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Home > Modeling Techniques of Submicron Gaas Mesfets and Hemts

Modeling Techniques of Submicron Gaas Mesfets and Hemts

Thesis Info

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Author

Memon, Noor Muhammad

Program

PhD

Institute

Mohammad Ali Jinnah University

City

Islamabad

Province

Islamabad

Country

Pakistan

Thesis Completing Year

2008

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/136

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726660754

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This thesis discusses the electrical response of submicron GaAs MESFETs and HEMTs to develop a physical model. Nine different FET models have been presented and their ability to simulate submicron GaAs MESFET characteristics are checked. To demonstrate the validity of a model, I-V characteristics of short channel MESFETs are simulated and compared with experimental data. The accuracy of a model is reported by evaluating its RMS error values. A comprehensive new model is developed to simulate I-V characteristics of short channel GaAa FETs. It has been demonstrated that the proposed model is a comprehensive one, capable of simulating DC characteristics of GaAs MESFETs including those having significant non-ideal Schottky barrier response. The model has also been applied successfully to I-V characteristics of GaAs HEMTs. The Schottky barrier interfacial layer dependent performance of submicron GaAs MESFETs has been discussed by using their output and transfer characteristics. The mobility of carriers, scattering from the channel into the Schottky barrier gate, increases significantly for the devices which have a relatively thicker interfacial layer. The negative effects of increased carriers’ mobility from MESFET Schottky barrier gate are discussed and a plausible explanation is given for reduced barrier lowering in the presence of interfacial layer. Based on the proposed explanation the definition of threshold voltage has been redefined involving the concept of interfacial layer thickness. A technique is developed to estimate intrinsic small signal parameters of GaAs MESFETs and HEMTs. In the proposed technique DC characteristics are first evaluated. Once a good DC match is attained then small signal parameters are evaluated. To check the validity of the proposed technique submicron GaAs MESFETs and HEMTs of varying gate length have been simulated. It has been shown that the proposed method is accurate as well as efficient in estimating AC parameters of GaAs FETs by using their DC characteristics, and could be employed as a useful tool in device simulation software.
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چشم کشا انٹر ویو

چشم کُشا انٹر ویو

پاکستان پیپلز پارٹی کن حالات و مقاصد کے لیے قائم ہوئی ،پارٹی سے قبل لاہور کی کن شخصیات سے بھٹو صاحب کی قربت تھی ۔شہید بھٹو کی پارٹی کے قیام سے پہلے لاہور ،لائلپور ،گجرات کے دوروں کے دوران عوام کی طرف سے والہانہ اظہار محبت کے کیا کیا واقعات پیش آئے ،تاسیسی اجلاس میں لاہور ،قصور ،راولپنڈی ،فیصل آباد ،سرگودھا ،ملتان ،ساہیوال ،وہاڑی اور سندھ سے شریک ہو نے والے مندوبین کون تھے ۔لیفٹ کی بھٹو شہید سے نفرت کے محرکات کیا ہیں ۔ہالا کنونشن میں معراج محمد خان کی طرف سے پرچی کی بجائے برچھی سے خون سوشلسٹ انقلاب کے مطالبہ پر قائد عوام نے کیا جواب دیا ۔۔۔۔یہ سب کچھ جاننے کے لیے پاکستان پیپلز پارٹی کے بانی،رکن ،شہید بھٹو کے ساتھی ،ترقی پسند دانشور ،شاعر ،محقق و ادیب جناب اسلم گورداسپوری کا چشم کشا مضمون ۔

عام تاثر یہی تھا اور اب بھی ہے کہ پاکستان پیپلز پارٹی والے کھلے ،ڈلے ،منہ پھٹ ،سر کش ، اپنی لیڈر شپ کے ساتھ زیادہ فرینک قسم کے لوگ ہوتے ہیں جبکہ مسلم لیگیے عموما کاروباری ٹائپ ، میسنے ،موقع شناس و موقع پرست چاپلوس قسم کی طبیعتوںکے مالک ہو تے ہیں جوکبھی ’’گیلے ‘‘پر پائوںنہیں رکھتے ،رسک نہیں لیتے ،انتہائی لچکدار ’’کردار ‘‘کے حامل ہوتے ہیں ۔ماضی کی حد تک یہ تاثر شاید درست بھی تھا کہ معراج محمد خان ،مختار رانا آف لائلپور ،جے اے رحیم اور حنیف رامے جیسے نرم مزاج ،دانشور مصور فنکار قسم کے لوگ بھی بھٹو جیسے بندے کے خلاف ڈھے گئے ۔جبکہ مسلم لیگ کے مزاج میں سازش اور ٹانگیں کھینچنا تو موجود تھا لیکن آنکھوں میں آنکھیں ڈال کر مزاحمت کا رواج ہر گز نہیں تھا لیکن اب تو یوں محسوس ہوتا ہے کہ رولز ہی ریورس ہوگئے...

