bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Growth Parameters in Oats (Avena sativa L.) with Application of Nano Urea Fertilizer: A Field-based Study
Authors: . Rajesh , Choudhary Madhu , Kumar Rakesh , Meena Rajesh Kumar , Ram Hardev , Kumar Manoj , Kumar Vijendra , Makarana Govind , Kumar Dinesh , Basu Umer
Published: March 2023

This study aimed to evaluate the efficacy of Nano nitrogen on various growth parameters of oats leads to growth and yield, including plant height, plant population, number of leaves, leaf length, leaf width, and the total number of tillers per plant. During the study, growth parameters were recorded at 30 days after sowing and after the I and II cuts. Results revealed that 30 days after seeding, applying 100% recommended dose of nitrogen (RDN) through Urea and 75% RDN with 25% nitrogen through Nano-N resulted in significantly greater plant heights as compared to the rest of the treatment combinations. Similarly, these treatments also had significantly higher plant heights during the I and II cuts. The number of leaves significantly increased with the application of nitrogen through all sources, either individually or in combination, highest number of leaves was observed when 100% RDN was applied through Urea or when 75% RDN was applied combined with 25% nitrogen through Nano-N. The leaf length and width of the oats were also significantly improved by nitrogen management practices, with the maximum leaf length observed when 100% RDN was applied through Urea or when 75% RDN was applied combined with 25% nitrogen through Nano-N. Similarly, the highest leaf width was observed with the application of 100% RDN through Urea at all stages, while 75% RDN + 25% Nano-N was comparable to 100% RDN through Urea. The number of tillers per plant was significantly affected by different nitrogen management practices at 30 days after sowing and after the I and II harvests, highest number of tillers per plant was observed through the application of 100% RDN through Urea. Overall, the results show that the use of Nano nitrogen can significantly improve the growth attributing characteristics as well as yield attributes and yield of oats, particularly when combined with traditional nitrogen sources. These findings are consistent with previous research in this area.
Growth and Flower Quality Influenced by Foliar Application of Potassium Nitrate and Sujala of Hybrid Tea Rose Cultivar Mohana
Authors: Atal Heera Lal , Srilakshmi Daripalli , Debbarma Kunal , Jena Lopamudra
Published: March 2023

An experiment was conducted from September 2019 to March 2020 to examine the effect of different combination of foliar applicable fertilizers on Hybrid tea rose cultivar Mohana. The study was performed with 9 treatments (T1-RDF, T2- KNO3 2.5g/l, T3- KNO3 5.0g/l, T4- Soluble fertilizer (Sujala) 1g/l, T5- Soluble fertilizer (Sujala) 2 g/l, T6- KNO3 1g/L+ Soluble fertilizer (Sujala) 1g/l, T7- KNO3 1 g/l + Soluble fertilizer (Sujala) 1.5g/l, T8- KNO3 1g/L + Soluble fertilizer (Sujala) 2g/l, T9- KNO3 1g/l+ Soluble fertilizer (Sujala) 2.5g/l) and 3 replications. From this study T8 (KNO3 1g/L + Soluble fertilizer (Sujala) 2g/l) gave best in case of vegetative and flower quality parameters and minimum days from FBE to cup shape and flower. While in case of cup shape to full bloom minimum days was taken in T1(RDF).
An Optimal Class of Fourth-order Iterative Methods without Restraint on the First Derivative
Authors: Khashoqji Malak M. , Al-Subaihi I. A.
Published: March 2023

In an attempt to create an iterative method that may converge even if the first derivative disappears during the recursive process. This paper sets out to develop a class of optimal fourth-order methods based on Wu's modified Newton scheme for solving nonlinear equations without constraints on the first derivative. Numerous numerical examples were given to demonstrate how effectively the proposed methods perform. In addition, the basins of attraction confirm the efficiency and performance of the suggested fourth-order method compared with some other fourth-order schemes.
Using Inpyrfluxam to Control Peanut (Arachis hypogaea L.) Foliar and Soil-Borne Diseases
Authors: Grichar W. James , Meador Chris B.
Published: March 2023

Aims: To determine peanut disease control and yield response to inpyrfluxam applied at various timings during the growing season.

Study Design: Randomized complete block design with 4 reps.

Place and Duration of Study: Field studies were conducted from 2016 through 2020 in the south Texas peanut growing region near Yoakum (29.276o N, 97.123o W).

Methodology: Fungicides were applied with a CO2-propellant sprayer. The spray boom was equipped with three D2-23 hollow-cone spray nozzles per row with the middle nozzle centered over each plant in the row and another nozzle located as such to spray on each side of the plant to provide thorough coverage with a spray volume was 187 L ha-1. Some studies included a non-treated control while other studies included chlorothalonil only at 1.26 kg ha-1 as the comparison treatment. Each plot consisted of four rows spaced 97 cm apart and 7.9 m long.

Results: Inpyrfluxam applied twice in a 4 to 5 fungicide spray program in combination with chlorothalonil provided early leaf spot control as good as or better than the standards of chlorothalonil plus either azoxystrobin alone or azoxystrobin plus benzovindiflupyr applied 2 times. Control of Rhizoctonia pod rot, caused by Rhizoctonia solani Kuhn, with inpyrfluxam at 0.04, 0.05. 0.075, or 0.1 kg ai ha-1 applied 2 times during the growing season was comparable to two applications of azoxystrobin at 0.22 kg ai ha-1. Control of southern blight, caused by Sclerotium rolfsii Sacc., with one to two applications of inpyrfluxam at 0.05 to 0.1 kg ha-1 was comparable to azoxystrobin plus benzovindiflupyr. Peanut yield response was influenced by the level of soilborne and foliar disease control exhibited with each fungicide program, as those programs which provided the best control also produced the highest yield.

