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排序方式: 共有125条查询结果,搜索用时 15 毫秒
61.
基于CRT显示器的显色特性,根据对立色的特点,采用CIELAB色空间作为表色系统,以CIE1976LAB色差公式为基础,提出了一种对立色彩色图像的对比度定义,通过对实际色块对比度的计算和人眼觉察以及与国外研究结果对比分析表明,此定义不仅同时考虑了图像亮度和色度的对比度,并且理论计算值与人眼视觉感受结果保持较好的一致性,计算简单,是一种实用的显示器输出图像对比度定义。 相似文献
62.
铝黄铜仿金合金色度研究 总被引:1,自引:0,他引:1
基于CIELAB色度学知识,定量研究了Cu含量在70%时,Al和Zn的成分变化对合金的颜色值、抗变色性以及氧化性的影响.结果发现,Al的添加会导致合金表面颜色黄色的因素减弱,从而使合金表面颜色与黄金色差加大,从而提高了合金的抗变色性以及合金的硬度.另外,探讨了影响抗变色性和抗氧化性的可能因素. 相似文献
63.
G.K. SKOUROUMOUNIS M.J. KWIATKOWSKI I.L. FRANCIS H. OAKEY D.L. CAPONE Z. PENG B. DUNCAN M.A. SEFTON E.J. WATERS 《Australian Journal of Grape and Wine Research》2005,11(3):355-368
This paper presents the results from an investigation to assess the development of a Riesling and a wooded Chardonnay wine over five years. The wines were bottled either with or without added ascorbic acid and stored under controlled temperature and humidity conditions. Ascorbic acid addition to wine at bottling had little effect on wine aroma and flavour when the wines in this study had been in bottle for 6 months or less. For both wines, at bottle storage times of 3 years or more, addition of ascorbic acid at bottling resulted in wines with no difference in aroma or less oxidised and/or more fresh fruity aromas, even if all the ascorbic acid had been depleted at the time of assessment, compared to wines without addition of ascorbic acid at bottling. In terms of colour, for the Chardonnay wines, the effect of ascorbic acid addition at bottling assessed between two weeks and two years after bottling suggested that wines without addition were browner and had more overall colour intensity. For the Riesling wines, ascorbic acid addition had no significant effect on brownness and overall colour intensity although the Riesling wines with ascorbic acid were generally higher in yellow colour. The A420 measurements, which are widely used to estimate the brown colour of wines, did not always appear to correlate with the brown scores obtained by visual assessment or colour measures by CIELAB when wines with and without ascorbic acid addition were compared together. For both wines, after three and five years storage, the concentration of the antioxidant sulfur dioxide was either little different or else slightly(statistically significantly) higher in wines to which ascorbic acid was added at bottling than those without addition. 相似文献
64.
Claudio?Ceballos María?José?Moyano Isabel?M.?Vicario José?Alba Francisco?J.?HerediaEmail author 《Journal of the American Oil Chemists' Society》2003,80(3):257-262
Six samples of virgin olive oil obtained from several varieties of olive fruits (Picual, Manzanilla, Lechín, and Arbequina)
were submitted to an accelerated oxidation process during a 63-h period under the conditions of the oil stability index (OSI),
as measured by a Rancimat (100°C) apparatus. Spectra were measured every 3 h, and chlorophyll and carotenoid indexes and CIFLAB
color ordinates were calculated. As oxidation time increased, remarkable changes in the spectral characteristics and color
ordinates were observed. Oxidation provoked less vivid colors (lower values for chroma, C
*
ab
) in all the samples; however, only some varieties became darker (lower values for lightness, L*). The pigment loss calculated for oxidized oils was 67% for the carotenoid index and 58% for the chlorophyll index. Mathematical
models are offered to predict color changes with time of storage at 20°C. 相似文献
65.
R. Huertas A. Yebra M.M. Prez M. Melgosa A.I. Negueruela 《Color research and application》2003,28(6):473-479
Spectroradiometric color measurements were performed at 26 regularly spaced points of a standard wine sampler into which 100 cc of wine were poured. Our goal is to describe the color changes occurring in this system, but not to propose a new method for wine‐color measurement. Three samples of three different wines (red, rosé and white) were studied. From experimental measurements, lines of constant lightness (L), chroma (C,10) and hue‐angle (hab,10) were plotted for each wine poured into the wine sampler, as well as lines of constant CIELAB color differences (ΔE,10), with respect to a reference point placed at the axis of the wine sampler and at the zone with the greatest diameter. Considering different points of the wine sampler, the color attribute undergoing the greatest change was lightness (ΔL about 16.0, 15.0 and 11.0 for the red, rosé and white wines, respectively), followed by chroma (ΔC,10 about 2.8, 3.8 and 2.6 for the red, rosé and white wines, respectively) and hue(ΔH,10 lower than 1.0 for all the wines). Lightness variations were related mainly to the thickness differences between various zones of the wine sampler. Large color differences were found among the different points of the wine poured into the wine sampler (about 20.0, 21.0 and 14.0 CIELAB units, for the red, rosé and white wines, respectively). Panels should be aware of these large color variations when wine is visually assessed using standard wine samplers. It should be concluded that a single color specification for a wine poured into a wine sampler gives incomplete information, but hue, which is the main color attribute considered by observers, is nearly constant in the wine sampler. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 473–479, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10200 相似文献
66.
