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排序方式: 共有285条查询结果,搜索用时 15 毫秒
1.
Abiodun B. Ogbesejana Zhong Ningning Oluwadayo O. Sonibare 《Petroleum Science and Technology》2019,37(18):1969-1977
The occurrence and distributions of dibenzofurans (DBFs) and benzo[b]naphthofurans were investigated in crude oils from Niger Delta, Nigeria, by gas chromatography-mass spectrometry-mass spectrometry. The distribution of DBFs was characterized by the predominance of C2-dibenzofurans. 4-Methyldibenzofuran was the most abundant among the methyldibenzofurans isomers while dimethyldibenzofuran-2 (DMDBF-2), ethyldibenzofuran-1, DMDBF-3, and DMDBF-6 occurred in higher amounts when compared with other DMDBFs. Among the benzonaphthofurans, the abundance of benzo[b]naphtho[2,1-d]furan was higher than other isomers. The DBFs distributions in the oils were not affected by source facies and depositional environments. However, the DBFs concentrations increased with increasing maturity in oils from ADL and MJO oilfields. 相似文献
2.
Lash Steven J.; Stephens Robert S.; Burden Jennifer L.; Grambow Steven C.; DeMarce Josephine M.; Jones Mark E.; Lozano Brian E.; Jeffreys Amy S.; Fearer Stephanie A.; Horner Ronnie D. 《Canadian Metallurgical Quarterly》2007,21(3):387
Although continuing care is strongly related to positive treatment outcomes for substance use disorder (SUD), participation rates are low and few effective interventions are available. In a randomized clinical trial with 150 participants (97% men), 75 graduates of a residential Veterans Affairs Medical Center SUD program who received an aftercare contract, attendance prompts, and reinforcers (CPR) were compared to 75 graduates who received standard treatment (STX). Among CPR participants, 55% completed at least 3 months of aftercare, compared to 36% in STX. Similarly, CPR participants remained in treatment longer than those in STX (5.5 vs. 4.4 months). Additionally, CPR participants were more likely to be abstinent compared to STX (57% vs. 37%) after 1 year. The CPR intervention offers a practical means to improve adherence among individuals in SUD treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Olu Lafe 《Engineering Applications of Artificial Intelligence》1997,10(6):581-591
A family of basis functions, generated from the evolving states of Cellular Automata (CA), is used to compress and encrypt data. The operations required in encoding and decoding the data are described under the umbrella Cellular Automata Transforms (CAT). There is a huge number of these transform bases. CAT can be used in the way other mathematical transforms (e.g., Fourier, Discrete Cosine, Laplace, Wavelet, etc.) are utilized. In data-compression applications, the rules and pertinent keys used to generate the CA are selected to favor those that yield basis functions with the best information-packing characteristics. On the other hand, for encryption the selection is biased towards those with the tendency to yield an avalanche effect. In the latter case the transform process must be error-free. 相似文献
4.
The need to address global environmental concerns on an international basis is discussed. Programs underway are noted. The role of the United Nations (UN) in the International Space Year is examined. Activities planned by the UN are described, and their purpose and funding are discussed 相似文献
5.
Josephine Eskaf William J. Cleveland Matthias L. Riess 《International journal of molecular sciences》2021,22(9)
Myocardial infarction is a leading cause for morbidity and mortality worldwide. The only viable treatment for the ischemic insult is timely reperfusion, which further exacerbates myocardial injury. Maintaining mitochondrial function is crucial in preserving cardiomyocyte function in ischemia reperfusion (IR) injury. Poloxamer (P) 188 has been shown to improve cardiac IR injury by improving cellular and mitochondrial function. The aim of this study was to show if P188 postconditioning has direct protective effects on mitochondrial function in the heart. Langendorff prepared rat hearts were subjected to IR injury ex-vivo and reperfused for 10 min with 1 mM P188 vs. vehicle. Cardiac mitochondria were isolated with 1 mM P188 vs. 1 mM polyethylene glycol (PEG) vs. vehicle by differential centrifugation. Mitochondrial function was assessed by adenosine triphosphate synthesis, oxygen consumption, and calcium retention capacity. Mitochondrial function decreased significantly after ischemia and showed mild improvement with reperfusion. P188 did not improve mitochondrial function in the ex-vivo heart, and neither further P188 nor PEG induced direct mitochondrial protection after IR injury in this model. 相似文献
6.
Olu Emmanuel Femi N. Ravishankar K. Chattopadhyay 《Journal of Materials Science》2016,51(15):7254-7265
This paper explores in detail, the microstructures and thermoelectric properties of Te-rich and Te-poor (Bi,Sb)2Te3 alloys. We show that tuning the composition of ternary Bi–Sb–Te type alloys allows us to synthesize a range of microstructures containing a primary solid solution of (Bi,Sb)2Te3 with varying amounts of Te solid solution or a (Bi,Sb)Te compound. Te exists as a constituent of the multilayer domain while (Bi,Sb)Te appears in the thin intercellular regions of the (Bi,Sb)2Te3 dendritic cells. The presence of Te imparts an n-type behavior to the composite while the (Bi,Sb)2Te3 with a small amount of (Bi,Sb)Te exhibits p-type properties. A maximum ZT value of ≈0.4 at 425 K was achieved, opening up the possibility of using these alloys for thermoelectric device applications. 相似文献
7.