Conclusion: These studies show the ability of inpyrfluxam to provide control of multiple diseases found in southwest peanut production.
Sequencing and the alignment of structural genes in the nqr operon encoding the Na+‐translocating NADH‐quinone reductase from Vibrio alginolyticus
Authors: Hayashi Maki , Hirai Kouji , Unemoto Tsutomu
Published: July 2002

We previously cloned a part of nqr operon encoding the Na+‐translocating NADH‐quinone reductase (NQR) from the marine Vibrio alginolyticus (Hayashi et al., FEBS Lett. 356 (1994) 330–332]. From its nucleotide sequences, four consecutive open reading frames (ORF) encoding the γ‐subunit (27.7 kDa), two unidentified ORFs of 22.6 kDa and 21.5 kDa, and the β‐subunit (45.3 kDa) were recognized. The gene encoding the α‐subunit was located upstream, and together with the recent report by Beattie et al. [FEBS Lett. 356 (1994) 333–338], the nqr operon was found to be constructed from six consecutive structural genes, where nqrl, nqr3 and nqr6 correspond to the α‐, γ‐, and β‐subunits, respectively, of the NQR complex.
Thermostable peroxidase activity with a recombinant antibody L chain‐porphyrin Fe(III) complex
Authors: Takagi Masahiro , Kohda Katsunori , Hamuro Takuya , Harada Akira , Yamaguchi Hiroyasu , Kamachi Mikiharu , Imanaka Tadayuki
Published: July 2002

In order to engineer a new type of catalytic antibody, we attempt to use a monoclonal antibody L chain as a host protein for a porphyrin. TCPP (meso‐tetrakis(4‐carboxyphenyl)porphyine) was chemically synthesized and Balb/c mice were immunized using TCPP as a hapten. Two hybridoma cells (03‐1, 13‐1), that produce monoclonal antibody against TCPP, were obtained. Genes for both H and L chains of monoclonal antibodies were cloned, sequenced and overexpressed using E. coli as a host. ELISA and fluorescence quenching method show that the independent antibody L chains from both Mab03‐1 and Mab13‐1 have specific interaction with TCPP. Furthermore, the recombinant antibody L chain from Mab13‐1 exhibits much higher peroxidase activity than TCPP Fe(III) alone. The enzyme activity was detectable with pyrogallol and ABTS (2,2‐azinobis‐3‐ethylbenzthiazolin‐6‐sulfonic acid) but not with catechol. This new catalytic antibody was extremely thermostable. Optimum temperature of the peroxidase reaction by the complex of 13‐1L chain and TCPP Fe(III) was 90°C, while that the TCPP Fe(III) alone was 60°C.
EVA mouthguards: how thick should they be?
Authors: Westerman Bill , Stringfellow Peter M. , Eccleston John A.
Published: July 2002

Abstract – A major consideration in the performance of mouthguards is their ability to absorb energy and reduce transmitted forces when impacted. This is especially important to participants in contact sports such as hockey or football. The thickness of mouthguard materials is directly related to energy absorption and inversely related to transmitted forces when impacted. However, wearer comfort is also an important factor in their use. Thicker mouthguards are not user‐friendly. While thickness of material over incisal edges and cusps of teeth is critical, just how thick should a mouthguard be and especially in these two areas? Transmitted forces through different thicknesses of the most commonly used mouthguard material, ethylene vinyl acetate (EVA) (Shore A Hardness of 80) were compared when impacted with identical forces which were capable of damaging the oro‐facial complex. The constant impact force used in the tests was produced by a pendulum and had an energy of 4.4 joules and a velocity of 3 meters per second. Improvements in energy absorption and reductions in transmitted forces were observed with increasing thickness. However, these improvements lessened when the mouthguard material thickness was greater than 4 mm. The results show that the optimal thickness for EVA mouthguard material with a Shore A Hardness of 80 is around 4 mm. Increased thickness, while improving performance marginally, results in less wearer comfort and acceptance.
Increased bone marrow vascularization in patients with acute myeloid leukaemia: a possible role for vascular endothelial growth factor
Authors: De Bont Eveline S. J. M. , Rosati Stefano , Jacobs Susan , Kamps Willem A. , Vellenga Edo
Published: July 2002

The present study demonstrated that the vessel number in bone marrow biopsies from acute myeloid leukaemia (AML) patients (n = 23) was significantly increased at diagnosis compared with normal bone marrow (P = 0·019) and was restored to normal levels after achieving complete remission (P = 0·03). The in vitro angiogenic potential of culture supernatant of AML cells was assessed using endothelial cell (EC) migration and proliferation assays. Increased EC migration and EC proliferation was induced in 7/20 and 19/20 AML supernatents respectively. The degree of in vivo neovascularization did not correlate with the ability of AML cells to stimulate in vitro endothelial cell migration and/or proliferation. This might be in part a result of the heterogeneous pattern of angiogenic factors produced by AML cells. The expression of different angiogenic factors was studied using reverse transcription polymerase chain reaction. Cells from 17/20 AML patients showed wide variation in spontaneous vascular endothelial growth factor (VEGF) expression, 4/19 expressed varied spontaneous blastic fibroblast growth factor mRNA levels and all patient samples showed spontaneous interleukin 8 mRNA expression. All AML samples expressed matrix metalloproteinase (MMP)‐2 and/or MMP‐9. VEGF mRNA expression correlated well with protein level (P = 0·006). A correlation was found between the degree of VEGF expression and neoangiogenesis (correlation coefficient = 0·448, P = 0·05). These results suggest that malignant cell proliferation, angiogenesis and VEGF expression are linked in AML and might contribute to the growth advantage of the malignant counterpart as a result of the paracrine production of growth factors produced by the surrounding endothelial cells.
A comparative study of root canal preparation with HERO 642 and Quantec SC rotary Ni–Ti instruments
Authors: Hülsmann M. , Schade M. , Schäfers F.
Published: July 2002

Aim

The purpose of this study was to compare several parameters of root canal preparation using two different rotary nickel–titanium instruments: HERO 642 (Micro‐Mega, Besancon, France) and Quantec SC (Tycom, Irvine, CA, USA).

