Unusual Defect Research Articles

Low‐Voltage, Optoelectronic CH3NH3PbI3−xClx Memory with Integrated Sensing and Logic Operations

AbstractNonvolatile optoelectronic memories integrated with the functions of sensing, data storage, and data processing are promising for the potential Internet of things (IoT) applications. To meet the requirements of IoT devices, multifunctional memory devices with low power consumption and secure data storage are highly desirable. This study demonstrates an optoelectronic resistive switching memory integrated with sensing and logic operations by adopting organic–inorganic hybrid CH3NH3PbI3−xClx perovskites, which possess unusual defect physics and excellent light absorption. The CH3NH3PbI3−xClx cell exhibits low operation voltage of 0.1 V with the assistance of light illumination, long‐term retention property, and multiple resistance states. Its unique optoelectronic characteristics enable to perform logic operation for inputting one electrical pulse and one optical signal, and detect the coincidence of electrical and optical signal as well. This design provides possibilities for smart sensor in IoT application.

A Neonate with an Unusual Midline Defect and Cardiovascular Anomaly.

We present a female neonate with a sternal cleft (SC) and additional aortic aneurysm who presented with respiratory failure. Stabilization of the SC was achieved by using the xyphoid process as an autologous graft bridging the upper part of the SC. We conclude that a step-wise correction of the SC with the use of an autologous graft may improve respiratory function, and should be considered when complete surgical correction is not feasible.

Unusual types of extended defects in synthetic high pressure–high temperature diamonds

Side view of a HPHT diamond with unusual cone-like defects and the high magnification image of the defect.

CD4+ T lymphocytopenia associated with sideropenia: case report

Importance of the issue: Idiopathic CD4 T lymphocytopenia is an unusual immune defect in which there is an unexplained deficit of CD4 T cells. This case presents a 39-year-old female patient, with CD4+ T lymphocytopenia, who was not infected with immunosuppressive viruses neither was she subjected to immunosuppressive therapies. Comments: While monitoring the patient, she was found to have very low serum ferritin and, after parenteral iron therapy, there were changes in CD4+ cell levels, indicating that, in this case, lymphocytopenia was secondary to sideropenia. The patient is being kept under strict control of serum iron and periodic immunological evaluation, and she has not showed any clinical and/or laboratory adverse events so far. It is known that iron deficiency is an important factor in the genesis of immunological changes that occur in patients with iron deficiency anemia. It is important to understand the effects of iron deficiency on the immune system due to its high prevalence worldwide. Moreover, it could also help to clarify several cases of idiopathic CD4 lymphocytopenia.

An Enigmatic Hypoplastic Defect of the Maxillary Lateral Incisor in Recent and Fossil Orangutans from Sumatra (Pongo abelii) and Borneo (Pongo pygmaeus)

Developmental dental pathologies provide insight into health of primates during ontogeny, and are particularly useful for elucidating the environment in which extant and extinct primates matured. Our aim is to evaluate whether the prevalence of an unusual dental defect on the mesiolabial enamel of the upper lateral incisor, thought to reflect dental crowding during maturation, is lesser in female orangutans, with their smaller teeth, than in males; and in Sumatran orangutans, from more optimal developmental habitats, than in those from Borneo. Our sample includes 49 Pongo pygmaeus (87 teeth), 21 P. abelii (38 teeth), Late Pleistocene paleo-orangutans from Sumatra and Vietnam (67 teeth), Late Miocene catarrhines Lufengpithecus lufengensis (2 teeth), and Anapithecus hernyaki (7 teeth). Methods include micro-CT scans, radiography, and dental metrics of anterior teeth. We observed fenestration between incisor crypts and marked crowding of unerupted crowns, which could allow tooth-to-tooth contact. Tooth size does not differ significantly in animals with or without the defect, implicating undergrowth of the jaw as the proximate cause of dental crowding and defect presence. Male orangutans from both islands show more defects than do females. The defect is significantly more common in Bornean orangutans (71 %) compared to Sumatran (29 %). Prevalence among fossil forms falls between these extremes, except that all five individual Anapithecus show one or both incisors with the defect. We conclude that maxillary lateral incisor defect is a common developmental pathology of apes that is minimized in optimal habitats and that such evidence can be used to infer habitat quality in extant and fossil apes.

Prevalence of an unusual hypoplastic defect of the permanent maxillary lateral incisor in great apes.

