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Investigation of Tolerable Laser Linewidth for Different Modulation Formats in CO-OFDM Systems

Optics and Photonics Journal 2017年第5期7卷 92-100页

作者： Divya Dhawan neena gupta PEC University of Technology Chandigarh India

The ideal behavior of communication system requires a single frequency carrier. In optical communication system, light is used as a carrier. Practical laser source has a finite linewidth due to variations in the frequency of operation, hence, resulting in undesired phase perturbations in the signal whereas the ideal requirement is the delta function spectral shape at the carrier frequency. The spectral shape gets broadened due to phase noise and is modeled as lorentzian shape. Linewidth is a measure of stability of laser phase noise with time. Coherent Optical Orthogonal frequency division multiplexing (CO-OFDM) along with the spectrally efficient Quadrature Amplitude Modulation (QAM) formats is emerging as one of the best solutions for future high speed fiber transmission systems. Though the coherent, receivers have advantages in terms of sensitivity and selectivity, laser phase noise is the main limitation of such systems as the laser phase noise further causes common phase rotation of all the subcarriers per symbol and also results in inter carrier interference. QAM formats are also susceptible to laser phase noise. Phase noise in coherent systems is governed by laser linewidth. Hence, it is very important to investigate the impact of laser linewidth in CO-OFDM systems. This paper investigates the tolerable laser linewidths for different QAM formats in a 40 Gbps COOFDM system.

关键词： Laser Phase Noise Linewidth Coherent Detection QAM SER OSNR

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Prevalence of Herpes Simplex Virus in Pregnant Women from Gangetic Plain Region of Allahabad, India

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Advances in Microbiology 2015年第6期5卷 404-408页

作者： Omar Ahmed Omar Amar Harish Kumar Bajaj neena gupta Ankit Singla Harison Masih Medical Technology Laboratory Sam Higginbottom Institute of Agriculture Technology and Sciences Allahabad India Department of Microbiology and Fermentation Technology Sam Higginbottom Institute of Agriculture Technology and Sciences Allahabad India

Herpes Simplex Virus (HSV) is a common pathogen that leads to lifelong latent infection and may be associated with transmission from mother to their fetus. A total of 191 blood samples of pregnant women were collected to check the prevalence of Herpes Simplex Virus (HSV). It was observed that 124 (64.9%) and 04 (2.1%) samples were positive for HSV IgG and HSV IgM, respectively. Seropositivity of HSV IgG was the highest for third trimester and it was followed by second and first trimester;while it was the highest for first trimester for HSV IgM and it was followed by third and second trimester. Seroprevalence of HSV IgG and IgM was statistically insignificant (P > 0.05) according to gestation age. A significant correlation was observed between HSV IgG and age groups of pregnant women;while it was insignificant for HSV IgM. Seroprevalence of HSV IgG+ IgM- was 32 (53.3%), 61 (66.3%), and 27 (69.2%) for first, second and third trimester, respectively. Seroprevalence of HSV IgG+ IgM+ group was 02 (3.3%), 01 (1.1%) and 01 (2.6%) for first, second and third trimester, respectively. Seroprevalence of HSV IgG- IgM- group was 26 (43.3%), 30 (32.6%), and 11 (28.2%) for first, second and third trimester, respectively.

关键词： Herpes Simplex Virus Seroprevalence IgG IgM Quantitative ELISA

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COVID-19 mortality and its risk factors:A single-center observational study

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Journal of Acute Disease 2021年第6期10卷 252-257页

作者： Ajay Kumar gupta neena Katoch Rachna Gulati Vikas Kumar Sharmendra Singh Ketan Garg Department of Pharmacology Army College of Medical SciencesDelhiIndia Deaprtment of Pharmacology Army College of Medical SciencesDelhiIndia Department of Pathology Army College of Medical SciencesDelhiIndia All India Institute of Medical Sciences RishikeshIndia Department of Pharmacology Subharti Medical CollegeMeerutIndia Kegan Pathology Laboratory New DelhiIndia

Objectives:To determine COVID-19 mortality and its risk factors in hospitalized patients at of a tertiary care center in north ***:A retrospective observational study was conducted of patients who were hospitalized from May 2020 to January *** in-hospital mortality was assessed,and demographic variables and comorbidities between COVID-19 deaths and survivors were ***:A total of 24000 patients were admitted during the study period,among which 17000 had shown positive results of the RT-PCR test for *** total mortality was 329 patients(1.37%),among which 232(70.52%)succumbed due to COVID-19,and 97(29.48%)died due to other *** mean age of the patients was(64.09依16.99)*** mean age was significantly higher in COVID-19 related deaths[(67.63±13.78)years]as compared to that of the survivors[(60.52±19.5)years](P<0.001).Compared to COVID-19 survivors,there were more males(72.41%v.s.61.5%)and less females(27.59%v.s.38.5%)in COVID-19 related deaths(P=0.001).Comorbidities such as hypertension,diabetes mellitus,and chronic kidney disease showed a significant correlation with COVID-19 mortality with an adjusted odds ratio of 2.389(95%CI:1.465-2.982),3.891(95%CI:2.059-5.392),and 6.358(95%CI:5.675-10.564),***:Elderly males with comorbidities have higher risk for mortality related to *** vaccination drive is rightfully prioritised to serve the high-risk category first.

关键词： COVID-19 Mortality Comorbidities Elderly

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Quantifying Design Parameters of Symbology Page for Automotive Head up Display

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Computer Technology and Application 2011年第8期2卷 658-662页

作者： gupta Sharad Karar Vinod Saini Surender Singh Jaggi neena Bajpai Phun Phun National Institute of Technology （NIT） Kurukshetra 136119 India Central Scientific Instruments Organisation （CSIR-CSIO） Chandigarh 160030 India

This paper gives an overview of studies on parameters displayed on the Automotive Head Up Display （A-HUD） including calculation and construction of symbology page based on study results. A study has been made on vital parameters required for car drivers and design calculations have been made based on design parameters like field of view, distance from the design eye position, minimum character size viewable from a distance of 1.5m between driver and the projected image, and optical magnification factor. lhe display format suitable for A-HUD applications depends upon the parameters required to be displayed. The aspect ratio chosen is 4：3. This paper also provides method to design the symbology page embedding six vital parameters with their relative positioning and size considering relative position between display device and optical elements which has been considered with a magnification factor of 2.5. The field of view obtained is 6.7° × 4.8°.

关键词： Automotive head up display (A-HUD) magnification symbology character size human factors field of view (FOV). design eye position (DEP).

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