bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron trapping kinetics at dislocations in relaxed Ge0.3Si0.7/Si heterostructures
Authors: Grillot P. N. , Ringel S. A. , Fitzgerald E. A. , Watson G. P. , Xie Y. H. 
Published: July 2002

The capture kinetics and trapping properties of a dislocation related electron trap detected in strain-relaxed, compositionally graded Ge0.3Si0.7/Si grown by rapid thermal chemical-vapor deposition are investigated by deep-level transient spectroscopy (DLTS). The volume DLTS trap concentration scales linearly with the areal threading dislocation density, as determined by electron-beam-induced current measurements on samples with different compositional grading rates, indicating that the detected trap is most likely associated with dislocation core states in these graded structures. The dislocation related trap exhibits both the logarithmic dependence of DLTS peak height on fill pulse time tp, and broadened DLTS peaks which typically characterize carrier trapping at dislocations. These effects are quantified and analyzed to gain insight into the trapping properties of dislocations in GeSi/Si heterostructures and to investigate the effects of dislocation related carrier trapping on DLTS measurements. It is demonstrated that the peak broadening, as characterized by the dimensionless broadening parameter FWHM/Tp, where FWHM and Tp are the full width at half-maximum of the DLTS peak and the DLTS peak temperature, respectively, monotonically decreases with decreasing fill pulse duration, and approaches point-defectlike behavior for tp&lt;100 μs.
The observed broadening is asymmetric about Tp, and occurs predominantly on the low-temperature side of the DLTS peak. This asymmetric broadening is shown to shift the ‘‘apparent’’ trap activation energy, as determined by Arrhenius analysis, from EC−0.6 eV to EC−0.9 eV (relative to the bulk conduction-band edge) as tp decreases from 5 ms to 50 μs. These observations are explained by the presence of a dislocation related distribution of energy levels within the GeSi band gap and the consequent fill-pulse-dependent local band bending. The lowest-energy states within this distribution are preferentially filled with electrons for short fill pulse times. The Arrhenius-determined ‘‘apparent’’ activation energy is hence interpreted as being a measure of the average energy of the filled defect states, weighted by the density of states distribution in this energy band and by the related fill-pulse-dependent local band bending. It is further demonstrated that the minority-carrier capture cross section may be enhanced by the presence of an attractive coulombic barrier for minority carriers at the dislocations, and we use the logarithmic capture equations to derive a value of 4×10−12 cm2 for this ‘‘effective’’ capture cross section.
Collisional energy transfer in highly excited molecules: Calculations of the dependence on temperature and internal, rotational, and translational energy
Authors: Clarke David L. , Oref I. , Gilbert Robert G. , Lim Kieran F. 
Published: July 2002

Classical trajectory calculations of the rate of collisional energy transfer between a bath gas and a highly excited polyatomic method, and the average energy transferred per collision, as functions of the bath gas translational energy and temperature, are reported. The method used is that of Lim and Gilbert [J. Phys. Chem. 94, 72 (1990)], which requires only about 500 trajectories for convergence, and generates extensive data on the collisional energy transfer between Xe and azulene, as a function of temperature, initial relative translational energy (E′T), and azulene initial internal energy (E′). The observed behavior can be explained qualitatively in terms of the Xe interacting in a chattering collision with a few substrate atoms, with the collision duration being much too brief to permit ergodicity but with a general tendency to transfer energy from hotter to colder modes (both internal and translational). At thermal energies, trajectory and experimental data show that the root-mean-squared energy transfer per collision, 〈ΔE2〉1/2, is relatively less dependent on E′ than the mean energy transfer 〈ΔE〉.
The calculated temperature dependence is weak: 〈ΔE2〉1/2∝T0.3, corresponding to 〈ΔEdown〉∝T0.23. Values for the calculated average rotational energy transferred per collision (data currently only available from trajectories, and required for falloff calculations for radical–radical and ion-molecule reactions) are of the order of kBT, and similar to those for the internal energy; there is extensive collision-induced internal-rotational energy transfer. The biased random walk ‘‘model B,’’ as discussed in text, is found to be in accord with much of the trajectory data and with experiment. This suggests that energy transfer is through pseudorandom multiple interactions between the bath gas and a few reactant atoms; the ‘‘kick’’ given by the force at the turning point of each atom–atom encounter governs the amount of energy transferred. Moreover, a highly simplified version of this model explains why average energies transferred per collision for simple bath gases have the order-of-magnitude values seen experimentally, an explanation which has not been provided hitherto.
The [FHCl]− molecular anion: Structural aspects, global surface, and vibrational eigenspectrum
Authors: Klepeis Neil E. , East Allan L. L. , Császár Attila G. , Allen Wesley D. , Lee Timothy J. , Schwenke David W. 
Published: July 2002