Methodology

Fifty extracted mandibular molars with root canal curvatures between 20° and 40° were imbedded into a muffle system. All root canals were prepared to size 45 (Quantec SC), or 40 (HERO 642), respectively. The following parameters were evaluated: straightening of curved root canals, postoperative root canal diameter, safety issues (file fractures, perforations, apical blockages, loss of working length), cleaning ability, and working time.

Results

Both Ni–Ti‐systems maintained curvature well; the mean degree of straightening was 2.3° for Quantec SC and 1.6° for HERO 642. Most procedural incidents occurred with Quantec SC instruments (five fractures, three apical blockages, eight cases of loss of working length), HERO 642 preparation resulted in three blockages and one perforation. Following preparation with HERO 642, 63% of the root canals showed a round, 24% an oval, and 17% an irregular diameter; Quantec SC preparations resulted in a round diameter in 24% of the cases, oval shape in 29%, and irregular cross‐section in 47% of the cases. Mean working time was shorter for HERO 642 (52 s) than for Quantec (117 s). Cleanliness of the root canal walls was investigated under the SEM using a five‐score system for debris and smear layer. For debris HERO 642 achieved better results (80% scores 1 and 2) than Quantec SC (76%). The results for smear layer were similar: cleaner root canal walls were found after preparation with HERO 642 (53% scores 1 and 2), followed by Quantec SC (41%).

Conclusions

Both systems respected original root canal curvature well and showed good cleaning ability; Quantec SC showed deficiencies in terms of safety.
Mini Nutritional Assessment in elderly subjects receiving home nursing care
Authors: Saletti A. , Johansson L. , Cederholm T.
Published: July 2002

Background: Old age and disease are risk factors for malnutrition. We assessed the nutritional status in elderly receiving home nursing care.

Methods: Eighty people (86% women) over the ages of 70 years (mean±SD 84±6) were investigated. One‐third had lung and/or cardiovascular disease, 10% had diabetes mellitus and the remainder had miscellaneous disorders. The Mini Nutritional Assessment (MNA) scale (0–30 points), consisting of 18 point‐weighted questions, including anthropometry, e.g. body mass index (BMI, kg m−2), was used.

Results: Fifty patients (62%) were assessed as having suspected malnutrition (MNA 17–23.5 points), while two were assessed as being malnourished (MNA < 17 points). The mean BMI was 22.7±5. One third of the subjects had BMI values <20 and 64% had BMI ≤ 23. Patients with cardiac failure and/or lung disease had the lowest MNA values (20.9±3.3 points) and 85% of these patients were assessed as being at risk for malnourishment. More than half drank ≤1 L of fluid per day. Over half of those who were malnourished or were suspected to be malnourished did not have meal support, whereas almost half of the well‐nourished patients had meal support.

Conclusion: Two‐thirds of the patients receiving home nursing care were assessed as having suspected or confirmed malnutrition, or were underweight. Nutritional routines may need more focus within home nursing care services.
Current treatment and outcome in orbital cellulitis
Authors: Mbbs M P Ferguson , Fraco A A McNab
Published: July 2002

Background: Bacterial orbital cellulitis is an uncommon condition previously associated with severe complications. The purpose of this paper is to describe current investigations and treatment in orbital cellulitis, establish their effectiveness and to describe the incidence of complications and surgical intervention.

Methods: A chart review of all patients admitted to the Royal Victorian Eye and Ear Hospital and the Royal Children’s Hospital, Melbourne with a diagnosis of orbital cellulitis for the period July 1993 to July 1997.

Results: A total of 52 patients fulfilling the diagnostic criteria for orbital cellulitis were identified. Paranasal sinus disease was the commonest predisposing cause, especially in the paediatric age group. Diagnosis was made clinically with radiological confirmation in all cases. Microbiological investigation and results varied. The commonest species isolated were Staphylococci and Streptococci. Three cases of mixed anaerobes and one of Clostridium were seen. Cultures from abscess cavities and infected sinuses gave the highest positive yield (50–100%). Blood cultures were taken in 26% of adults and in 56% of children; none was positive. Treatment was either by intravenous broad‐spectrum antibiotics alone or with surgery to drain orbital abscesses, usually in conjunction with sinus surgery. No patient suffered permanent visual impairment other than one case of enucleation for endophthalmitis that had caused orbital cellulitis. There was one case of permanent ocular motility impairment, and one of meningitis.

Conclusions: Despite its past history of severe morbidity and even mortality, adequately treated orbital cellulitis rarely has significant morbidity today. Paranasal sinus disease remains the commonest cause. Culture of infected paranasal sinuses or pus from abscesses is most likely to yield significantly positive results in this study. Blood cultures were not helpful.
Alcohol consumption, Type 2 diabetes mellitus and impaired glucose tolerance in middle‐aged Swedish men
Authors: Carlsson S. , Hammar N. , Efendic S. , Persson P. ‐G. , Östenson C. ‐G. , Grill V.
Published: July 2002

SUMMARY

Aims  To investigate the association between alcohol consumption and impaired glucose tolerance and Type 2 diabetes mellitus.

