溢油应急决策中的物资调度方法

针对多出救点多物资多目标应急调度问题的特点,并结合溢油敏感区等对响应时间的限制,提出了基于不同响应时间段的动态优化模型．以应急救援时间最早和出救点数目最少为优化目标,对不同响应时间段分别运用理想点法和构造剔除集合确定最优调度方案．最后通过算例验证了所提出调度方法的可行性．     

Evaluation of chromium release during the decomposition of leather meal fertilizers applied to the soil

Greenhouse studies of 14 soils, having a range in DTPA extractable Mn, were made to determine the critical deficiency level of Mn in ustochrepts for predicting response of green gram to Mn application. Soil Mn was significantly related with Bray's per cent dry matter yield (r = 0.68^**). Soil application of 20 mg Mn kg^–1 soil significantly increased the yield. Both graphical and statistical models of Cate and Nelson indicated the critical level to be 2.9 mg kg^–1 soil of DTPA extractable Mn. The critical deficiency level in youngest matured terminal leaf (YML) of 40 day green gram plants was 19.0µg g^–1. The predictability of soil and plant critical Mn level was 93 per cent.     

<Emphasis Type="Italic">In situ</Emphasis> monitoring of solid fat content by means of pulsed nuclear magnetic resonance spectrometry and ultrasonics

An ultrasonic technique was developed to study the crystallization process of edible fats on-line. A chirp wave was used instead of the conventional pulser signal, thus achieving a higher signal-to-noise ratio. This enabled measurements to be made in concentrated systems [≈20% solid fat content (SFC)] through a 8.11-cm thick sample without significant signal loss. Fat samples were crystallized at 20, 25, and 30°C at a constant agitation rate of 400 rpm for 90 min. The crystallization process was followed by ultrasonic spectroscopy and a low-resolution pulsed nuclear magnetic resonance spectrometer. Specific relationships were found between ultrasonic parameters [integrated response, time of flight (TF), and full width half maximum] and SFC. TF, which is an indirect measurement of the ultrasonic velocity (v), was highly correlated to SFC (r ²>0.9) in a linear fashion (v=2.601 SFC+1433.0).     

Response surface methodology study on electrochemical adsorption regeneration of water-based drilling fluid waste

ABSTRACT

This study explores an electrochemical adsorption method on the regeneration of aqueous drilling fluid waste. Response surface analysis was applied to investigating the electrochemical factors on the adsorption performance. The response surface polynomial model optimized the preferred electrochemical adsorption conditions with adsorption time of 20 min, spacing electrodes of 5 cm, adsorption concentration of 5% and NaCl concentration of 2 g/L. The model calculated electrochemical adsorption amount of drilling fluid showed only 1.3% deviation from the experimental results. Thus, the model could provide effective support for the device design and application of drilling fluid electrochemical adsorption process.     

A minimum variance distortionless response filter based on the bifrequency spectrum for single-channel noise reduction

This paper deals with the problem of single-channel noise reduction in the short-time Fourier transform (STFT) domain. Many algorithms have been developed to solve this important problem, most of which generally assume that the STFT coefficients in different frequency bands are uncorrelated, so the noise reduction is achieved by applying a gain function to the STFT of the noisy speech in each frequency band. However, this assumption is not accurate and the STFT coefficients of speech signals between neighboring frequency bands are correlated in practice due to the use of small lengths of the fast Fourier transform (FFT) and overlap add/save techniques in implementation. This paper formulates the noise reduction problem by taking into account the interband correlation using the so-called bifrequency spectrum. Based on this formulation, a single-channel minimum variance distortionless response (MVDR) filter is derived, which is shown to be able to significantly improve the signal-to-noise ratio (SNR) and meanwhile maintain the desired speech not much distorted. Simulations are presented to justify the claimed merits of the developed MVDR filter.     

