| 1. |
- Ahsan, Naveed, 1974-, et al.
(författare)
-
A Design Approach for Flexible RF Circuits Using Reconfigurable PROMFA Cells
- 2009
-
Ingår i: Analog Integrated Circuits and Signal Processing. - 0925-1030 .- 1573-1979.
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a design approach for flexible RF circuits using Programmable Microwave Function Array (PROMFA) cells. The concept is based on an array of generic cells that can be dynamically reconfigured. Therefore, the same circuit can be used for various functions e.g. amplifier, tunable filter and tunable oscillator. For proof of concept a test chip has been implemented in 90nm CMOS process. The chip measurement results indicate that a single unit cell amplifier has a typical gain of 4dB with noise figure of 2.65dB at 1.5GHz. The measured input referred 1dB compression point is -8dBm with an IIP3 of +1.1dBm at 1GHz. In a single unit cell oscillator configuration, the oscillator can achieve a wide tuning range of 600MHz to 1.8GHz. The measured phase noise is -94dBc/Hz at an offset frequency of 1MHz for the oscillation frequency of 1.2GHz. A single unit cell oscillator consumes 18mW at 1.2GHz while providing -8dBm power into 50Ω load. In a single unit cell filter configuration, the tunable band pass filter can achieve a reasonable tuning range of 600MHz to 1.2GHz with a typical power consumption of 13mW at 1GHz. A single unit cell has a total chip area of 0.091mm2 including the coupling capacitors.
|
|
| 2. |
- Bengtsson, Marie, 1977-
(författare)
-
The Art of Replicating
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fokus för den här avhandlingen är företag som växer genom replikering, det vill säga genom att skapa och driva liknande enheter på många olika platser, så som t.ex. McDonald’s och Starbucks. Replikerande företags livscykel beskrivs normalt i termer av en initial utforskande fas, följt av en exploateringsfas där standardisering är en hörnsten i företagets strategi - vad som därefter följer är emellertid oklart. Varsamt åldrande innebär dock vanligtvis att man måste anta de utmaningar som följer i kölvattnet av stabilitet och förändring.Modeindustrin kan beskrivas som oberäknelig och föränderlig, och har varit så i århundraden. Konkurrensen är stenhård och efterfrågan är svår att förutse då mode och trender hela tiden förändras. Med tanke på det beroende av standadisering som finns i replikerande företag kan man fråga sig hur ett företag i modebranschen kan hantera en replikeringsstrategi. Den trade-off som finns mellan fördelarna av standardisering och fördelarna av lärande och anpassning ställs på sin spets i ett sådant företag.Renässansen stora konstnärer mötte en liknande utmaning om än i lite annan form. Baserat på kollektivt arbete skapade renässansens verkstäder såväl replikor som nya verk i mästarens namn. För verkstaden betydde det att de skulle replikera mästarens stil till den grad att enskilda bidrag från lärlingar inte gick att skilja från mästarens eget arbete. Nya lärlingar var tvungna att lära sig att “emulera” mästarens stil och fungerar som en förlängning av hans hand och öga.Den här avhandlingen tar därför avstamp i konstens värld, mer specifikt i Renässansen, för att utforska hur ett konstinspirerat förhållningssätt kan öka vår förståelse av replikeringsprocesser i erfarna företag som är verksamma i starkt föränderliga branscher och vars strategi bygger på replikering. Det empiriska underlaget för avhandlingen är en djupgående fallstudie av den svenska modekedjan Hennes & Mauritz, och bygger på deltagande observation såväl i etablerade butiker som under öppningen av nya.