The [FHCl]− molecular anion has been investigated in detail by means of state-of-the-art ab initio electronic structure methods, including restricted Hartree–Fock (RHF), Mo/ller–Plesset perturbation theory (MP2–MP4), and coupled-cluster and Brueckner methods incorporating various degrees of excitation [CCSD, CCSD(T), BD, BD(T), and BD(TQ)]. The one-particle Gaussian basis sets ranged in quality from F[6s4p2d], Cl[10s7p2d], and H[4s2p] to F[18s13p6d4f], Cl[20s14p7d5f], and H[8s3p2d1f]. The first phase of the investigation focused on the prediction of thermochemical, spectroscopic, and bonding properties of [FHCl]− and the chemical interpretation thereof.
The final proposals for the geometric structure and binding energy of the complex are re(H–F)=0.963±0.003 Å, Re(H–Cl)=1.925±0.015 Å, and D0(HF+Cl−)=21.8±0.4 kcal mol−1. A Morokuma decomposition of the ion-molecule bonding gave the following electrostatic (ES), polarization (PL), exchange repulsion (EX), dispersion (DISP), and charge-transfer plus higher-order mixing (CT+MIX) components of the vibrationless complexation energy: −27.3 (ES), −5.2 (PL), +18.3 (EX), −4.5 (DISP), and −5.0 (CT+MIX) kcal mol−1. The second phase of the work involved the construction of a CCSD global surface from 208 and 228 energy points for linear and bent conformations, respectively, these being fit to rms errors of only 3.9 and 9.3 cm−1, respectively, below 8000 cm−1. The surface was represented by a flexible analytic form which reproduces the quartic force field at equilibrium, exhibits the proper asymptotic properties, and is generally applicable to ion-molecule systems. The final phase of the study entailed the determination of converged J=0 and J=1 variational eigenstates of the [FHCl]− surface to near the HF+Cl− dissociation threshold by employing Jacobi coordinates and vibrational configuration interaction expansions in terms of natural modals.
The fundamental vibrational frequencies given by the analysis were ν1=247, ν2=876, and ν3=2884 cm−1. The complete vibrational eigenspectrum was then analyzed in terms of several contemporary dynamical issues, including vibrational adiabaticity, anharmonic resonances, densities of high-lying states, and signatures of quantum ergodicity.
Turks and Tatars in Bulgaria and the Balkans
Authors: Eminov Ali 
Published: July 2002

The Koran and the Bible are God's grace Which is what all four holy Books embrace; To scorn and segregate this or that race Would be the darkest stains on one's face.Aşik VeyselNationalist movements everywhere aim to create “territorially bounded political units (states) out of homogeneous cultural communities (nations).” Unfortunately, ethnic, linguistic, religious, political, and personal identities rarely coincide with geographical boundaries that enclose nation states. There are always groups within nation states whose identities are different from the majority. The leaders of nation states often see the presence of multiple ethnic communities within a single nation state as a sign of tension and instability, a threat to the integrity and indeed the very survival of a nation state. Consequently, they seek ways to culturally homogenize the nation so that the state and the nation come to coincide with one another.
Mechanism of the Facilitation of PC2 Maturation by 7B2: Involvement in ProPC2 Transport and Activation but Not Folding
Authors: Muller Laurent , Zhu Xiaorong , Lindberg Iris 
Published: July 2002