Josephine L. P. Soh Feng Wang Nathan Boersen Rodolfo Pinal Garnet E. Peck 《Drug development and industrial pharmacy》2013,39(10):1022-1035
This article aimed to model the effects of raw material properties and roller compactor operating parameters (OPs) on the properties of roller compacted ribbons and granules with the aid of principal component analysis (PCA) and partial least squares (PLS) projection. A database of raw material properties was established through extensive physical and mechanical characterization of several microcrystalline cellulose (MCC) and lactose grades and their blends. A design of experiment (DoE) was used for ribbon production. PLS models constructed with only OP-modeled roller compaction (RC) responded poorly. Inclusion of raw material properties markedly improved the goodness of fit (R2?=?.897) and model predictability (Q2?=?0.72). 相似文献
8.
Cowpea varieties (IT88D-867-11, IT89KD-288 and MALA) were boiled, roasted, dehulled and later milled into powder. The proximate composition, functional and pasting properties as well as anti-nutritional contents (Tannin) of the product was subsequently determined. The result of the study revealed significant increase (P < 0.05) in the crude protein, crude ash, swelling power and water absorption capacity. Conversely, significant decrease (P < 0.05) was observed in crude fat, starch content, moisture content, solubility and peak viscosity. Boiled samples have significantly higher (P < 0.05) crude protein, swelling power, water absorption capacity, with concomitantly lower solubility and tannin content. Crude ash, moisture, solubility and tannin content of dehulled samples decreased significantly with an increase in protein, swelling power and water absorption capacity. However, IT89KD-288 has the highest protein content irrespective of the processing used. But raw IT89KD-288 showed highest percentage of swelling power, solubility, water absorption capacity and Tannin content. The result revealed that both boiling and dehulling will greatly reduce tannin content of cowpea. 相似文献
9.
A control strategy is developed to control molecular weight of recycled poly(ethylene terephthalate), PET, to overcome its degradation through an extrusion process. To obtain dynamic model of a twin screw extruder, steady‐state, and unsteady‐state experiments were performed. Discrete convolution models between inputs and outputs were obtained. Process inputs were considered as screw speed (SS), feed rate, and barrel temperatures and the output was viscosity average molecular weight (Mv) of the extrudate. SS and molecular weight of the product were chosen as the manipulated, controlled variable pair by considering singular value decomposition (SVD) technique. Model based PID controller and model predictive controller were used in the designed control scheme. By the simulation studies, both controllers were found to be successful for set‐point tracking, disturbance rejection cases; and were proven to be robust under modeling errors. POLYM. ENG. SCI., 54:459–465, 2014. © 2013 Society of Plastics Engineers 相似文献
10.
Robert A. Gibson Mark A. Neumann Sharon L. Burnard Josephine A. Rinaldi Glen S. Patten Edward J. McMurchie 《Lipids》1992,27(3):169-176
Adult male marmoset monkeys were fed eicosapentaenoic acid (20∶5n−3) as the ethyl ester in diets containing either 32% (reference
diet, no added cholesterol) or 7% (atherogenic diet with 0.2% added cholesterol) linoleic acid (18∶2n−6) for 30 wk. No changes
were seen in the level of phosphatidylcholine (PC) or phosphatidylethanolamine (PE) but minor changes were observed in both
the sphingomyelin (SPM) and phosphatidylinositol plus phosphatidylserine (PI+PS) fractions of erythrocyte lipids. The extent
of total n−3 fatty acid incorporation into membrane lipids was higher in atherogenic diets (polyunsaturated/monounsaturated/saturated
(P/M/S) ratio 0.2∶0.6∶1.0) than reference diets (P/M/S ratio 1∶1∶1) and this was true for both PE (33.4±1.0%vs 24.3±1.1%) and PC (9.3±0.5%vs 4.9±0.3%). Although suitable controls for cholesterol effects were not included in the study, earlier results obtained with
marmosets lead us to believe such effects were probably small. Regardless of basic diet (atherogenic, reference), 20∶5n−3
was preferentially incorporated into PE (10.8±0.2%, 6.0±0.02%) while smaller amounts were incorporated into PC (6.9±0.4%,
3.2±0.2%). The major n−3 polyunsaturated fatty acid found in PE in response to dietary 20∶5n−3 was the elongation metabolite
22∶5n−3 in both the atherogenic (17.7±0.7%) and reference (14.3±1.0%) dietary groups; 22∶6n−3 levels were less affected by
diet (4.7±0.3% and 3.9±0.2%, respectively). The results can be interpreted to indicate an inverse relationship between the
amount of dietary 18∶2n−6 and incorporation of 20∶5n−3 into erythrocyte membrane phospholipids regardless of whether the major
dietary n−3 fatty acid was α-linolenate (18∶3n−3) or 20∶5n−3. This interpretation is supported by theoretical calculations. 相似文献