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41.
The objective of this work was to study production costs for the supercritical CO2 extraction of a pre-pressed oilseed (packed bed with 2-mm particles) in a 2-m3 industrial multi-vessel plant operating at 40 °C and 30 MPa, using a fully predictive mass transfer model to simulate the process. We modified the inner diameter (47.3 ≤ D ≤ 65.6 cm) and number (n = 2, 3, or 4) of extraction vessels, and the mass flow rate of CO2 (Q = 3000 or 6000 kg/h), thus changing the aspect ratio of the extraction vessels (3 ≤ L/D ≤ 8), and superficial velocity (2.71 ≤ U ≤ 10.8 mm/s) and specific mass flow rate (6 ≤ q ≤ 24 kg/h per kg substrate) of CO2. Production cost decreased when increasing the mass flow rate of CO2 or the number of extraction vessels (or when increasing q). Production cost did not depend on the geometry of extraction vessel for a constant specific mass flow rate of CO2, but it decreased with a decreasing of the L/D ratio of the vessel for a constant superficial velocity of CO2. For any given plant, the contribution of fixed cost items (capital, labor) to the production cost increased with extraction time, unlike that of variable cost items (substrate, CO2, energy), which decreased. Thus, there was an optimal extraction time that minimized production cost for each plant. This work proposes an expression for capital cost of an industrial multi-vessel plant as a function of the mass flow rate of CO2 (which defines the cost of the solvent cycle of the plant), and the volume of the extraction vessels (which together with number of extraction vessels define the cost of extraction section of the plant), with a scaling factor of 0.48 for both items. Under optimal conditions, capital cost represented 30–40% of the production cost, but uncertainties in capital cost estimates (about ±50% using the proposed expression) may largely affect these estimates. The lowest production cost estimated in this work was USD 7.8/kg oil for the extraction of prepressed oilseed in a four-vessel plant using 6000 kg/h of CO2. The mass flow rate of CO2 and number of extraction vessels also affected annual productivity that was about 360 ton oil for the same plant operating 7200 h per year. Oil yields were above 90% for both three- and four-vessel plants. 相似文献
42.
Temperature effects on fatty acid composition during development of low-linolenic oilseed rape (Brassica napus L.) 总被引:1,自引:0,他引:1
The influence of temperature during seed development on the fatty acid composition of oilseed rape (Brassica napus L.) was studied in one low-linolenic and one conventional canola cultivar. The cultivar Regent produces seed oil with ∼20%
linoleic acid (C18:2) and ∼8% linolenic acid (C18:3), whereas Stellar is relatively high in C18:2 (∼25%) and low in C18:3
(∼2.5%). Both cultivars were grown in the field, and the fatty acid compositions of the seed oils were monitored throughout
the period of seed development. In the field, the content of saturated (C16:0+C18:0) and monounsaturated (C18:1) fatty acids
in the seed oil increased when seed developed under high temperatures. C18:3 levels were higher in seed harvested at sites
with lower average daily temperatures. The low C18:3 trait of the cultivar Stellar was relatively stable over environments.
Both temperature and duration of exposure to the temperature during seed development affected the fatty acid composition of
the seed in a controlled environment study. Plants subjected to a high-temperature treatment (30/25°C day/night) for 40 d
produced seed with the lowest C18:3 content and the highest levels of C16:0+C18:0 and C18:1. This was observed in both cultivars. 相似文献
43.
The effects of RE on increasing crop productivity and stress tolerance were reported inpast years[' '2). La ion acts as a calcium-influxinhibitor by displacing Ca2 from cell wallsand occupying Ca2 -binding sites on the plasmalemma, as effective as Ca in the deferral ofsenescence. Besides blocking calcium channels, La has been frequently reported to mimicCa2 effect on plant ion transport. Migliaccioet al. found that both Ca2 and La3 stimulated auxin uptake into pea epicotyl segmentsfr… 相似文献
44.