Methods  A population‐based cross‐sectional study consisting of 3128 Swedish men, aged 35–56 years. Oral glucose tolerance testing identified 55 cases of Type 2 diabetes and 172 cases of impaired glucose tolerance. Information on alcohol consumption, family history of diabetes, smoking and physical activity was obtained by questionnaire.

Results  After adjustment for family history, smoking, physical activity and body mass index, the odds ratio of diabetes was 2.1 (95% confidence interval (CI) 1.0–4.5) in men with high consumption of alcohol (corresponding to over 12 drinks per week) and 0.7 (0.3–1.8) in moderate consumers (7–12 drinks), compared to occasional drinkers. For impaired glucose tolerance, the corresponding odds ratios were 0.7 (0.5–1.1) and 0.6 (0.4–1.0), respectively. Separate analyses for type of beverage indicated that high consumers of beer, spirits and wine had an odds ratio for diabetes of 2.9 (1.2–6.9), 3.3 (1.4–7.8) and 1.2 (0.5–2.7), respectively.

Conclusions  The results indicated that high consumption of alcohol increases the occurrence of Type 2 diabetes and that this may primarily concern consumption of beer and spirits. For impaired glucose tolerance, regular alcohol consumption was associated with a reduced prevalence, particularly at moderate levels.
Sonography of pregnancies with first‐trimester bleeding and a viable embryo: a study of prognostic indicators by logistic regression analysis
Authors: Falco P. , Milano V. , Pilu G. , David C. , Grisolia G. , Rizzo N. , Bovicelli L.
Published: July 2002

The objective of our study was to investigate the relationship between sonographic findings and the occurrence of abortion in pregnancies complicated by first‐trimester bleeding in which fetal cardiac activity was documented upon admission.

A prospective study of transvaginal sonography was performed in 270 pregnant patients with bleeding between 5 and 12 weeks' gestation. The study group included 149 cases in which a singleton fetus with cardiac activity was initially documented. The outcome variable was pregnancy loss prior to 20 weeks. The influence of sonographic findings on admission was studied by univariate analysis and logistic regression.

The prevalence of abortion was 23/149 (15%). A significant relationship (p < 0.05) was found between the occurrence of abortion and the following: fetal bradycardia (heart rate less than −1.2 SD from the mean), a discrepancy between the diameter of the gestational sac and crown‐rump length less than −0.5 SD from the mean, and a discrepancy between menstrual and sonographic age of more than 1 week. According to the logistic regression equation that was obtained, the probability of abortion in first‐trimester bleeding with documented fetal cardiac activity upon admission varied between a minimum of 6% when none of the above risk factors were present and a maximum of 84% when all were present. The presence of any of the above factors identified 84% of all subsequent abortions. Copyright © 1996 International Society of Ultrasound in Obstetrics and Gynecology
Patterns in cataract referral: room for improvement?
Authors: Latham Keziah , Misson Gary
Published: July 2002

Purpose: Optometrists are expected to refer patients with any abnormality of the eye excluding normal changes due to age to their general practitioner. It can be difficult to decide when a cataract ceases to be a normal age‐related change and becomes an ocular abnormality. This study examines the criteria adopted by optometrists and GPs for referring patients with cataract and compares this to the referral criteria suggested by ophthalmologists.

Method: Questionnaires were sent to all optometrists and GPs registered with Birmingham Health Authority and ophthalmologists in the West Midlands area. Questions covered methods of subjective and objective assessment of lens opacities, subjective referral criteria, and views on communications between the three professions.

Results: For all professions, the main factors influencing referral are visual acuity, subjective visual impairment and the need to drive. Optometrists and GPs generally refer patients with cataract at a VA level of 6/18–6/24, whilst ophthalmologists would be willing to see patients with cataract at a VA of 6/9–6/12. However, most ophthalmologists report that sometimes patients are referred too soon, regardless of their acuity level, because the patient is not yet impaired by their level of vision or does not want surgery.

Conclusion: Suggestions for improvements in the referral of cataract will be discussed. It is important for optometrists to make clear whether a letter to a GP is for information only or referral. If referral is warranted the following information, in addition to acuity, will assist an ophthalmologist in prioritizing appointments: age, occupation, brief description of disability and the need to drive legally.
Stromules: Mobile Protrusions and Interconnections Between Plastids
Authors: Gray J. C. , Sullivan J. A. , Hibberd J. M. , Hansen M. R.
Published: July 2002

Abstract: Stroma‐filled tubules, recently named stromules, extend from the surface of plastids in most cell types and plant species examined. Stromules are highly dynamic structures, continuously and rapidly changing shape. They have been shown to interconnect plastids and permit the exchange of green fluorescent protein (GFP) between plastids. Stromules are enclosed by the inner and outer plastid envelope membranes and are 0.4 ‐ 0.8 μm in diameter and up to 65 μm long. Movement of stromules is dependent on the actin cytoskeleton and the ATPase activity of myosin. Stromules are more abundant in cells containing a relatively small plastid volume and provide a means of enormously increasing the plastid surface area. Many important questions on the structure, function and mobility of stromules remain unanswered.
Zn diffusion enhancement of interdiffusion in a GaAs-InGaPAs heterostructure
Authors: Park H.-H. , Lee K. H. , Stevenson D. A.
Published: July 2002

The influence of concurrent Zn diffusion on the interdiffusion in an In0.06Ga0.94P0.05As0.95-GaAs heterostructure grown by liquid phase epitaxy was investigated. A 25 h, 700 °C diffusion anneal was performed using an equilibrium ternary diffusion source and profiles of In and P were measured with secondary-ion mass spectrometry. The Zn diffusion selectively enhances the cation (In-Ga) interdiffusion; with concurrent Zn diffusion, the interdiffusion coefficient for the In-Ga components is ≊5×10−14 cm2/s, as compared to ≊6×10−16 cm2/s for anions (As-P). A kick-out mechanism is proposed to explain the results.
Effects of temperature and electrical stress on the performance of thin-film transistors fabricated from undoped low-pressure chemical vapor deposited polycrystalline silicon
Authors: Dimitriadis C. A. , Coxon P. A.
Published: July 2002