Olfactory coding in the perception of semiochemicals

Information processing in the olfactory pathway underlying the perception of semiochemicals by insects is discussed. Both the chemical message for mates and the message for food consist of blends of chemicals. Olfactory receptors in an insect species are tuned to the detection of those compounds which comprise such chemical messages for that species. The classification of receptors as specialists or generalists coincides with two concepts of information processing, i.e., labeled lines and across-fiber patterns, respectively. The olfactory code coming from antennal receptors inPieris brassicae larvae is a combination of labeled lines and across-fiber patterning. When antennae of adult Colorado potato beetles,Leptinotarsa decemlineata, are stimulated by binary mixtures of leaf odor components, the pattern of neural activities in the olfactory receptors shows some separation into two channels, quantitative versus qualitative detection. The separation is complete in the antennal lobe of this beetle.Presented at the Symposium on Insect Chemical Communications: Unifying Concepts. ACS 194th National Meeting, New Orleans, Louisiana, August 31, 1987.     

Application strategies for Sechura phosphate rock use on permanent pasture

At two phosphate (P) responsive sites in hill country the effectiveness of Sechura phosphate rock (SPR) as a direct application P fertilizer for permanent pasture was evaluated. Sechura was applied at two rates, in three different application strategies. The treatments were 16.7 and 50 kgP ha^–1 annually, 25 and 75 kgP ha^–1 biennially, and 50 and 150 kgP ha^–1 triennially giving a total of 50 and 150 kgP ha^–1, respectively, over three years. Single superphosphate (SSP) served as the standard P fertilizer. A comparison was also made between SPR and Chatham Rise phosphorite (CRP), another reactive PR. Total pasture and legume production and P uptake by pasture was measured with all fertilizer treatments over a three year period.In the year of application, SPR was as effective as SSP in stimulating total pasture and legume production and P uptake by pasture. This reflects the very reactive nature of this PR. In the second and third years of measurement, SPR did not show superior residual efffects to SSP. The ability of CRP to stimulate legume growth more than SPR in the second year following application demonstrates the danger of generalizing about the residual effects of reactive PR materials. Of the application strategies evaluated, a biennial appplication of 25 kgP ha^–1 as SPR maintained legume growth at a higher level than a smaller (16.7 kgP ha^–1) annual dressing. The biennial strategy also increased total pasture yield, in addition to legume production to a greater extent in the second and third years than a single (50 kgP ha^–1) triennial application.     

Simulation of reverse flow operation for manipulation of catalyst surface coverage in the selective oxidation of ammonia

A mathematical model has been developed for the simulation of the ammonia oxidation in a reverse flow reactor. Computer simulations were carried out with a kinetic scheme, based upon elementary reaction steps. Aim was to explore the potential of a reverse flow reactor for selective oxidation of NH₃ to produce either N₂, NO, or N₂O via a dedicated operation procedure. Therefore, the conversion of NH₃ and the selectivity toward N₂, NO, or N₂O, were compared for a reverse flow operation and a steady state, once-through operation.A new operation concept of reverse flow operation in combination with a periodically lower feed concentration is proposed. The novel reactor concept shows a better performance compared to normal reverse flow operation and to steady state, once-through operation. The results indicate that reverse flow operation can be applied for manipulation of conversion and selectivity. A periodically lower feed concentration may increase the conversion, even up to levels that exceed the steady state value.     

高密度航天发射试验风险应对措施

以高密度条件下航天发射试验为对象,对发射试验风险因素进行了系统分析,在此基础上,构建了风险评估指标体系,并针对高密度条件下航天发射试验主要风险,从人力资源风险、设备资源风险和进度风险等方面提出了具体应对措施,对航天发射试验风险管理具有一定的现实意义。     

响应面法优化甘油歧化产1,3-丙二醇菌培养基的研究

以甘油为原料,在单因素试验的基础上,利用响应面法研究了(NH4)2HPO4、K2HPO4/KH2PO4、pH值对1,3-丙二醇产量的影响,得到二次多项式回归模型.结果表明:回归模型能很好地反映各因素水平与响应值之间的关系,同时得出这3因素的最佳用量为(NH4)2HPO42.76 g/L、K2HPO4/KH2PO4(质量比1∶1)3.98 g/L、pH值7.58,此时1,3-丙二醇理论产量为28.702 g/L,实际产量为27.597 g/L,比优化前提高了19.02%.