In this article, I describe a previously unreported maxillary lateral incisor defect (MLID) of the enamel in great apes and evaluate potential general causes (genetic, systemic stress, or localized disturbance), as well as examine differences in prevalence among the represented taxa. This defect occurred only on the labial surface of the maxillary lateral incisor and extended from the cervical-mesial quarter of the crown to the mesial edge of the cementoenamel junction (CEJ). The study sample consisted of 136 great ape specimens, including 41 gorillas, 25 chimpanzees, and 70 orangutans from the Smithsonian's National Museum of Natural History great ape collection. I used logistic regression to assess the prevalence of this defect in the sample and a binomial probability test for bilaterality. This defect of the maxillary lateral incisor is the second most common defect I observed in the study sample (30.1% of individuals affected), and was more likely to occur in individuals with linear enamel hypoplasia (LEH) and pit defects than those without these defects. Among specimens with both maxillary lateral incisors present, the defect was mostly bilateral. Pan and Pongo were significantly more likely to exhibit the defect than Gorilla. Between Pongo species, Pongo pygmaeus was significantly more likely to exhibit the defect than Pongo abelii. Between subspecies of Gorilla, although Gorilla gorilla gorilla exhibited the defect and Gorilla gorilla beringei did not, the difference was not significant. No sex differences were evident in this sample. The prevalence of this defect indicates it is not hereditary. The bilateral trend indicates a systemic cause, although the high inter-tooth specificity suggests a local disturbance and a combination of both is possible.

High-Voltage Capacitor Failure on a Downhole Oilfield PCB

Abstract This article explains how the failure of a high-voltage capacitor led to the discovery of an unusual defect. Testing showed that the capacitor shorted due to silver migration, which investigators believe was facilitated by voids in the dielectric that had been present from the time of manufacture. Through some combination of time, electric potential, trapped humidity, and elevated operating temperature, plate material migrated into the voids, creating a short path that led to the failure. Using acoustic images as a guide, the failed capacitor was cross-sectioned, allowing investigators to examine the voids more closely and thereby confirm their theory.

Holoprosencephaly and Pure Red Cell Aplasia in a Feline Leukaemia Virus-Positive Kitten

A 9-month-old, female, domestic longhair cat with severe anaemia tested positive for feline leukaemia virus (FeLV) and was humanely destroyed and submitted for necropsy examination. Gross findings included a non-divided rostral telencephalon, consistent with semilobar holoprosencephaly. Histological examination of the bone marrow revealed an almost complete absence of erythroid precursor cells, consistent with pure red cell aplasia, and mild to moderate myelofibrosis. This case demonstrates a very unusual central nervous system defect, as well as an atypical presentation of pure red cell aplasia, in a FeLV-positive kitten.

Silicon Pipeline or Dislocation Defect?

Abstract Silicon pipeline defects are a growing concern in semiconductor manufacturing with no proposed methodology on how to effectively analyze them and separate the underlying causes. In light of this need, a study was conducted using complementary FA techniques to examine these unusual silicon crystal defects and gain a better understanding of their signature characteristics and their effect on device failure. This article, authored by the lead investigator, describes the tests that were performed and presents relevant findings and theories on the factors that contribute to "pipeline" and how they can be controlled. It also presents guidelines for distinguishing between pipeline and dislocation defects and explains how they are related.

How I Reached the Age of 65 with a Congenital Heart Disease and Atherosclerosis

The number of congenital heart diseases is rapidly growing in the United States; they require the most expensive treatment [1] and are often caused by external effects [2]. My parents were born far from each other and had different nationalities and therefore their three children may have had unusual birth defects. My sister was born in the amniotic membrane (shirt), my brother had the 33-th tooth and when I was already adult, a heart defect of my heart — a false chord in the left ventricle — was found. I was born in 1951 and I felt no discomfort to the heart for a long time; after school I did sports and even had local awards. Later, as a student, apart from the usual physical education lessons, I either swam with fins in the pool (4 times a week) 5 km per training or practiced boxing. Suddenly, in the swimming pool I felt discomfort in the heart after my summer break. The heart test found a heart murmur but physicians thought these were the effects of active sports. However, after 8 years after the end of my sports career and sedentary life, the heart palpitations began to appear during the motion activity. For twenty years, I have kept my memory the fact that the Russian skater Yevgeny Grishin who had the congenital heart disease became the Olympic champion and I decided to eliminate the discomfort with the physical activity. Modern research has confirmed the beneficial effects of physical activity for the heart [3,4].

Unusual manufacturing defect of the endotracheal tube: Problem revisited.