Glucose Insulin Ratio in Hyper Insulinemic Women with Polycystic Ovarian Syndrome

Background: Women with polycystic ovarian syndrome (PCOS) have insulin resistance and hyperinsulinemia that may play a key role in the pathogenesis of PCOS. Objectives: To determine and compare glucose-insulin ratio in hyper-insulinemic women with the polycystic ovarian syndrome and healthy controls. Materials & Methods: A cross-sectional comparative study was conducted at Lahore General Hospital. A total of 80 women 24-35 years of age were recruited from Lahore General Hospital. 50 women had PCOS, and 30 were healthy controls. PCOS was diagnosed by using the Rotterdam criteria. Height, weight, and waist circumference were measured. Glucose and insulin were estimated by the glucose oxidase method and ELISA, respectively. HOMA-IR was calculated to determine insulin resistance (IR). HOMA- β was calculated to assess the β-cell function. Fasting glucose and insulin ratio were also calculated. Results: Mean age of the women with PCOS and healthy controls was 29.89±3.54 and 28.60±1.12 years, respectively (p>0.54). BMI and waist circumference of women with PCOS were higher compared to healthy controls (p>0.45). Fasting glucose, fasting insulin, HOMA- β, and IR were significantly higher in women with PCOS compared to healthy controls (p<0.001). Conclusion: In addition to HOMA IR, the glucose-insulin ratio may be considered to assess hyperinsulinemia in women with polycystic ovary syndrome.

Comparison of Vaginal Microbiota in Women With Spontaneous Preterm Labour Versus Those With Term Labour

Background: Preterm birth presents a challenge on a global scale with a disease burden that is on the rise. It is a leading cause of perinatal morbidity and mortality worldwide with approximately 15 million preterm births every year. Kenya has a 12% preterm birth rate with about 190,000 babies born preterm every year. The female lower genital tract bacterial community plays a vital role in maternal and neonatal health. An association between altered vaginal microbial composition and preterm birth has been demonstrated in previous studies. However, findings in terms of composition and diversity of these bacteria across the few studies available have differed. With the progress and increased availability of using gene sequencing based techniques, the contribution of these vaginal microbial community changes to preterm birth have emerged as an area for research focus. Study Objective: The study objective was to compare the vaginal microbiota of women who presented with spontaneous preterm labour with those with term labour using 16S ribosomal RNA gene sequence-based techniques. Methodology: The study was a case control study set in AKUH Nairobi labour ward. Vaginal swabs were collected from mothers who presented between 26 weeks to 36 weeks of gestational age with diagnosis of preterm labour as well as controls matched for age and parity who presented in labour past 37 weeks of gestation. The vaginal microbiota of women who were in preterm labour was compared to those in term labour using 16S ribosomal RNA (rRNA) gene sequences. Results: In total, 100 participants were recruited for the study with 50 cases of preterm labour and 50 matched controls. Vaginal gene sequencing was done for 46 cases and 19 control with high quality reads achieved from 52 samples. The vaginal microbiota in both study groups was rich in the Lactobacillus genus of organisms. Fourty seven samples (90.4%) had a microbiota rich in different Lactobacillus species including unclassified Lactobacillus (n=35), Lactobacillus. iners (n=23), Lactobacillus. helviticus (n=18), Lactobacillus. vaginalis (n=17), Lactobacillu.mucosae (n=2), Lactobacillus. zeae (n=1) and Lactobacillus. coleohominis (n=1) existing with several overlaps. There was high diversity of the vaginal microbiota although it did not fall into any assigned community state type. Conclusions: This study demonstrates a spectrum of diversity in the vaginal microbiota without clear evidence of any specific microbiota patterns that have a correlation with preterm labour.