改进光电晶体管线性运行的反馈电路

当设计者用光电晶体管将一个调制后的光信号转换成电信号时,如果有高亮度的背光使光电晶体管饱和,就会遇到麻烦.当光电晶体管基极端悬浮时,其集电极/射极电压只取决于信号与背光重叠而产生的光电流.光电晶体管增益及其作用区范围由R1阻值(见图1)确定.R1阻值较高时,电路的增益增加,但光电晶体管会很快饱和.图1中没有背光照射时,晶体管工作在其线性区的偏置点φ2,Q1的集电极电压围绕VCE作线性变化.其输出VOUT准确地重复使调制光信号产生幅度波动.当施加外部稳定的背光照明时,电路的工作点移至偏置点φ3,输出电压被压缩并出现失真.     

探讨RPU整理剂在针织面料中的应用

介绍了针织面料弹性整理的反应机理,探讨RPU弹性整理工艺中RPU整理剂的用量、定形温度、整理工艺对整理效果的影响,从而确定最佳应用工艺条件.试验结果表明:经RPU弹性整理后的面料赋予卓越的弹性回复及优异的吸水性等效果,且手感有很大提高,服用性能优于其它整理剂.     

Efficiency of modified urea fertilizers for tropical irrigated rice

An objective of the International Network on Soil Fertility and Fertilizer Evaluation for Rice (INSFFER) network is to field evaluate deep-point placement (urea supergranules) and slow-release (sulfur coated urea) N fertilizers in irrigated rice. These N sources were compared for performance with split application of prilled urea at 19 sites in Asia in wet season 1981.SCU or USG differed significantly in response curves from prilled urea at 12 of the 17 sites where N response was observed. Over these 17 sites, 22–25% less N as SCU or 29–31% less N as USG provided the same yield increment as the comparatively higher level of N as prilled urea.High profit N rates were derived for 5 sites. The optimal N levels for SCU or USG were less than for prilled urea. However, in one case for both test materials prilled urea was more profitable than SCU or USG. The marginal rates of return of using SCU or USG as opposed to OPU were calculated for the 11 sites where the response functions of the test materials differed significantly from prilled urea. In other than 2 sites for SCU the MRR exceeded 2.0 for 29 and 58 kg N ha^–1, indicating the general profitability of these materials when compared to prilled urea.     

Increasing productivity and protein content using early-maturing rices and efficient nitrogen management

Germplasm with shorter duration than that of the currently grown varieties is being generated to maximize productivity of irrigated rice. However, short-duration varieties often produce yields lower than the medium- and long-duration varieties. Experiments were conducted during the 1980–82 dry and wet seasons to increase productivity through the use of very early-maturing rices and the improved management of nitrogen (N) fertilizers.Results over three years showed that IR58 and IR9729-67-3 (growth duration 100 ± 5 days) yield as well as or higher than IR36 although earlier maturing. They generally had a higher productivity (kg ha^–1 day^–1) than IR36 (110 ± 5 days).Three years' data suggest that the improved timing of broadcast applications of urea in split doses increased grain yield comparable with the basal incorporation of slow-release sulfur-coated urea (SCU) or deep point-placement of urea supergranules (USG).Results on elite breeding lines showed that the early-maturing IR9729-67-3 produced higher protein yield ha^–1 than longer duration varieties such as IR8 and IR42 in the dry season. Furthermore, contrary to earlier results, single basal incorporation of slow-release SCU increased the protein yield of rice by 53 kg ha^–1 and deep point-placement of USG by 43 kg ha^–1 over split application of prilled urea.     

Fate and efficiency of nitrogen fertilizers applied to wetland rice. II. Punjab,India

Two modified urea products (urea supergranules [USG] and sulfur-coated urea [SCU]) were compared with conventional urea and ammonium sulfate as sources of nitrogen (N), applied at 58 kg N ha^–1 and 116 kg N ha^–1, for lowland rice grown in an alkaline soil of low organic matter and light texture (Typic Ustipsamment) having a water percolation rate of 109 mm day^–1. The SCU and USG were applied at transplanting, and the whole dose of nitrogen was¹⁵N-labeled; the SCU was prepared in the laboratory and was not completely representative of commercial SCU. The SCU was broadcast and incorporated, whereas the USG was point-placed at a depth of 7–8 cm. The urea and ammonium sulfate applications were split: two-thirds was broadcast and incorporated at transplanting, and one-third was broadcast at panicle initiation. All fertilizers except the last one-third of the urea and ammonium sulfate were labeled with¹⁵N so that a fertilizer-N balance at flowering and maturity stages of the crop could be constructed and the magnitude of N loss assessed.At all harvests and N rates, rice recovered more¹⁵N from SCU than from the other sources. At maturity, the crop recovered 38 to 42% of the¹⁵N from SCU and only 23 to 31% of the¹⁵N from the conventional fertilizers, urea and ammonium sulfate, whose recovery rates were not significantly different. In contrast, less than 9% of the USG-N was utilized. Fertilizer nitrogen uptake was directly related to the yield response from the different sources. Most of the fertilizer N was taken up by the time the plants were flowering although recovery did increase up to maturity in some treatments.Analysis of the soil plus roots revealed that less than 1% of the added¹⁵N was in the mineral form. Between 20 and 30% of the¹⁵N applied as urea, SCU, and ammonium sulfate was recovered in the soil plus roots, mainly in the 0–15 cm soil layer. Only 16% of the¹⁵N applied as USG was recovered in the soil, and this¹⁵N was distributed throughout the soil profile to a depth of 70 cm, which was the lowest depth of sampling.Calculations of the¹⁵N balance showed that 46 to 50% of the urea and ammonium sulfate was unaccounted for and considered lost from the system. Only 27 to 38% of the¹⁵N applied as SCU was not recovered at maturity, but 78% of the USG application was unaccounted for. The extensive losses and poor plant recovery of USG at this site are discussed in relation to the high percolation rate, which is atypical of many ricegrowing areas.     