The stability of thin-film transistors (TFTs) fabricated from undoped low-pressure chemical vapor deposited polycrystalline silicon under stress conditions (dc voltage and temperature) is investigated. It is demonstrated that the Si-SiO2 interface morphology is critical for the TFT device performance. Device degradation and threshold voltage instabilities are mainly attributed to the roughened Si-SiO2 interface.
Influence of hydroxyls on the adhesion of Au films to GaAs
Authors: Bardin T. T. , Pronko J. G. , Kozak D. A.
Published: July 2002

The adhesion of Au metallization to GaAs substrates was studied as a function of the time to which freshly cleaved GaAs surfaces were exposed to de-ionized water or pure dry oxygen. It was found that the adhesion strength of Au metallization deposited on these surfaces is weakened from exposure to de-ionized water and the degradation is directly related to the length of the exposure. Exposure of the substrate surfaces to pure dry oxygen had no effect on the adhesion. The substrate surfaces were characterized as a function of exposure to these two environments and it was found that the Ga and As combine with the hydroxyl groups in the de-ionized water to form hydroxides and the As hydroxide dissolves leaving the surface As deficient. The extent of this reaction is dependent on the length of time the surface is exposed to the hydroxyl groups. Exposure of the substrate surface to pure dry oxygen results in a thin stable oxide layer.
Improved fiber-optic interferometer for atomic force microscopy
Authors: Rugar D. , Mamin H. J. , Guethner P.
Published: July 2002

A high-sensitivity fiber-optic displacement sensor for atomic force microscopy is described. The sensor is based on the optical interference occurring in the micron-sized cavity formed between the cleaved end of a single-mode optical fiber and the microscope cantilever. As a result of using a diode laser light source and all-fiber construction, the sensor is compact, mechanically robust, and exhibits good low-frequency noise behavior. Peak-to-peak noise in a dc to 1 kHz bandwidth is less than 0.1 Å. Images are presented demonstrating atomic resolution of graphite and magnetic force imaging of bits written on a magnetic disk.
Oscillations up to 420 GHz in GaAs/AlAs resonant tunneling diodes
Authors: Brown E. R. , Sollner T. C. L. G. , Parker C. D. , Goodhue W. D. , Chen C. L.
Published: July 2002

We report room-temperature oscillations up to frequencies of 420 GHz in a GaAs resonant tunneling diode containing two 1.1-nm-thick AlAs barriers. These results are consistent with a recently proposed equivalent circuit model for these diodes in which an inductance accounts for the temporal delay associated with the quasibound-state lifetime. They are also in accordance with a generalized impedance model, described here, that includes the effect of the transit time delay across the depletion layer. Although the peak-to-valley ratio of the 420 GHz diode is only 1.5:1 at room temperature, we show that its speed is limited by the parasitic series resistance rather than by the low negative conductance. A threefold reduction in this resistance, along with a comparable increase in the peak-to-valley ratio, should allow oscillations up to about 1 THz.
Synchrotron radiation assisted deposition of carbon films
Authors: Ohashi Haruhiko , Inoue Katsushi , Saito Yoji , Yoshida Akira , Ogawa Hiroshi , Shobatake Kosuke
Published: July 2002

Photochemical vapor deposition of carbon films from n-butane gas has been successfully done, for the first time, at room temperature using synchrotron radiation as a light source. The deposited films are hydrogenated amorphous carbon films with sp3 bonds. The deposition rate increases with negative bias.
Anomalous field dependence of magnetoresistance in Fe/Gd multilayered ferrimagnets
Authors: Kamiguchi Y. , Hayakawa Y. , Fujimori H.
Published: July 2002

The magnetoresistance of Fe/Gd ferrimagnetic multilayered films prepared by sputtering was investigated. The longitudinal magnetoresistance ρl increases first, followed by a deep decrease, and then increases again, with an increasing applied field. The transverse magnetoresistance ρt behaves in an opposite manner such that ρl and ρt play a crossover at an intermediate field. This new type of field dependence of ρl and ρt can be explained in terms of the spin flop of artificial ferrimagnetism which gives rise to an anomalous up-turn curve in magnetization versus field.
Direct observation of the silicon nitride on amorphous silicon interface states
Authors: Gelatos A. V. , Kanicki J.
Published: July 2002

We report on the investigation of the silicon nitride/hydrogenated amorphous silicon interface by capacitance measurements. We observe that the ‘‘slow’’ interface states are located inside the silicon nitride layer, while the energy distribution of the ‘‘fast’’ interface states is peaked at 0.7 eV below the hydrogenated amorphous silicon conduction band with an integrated value of 2×1011 cm−2.
Effect of cathode spacer layer on the current-voltage characteristics of resonant tunneling diodes
Authors: Mounaix P. , Vanbesien O. , Lippens D.
Published: July 2002

The effect of a lightly doped cathode spacer layer on resonant tunneling of Al0.3Ga0.7As-GaAs double-barrier heterostructures is examined. A self-consistent band-bending calculation combined with a quantum calculation of current-voltage characteristics is used to model the experimentally observed I-V curves. It is found that the I-V characteristics show additional structures, sensitively dependent upon temperature. These effects result from the formation of a wide barrier by space-charge reaction in the spacer layer leading to two possible resonant states. The validity of the theoretical approach is supported by the good agreement with experimental results.
Amplified spontaneous emission in Tm3+-doped monomode optical fibers in the visible region
Authors: Gomes A. S. L. , de Araujo Cid B. , Ainslie B. J. , Craig-Ryan S. P.
Published: July 2002

