the fertilizer response is slightly poor
The SF-36: a simple, effective measure of mobility disability for epidemiological studies
No full textBackgroundMobility disability is a major problem in older people. Numerous scales exist for the measurement of disability but often these do not permit comparisons between study groups. The physical functioning (PF) domain of the established and widely used Short Form-36 (SF-36) questionnaire asks about limitations on ten mobility activities.ObjectivesTo describe prevalence of mobility disability in an elderly population, investigate the validity of the SF-36 PF score as a measure of mobility disability, and to establish age and sex specific norms for the PF score.MethodsWe explored relationships between the SF-36 PF score and objectively measured physical performance variables among 349 men and 280 women, 59-72 years of age, who participated in the Hertfordshire Cohort Study (HCS). Normative data were derived from the Health Survey for England (HSE) 1996.Results32% of men and 46% of women had at least some limitation in PF scale items. Poor SF-36 PF scores (lowest fifth of the gender-specific distribution) were related to: lower grip strength; longer timed-up-and-go, 3m walk, and chair rises test times in men and women; and lower quadriceps peak torque in women but not men. HSE normative data showed that median PF scores declined with increasing age in men and women.ConclusionOur results are consistent with the SF-36 PF score being a valid measure of mobility disability in epidemiological studies. This approach might be a first step towards enabling simple comparisons of prevalence of mobility disability between different studies of older people. The SF-36 PF score could usefully complement existing detailed schemes for classification of disability and it now requires validation against them
Complex calcium ferrites in the blast furnace process: Fluxed sinter formation and SFCA reduction under simulated conditions
No full textCivil Engineering and Geoscience
Softening in the blast furnace process: Local melt formation as the trigger for softening of ironbearing burden materials
No full textCivil Engineering and Geoscience
Micromilling of hardened tool steels
No full textMiniaturized parts are increasingly demanded in different fields like medical, transportation, environmental, and communication industries. In order to manufacture these parts in an economical way, mass replication methods, such as micro injection molding, have to be applied. Currently, Electro Discharge Machining (EDM) process is mainly used to manufacture the needed moulds for micro injection molding in industries. In order to achieve the final shape, several electrodes have to be made by milling with different levels of geometrical accuracy. Besides, the material removal rate of EDM is relatively low. This results in a long throughput-time and high manufacturing cost. Therefore, industries are looking for alternative technologies to overcome these drawbacks; micromilling is one of the promising technologies. The advantages of the micromilling technology include the applicability of a broad range of materials including hardened tool steels, the capability of manufacturing three dimensional geometries, accurate machining of complex features, and it is economical for small and medium lot sizes, etc. However, although micromilling in principle is a good alternative for the EDM process, it is found in research that some challenges have to be overcome before this technology is ready to be adopted in industrial applications. The literature survey shows that the fundamental micro cutting mechanism has been well investigated and understood through the study of micro orthogonal cutting and ultraprecision machining. Issues related to the application of micromilling have however not yet been well studied. Besides, inconsistent observations are commonly seen in literature. This is because observed results in micromilling are highly dependent on the experimental conditions. Based on the literature survey and initial micromilling tests, the general goal of this research has been defined as to develop and describe a reliable micromilling process for precision machining of hardened tool steels. It was decided to first improve lives of micro endmills to achieve a reliable cutting, and then to improve the performance of the process through process planning. In this research, experiments were mainly done with Ø 0.5 mm square endmills on hardened tool steels (AISI H11, H13, etc.). Experimental investigations were done to identify the main problems in micromilling. It was observed that the used commercial micro tools suffered severe wear, the tool life was too short to conduct a successful task, and the workpiece quality was not achieving the requirements. Investigations were conducted to understand tool wear types and mechanism. The factors which influence the tool performance were analyzed. It was found that the geometry of commercial tools is mainly derived from macro endmills, with which the cutting edge corners have the highest stress level. The machining parameters and tool paths are two factors that have significant effect on the tool performance; however, there was no good method available for the planning of the micromilling process. The geometry of micro endmills was studied theoretically by means of analytical modeling and FEA method. Having understood the relationship between geometrical features of the cutting tool and their influence on the tool performance (stiffness and strength of the cutting edge corners), the geometry of the micro endmill can be designed specifically for a given application to achieve the desired performance. This method was demonstrated by designing the micro square endmill especially for hard milling applications. The newly designed tools were manufactured and validated through experiments in comparison with the commercial tools. The experimental results have shown that the new designs have improved the tool performance as expected. The planning of the micromilling process has been divided into two parts. In the first part, design of experiments has been used to understand the relationship between input variables (machining parameters and tool paths) and process response (tool wear and surface finish). With this method, the significant variables can be identified by means of ANOVA analysis, and the cutting conditions can be planned accordingly to optimize the process output. For example, to have a long tool life is important for the roughing operation, and to achieve a good surface finish is of interest for the finishing operation. In the second part of the process planning, a knowledge-based method is used to plan cutting conditions for the machining of micro features with high aspect ratios. The selection of machining parameters was done by means of a force model, which describes the relation between machining parameters and average forces. The tool paths were tested by a FEM model. An improved tool path was proposed to overcome the disadvantage of the conventional tool path. Experiments were done with conditions chosen by the theoretical analysis, and the results proved the validity of the developed method. Micro ribs with aspect ratios higher than 50 could be machined successfully.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin
Design of a Micro Milling Setup with an Active Magnetic Bearing Spindle
No full textThis thesis describes the design of a micro milling setup with an active magnetic bearing spindle. Micro milling is the mechanical removal of material with sub millimeter tools. An active magnetic bearing typically consists of a set of magnetic actuators, a control loop and position sensors. Active Magnetic Bearings enable a very high rotational speed of 150.000 rpm and a high positioning accuracy. The use of bearing signals for process monitoring is a separate research topic in the same project. Special attention has been given to the design of magnetic actuators with low rotating losses. A design with an axial bias flux generated by permanent magnets has been applied. The rotordynamic modelling of the spindle is described as well as the controller design. The spindle has been realized and a rotational speed of 150.000 rpm has been achieved. The spindle has been integrated into a micro milling setup, where the work piece is positioned using an xy stage driven by Lorentz actuators. A novel tool clamping device had to be developed which matches the reduced dimensions of the spindle and which is able to withstand the very high rotational speed. A monolithic tool holder has been designed in which the clamping force increases with increasing rotational speed. The main improvements that can be made require the increase of the rotational speed and an increase of the flexural spindle resonance frequencies. A novel design has been presented to support a short, disk shaped rotor. This rotor shape has required the design of a controller which compensates the strong gyroscopic coupling in a rotating disk.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin
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