|
|
| 3. |
- Boson, Jonas, 1976-
(författare)
-
Improving accuracy of in situ gamma-ray spectrometry
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gamma-ray spectrometry measurements performed on site, or “in situ”, is a widely used and powerful method that can be employed both to identify and quantify ground deposited radionuclides. The purpose of this thesis is to improve the calibration of high purity germanium (HPGe) detectors for in situ measurements, and calculate the combined uncertainty and potential systematic effects. An improved semi-empirical calibration method is presented, based on a novel expression for the intrinsic detector efficiency that includes both the energy and angular response of the detector. A three-layer model for the description of the depth distribution of the radionuclide and the soil density is proposed. The combined uncertainty of intrinsic detector efficiency calibrations and in situ measurements according to the proposed method was estimated. The uncertainty in the intrinsic detector efficiency was found to be 5.1 and 8.1% (coverage factor k=1, i.e. for a confidence interval of about 68%), for the two detectors calibrated. These numbers were, however, at a later stage reduced to 3.7 and 4.2%, using a revised expression for the intrinsic detector efficiency. For in situ measurements, the combined standard uncertainty was found to be 15-20% (k=1), based on the original expression for the intrinsic detector efficiency. Monte Carlo models of the two detectors were created and Monte Carlo calculated values for intrinsic detector efficiency were compared with experimental data. As a discrepancy was found, a thorough investigation of the detector response was performed. Scanning of the detector surface with a collimated 59.5 keV photon beam revealed the detector response to be highly irregular over the detector surface. It was concluded that the efficiency deficit of the detector could most likely be attributed to an increase in dead layer thickness compared with manufacturer supplied data. The thickness of the dead layer was estimated to be 1.5-1.9 mm, whereas the nominal value was 0.7 mm. Radiographs of the detectors were produced that provided valuable information about the physical dimensions of the germanium crystal, as well as its actual location within the detector housing. The Monte Carlo models were employed to calculate in situ measurement efficiencies for measurements of 137Cs deposition from the Chernobyl fallout. Results from the Monte Carlo simulations were compared both with the semi-empirical method and with soil sample data, and satisfactory agreement was confirmed. It was then proceeded to employ the Monte Carlo model to calculate the effect on in situ measurement results by two influencing parameters: ground curvature and activity in trees. Neither of these parameters was found to influence the result by more than about 25%. This deviation is comparable with the measurement uncertainty, and should not deter from measurements in such terrain.
|
|
| 4. |
- He, L, et al.
(författare)
-
Glomerulus-specific mRNA transcripts and proteins identified through kidney expressed sequence tag database analysis
- 2007
-
Ingår i: Kidney International. - 1523-1755 .- 0085-2538. ; 71:9, s. 889-900
-
Tidskriftsartikel (refereegranskat)abstract
- The kidney glomerulus plays a crucial role in blood filtration but the molecular composition and physiology of the glomerulus is not well understood. We previously constructed and large-scale sequenced four mouse glomerular expressed sequence tag (EST) libraries from newborn and adult mouse glomeruli. Here, we compared glomerular EST profiles with whole kidney EST profiles, thereby identifying 497 transcripts corresponding to UniGene clusters that were glomerulus-enriched, that is expressed more abundantly in glomeruli than in whole kidney. These include several known protein-coding glomerulus-specific transcripts critical for glomerulus development and function, but also a large number of gene transcripts, which have not previously been shown to be expressed in the glomerulus, or implicated in glomerular functions. We used in situ hybridization to demonstrate glomerulus-specific RNA expression for six novel glomerular genes and the public Human Protein Atlas to verify glomerular protein expression for another two. The higher mRNA abundance for the eight genes in glomeruli compared with whole kidney was also verified by Taqman quantitative polymerase chain reaction. We surmise that the further characterization of these genes and proteins will increase our understanding of glomerular development and physiology.
|
|
| 5. |
- He, Liqun, et al.
(författare)
-
The glomerular transcriptome and a predicted protein-protein interaction network
- 2008
-
Ingår i: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 19:2, s. 260-268
-
Tidskriftsartikel (refereegranskat)abstract
- To increase our understanding of the molecular composition of the kidney glomerulus, we performed a meta-analysis of available glomerular transcriptional profiles made from mouse and man using five different methodologies. We generated a combined catalogue of glomerulus-enriched genes that emerged from these different sources and then used this to construct a predicted protein-protein interaction network in the glomerulus (GlomNet). The combined glomerulus-enriched gene catalogue provides the most comprehensive picture of the molecular composition of the glomerulus currently available, and GlomNet contributes an integrative systems biology approach to the understanding of glomerular signaling networks that operate during development, function, and disease.
|
|
| 6. |
|
|
| 7. |
- Hjerpe, Thomas, et al.
(författare)
-
Shielded and unshielded geometries in the search for orphan sources.
