| 1. |
- Adcox, K, et al.
(författare)
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PHENIX detector overview
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Adler, SS, et al.
(författare)
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PHENIX on-line systems
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 560-592
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX On-Line system takes signals from the Front End Modules (FEM) on each detector subsystem for the purpose of generating events for physics analysis. Processing of event data begins when the Data Collection Modules (DCM) receive data via fiber-optic links from the FEMs. The DCMs format and zero suppress the data and generate data packets. These packets go to the Event Builders (EvB) that assemble the events in final form. The Level-1 trigger (LVL1) generates a decision for each beam crossing and eliminates uninteresting events. The FEMs carry out all detector processing of the data so that it is delivered to the DCMs using a standard format. The FEMs also provide buffering for LVL1 trigger processing and DCM data collection. This is carried out using an architecture that is pipelined and deadtimeless. All of this is controlled by the Master Timing System (MTS) that distributes the RHIC clocks. A Level-2 trigger (LVL2) gives additional discrimination. A description of the components and operation of the PHENIX On-Line system is given and the solution to a number of electronic infrastructure problems are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
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| 4. |
- Enfors, Sven-Olof, et al.
(författare)
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Physiological responses to mixing in large scale bioreactors
- 2001
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Ingår i: Journal of Biotechnology. - 0168-1656 .- 1873-4863. ; 85:2, s. 175-185
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli fed-batch cultivations at 22 m(3) scale were compared to corresponding laboratory scale processes and cultivations using a scale-down reactor furnished with a high-glucose concentration zone to mimic the conditions in a feed zone of the large bioreactor. Formate accumulated in the large reactor, indicating the existence of oxygen limitation zones. It is suggested that the reduced biomass yield at large scale partly is due to repeated production/reassimilation of acetate from overflow metabolism and mixed acid fermentation products due to local moving zones with oxygen limitation. The conditions that generated mixed-acid fermentation in the scale-down reactor also induced a number of stress responses, monitored by analysis of mRNA of selected stress induced genes. The stress responses were relaxed when the cells returned to the substrate limited and oxygen sufficient compartment of the reactor. Corresponding analysis in the large reactor showed that the concentration of mRNA of four stress induced genes was lowest at the sampling port most distant from the feed zone. It is assumed that repeated induction/relaxation of stress responses in a large bioreactor may contribute to altered physiological properties of the cells grown in large-scale bioreactor. Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.
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| 5. |
- Li, D. Z., et al.
(författare)
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Study of interaction between red-tide toxin, domoic acid and double-stranded DNA by capillary zone electrophoresis
- 2004
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 15:9, s. 1079-1082
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between amnesic red-tide toxin, domoic acid (DA) and 14mer double-stranded DNA (dsDNA with three kinds of sequences) were studied by capillary zone electrophoresis (CZE). For the dsDNA with a sequence of 5'-CCCCCTATACCCGC-3', the amount of free dsDNA decreases with the increase of added DA; and the signal of DA-dsDNA complex was observed. Meanwhile, the other two dsDNAs, 5'-(C)12GC-3' and 5'-(AT)7-3', the existence of DA could not lead to the change of dsDNA signal and indicated that there is no interaction between DA and these two dsDNAs.
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| 6. |
- Zhang, J. G., et al.
(författare)
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Microstructure and mechanical properties of spray formed ultrahigh-carbon steels
- 2004
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 383:1, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure and mechanical properties of the spray formed 1.25C-3.0Si-1.5Cr ultrahigh-carbon steel (UHCS) were described. The 1.25C-3.0Si-1.5Cr UHCS was processed by spray forming to break up carbide networks. The fine pearlites with average interlamellar spacing of 0.20 mum was observed in the as-sprayed microstructure. The ultimate tensile strength and the pearlite spacing can be related by the Hall-Petch equation. The as-sprayed 1.25C-3.0Si-1.5Cr UHCS consisting of fine lamellar pearlites has been shown to exhibit superplastic behavior at elevated temperature. The dramatic change of microstructure from fine lamellar pearlites to equiaxed grains stabilized by spheroidized particles during superplastic deformation has been observed. The estimation on the basis of thermodynamics shows that the content of chromium of 1.54 wt.% is needed to inhibit graphite formation in the l.25C-3.OSi-1.5Cr UHCS.