Sir, Manufacturing defects of endotracheal tube (ETT) are still encountered in routine anesthesia practice. Many such defects go unnoticed during routine inspection prior to their use. We report a case of manufacturing defect at the junction of pilot balloon and spring-loaded one-way valve in a prepacked, single use, cuffed ETT. This case highlights the significance of standard monitoring of ventilation and the role of a vigilant clinician in detecting such defects and avoiding critical events that can arise from the use of such defective ETTs. It also emphasizes the need for double-checking ETT prior to their use. Difficulty in ventilating a tracheally intubated patient as a result of ETT defect is known in anesthesia practice. Despite the common practice of visual inspection and testing of ETTs for physical defects prior to use, some manufacturing defects still go unnoticed.[1] The patient, 8-year-old female weighing 24 kg, posted for fistulectomy for internal fistula of the left eye under general anesthesia. Her trachea was intubated with a 6.0 mm ID cuffed ETT and was ventilated with tidal volume (Vt) of 200 ml with a rate of 15/min. The correct placement of the tube was ensured and after three to four machine delivered breaths exhaled Vt started decreasing by more than 60 ml at around 20 cm H2O of cuff pressure. The tube in question is a CE-certified product (Hansraj Nayyar, Mumbai, India). We initially thought that the cuff needs to be inflated but in spite of inflating it the exhaled Vt would increase but only to decrease after a few breaths. When the leak was significant and end-tidal carbon dioxide started building up, we removed the tube and inserted a new tube, and thereafter ventilation was satisfactory. When we inserted the cuff of the tube in a bowl of water to check its potency, we did not find any leak, but the cuff was not sustaining the pressure to which it was inflated as measured by the cuff manometer. To our surprise, when we dipped both the pilot balloon and the cuff, the leak was detected at the junction of spring-loaded one-way valve and the pilot balloon [Figure 1] [Video], which is first of its kind to be reported. Figure 1 Original photograph showing the leak at the junction between pilot balloon and spring-loaded one-way valve A manufacturing defect in an ETT can lead to difficulty in ventilation involving any part of the ETT. Cuff defects leading to herniation of the ETT cuff and intraluminal tracheal obstruction,[2,3] elliptical defects in the wall of the tube causing air leak,[4] and kinking of ETT [5] have been described. In conclusion, double-checking of ETTs before their use aids in avoiding unnecessary intraoperative problems that can arise from the use of defective ETT although the method is not full proof. Most of the ETT defects described in literature could not be identified during routine preoperative inspection at least of this nature. Thus, the role of a vigilant anesthetist as well as standard monitoring of ventilation is invaluable for patient safety in the presence of a defective ETT. Further, the report points to the manufacturing practice and the need for stringent quality control of the manufacturer concerned in the production of such lifesaving equipment. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Investigation of Effect of Al3+-Doping on Mass/Charge Transport Properties of La2NiO4+δ by Blocking Cell Method

In this work, effect of doping of a fixed-valence non-transition metal ion Al3+ on B-site of La2NiO4+δ (LNO) system is investigated by a blocking cell experiment. The mass and charge transport properties of La2Ni0.95Al0.05O4.025+δ (LNAO) in isothermal conditions are investigated and ionic charge of transport (α*i), which is a measure of cross-effect between ionic and electronic flows and corresponds to the number of electrons dragged by a cation in the absence of the direct cause of electron flow, and partial electronic conductivity under a blocking condition is measured and values of Onsager transport coefficients are extracted by constructing an Onsager matrix. α*i shows a minimum during its variation with oxygen partial pressure (pO2) which might be related to the unusual defect structure of LNO systems. Oxygen chemical diffusivities as a function of pO2 at different temperatures are extracted from Onsager coefficients to calculate defect diffusivity of interstitial oxygen (Di) and oxygen self-diffusivity(DO). Di values for LNAO are nearly 2 orders of magnitude lower than those for LNO, which might be due to the reduction in free-volume of perovskite layer on Al3+ doping. Partial ionic conductivity (σi) and oxygen permeation flux are calculated from Onsager coefficients, and values are compared with LNO.

Chemical instability leads to unusual chemical-potential-independent defect formation and diffusion in perovskite solar cell material CH3NH3PbI3

The near-zero enthalpy of formation of MAPbI3 leads to unusual defect formation energies that are free from elemental chemical potential dependence.

Geometrical effect ‘stiffens’ graphene membrane at finite vacancy concentrations

The presence of defects not only modifies the stiffness and strength of materials, but also changes their morphologies. The latter effect is extremely significant for low-dimensional materials such as graphene. We show in this work that graphene swells while point defects such as mono-vacancies are created at finite concentrations. The distorted geometry resulted from this areal expansion, in combination with the in-plane softening effect, predicts an unusual defect concentration dependence of stiffness measured for supported graphene membrane in nanoindentation tests, which leads to a defect-induced stiffening phenomenon. The mechanism is elucidated through an analytical membrane model as well as numerical simulations at atomistic and continuum levels. In addition to elucidate the counter-intuitive observations in experiments and computer simulations, our findings also highlight the role of defect-modulated morphology engineering that can be applied to design nanoscale material and structural applications.

