| 1. |
- Zhang, Jian, 1978, et al.
(författare)
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Examinations on closure models of conditionally filtered LES
- 2011
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Ingår i: Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics. - 0253-231X. ; 32:2, s. 357-359
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Tidskriftsartikel (refereegranskat)abstract
- The DNS and the conditionally filtered LES (CFLES) were combined to examine the validity of the linear-diffusion approximation and the first-order closure in CFLES equation. The linear-diffusion approximation was applied to closing transport term in mixture-fraction space in CFLES equation, and the first-order closure was used in closing conditionally filtered reaction source term. The first two order moments of filtered mass-fraction of the reactant were obtained by using CFLES and were closed to results of the DNS, which well examined the validity of the approximations mentioned above.
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| 2. |
- Liu, Ning, et al.
(författare)
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Transcriptional regulation mechanisms of hypoxia-induced neuroglobin gene expression.
- 2012
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Ingår i: The Biochemical journal. - 1470-8728 .- 0264-6021. ; 443:1, s. 153-164
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Tidskriftsartikel (refereegranskat)abstract
- Ngb (neuroglobin) has been identified as a novel endogenous neuroprotectant. However, little is known about the regulatory mechanisms of Ngb expression, especially under conditions of hypoxia. In the present study, we located the core proximal promoter of the mouse Ngb gene to a 554bp segment, which harbours putative conserved NF-κB (nuclear factor κB)- and Egr1 (early growth-response factor 1) -binding sites. Overexpression and knockdown of transcription factors p65, p50, Egr1 or Sp1 (specificity protein 1) increased and decreased Ngb expression respectively. Experimental assessments with transfections of mutational Ngb gene promoter constructs, as well as EMSA (electrophoretic mobility-shift assay) and ChIP (chromatin immunoprecipitation) assays, demonstrated that NF-κB family members (p65, p50 and cRel), Egr1 and Sp1 bound in vitro and in vivo to the proximal promoter region of the Ngb gene. Moreover, a κB3 site was found as a pivotal cis-element responsible for hypoxia-induced Ngb promoter activity. NF-κB (p65) and Sp1 were also responsible for hypoxia-induced up-regulation of Ngb expression. Although there are no conserved HREs (hypoxia-response elements) in the promoter of the mouse Ngb gene, the results of the present study suggest that HIF-1α (hypoxia-inducible factor-1α) is also involved in hypoxia-induced Ngb up-regulation. In conclusion, we have identified that NF-κB, Egr1 and Sp1 played important roles in the regulation of basal Ngb expression via specific interactions with the mouse Ngb promoter. NF-κB, Sp1 and HIF-1α contributed to the up-regulation of mouse Ngb gene expression under hypoxic conditions.
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| 3. |
- Zhang, Jian, 1978, et al.
(författare)
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Linearity improvement using a modified derivative superposition method in cascaded stages amplifier
- 2012
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Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 6:8, s. 922-928
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Tidskriftsartikel (refereegranskat)abstract
- A modified derivative superposition (DS) method using cascaded stages transistor is described. It uses the third order intermodulation (IMD3) current generated from the preceding stage to cancel those at the output of the following stage. This analysis demonstrates that an IMD3 minimum occurs near the output power compression point. A balanced X-band linear power amplifier (PA) monolithic microwave integrated circuit (MMIC) using this concept is presented. The results of measurement showed a carrier-to-IMD3 ratio (C/I3) improvement more than 30 dB compared with the conventional cascaded stages configuration.
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| 4. |
- Zhang, Jian, 1978, et al.
(författare)
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Transformer-Based Broadband High-Linearity HBT Gm-Boosted Transconductance Mixers
- 2014
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 62:1, s. 92-99
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Tidskriftsartikel (refereegranskat)abstract
- A Gm-boosted transconductance configuration mixer is proposed. Based on this topology, two broadband monolithic InGaP HBT mixers, one single device and one balanced, have been developed for C-Ku-band applications. The single device mixer has a conversion gain of 4.5 +/- 1.5 dB within the RF frequency range from 5 to 17 GHz. The balanced design has about 3.5 +/- 1.5-dB conversion gain within a frequency range of 6-18 GHz. The two mixers have very good linearity with a third-order intermodulation intercept point (IIP3) higher than 16 and 20 dBm for the single device mixer and single balanced mixer, respectively. Both mixers are pumped by a local oscillator power of 5 dBm. To the authors' best knowledge, the designed mixers demonstrate the highest IIP3 with positive conversion gain in this frequency range. Compact designs are achieved with chip sizes less than 0.5 mm(2). DC power consumptions are 30 and 50 mW, for the single device and single balanced mixer, respectively.
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| 5. |
- Zhou, Jingmin, et al.
(författare)
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Rationale and design of the beta-blocker in heart failure with normal left ventricular ejection fraction (beta-PRESERVE) study.
- 2010
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Ingår i: European journal of heart failure : journal of the Working Group on Heart Failure of the European Society of Cardiology. - : Wiley. - 1879-0844. ; 12:2, s. 181-5
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Tidskriftsartikel (refereegranskat)abstract
- Chronic heart failure with normal left ventricular ejection fraction (HFNEF) is not only common, but also carries a high risk of substantial morbidity and mortality. However, few studies have been conducted in this population and no proven treatment is available. Although beta-blockers are evidence-based first-line therapy in systolic heart failure, they have not been well studied in HFNEF.
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