Among the members of the prohormone convertase (PC) family, PC2 has a unique maturation pattern: it is retained in the ER for a comparatively long time and its propeptide is cleaved in the TGN/ secretory granules rather than in the ER. It is also unique by its association with the neuroendocrine protein 7B2. This interaction results in the facilitation of proPC2 maturation and in the production of activatable proPC2 from CHO cells. In the present study, we have investigated the mechanism of this interaction.
ProPC2 binds 7B2 in the ER, but exits this compartment much more slowly than 7B2. We found that proPC2 was also slow to acquire the capacity to bind 7B2, whereas 7B2 could bind proPC2 rapidly after synthesis. This indicated that proPC2 folding was the limiting step in the formation of the complex. Indeed, sensitivity of native proPC2 to N-glycanase F digestion and inhibition of proPC2 folding supported the notion that 7B2 is not involved in the early steps of proPC2 folding, and that proPC2 must fold before binding 7B2. Under experimental conditions that prevent propeptide cleavage, 7B2 expression increased proPC2 transport to the Golgi. This increase exhibited the same kinetics as the facilitation of the removal of the propeptide. Finally, proPC2 activation could be reconstituted in Golgi- enriched subcellular fractions. In vitro, 7B2 was required for proPC2 activation at an acidic pH.
Taken together, our results demonstrate that rather than promoting proPC2 folding, 7B2 acts as a helper protein involved in proPC2 transport and is required in the proPC2 activation process. We propose, therefore, that 7B2 stabilizes proPC2 in a conformation already competent for these two events.
A-Cell: graphical user interface for the construction of

biochemical reaction models
Authors: Ichikawa Kazuhisa 
Published: July 2002

Abstract
Summary: A-Cell is a tool for constructing models of complex and complicated biochemical reactions. An important feature of A-Cell is its graphical user interface for constructing biochemical reactions. In addition, it has a capability of importing previously constructed models, combining them, and constructing a comprehensive model. The simulation program for the model is automatically generated by A-Cell.
Availability: http://www.fujixerox.co.jp/crc/cng/A-Cell/
Contact: kazuhisa.ichikawa@fujixerox.co.jp
Structural insights into human serum albumin‐mediated prostaglandin catalysis
Authors: Yang Jinsheng , Petersen Charles E. , Ha Chung‐Eun , Bhagavan Nadhipuram V. 
Published: July 2002

AbstractPrevious studies have shown that many arachidonic acid metabolites bind to human serum albumin (HSA) and that the metabolism of these molecules is altered as a result of binding. The present study attempted to gain insights into the mechanisms by which prostaglandins bound to subdomain 2A of HSA are metabolized by catalytic processes. The breakdown of the prostaglandin 15‐keto‐PGE2 to 15‐keto‐PGA2 and 15‐keto‐PGB2 in the presence of wild‐type HSA and a number of subdomain 2A mutants was examined using a previously validated spectroscopic method which monitors absorbance at 505 nm. The species examined using this method were wild‐type HSA, K195M, K199M, F211V, W214L, R218M, R218P, R218H, R222M, H242V, R257M, and bovine serum albumin. Previous studies of HSA‐mediated catalysis indicated that the breakdown of HSA‐bound prostaglandins results from an alkaline microenvironment in the binding site. Our results show that the catalytic breakdown of HSA‐bound 15‐keto‐PGE2 to 15‐keto‐PGB2 results from two specific processes which are modulated by specific amino acid residues. Specifically, some amino acid residues modulate the rate of step 1, the conversion of 15‐keto‐PGE2 to 15‐keto‐PGA2, while other residues modulate the rate of step 2, the conversion of 15‐keto‐PGA2 to 15‐keto‐PGB2. Some residues modulate the rate of steps 1 and 2. In total, while our results support the involvement of certain basic amino acid residues in the catabolism of HSA‐bound 15‐keto‐PGE2, our data suggest that metabolism of HSA‐bound prostaglandins may be a more complex and specific process than previously thought.
Association Between Psychological Distress and Incident Dementia in a Population-Based Cohort in Finland
Authors: Sulkava Sonja , Haukka Jari , Sulkava Raimo , Laatikainen Tiina , Paunio Tiina 
Published: December 2022