Prenatally Diagnosed Type II Arnold Chiari Malformations-A Rare Congenital Anomaly with Some Unusual Associated Defects

Arnold Chiari malformation (ACM) is one of the common anomalies of the craniovertebral junction involving both the skeletal as well as the neural structures. Among the four types of ACM, type II ACM is considered as commonest. A case of Type II Arnold Chiari malformations; a rare congenital anomaly with some unusual associated defects has been reported here. A 29 year old lady with 21weeks gestation was diagnosed to have a male foetus with type II ACM at antenatal clinic of department of Gynaecology, Sree Mookambika Institute of Medical Sciences, Kulasekaram, Tamil Nadu, India during routine antenatal check-up. Though the commonly observed malformations of type II ACM such as herniation of cerebellar tonsil, spina bifida and hydrocephalous were observed in the present case, it differed from general pattern of type II ACM in presence of a large cyst abutting spina bifida and mild scoliosis.

Unusual defects, generated by wafer sawing: An update, including pick&place processing

At ESREF 2008, the paper “Unusual defects, generated by wafer sawing: Diagnosis, mechanisms and how to distinguish from related failures” had won the Best Paper Award. In the meantime, new experiences were collected, related to new methods as laser sawing and its specific ESD risks and additional failure mechanisms as backside damage, charging of foils, pad corrosion and sawing residue damages. This paper explains in detail these failure sources, including detailed explanations on root causes and physical mechanisms as well as important hints for failure analysts how to distinguish related failure signatures from those, which look similar but are of other origin.

Si Dopant Behavior in InGaAs

Si Dopant Behavior in InGaAs

Correlating the Local Defect-Level Density with the Macroscopic Composition and Energetics of Chalcopyrite Thin-Film Surfaces.

The unusual defect chemistry of polycrystalline Cu(In,Ga)Se2 (CIGSe) thin films is a main issue for a profound understanding of recombination losses in chalcopyrite thin-film solar cells. Especially, impurity-driven passivation of electronic levels due to point defects segregating at the surface and at grain boundaries is extensively debated. By combining current imaging tunneling spectroscopy with photoelectron spectroscopy, the local defect-level density and unusual optoelectronic grain-boundary properties of this material are correlated with the macroscopic energy levels and surface composition. Vacuum annealing of different CIGSe materials provides evidence that Na diffusion from the glass substrate does not affect the surface defect passivation or grain-boundary properties of standard Cu-poor materials. Furthermore, we find no major impact on the observed thermally activated dipole compensation or the accompanying change in surface band bending (up to 0.6 eV) due to Na. In contrast, Cu-rich CIGSe shows an opposing surface defect chemistry with only minor heat-induced band bending. Our results lead to a comprehensive picture, where the highly desirable type inversion at the p/n interface in standard chalcopyrite thin-film solar cells is dominated by band bending within the CIGSe absorber rather than the result of Na impurities or an n-type defect phase segregating at the interface. This is in accordance with recent studies suggesting a surface reconstruction as the origin for Cu depletion and band-gap widening at the surface of chalcopyrite thin films.

Growing antiphase-domain-free GaAs thin films out of highly ordered planar nanowire arrays on exact (001) silicon

We report the use of highly ordered, dense, and regular arrays of in-plane GaAs nanowires as building blocks to produce antiphase-domain-free GaAs thin films on exact (001) silicon. High quality GaAs nanowires were grown on V-grooved Si (001) substrates using the selective aspect ratio trapping concept. The 4.1% lattice mismatch has been accommodated by the initial GaAs, a few nanometer-thick with high density stacking faults. The bulk of the GaAs wires exhibited smooth facets and a low defect density. An unusual defect trapping mechanism by a “tiara”-like structure formed by Si undercuts was discovered. As a result, we were able to grow large-area antiphase-domain-free GaAs thin films out of the nanowires without using SiO2 sidewalls for defect termination. Analysis from XRD ω-rocking curves yielded full-width-at-half-maximum values of 238 and 154 arc sec from 900 to 2000 nm GaAs thin films, respectively, indicating high crystalline quality. The growth scheme in this work offers a promising path towards integrated III-V electronic, photonic, or photovoltaic devices on large scale silicon platform.

All that appears well is not well: A novel method to detect an unusual manufacturing defect of the endotracheal tube.

All that appears well is not well: A novel method to detect an unusual manufacturing defect of the endotracheal tube.