Sol-gel yöntemiyle hazırlanan WO3 filmlerin elektriksel ve optik özelliklerinin incelenmesi

ÖZETSOL-GEL YÖNTEMİYLE HAZIRLANAN WO3 FİLMLERİN ELEKTRİKSEL VE OPTİK ÖZELLİKLERİNİN İNCELENMESİ Tungsten oksit (WO3), katot malzemesi olarak elektrokromik aygıtların yapımında birinci derece öneme sahip bir malzemedir ve bugüne kadar n-tip yarıiletkenler arasında görünür bölge ve kızıl ötesi bölgelerdeki elektrokromik özelliklerine bağlı olarak üzerinde en çok çalışılan elektrokromik malzeme olmuştur. Bu Yüksek Lisans tez çalışmasında, başlangıç maddesi olarak tungsten heksa klorit (WCl6) kullanılarak katkısız ve değişik oranlarda Ti katkılanmış WO3 ince filmler hazırlanmıştır. Filmler, cam altlıklar üzerine fotolitografi tekniği ile oluşturulmuş İnter dijital elektrot yapısı üzerine (IDT) hazırlanmıştır. Bu filmlerin, yapısal, elektriksel ve optik karakterizasyonları yapılmıştır. Filmlerin yapısal özellikleri XRD yöntemiyle belirlenmiş ve WO3 filmlerin triklinik kristal yapıda oldukları görülmüştür. Filmlerin d.c ve a.c elektriksel özellikler 303-523 K sıcaklık aralığında incelenmiştir. Bu incelemeler sonucunda, gerek katkılı gerekse katkısız filmlerde d.c davranışın ısıl olarak uyarılmış taşıyıcılar tarafından belirlendiği sonucuna varılmıştır. Filmlerde a.c yük iletim mekanizmasının ise Reider tarafından önerilen site enerjilerini, engel yüksekliğini siteler arasındaki uzaklığı da göz önünde bulunduran model ile açıklanabileceği sonucuna varılmıştır. Filmlerin optik özellikleri 285-800 nm dalga boyu aralığındaki soğurma ve geçirgenlik özellikleri ölçülmek suretiyle belirlenmiştir. Bu ölçümlerden, gerek katkılı gerekse katkısız filmlerde soğurmanın artan dalga boyu ile azalırken, geçirgenliğin artan dalga boyu ile arttığı belirlenmiştir.AbstractINVESTIGATION OF ELECTRICAL AND OPTICAL PROPERTIES OF SOL-GEL DERIVED WO3 THIN FILMSTungsten oxide (WO3) has an important cathode material for fabricating electrochromic devices. Until now it has been extensively studied material among n-type semiconductors depending on electrochromic properties in the visible and infrared regions. In this master thesis, undoped and Ti doped tungsten oxide (WO3) thin films were prepared by using tungsten hexa chloride (WCl6) as starting material. The films were deposited onto glass substrates which are photolitographically patterned on the interdigitated electrodes structures (IDT). Structural, electrical and optical characterizations of the films were performed. Crystal structure of the films was investigated by means of X-ray diffraction method. X-ray diffraction results showed that the crystal structure of the WO3 films was triclinic. D.c and a.c electrical properties of the films were investigated in the temperature range of 303-523 K. These results reveal that d.c electrical behavior of undoped and doped films can be represented by thermally stimulated carriers. A.c charge transport mechanism of the films can be explained by the model proposed by Reider. This model suggest a hopping, based on a hopping over barriers, which includes both, a variation of site energies, barrier heights, and of intersite distances. Optical properties of the films were determined by means of absorption and transmission measurements between the wavelengths of 285-800 nm. It was observed from these measurements that, while absorption of undoped and doped films decreases with increase in wavelength transmission increases with increase in wavelength

Stepwise Approach in Asthma Revisited 2023: Expert Panel Opinion of Turkish Guideline of Asthma Diagnosis and Management Group

Introduction of inhaled corticosteroids (ICS) has been the cornerstone of the long-term management of asthma. ICSs either alone or in combination with long-acting beta-2 agonists have been shown to be associated with favorable asthma outcomes. However, asthma con-trol is still reported to be below expectations all around the world. Research in the last decades focusing on the use of ICS/formoterol both as maintenance and as needed (maintenance and reliever therapy approach) showed improved asthma outcomes. As a result of recent developments, Turkish Asthma Guidelines group aimed to revise asthma treatment recommendations. In general, we recommend physicians to consider the risk factors for poor asthma outcomes, patients’ compliance and expectations and then to determine “a personalized treatment plan.” Importantly, the use of short-acting beta-2 agonists alone as a symptom reliever in asthma patients not using regular ICS is no longer recommended. In stepwise treatment approach, we primarily recommend to use ICS-based controllers and initiate ICS as soon as possible. We define 2 different treatment tracks in stepwise approaches as maintenance and reliever therapy or fixed-dose therapy and equally recommend each track depending on the patient’s risks as well as decision of physicians in a personalized manner. For both tracks, a strong recommendation was made in favor of using add-on treatments before initiating phenotype-specific treatment in step 5. A strong recommendation was also made in favor of using biologic agents and/or aspirin treatment after desensitization in severe asthma when indicated

Clinical Characteristics and Outcomes of COVID-19 in Turkish Patients with Hematological Malignancies

Objective: Patients with solid malignancies are more vulnerable to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection than the healthy population. The outcome of SARS-CoV-2 infection in highly immunosuppressed populations, such as in patients with hematological malignancies, is a point of interest. We aimed to analyze the symptoms, complications, intensive care unit admissions, and mortality rates of patients with hematological malignancies infected with SARS-CoV-2 in Turkey. Materials and Methods: In this multicenter study, we included 340 adult and pediatric patients diagnosed with SARS-CoV-2 from March to November 2020. Diagnosis and status of primary disease, treatment schedules for hematological malignancies, time from last treatment, life expectancy related to the hematological disease, and comorbidities were recorded, together with data regarding symptoms, treatment, and outcome of SARS-CoV-2 infection. Results: Forty four patients were asymptomatic at diagnosis of SARSCoV-2 infection. Among symptomatic patients, fever, cough, and dyspnea were observed in 62.6%, 48.8%, and 41.8%, respectively. Sixtynine (20%) patients had mild SARS-CoV-2 disease, whereas moderate, severe, and critical disease was reported in 101 (29%), 71 (20%), and 55 (16%) patients, respectively. Of the entire cohort, 251 (73.8%) patients were hospitalized for SARS-CoV-2. Mortality related to SARS-CoV-2 infection was 26.5% in the entire cohort; this comprised 4.4% of those patients with mild disease, 12.4% of those with moderate disease, and 83% of those with severe or critical disease. Active hematological disease, lower life expectancy related to primary hematological disease, neutropenia at diagnosis of SARS-CoV-2, ICU admission, and first-line therapy used for coronavirus disease-2019 treatment were found to be related to higher mortality rates. Treatments with hydroxychloroquine alone or in combination with azithromycin were associated with a higher rate of mortality in comparison to favipiravir use. Conclusion: Patients with hematological malignancy infected with SARS-CoV-2 have an increased risk of severe disease and mortality