- 2006
-
Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043. ; 64:Dec 29, s. 551-555
-
Tidskriftsartikel (refereegranskat)abstract
- A car-borne NaI(TI) spectrometric system was used together with a Cs-137 source to obtain realistic data in the search for unshielded and semi-shielded orphan sources. The potassium-stripped counts (PSC) method was used to estimate the influence by the shielding on the detection ability. A reduction of about 5% in the critical distance was obtained for the semi-shielded source. A curve fitting method was also developed and evaluated. Results from the curve fitting method showed inferior ability to find the source compared to the PSC method. However, it can be a useful complementary tool, for characterisation of the source shielding, and estimation of the distance from the road. (c) 2005 Elsevier Ltd. All rights reserved.
|
|
| 8. |
- Roos, Birgitta, et al.
(författare)
-
The behaviour of Rn-222 decay products at the air-glass interface and its implication for retrospective radon exposure estimates
- 2005
-
Ingår i: Natural Radiation Environment VII. - 9780080441375 ; 7, s. 813-819
-
Konferensbidrag (refereegranskat)abstract
- Glass sheets investigated regarding their Po-210 signal originating from indoor radon exposure will have a depth distribution down to about 100 nm. The geometrical probability of implantation into glass of glass-attached radon daughter activity in one alpha recoil event is 50%. A particulate layer on the glass sheet (dust, grease or other particles) will stop the alpha recoil nucleus partly or totally, and the alpha-recoiled Po-210 nucleus will be implanted into the glass surface at a lesser depth. Clean glass sheets were pre-exposed to different types of nonradioactive aerosol particles and then exposed to radon-laden air. After a build-up period, the surface activity of Po-210 was determined by alpha spectrometry. The implanted fraction of (210)po for these sheets of glass, with respect to mass load and type of particulate surface layer, was determined to be between 30 and 80% depending on the mass load (mu g cm(-2)).
|
|
| 9. |
- Takemoto, Minoru, et al.
(författare)
-
Large-scale identification of genes implicated in kidney glomerulus development and function.
- 2006
-
Ingår i: The EMBO journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 25:5, s. 1160-74
-
Tidskriftsartikel (refereegranskat)abstract
- To advance our understanding of development, function and diseases in the kidney glomerulus, we have established and large-scale sequenced cDNA libraries from mouse glomeruli at different stages of development, resulting in a catalogue of 6053 different genes. The glomerular cDNA clones were arrayed and hybridized against a series of labeled targets from isolated glomeruli, non-glomerular kidney tissue, FACS-sorted podocytes and brain capillaries, which identified over 300 glomerular cell-enriched transcripts, some of which were further sublocalized to podocytes, mesangial cells and juxtaglomerular cells by in situ hybridization. For the earliest podocyte marker identified, Foxc2, knockout mice were used to analyze the role of this protein during glomerular development. We show that Foxc2 controls the expression of a distinct set of podocyte genes involved in podocyte differentiation and glomerular basement membrane maturation. The primary podocyte defects also cause abnormal differentiation and organization of the glomerular vascular cells. We surmise that studies on the other novel glomerulus-enriched transcripts identified in this study will provide new insight into glomerular development and pathomechanisms of disease.
|
|
| 10. |
|
|
| 11. |
- Xu, Jianqiang, et al.
(författare)
-
Assessment of 4-nitro-1,8-naphthalic anhydride reductase activity in homogenates of bakers' yeast by reversed-phase high-performance liquid chromatography
- 2007
-
Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 847:2, s. 82-87
-
Tidskriftsartikel (refereegranskat)abstract
- A simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of yield and conversion ratio of 4-nitro-1,8-naphthalic anhydride to 4-amino-1,8-naphthalic anhydride following incubation with a crude bakers’ yeast homogenate. The analytes were separated on a C18 column in gradient mode. The detection limit of 4-amino-1,8-naphthalic anhydride is 10 ng/μl when using a 10 μl sample injection volume. The nitroreductase activity in the homogenate system can be assessed during the bioconversion process. The method can be used for the simultaneous detection of 4-hydroxylamino-1,8-naphthalic anhydride, an intermediate with limited stability.
|
|
