Model Building of Backup Roller Diameter Effect Rate in 4-High Mill

Software for calculating the strip profile in 4-high hot rolling mill was developed using influence coefficient method. Regularity of backup roller diameter effect rate was studied systematically using the software. The results show that backup roller diameter effect rates decrease versus the increase of strip width, increase significantly versus the increase of backup roller diameter and obscurely increase versus the increase of reduction. The difference between backup roller diameter effect rate and it is reference value increases versus strip width increasing. When backup rollers diameter is set to be 1.64 m and strip width is 1.85 m, the error of strip profile calculated using the model of backup roller diameter effect rate reference value will be 3.55μm. Based on the results, reference values of roller diameter effect rate and six power polynomial fitting coefficients of modification coefficients were determined considering coherent parameters. The high precision model of backup roller diameter effect rate was established. When the model is used to predict strip profile, the accuracy is less than 5.0 μm.

Effect of Load Distribution on Strip Crown in Hot Strip Rolling

In order to establish precision model, a software to calculate the strip crown of four-high hot rolling mill was developedby using affecting function method according to the strip crown calculation theory. The effect of work roll diameter,unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction, etc, on load distributioneffect rate was simulated by using the software. The results show that the load distribution effect rate increaseswith the increase of strip width, work roll diameter, unit width rolling load, roll bending force, work roll crown,initial strip crown and reduction. Based on the simulation results, base value of load distribution effect rate andfitting coefficients of six power polynomial of load distribution effect rate modification coefficient were determinedconsidering all of the above parameters. A simplified mathematical model for calculating load distribution effect ratewas established.

Off-line Simulation of PFC for Hot Rolling Strip

In order to improve the quality of the strip for the hot continuous rolling, the high accuracy set-up control must be applied to production. In the paper, we analyze the RFC (profile and flatness control) system and simulate the set-up process. Calculation results are in agreement to the actual measurements. It is the basis on the developing model.

Rice Ferredoxin-Dependent Glutamate Synthase Regulates Nitrogen-Carbon Metabolomes and Is Genetically Differentiated between japonica and indica Subspecies

Plants assimilate inorganic nitrogen absorbed from soil into organic forms as Gin and Glu through the glutamine synthetase/glutamine：2-oxoglutarate amidotransferase （GS/GOGAT） cycle. Whereas GS cata- lyzes the formation of Gin from Glu and ammonia, GOGAT catalyzes the transfer of an amide group from Gin to 2-oxoglutarate to produce two molecules of Glu. However, the regulatory role of the GS/GOGAT cycle in the carbon-nitrogen balance is not well understood. Here, we report the functional characterization of rice ABNORMAL CYTOKININ RESPONSE 1 （ABC1） gene that encodes a ferredoxin-dependent （Fd）- GOGAT. The weak mutant allele abcl-1 mutant shows a typical nitrogen-deficient syndrome, whereas the T-DNA insertional mutant abcl-2 is seedling lethal. Metabolomics analysis revealed the accumulation of an excessive amount of amino acids with high N/C ratio （Gin and Asn） and several intermediates in the tricarboxylic acid cycle in abcl-1, suggesting that ABC1 plays a critical role in nitrogen assimilation and carbon-nitrogen balance. Five non-synonymous single-nucleotide polymorphisms were identified in the ABC1 coding region and characterized as three distinct haplotypes, which have been highly and specifically differentiated between japonica and indica subspecies. Collectively, these results suggest that ABC1/ OsFd-GOGAT is essential for plant growth and development by modulating nitrogen assimilation and the carbon-nitrogen balance.

Heteromeric Geranyl（geranyi） Diphosphate Synthase Is Involved in Monoterpene Biosynthesis in Arabidopsis Flowers

Dear Editor,Monoterpenes, together with sesquiterpenes, play varying roles in plant interactions with the environment depending on the organs in which they are produced; these compounds likely function to attract pollinators when they are present in flowers and can protect plants against herbivores or microbes when produced in leaves or in roots. It is well known that geranyl diphosphate （GPP）, the common precursor of monoterpenes, is biosynthesized by geranyl diphosphate synthase （GPPS）. To date, two types of GPPS （EC 2.5.1.1） have been reported from plants： homomeric GPPS and heteromeric GPPS. Heteromeric GPPS is composed of one inactive small subunit （SSU; SSUs can be divided into two types： SSU I and SSU II） and one large subunit （LSU） （Burke et al., 1999; Tholl et al., 2004; Wang and Dixon, 2009）. In the Arabidopsis genome, there are 12 GGPPS paralogs and one homomeric GPPS gene （At2g34630） （Bouvier et al., 2000; Lange and Ghassemian, 2003; Beck et al., 2013）. A previous in vitro study characterized a heteromeric G（G）PS composed of GGPPS12 （also known as AtSSU, encoded by At4g38460 and belonging to the type II SSU type） and GGPPS11 （also known as AtLSU, encoded by At4g36810） （Wang and Dixon, 2009）. However, there is controversy as to which type of GPPS is involved in monoterpene biosynthesis in Arabidopsis. This controversy stems from the fact that both homomeric and heteromeric GPPS enzyme complexes catalyze the condensation of dimethylallyl pyrophosphate （DMAPP） and isopentenyl pyrophosphate （IPP） to form GPP when assayed in vitro （Bouvier et al., 2000; Wang and Dixon, 2009）. In the study reported here, we comprehensively analyzed transgenic GGPPS12, GGPPS11, and GPPS Arabidopsis plants and provide solid genetic evidence to support the supposition that heteromeric G（G）PPS, and not homomeric GPPS, is involved in monoterpene biosynthesis, at least in the flowers of Arabidopsis.