Perilla frutescens, an edible oilseed of Northeast India, was evaluated for its nutrient composition and protein quality. It was found to be
a rich source of protein (17.0%) and fat (51.7%). The fatty acid profile indicated that perilla oil is rich in polyunsaturated
fatty acids, such as linolenic (56.8%) and linoleic (17.6%). The amino acid composition showed that valine was the limiting
amino acid of perilla protein. The protein efficiency ratio of the seed protein (2.07) was lower than that of casein (2.99),
but comparable to common oilseeds. True digestibility of the seed protein (82.6%) was also lower than that of casein (89.3%). 相似文献
45.
During 1993–1994, a collaborative study of the determination of the nitrogen content of oilseed meals by the nitrogen combustion
method was conducted among 24 laboratories in seven countries for the analysis of cottonseed, soybean (two samples), peanut,
canola and safflower (two samples). These meals were also analyzed by the CuSO4/TiO2 Kjeldahl method (Official Methods and Recommended Practices of the American Oil Chemists' Society, 4th edn., 1989, Method Ba 4d-90) in the 1993–1994 Smalley Check Sample Program Oilseed Meal Series [Brown, J.,INFORM 5:640 (1994)]. Some participants used commercial nitrogen combustion instruments. In the Smalley Program, CuSO4/TiO2 Kjeldahl analysis gave nitrogen values that ranged from 0.05 to 0.13% lower than values obtained by the combustion method
in the collaborative study. Nitrogen values obtained by the combustion method on an optional basis in the Smalley Program
were generally lower by 0.01 to 0.03% than nitrogen values obtained by the combustion method in the collaborative study reported
here. 相似文献
46.
William R. Newson Ramune Kuktaite Mikael S. Hedenqvist Mikael Gällstedt Eva Johansson 《Journal of the American Oil Chemists' Society》2013,90(8):1229-1237
With the increased use of plant oils as sustainable feedstocks, industrial oilseed meal from Crambe abyssinica (crambe) and Brassica carinata (carinata) can become a potential source for oilseed meal based plastics. In this study, crambe and carinata oilseed meal plastics were produced with 10–30 % glycerol and compression molding at 100–180 °C. Size exclusion HPLC was used to relate tensile properties to changes in protein solubility and molecular weight distribution. By combining glycerol and thermal processing, increased flexibility has been observed compared to previous work on unplasticized oilseed meal. Tensile results varied from a brittle crambe based material (10 % glycerol, 130 °C), Young’s modulus 240 MPa, strain at maximum stress of 2 %, to a soft and flexible carinata based material (30 % glycerol, 100 °C), Young’s modulus 6.5 MPa, strain at maximum stress of 13 %. Strength and stiffness development with increasing molding temperature is in agreement with the protein profiles obtained. Thus, the highest mechanical parameters were obtained at the protein solubility minimum at 140 °C. Higher temperatures caused protein degradation, increasing the level of low molecular weight extractable proteins. In carinata based materials the strain at maximum stress decreased as the protein aggregation developed. Results presented indicate that both crambe and carinata oilseed meal based materials can have their properties modulated through thermal treatment and the addition of plasticizers. 相似文献
47.
对湖南永顺植物油厂提供的桐油饼、茶子粕及菜子粕等样品中的N、P_2O_5、K_2O等含量进行了分析测试,并对其作为专用肥基料的应用前景进行了分析探讨。 相似文献
48.