ImportanceSymptoms of psychological distress have shown association with subsequent dementia, but the nature of association remains unclear.ObjectiveTo examine the association of psychological distress with etiological risk of dementia and incidence of dementia in presence of competing risk of death.Design, Setting, and ParticipantsThis cohort study consisted of population-based cross-sectional National FINRISK Study surveys collected in 1972, 1977, 1982, 1987, 1992, 1997, 2002, and 2007 in Finland with register-based follow-up; and the cohort was linked to Finnish Health Register data for dementia and mortality for each participant until December 31, 2017. Participants included individuals without dementia who had complete exposure data. Data were analyzed from May 2019 to April 2022.ExposuresSelf-reported symptoms of psychological distress: stress (more than other people), depressive mood, exhaustion, and nervousness (often, sometimes, never).Main Outcomes and MeasuresIncident all-cause dementia, ascertained through linkage to national health registers. Poisson cause-specific hazard model (emphasizing etiological risk) and Fine–Gray subdistribution hazard model (emphasizing effect on incidence) considering dementia and death without dementia as competing risks. Covariates of age, sex, baseline year, follow-up time, educational level, body mass index, smoking, diabetes, systolic blood pressure, cholesterol, and physical activity. Sensitivity analysis was performed to reduce reverse causation bias by excluding individuals with follow-up less than 10 years.ResultsAmong 67 688 participants (34 968 [51.7%] women; age range, 25 to 74 years; mean [SD] age, 45.4 years), 7935 received a diagnosis of dementia over a mean follow-up of 25.4 years (range, 10 to 45 years). Psychological distress was significantly associated with all-cause dementia in a multivariable Poisson model, with incidence rate ratios from 1.17 (95% CI, 1.08-1.26) for exhaustion to 1.24 (95% CI, 1.11-1.38) for stress, and remained significant in sensitivity analyses. A Fine–Gray model showed significant associations (with hazard ratios from 1.08 [95% CI, 1.01-1.17] for exhaustion to 1.12 [95% CI, 1.00-1.25] for stress) for symptoms other than depressive mood (hazard ratio, 1.08 [95% CI, 0.98-1.20]). All the symptoms showed significant associations with competing risk of death in both models.Conclusions and RelevanceIn this cohort study, psychological distress symptoms were significantly associated with increased risk of all-cause dementia in the model emphasizing etiological risk. Associations with real incidence of dementia were diminished by the competing risk of death.
Machine performance and stability of the first clinical self‐shielded stereotactic radiosurgery system: Initial 2‐year experience
Authors: Srivastava Shiv P. , Sorensen Stephen P. , Jani Shyam S. , Yan Xiangsheng , Pinnaduwage Dilini S. 
Published: December 2022

AbstractThis study provides insight into the overall system performance, stability, and delivery accuracy of the first clinical self‐shielded stereotactic radiosurgery (SRS) system. Quality assurance procedures specifically developed for this unit are discussed, and trends and variations over the course of 2‐years for beam constancy, targeting and dose delivery are presented. Absolute dose calibration for this 2.7 MV unit is performed to deliver 1 cGy/MU at dmax = 7 mm at a source‐to‐axis‐distance (SAD) of 450 mm for a 25 mm collimator. Output measurements were made with 2‐setups: a device that attaches to a fixed position on the couch (daily) and a spherical phantom that attaches to the collimating wheel (monthly). Beam energy was measured using a cylindrical acrylic phantom at depths of 100 (D10) and 200 (D20) mm. Beam profiles were evaluated using Gafchromic film and compared with TPS beam data. Accuracy in beam targeting was quantified with the Winston‐Lutz (WL) and end‐to‐end (E2E) tests. Delivery quality assurance (DQA) was performed prior to clinical treatments using Gafchromic EBT3/XD film. Net cumulative output adjustments of 15% (pre‐clinical), 9% (1st year) and 3% (2nd year) were made. The mean output was 0.997 ± 0.010 cGy/MU (range: 0.960–1.046 cGy/MU) and 0.993 ± 0.029 cGy/MU (range: 0.884–1.065 cGy/MU) for measurements with the daily and monthly setups, respectively. The mean relative beam energy (D10/D20) was 0.998 ± 0.004 (range: 0.991–1.006). The mean total targeting error was 0.46 ± 0.17 mm (range: 0.06–0.98 mm) for the WL and 0.52 ± 0.28 mm (range: 0.11–1.27 mm) for the E2E tests. The average gamma pass rates for DQA measurements were 99.0% and 90.5% for 2%/2 mm and 2%/1 mm gamma criteria, respectively. This SRS unit meets tolerance limits recommended by TG‐135, MPPG 9a., and TG‐142 with a treatment delivery accuracy similar to what is achieved by other SRS systems.
Emerging Halide Perovskite Ferroelectrics
Authors: Zheng Weilin , Wang Xiucai , Zhang Xin , Chen Bing , Suo Hao , Xing Zhifeng , Wang Yanze , Wei Han‐Lin , Chen Jiangkun , Guo Yang , Wang Feng 
Published: December 2022