Development of a microassay for estradiol receptors

The calculation of equilibrium binding constants for a specific receptor-hormone interaction requires the exact determination of the unbound ligand concentration and the specifically bound concentration at equilibrium. These determinations usually require corrections for the contribution of non-specific binding. We introduce several parameters allowing equilibrium concentrations to be calculated from experimental concentration values; these parameters can be measured for the particular receptor assay procedure used. These parameters are used in a microassay of estradiol-receptor complex by selective retention on DE-81 cellulose paper.     

Polarographic determination of robenidine residues in chicken tissues, eggs, litter, soil, and plant tissue

Polarographic residue methods have been developed for determining robenidine (Robenz), 1,3-bis[p-chlorobenzylidene)amino]-guanidine monohydrochloride, in chicken tissues, eggs, litter, soil, and plants. The compound is extracted from chicken fat, skin, muscle, liver, and eggs with ethyl acetate; from blood with acetone; from plant tissue, litter, and kidney with acidic acetone; and from soil with basic methanol. After extraction by high-speed blending or overnight shaking, the extract is cleaned up by evaporation, solvent partition and/or elution from CG-50 ion exchange resin. Robenidine is quantitated by differential cathode ray polarography, using acidic aqueous methanol or acetic acid (1+1) supporting electrolyte. Recoveries ranged from 64 to 125% with an average overall recovery of 90%. The validated sensitivity is 0.1 ppm for chicken tissues, soil, and plants, 0.01 ppm for eggs, and 1 ppm for litter.     

Surgical treatment of renovascular hypertension

Two hundred sixty-four patients exhibiting renal artery occlusive disease underwent operation for renovascular hypertension between 1961 and 1977. Included were 27 pediatric patients. Fibrodysplastic disease affected 132 adults. Atherosclerotic lesions affected 51 patients with and 54 patients without clinically overt extrarenal arteriosclerotic cardiovascular disease. Ischemic kidney renin hypersecretion (renal: systemic index greater than 0.48), associated with suppressed contralateral kidney renin secretion (renal: systemic index approaching 0.0) predicted curability most reliably. Three hundred forty-eight operations were performed, of which 297 were primary and 51 were secondary procedures. Nephrectomy was initial therapy in 15 cases. Three operative deaths occurred among 51 patients manifesting overt extrarenal arteriosclerotic disease. No operative mortality was encountered among the other 213 patients. Surgical benefits were afforded 96% of pediatric patients and adults with fibrodysplastic disease, 91% of patients with focal renal arteriosclerosis, and 73% of those exhibiting overt extrarenal arteriosclerosis.     

Concurrent mapping of brain sites for sensitivity to the direct application of morphine and focal electrical stimulation in the production of antinociception in the rat

The effect of morphine microinjection (5 microgram/0.5 microliter) and focal electrical stimulation on the animal's response to radiant heat and noxious pinch was studied concurrently at 117 brain loci extending from the medial thalamus caudally to the periaqueductal gray area (PAG). Three populations of brain sites were discernible based on their responsiveness to focal electrical stimulation and morphine microinjection in the production of antinociception: (a) sites which support stimulation-produced analgesia (SPA, n = 24), (b) sites which were sensitive to the direct application of morphine (n = 8), (c) sites responsive to both manipulations (n = 8). With a few exceptions, all morphine sensitive sites were located within the anatomical boundaries of the PAG while sites supporting SPA were located not only within the PAG but also in the brain regions peripheral to this structure. Sites responsive to both manipulations were generally distributed throughout thf lateral aspect of the posteroventral PAG. Stimulation strength-effect curves for sites subserving SPA were also obtained. No differences were discovered between curves obtained from morphine-sensitive and -insensitive brain loci.