Brian F McNamee Ann M Fearon Jack Pearce 《Journal of the science of food and agriculture》2002,82(7):677-684
The objective of this study was to compare the effects of oilseed‐based supplements, rapeseed and linseed, against a barley‐based control, on the fatty acid composition, and subsequent solid fat ratio, of the milk fat from dairy cows. In addition, as a means of understanding the digestive processes which influence the milk fat composition, ruminal extracts were collected from the cows and analysed for fatty acid composition. Four lactating dairy cows each fitted with a rumen fistula were provided with silage and one of four concentrate diets. The main constituent of the concentrate supplements was either rapeseed (ground or unground), linseed (unground) or a barley control. The diets were offered in accordance with a 4 × 4 Latin square arrangement. The oilseed‐supplemented concentrates provided the cows with 620–640 g fatty acids day?1. Experimental treatments were provided to the cows for 2 weeks, after which ruminal extracts were collected over a 24 h period and a milk sample was taken. All extracts were analysed for fatty acid composition. The diets fed influenced the long‐chain fatty acid composition of the ruminal extracts and milk fat. The proportion of C18:1n‐9 in the ruminal extracts increased from 202–224 to 282–321 g kg?1 of the total fatty acids when the cows were provided with the rapeseed‐based diets. The linseed‐based diet increased the C18:1n‐9 proportion of the ruminal extracts from 164 to 218 g kg?1 of the total fatty acids. Both rapeseed‐based diets also resulted in a higher proportion of C18:0 in the ruminal extract, possibly owing to biohydrogenation of the dietary fatty acids. This proportion of C18:0 in the ruminal extract was lowest immediately after feeding, increasing to a maximum 4–6 h later. Both rapeseed‐based concentrates increased the proportion of C18:1n‐9 in the milk fat to approximately 300 g kg?1 of the total fatty acids as compared with 214 g kg?1 for the control. The proportion of C18:1n‐9 in the milk fat from the cows offered the linseed‐based concentrate was 246 g kg?1 of the total fatty acids. There were also significant decreases in the proportions of C16:0 in the milk fat from the cows offered all oilseed‐based concentrates. There was no difference between the fatty acid compositions of the milk fats from the cows fed the ground or unground rapeseed‐based supplements. The oilseed‐based supplements also resulted in significant decreases in the solid fat content of the milk fat at temperatures ranging from 0 to 35 °C, which would be indicative of a softer, more spreadable butter. © 2002 Society of Chemical Industry 相似文献
49.
In 2009, the Renewable Energy Directive (RED), established sustainability criteria for biofuels including legal thresholds for specific greenhouse gas (GHG) emissions, expressed as g CO2eq per MJ of biofuel. Because biofuels are a major market for winter oilseed rape (WOSR), investigating the possible impact of the RED on WOSR cropping practices is prudent. This study analyses GHG emissions for WOSR cropping practices (namely N fertilization intensity, tillage method and crop rotation) basing on a 6-year field trial in a high yielding area of northern Germany. Using the International Panel on Climate Change (IPCC) methodology the field emissions of nitrous oxide (N2O) are calculated from the nitrogen (N) inputs to the cropping system.Results showed that the predominant source of GHG emissions is the N related emissions from production of fertilizer and N2O field emissions. Specific GHG emissions are lowest without N fertilizer but rise continuously with increasing N rates. Yield per ha also responded to N fertilization resulting in lowered acreage productivity when reducing GHG emissions by reducing N fertilization level. Most calculated scenarios and cropping systems result in a drastic decrease of N fertilization to achieve thresholds, causing substantial yield losses. To a certain extent, the required drastic reduction of N fertilization in some scenarios is driven by using the IPCC methodology for calculating N2O emissions. Therefore characteristics of this methodology are also discussed within this study. To mitigate the impact of the RED on WOSR, peas (legumes) may be a possible preceding crop to WOSR. 相似文献
50.
Manpreet Kaur Balwinder Singh Amritpal Kaur Narpinder Singh 《International Journal of Food Science & Technology》2021,56(12):6732-6741
Proximate, minerals, amino acids (AAs), phenolic composition, antioxidant and functional properties of flaxseed (FSC), sesame (SSC), mustard (MSC), nigella (NSC) and groundnut (GSC) seedcakes were studied. SSC exhibited higher ash and fat contents while GSC and FSC had more protein and mineral contents (P, Mg, Mn and Cu), respectively. The total flavonoids, phenolics and antioxidant activity were higher in NSC (18.60 mg QE g−1), MSC (5.12 mg GAE g−1) and FSC (12.28 µmol TE g−1), respectively. NSC exhibited the highest oil absorption capacity (2.10 g g−1) and emulsifying activity index (89.52 m2 g−1). Twenty-one AAs including citrulline and ɣ-aminobutyric acid were detected in oilseed cakes (OSC). MSC had more essential AAs (methionine, isoleucine, tryptophan, threonine and lysine) while GSC had more total hydrophobic, acidic and basic AAs. Syringic acid and rutin were identified as major phenolic compounds in GSC and MSC, respectively. The total free phenolic acids were more in GSC while FSC had high total bound phenolic acids and flavonoids. OSC can be utilised in food products as a supplement to improve nutritional properties. 相似文献