AbstractHalide perovskites have gained tremendous attention in the past decade owing to their excellent properties in optoelectronics. Recently, a fascinating property, ferroelectricity, has been discovered in halide perovskites and quickly attracted widespread interest. Compared with traditional perovskite oxide ferroelectrics, halide perovskites display natural advantages such as structural softness, low weight, and easy processing, which are highly desirable in applications pursuing miniaturization and flexibility. This review focuses on the current research progress in halide perovskite ferroelectrics, encompassing the emerging materials systems and their potential applications in ferroelectric photovoltaics, self‐powered photodetection, and X‐ray detection. The main challenges and possible solutions in the future development of halide perovskite ferroelectric materials are also attempted to be pointed out.
On the Design of Multibeam Digital Metasurfaces With Multiple Feeds
Authors: Rezaee Rezvan Behrad , Yazdi Mohammad , Hosseininejad Seyed Ehsan 
Published: December 2022

AbstractIn this paper, an analytical design procedure for multibeam metasurfaces with multiple feeds is presented. Considering arbitrary number of input and output beams, the required amplitude and phase distributions on the metasurface plane are theoretically derived without any optimization process. How the limitation of using only passive metasurfaces poses different challenges in the practical implementation of the amplitude profile is discussed. Then, to resolve these problems, a filtering procedure is proposed which effectively produces the desired output pattern. Moreover, the design method is verified through introducing a reflective metasurface with three input beams and sixteen output beams in arbitrary directions. It utilizes a graphene‐based unit cell providing simultaneous 2/2‐bit phase/amplitude modulation, that is, totally 16 states. For validation purposes, the analytical results are compared with numerical full‐wave simulation ones in which a good agreement between them is observed. In addition, by using the proposed design method, three different practical cases for wave manipulation functionalities, including power control, beam steering, and radar cross section (RCS) reduction capabilities are demonstrated. The presented approach paves the way for efficient design of the metasurfaces for a multitude of applications, including reconfigurable intelligent surfaces and multifunctional surfaces.
Experimental solid–liquid equilibria and solid formation kinetics for carbon dioxide in methane for LNG processing
Authors: Sampson Catherine C. , Metaxas Peter J. , Barwood Mark T. J. , Sinclair‐Adamson Rebecca , Falloon Peter E. , Stanwix Paul L. , Johns Michael L. , May Eric F. 
Published: December 2022

AbstractIn cryogenic liquefaction processes, CO2 poses a solid‐formation risk even in trace concentrations. We present solid–fluid equilibrium (SFE) data for CO2 in liquid methane at CO2 concentrations from (52 to 500) ppm, extending the available data and indicating that models tuned to existing data over predict the solubility of CO2 at LNG storage temperatures (~112 K) by nearly a factor of 3. The new data are used to improve the SFE model in the ThermoFAST software package. The formation kinetics of CO2 solids in liquid methane are elucidated at conditions relevant to cryogenic gas processing. Repeated, ramped‐temperature formation measurements provide a statistical basis for quantifying solidification risk. Nucleation rates extracted from the ramped‐temperature data, consistent with those measured at fixed temperature, were used to extract parameters describing CO2 solid formation in methane. These results significantly improve the ability to predict CO2 solid formation risk in cryogenic natural gas processing.
Facile Synthesis of Fully Substituted 1,2,4‐Triazoles via [3+2] Cycloaddition of Nitrileimines with Amidine under Transition Metal‐Free Conditions
Authors: Wang Dahan , Wan Xiaoyuan , Zhou Yazheng , Liu Jinbing , Cai Jinhui , Deng Guo‐Jun 
Published: December 2022

AbstractAn efficient synthesis of densely 1,2,4‐triazoles has been achieved by [3+2] cycloaddition of nitrileimides with amidine hydrochlorides under transition metal‐free conditions. This method features mild reaction conditions, wide substrate scope and good functional group tolerance. A series of aryl, heterocyclic and alkyl substituted 3‐CF3‐1,2,4‐triazoles were synthesized smoothly under the promotion of NaHCO3 and yield up to 96%. In addition, both gram‐scale reaction and synthetic transformations are smoothly elaborated to indicate the utility of this reaction.