67.
Ramón Madrid Eva Maria Barba Antonio Sánchez Antonio Lino García 《Journal of the science of food and agriculture》2009,89(15):2608-2615
BACKGROUND: The objective of this work was to study the influence of irrigation and organic fertilisation on quality attributes of tomato fruit (cv. Nautilus) grown for the canning industry. The assay was carried out during two consecutive years (2006 and 2007) in agricultural soil. Nine treatments resulting from the combination of three fertilisation types (sheep manure, a mixture of sheep manure and peat and an inorganic fertiliser (control)) with three levels of drip irrigation (3.30, 5.00 and 6.70 mm day?1) under black polyethylene mulch were applied (n = 3). RESULTS: For the chromatic attributes L*, H*, C* and S* the highest values corresponded to the treatments with organic matter. However, the a*/b* ratio and colour index value were higher for the control treatment. In all cases the estimated optimal ripening time was the same, and on this date a decline in the ratios was observed. The values of the physical properties increased with increasing irrigation, higher values always being obtained in the treatments with organic fertilisers. The highest production for all irrigation levels corresponded to the treatment with mixed sheep manure and peat fertiliser. CONCLUSION: Cultivation involving fertilisation with the manure/peat mixture and an irrigation level slightly above 5.00 mm day?1 can be recommended as optimal, since it gave the most satisfactory values with respect to the quality attributes of tomato fruit grown for the canning industry. Copyright © 2009 Society of Chemical Industry 相似文献
68.
Blanching and one year freezer storage were performed on one purple, two white and two green varieties of cauliflower (Brassica oleracea L. ssp. botrytis) to assess the effects on several health-related phytochemicals. Blanching, prior to freezing, reduced total aliphatic and indole glucosinolates (GLS) by 31% and 37%, respectively. l-ascorbic acid (L-AA), total phenols (TP), anthocyanins, FRAP and ORAC were on average reduced by 19, 15, 38, 16 and 28%, respectively. The colour measured as CIELAB parameters was partly affected by blanching: lightness was significantly reduced in the white cultivars and in a romanesco type cultivar. Chromaticity was reduced in the coloured cultivars with a twice-as-large reduction in the purple cultivars. Hue increased for all samples, except for the purple cultivar where a decrease was found. Long-term freezer storage did not affect total aliphatic and indole GLS in cauliflower in a major way. Freezer storage did result in an average L-AA decrease of 24% for all but the purple cultivar. Some reductions in the TP levels were also found but not to the extent found for L-AA. When an effect was found in the FRAP and ORAC values, the reductions occurred towards the end of the storage period and were 15% and 37%, on average, respectively. Long-term freezer storage did not affect the anthocyanin content and only minor effects were found for the colour parameters. 相似文献
69.
70.
Chiuhsiang Joe Lin Yogi Tri Prasetyo Nio Dolly Siswanto Bernard C. Jiang 《Color research and application》2019,44(3):367-380
The assessment of military camouflage is a key consideration in the modern military field. Traditionally, the assessment relies on traditional human visual detection tests because a large scale multi‐level and multi‐factor experiments are time‐ and resource‐consuming. One aspect of camouflage assessment, to which this current study pertains, entails improving upon or “enhancing” an existing or “selected” design. The current study presents a new and practical approach for enhancing the selected military camouflage by utilizing response surface methodology (RSM) of %L*, %a*, and %b* in CIELAB color space. Ten participants were recruited to evaluate 35 variations of %L*, %a*, and %b* on camouflage similarity index (CSI) and reaction time (RT). Based on RSM, the optimum combination occurs at L*: 61.4966, a*: ?5.6505, and b*: 10.5114. In addition, a predictive algorithm to calculate the optimum shift of %L*, %a*, and %b* from the original camouflage to the improved camouflage derived from RSM is also proposed. The optimum shift occurs at ?25%L*, ?55%a*, and + 80%b*. In the end, a new design guideline is proposed for the enhancement of selected military camouflage, which adopts the present study's research findings. 相似文献