We report the observation of amplified spontaneous emission in silica-based single-mode optical fibers doped with Tm3+. Frequency upconverted emission was observed in a number of visible and near-infrared lines after pumping by 1064 nm radiation. The upconversion process is induced via the nonlinear absorption of the infrared beam and enhanced by stimulated Raman scattering in the fiber, leading to amplified spontaneous emission in the blue (∼473 nm) region.
Enhanced impurity diffusion resulting from rapid thermal nitridation of thin SiO2
Authors: Bustillo James , Chang Chi , Haddad Sameer , Wang Arthur
Published: July 2002

The materials-related effects due to rapid thermal nitridation and reoxidation of thermally grown SiO2 were studied in the underlying silicon. Depth profiles using spreading resistance, auger electron spectroscopy, and secondary-ion mass spectroscopy are presented to show that enhanced dopant diffusion and surface depletion result from rapid thermal process treatments. Silicon interstitial injection from the nitrogen supersaturated oxynitride interface facilitates the diffusion of boron, phosphorus, and arsenic atoms in the silicon substrate. An appreciable amount of nitrogen was found below the silicon surface, suggesting that nitrogen interstitials may play an important role in the observed enhanced impurity diffusion.
20 GHz electro-optic polymer Mach–Zehnder modulator
Authors: Girton D. G. , Kwiatkowski S. L. , Lipscomb G. F. , Lytel R. S.
Published: July 2002

An electro-optic (EO) polymer-based integrated optic Mach–Zehnder modulator with a measured frequency response up to 20 GHz is reported. The device was fabricated with an EO polymer supplied by Akzo Research, bv, and utilized 50 Ω microstrip drive electrodes. A half-wave voltage of Vπ=9 V and a modulation depth of 90% were measured at 2 kHz. Modulation was observed out to 8.0 GHz using direct detection and out to 20 GHz using a frequency mixing technique, limited by the drive and receiver electronics.
Infrared radiation generated by quasi-phase-matched difference-frequency mixing in a periodically poled lithium niobate waveguide
Authors: Lim E. J. , Hertz H. M. , Bortz M. L. , Fejer M. M.
Published: July 2002

We report quasi-phase-matched difference-frequency generation of 2.1 μm radiation at room temperature using the d33 nonlinear coefficient in a periodically poled lithium niobate channel waveguide. A tunable Ti:Al2O3 laser (λ≊0.8 μm) and a Nd:YAG laser (λ=1.32 μm) were the pump and signal sources, respectively. With 160 mW of 0.81 μm and 1 mW of 1.32 μm radiation coupled into the waveguide, 1.8 μW of 2.1 μm radiation was generated, tunable over a 6 nm bandwidth. We also show that the annealed proton exchange process can change the shape of ferroelectric domains in lithium niobate.
Electronic structure of light-emitting porous Si
Authors: Vasquez R. P. , Fathauer R. W. , George T. , Ksendzov A. , Lin T. L.
Published: July 2002

Characterization of light-emitting porous Si films with x-ray photoelectron spectroscopy is reported. Only traces of O are detected on HF-etched samples, in contradiction to an earlier report that oxides are a significant component of porous Si. Si 2p and valence-band measurements demonstrate that the near-surface region of high porosity films which exhibit visible luminescence consists of amorphous Si.
De-mixing of Nd2Fe14B during mechanical milling
Authors: Alonso T. , Yang H. , Liu Y. , McCormick P. G.
Published: July 2002

The effect of mechanical milling on the structure of the Nd2Fe14B intermetallic has been investigated using x-ray diffraction and electron microscopy. The milling resulted in the decomposition of Nd2Fe14B into α-Fe and an amorphous phase. Attempts to mechanically alloy Fe and Nd powders resulted in a nanocrystalline mixture of the same two phases.
Cholesteric liquid crystal/polymer dispersion for haze-free light shutters
Authors: Yang D.-K. , Chien L.-C. , Doane J. W.
Published: July 2002

A new dispersion involving a polymer in low concentration with a cholesteric liquid crystal is reported. Two types of light modulators from these materials are described as a normal mode shutter which is opaque (light scattering) in the field-OFF state and transparent in the field-ON state and a reverse-mode shutter with the opposite field conditions. The transparent state of both cells is haze-free for all viewing angles making the material attractive for window applications and direct view displays.
In situ real-time determination of the free-carrier density in doped ZnSe films during molecular beam epitaxial growth
Authors: Rouleau C. M. , Park R. M.
Published: July 2002

The characteristic blue/green cathodoluminescence (CL) emission observed while analyzing doped ZnSe films using the reflection high energy electron diffraction technique during molecular beam epitaxial growth has been detected ex vacuo and its intensity has been quantified. By employing a CdS-based photoresistor mounted outside the vacuum system it has been determined for the examined case of Cl doped n-type ZnSe/GaAs films that the CL intensity varies linearly as a function of free-carrier density in the films. Specifically, log(CL intensity) was found to be proportional to log(free-electron density) over the room-temperature free-electron density range, 1017–5×1018 cm−3. This work demonstrates that the free-carrier density in doped ZnSe films grown by molecular beam epitaxy can be monitored in real time during growth which should significantly enhance process control.
Cathodoluminescence investigation of impurities and defects in single crystal diamond grown by the combustion-flame method
Authors: Graham R. J. , Ravi K. V.
Published: July 2002