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| 7. |
- Filipi, Z., et al.
(författare)
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Combined optimisation of design and power management of the hydraulic hybrid propulsion system for the 6 × 6 medium truck
- 2004
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Ingår i: International Journal of Vehicle Design. Heavy Vehicle Design. - 1744-232X .- 1741-5152. ; 11:3-4, s. 372-402
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid propulsion systems are one of the critical technologies on the roadmap to future ultra-efficient trucks. While there is a significant body of work related to hybrid passenger cars and light commercial trucks, there are many open issues related to hybridisation of heavier trucks intended for both on- and off-road use. This work addresses those questions through a systematic analysis of the proposed parallel hydraulic hybrid powertrain for the Family of Medium Tactical Vehicles (FMTV). A representative duty cycle for the FMTV is generated based on information about the typical vehicle mission. A methodology for sequential optimisation of hybrid propulsion and power management systems is applied to a hydraulic hybrid configuration with posttransmission motor location, This analysis is critical in evaluating the fuel economy and mobility potential of the hybrid propulsion system, as well as enhancing our understanding of the phenomena leading to predicted fuel economy values.
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| 8. |
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| 9. |
- Lin, H. Y., et al.
(författare)
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Change of extracellular cAMP concentration is a sensitive reporter for bacterial fitness in high-cell-density cultures of Escherichia coli
- 2004
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 87:5, s. 602-613
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Tidskriftsartikel (refereegranskat)abstract
- Guanosine-3'5'-tetraphosphate (ppGpp) and as, two regulators of the starvation response of Escherichia coli, have received increasing attention for monitoring cell physiological changes in production processes, although both are difficult to quantify. The kinetics of cAMP formation and degradation were not yet investigated in such processes, although the complex regulation of cAMP by synthesis, release, and degradation in connection with straightforward methods for analysis renders it a highly informative target. Therefore, we followed the cAMP concentration in various nonrecombinant and in four different recombinant glucose-limited fed-batch processes in different production scales. The intracellular cAMP concentration increases strongly at the end of the batch phase. Most cAMP is released to the cultivation medium. The rates of accumulation and degradation of extracellular cAMP are growth-rate-dependent and show a distinct maximum at a growth rate of about 0.35 h(-1). At very low growth rates, below 0.05 h(-1), extracellular cAMP is not produced but rather degraded, independent of whether this low growth rate is caused by glucose limitation or by the high metabolic load of recombinant protein production. In contrast to intracellular cAMP, which is highly unstable, analysis of extracellular cAMP is simpler and the kinetics of accumulation and degradation reflect well the physiological situation, including unlimited growth, limitation, and severe starvation of a production host.
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| 10. |
- Lin, H. Y., et al.
(författare)
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Determination of the maximum specific uptake capacities for glucose and oxygen in glucose-limited fed-batch cultivations of Escherichia coli
- 2001
-
Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 73:5, s. 347-357
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Tidskriftsartikel (refereegranskat)abstract
- A simple pulse-based method for the determination of the maximum uptake capacities for glucose a nd oxygen in glucose limited cultivations of E. coli is presented. The method does not depend on the time-consuming analysis of glucose or acetate, and therefore can be used to control the feed rate in glucose limited cultivations, such as fed-batch processes. The application of this method in fed-batch processes of E. coli showed that the uptake capacity for neither glucose nor oxygen is a constant parameter, as often is assumed in fed-batch models. The glucose uptake capacity decreased significantly when the specific growth rate decreased below 0.15 h(-1) and fell to about 0.6 mmol g(-1) h(-1) (mmol per g cell dry weight and hour) at the end of fed-batch fermentations, where mu was approximately 0.02 h(-1). The oxygen uptake capacity started to decrease somewhat earlier when mu declined below 0.25 h(-1) and was 5 mmol g(-1) h(-1) at the end of the fermentations. The behavior of both uptake systems is integrated in a dynamic model which allows a better fitting of experimental values for glucose in fed-batch processes in comparison to generally used unstructured kinetic models.
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