Cathodoluminescence (CL) in a transmission electron microscope has been used to investigate impurities and defects in single crystals in diamond films grown by the combustion-flame method and correlate them with the microstructure. Nitrogen was present in a number of different impurity defect forms; band A emission was correlated with dislocations while the defect giving rise to the 575 nm vibronic band was the only defect observed in fault-free crystal. Several other nitrogen-related defects were also observed to a lesser extent. The spatial distribution of these defects varied greatly and residual stresses in the 0.7–1.8 GPa range were estimated. In one single crystal, the relative intensities of the bands in the CL spectra acquired at various locations suggest that dislocation density, though variable, is highest at the nucleation end.
Metalorganic deposition of high critical current thin films in the Bi-Sr-Ca-Cu-O system on {100} LaAlO3 substrates
Authors: Golden S. J. , Lange F. F. , Clarke D. R. , Chang L. D. , Necker C. T.
Published: July 2002

Superconducting thin films of the two Cu-layer phase in the Pb-doped Bi-Sr-Ca-Cu-O system have been fabricated on {100} LaAlO3 single crystals by the metalorganic deposition from ethyl hexanoate precursors. Thin films given heat treatments in air at 850–860 °C had resistive transitions with a Tc of 86–89 K. The zero-field transport critical current densities were in the range of 2–4×105 A/cm−2 at 77 K and 106 A cm−2 at 45 K in 200–300-nm-thick films. In contrast to c-axis oriented films grown on {100} MgO, x-ray pole figures show that the films grown on {100} LaAlO3 are epitaxial, a result confirmed by electron channeling patterns.
Increased optical damage resistance in Sc2O3-doped LiNbO3
Authors: Yamamoto Joyce K. , Kitamura Kenji , Iyi Nobuo , Kimura Shigeyuki , Furukawa Yasunori , Sato Masayoshi
Published: July 2002

The optical damage of 1 mol % Sc2O3-doped LiNbO3 was approximately two times smaller than an optical grade LiNbO3 measured as a function of Ar+ (λ=488 nm) irradiation time. Severe Ar+ beam distortion observed in the undoped LiNbO3 was not present in the Sc2O3-doped LiNbO3. There was negligible shift in the OH− absorption band but a 10 nm blue shift was observed in the absorption edge, indicating that Sc3+ and Mg2+ incorporation may proceed by a different mechanism. This is the first of reported results, to the authors’ knowledge, of a trivalent dopant increasing the damage resistance level in LiNbO3.
Direct evidence for substitutional Li after ion-implantation into highly phosphorus-doped Si
Authors: Wahl U. , Hofsäss H. , Jahn S. G. , Winter S. , Recknagel E.
Published: July 2002

Radioactive 8Li (t1/2=0.8 s) was ion implanted into single-crystalline n-Si of low resistivity (9×1019 P cm−3) at temperatures between 50 and 670 K. Channeling measurements of the alpha-particles emitted during the decay of 8Li gave direct evidence that 35% of the implanted Li occupied substitutional sites between 350 and 670 K. Below room temperature the major fraction of Li was found to be on tetrahedral sites. The increase in the substitutional fraction around room temperature is attributed to diffusion of Li and capture by vacancy-related defects.
ZnO/CdS/CuInSe2 thin-film solar cells with improved performance
Authors: Stolt Lars , Hedström Jonas , Kessler John , Ruckh Martin , Velthaus Karl-Otto , Schock Hans-Werner
Published: July 2002

An important milestone in the development of photovoltaic thin-film solar cells is the achievement of 15% conversion efficiency. This letter describes the highest efficiency single junction thin-film cell reported to date. An active area efficiency of 14.8% is obtained with the cell structure n-ZnO/n-CdS/p-CuInSe2 deposited on a soda-lime glass substrate. The current achievements are due to improved properties of the CuInSe2 layer and the heterojunctions compared to previously reported results. The rate and substrate temperature profiles used during the coevaporation process yield a relatively large-grained material with very strong 〈112〉 orientation and low porosity. This results in reduced recombination rates, hence higher open circuit voltage and fill factor.
Photon-assisted avalanche spreading in reach-through photodiodes
Authors: Lacaita A. , Cova S. , Spinelli A. , Zappa F.
Published: July 2002

We have investigated the spreading of the avalanche process over the area of reach-through avalanche photodiodes operated in Geiger mode. A comparison between the measurements and the results of a computer simulation suggests that photons emitted from hot carrier relaxations play the dominant role in the avalanche dynamics. It is the randomness of the photon-assisted process which impairs the performance of these detectors in timing measurements.
Voltage-tunable dual-mode operation InAlAs/InGaAs quantum well Infrared photodetector for narrow- and broadband detection at 10 μm
Authors: Wang Y. H. , Li Sheng S. , Ho Pin
Published: July 2002

A new photoconductive (PC) and photovoltaic (PV) dual-mode operation quantum well infrared photodetector using a lattice-matched n-type In0.52Al0.48As/In0.53Ga0.47As system has been developed for both the narrow-band (Δλ/λp=7%) and broadband (Δλ/λp=24%) detection with a peak spectral response around λp=10 μm. The detection scheme utilizes a voltage-tuned bound-to-miniband transition from the ground state in the In0.53Ga0.47As(110 Å) quantum well to the global miniband states in the InAlAs/InGaAs superlattice barrier layers. The detectivity D*λ for the PV mode operation was found to be 5.7×109 cm √Hz/W at λp=10 μm and T=67 K, while D*λ for the PC mode operation was found to be 5.8×109 √Hz/W at Vb =0.5 V, λp=10.3 μm, and T=67 K.
Quantum well infrared photodetection induced by interband pumping
Authors: Berger V. , Rosencher E. , Vodjdani N. , Costard E.
Published: July 2002

We present a new type of quantum well infrared photodetector. The structure is not doped and the electrons necessary for the photodetection are optically injected by interband absorption. The functioning of the photodetector is then completely controlled by the near-infrared pump beam. We have used coupled quantum wells in order to increase the lifetime of the carriers and hence increase the photoinduced electron density. The behavior of the device versus infrared wavelength, pump wavelength, and applied bias is studied.
New liquid crystal display with bistability and selective erasure using scattering in filled nematics
Authors: Kreuzer M. , Tschudi T. , de Jeu W. H. , Eidenschink R.
Published: July 2002

We present a new bistable scattering effect in a filled nematic liquid crystal, and its application to a high resolution laser-addressed display. The filled nematic consists of a small fraction of inorganic particles of nm size in a nematic liquid crystal with positive dielectric anisotropy. The scattering ON state is reached by locally writing with a laser. The transparent OFF state can be obtained by combining a moderate voltage with selective application of the laser to the part to be erased. The key parameters controlling the processes and the possible physical mechanisms involved are discussed.
Experimental studies of ionization processes in the breakdown phase of a transient hollow cathode discharge
Authors: Choi P. , Aliaga R. , Blottiere B. , Favre M. , Moreno J. , Chuaqui H. , Wyndham E.
Published: July 2002

The ionization process in the prebreakdown phase of a transient hollow cathode discharge (THCD) is investigated. The discharge is operated in H2 and N2 at pressures between 30 and 750 mTorr with applied voltages up to 30 kV. A capacitive probe array is used to measure the spatial and temporal evolution of plasma formation in the interelectrode spacing. The results obtained are consistent with the formation of a moving virtual anode. The growth and evolution of the virtual anode are closely linked to the formation of electron beams emitted from the hollow cathode region before and at the time of electric breakdown.
Integrated nanofabrication with the scanning electron microscope and scanning tunneling microscope
Authors: Rosolen G. C. , Hoole A. C. F. , Welland M. E. , Broers A. N.
Published: July 2002

The combination of electron beam lithography using the scanning electron microscope (SEM) and direct nanofabrication with the scanning tunneling microscope (STM) has been used to fabricate a nanometer size link between two prefabricated nanometer size wires. The wires were fabricated by electron beam lithography using a high resolution SEM. This sample was then transferred to a combined SEM and STM instrument which is used to locate the wires, position them beneath the STM tip, and fabricate the link using the technique of tip bias pulsing with the STM.
Efficient laser performance of Nd3+:Sr5(PO 4)3F at 1.059 and 1.328 μm
Authors: Zhang X. X. , Hong P. , Loutts G. B. , Lefaucheur J. , Bass M. , Chai B. H. T.
Published: July 2002

High efficiency, low threshold laser performance of Nd3+ doped Sr5(PO4)3F, or S-FAP, crystals has been demonstrated. Its performance and properties compared with commercially available Nd:YVO4 indicate that Nd:S-FAP is an outstanding medium for diode pumped laser applications at both 1.059 and 1.328 μm.
High dielectric constant (Ba,Sr)TiO3 thin films prepared on RuO2/sapphire
Authors: Takemura Koichi , Sakuma Toshiyuki , Miyasaka Yoichi
Published: July 2002

RuO2 thin films have been prepared onto sapphire by reactive sputtering with Ar+O2 plasma and their application as the bottom electrode in the high dielectric constant (Ba0.5Sr0.5)TiO3 (BST) thin film capacitor has been studied. RuO2 films with rutile structure are obtained with O2 content greater than 0.7. The dielectric constants of the sputtered (Ba0.5Sr0.5)TiO3 films on the RuO2 films are 250 for 49-nm-thick film and 460 for 130-nm-thick film. These values are comparable with those on Pt and Pd, which are commonly used as the bottom electrodes. No remarkable interdiffusion at the BST/RuO2 interface region and no hillocks at the RuO2 surface were observed, even after BST film deposition at 620 °C. RuO2 is one of the promising materials for use as the bottom electrode for the (Ba0.5Sr0.5)TiO3 thin film capacitor.
Reduction of secondary defects in BF2 implanted Si(100) by ion beam defect engineering
Authors: Zhao Qing-tai , Wang Zhong-lie , Xu Tian-bing , Zhu Pei-ran , Zhou Jun-si
Published: July 2002

Reduction of secondary defects in 50 keV, 2×1015 BF2/cm2 implanted Si(100) has been studied by Rutherford backscattering and channeling technique. Secondary defects with high densities have been found in BF2 implanted Si(100) after thermal annealing and rapid thermal annealing. However, a noticeable reduction of secondary defects in BF2 damaged region was observed when a buried amorphous layer was formed by an additional irradiation of 1.0 MeV Si+ ions prior to annealing (i.e., ion beam defect engineering process).
Mechanisms of epitaxial CoSi2 formation in the multilayer Co/Ti-Si(100) system
Authors: Hong Feng , Rozgonyi George A. , Patnaik Bijoy K.
Published: July 2002

We describe how the unique growth environment provided by a multilayer Co/Ti(O)-Si structure leads to the formation of epitaxial CoSi2/Si(100). A key factor is the preferential nucleation of (311) CoSi which is the dominant phase from 650 to 800 °C in this multilayer system. Epitaxial CoSi2 then nucleates at the (311) CoSi/(100) Si interface and grows during a 900 °C second annealing. Having Ti as the first layer in contact with the Si substrate reduces the native Si oxide and residual impurities. The amorphous Ti(O) provides a uniform supply of slowly diffusing Co that promotes preferential CoSi formation. The upper Co and Ti layers serve to stabilize the reaction and suppress agglomeration.