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To summarize the awareness levels of breast cancer (BC) worldwide and investigate factors associated with BC awareness to determine differences in awareness between China and other countries.This systematic review followed the PRISMA guidelines and included 92 articles up to July, 2021. We calculated percentages for BC awareness levels and conducted subgroup analysis and cumulative meta-analysis.A total 84% (95% confidence interval [95%CI]: 78-90%) of women knew about BC; however, only 51% (95%CI: 37-66%) and 40% (95%CI: 24-56%) of women were aware of BC symptoms and BC risk factors, respectively. The most commonly known BC symptom was breast lump (71%, 95%CI: 62-80%), and BC family history was the most well-known BC risk factor (61%, 95%CI: 54-69%). Subgroup analysis showed lower awareness levels among Chinese and Asian women than women from other countries. Cumulative meta-analysis showed no obvious progress in BC awareness levels over time. We investigated 15 awareness-related factors, the most frequent of which were education level (61.8%), occupation (29.4%), and age (26.5%).BC awareness levels remain low. Improving BC awareness is critical, especially in developing countries.Effective education programs are urgently needed to improve women's BC awareness.

The quantum-confinement effect profoundly influences the exciton energy-level structures and recombination dynamics of semiconductor nanostructures but remains largely unexplored in traditional one-dimensional nanowires mainly due to their poor optical qualities. Here, we show that in defect-tolerant perovskite material of highly luminescent CsPbBr

The combination of chirality and semiconducting properties has enabled chiral metal-halide semiconductors (MHS) to be promising candidates for spin- and polarization-resolved optoelectronic devices. Although several chiral MHS with rich chemical and structural diversity have been reported lately, the macroscopic origin of chiroptical activity remains elusive. Here, combining spectroscopic measurements and Mueller matrix analysis, we discover that the previously reported "apparent" anisotropy factor measured from circular dichroism (CD) in chiral MHS thin films is not an intrinsic chiroptical property, but rather, arising from an interference between the film's linear birefringence (LB) and linear dichroism (LD). We verify the presence of LB and LD effects in both one-dimensional and zero-dimensional chiral MHS thin films. We establish spectroscopic methods to decouple the genuine CD from other spurious contributions, which allows a quantitative comparison of the intrinsic chiroptical activity across different chiral MHS. The relationship between the structure and the genuine chiroptical activity is then uncovered, which is well described by the chirality-induced spin-orbit coupling in the chiral structures. Our study unveils the macroscopic origin of chiroptical activity of chiral MHS and provides design principles for obtaining high anisotropic factors for future chiral optoelectronic applications.

A clean and efficient route for the utilization of ilmenite concentrates was proposed by direct carbothermic reduction in microwave field. High dosage of Na2CO3, which can be recycled, was added to accelerate the reduction reaction of ilmenite concentrates. After microwave heating in the temperature range of 1073−1123 K for 20 min, the main products were Na2TiO3 and metallic Fe with the metallization ratios being as high as 92.67%−93.21%. The reduction products were processed by water leaching, ball-milling in CO2 atmosphere and magnetic separation in turn. The final products after magnetic separation were Fe-rich materials and Ti-rich materials (90.04 wt.% TiO2), which can be used to produce iron and TiCl4 or TiO2. The optimized heating temperature was 1123 K in terms of metallization ratios, magnetic separation and caking property of the reduction products. Besides, the reduction mechanism of ilmenite concentrates with the addition of Na2CO3 in microwave field was also proposed.

Background:. Although breast-conserving surgery is one of the standard treatments for breast cancer, few studies have assessed its recent implementation in China. We aimed to clarify the current real-world status of breast-conserving surgery in China. Methods:. This cross-sectional survey relied on data collected by the Chinese Society of Breast Surgery (CSBrS) to examine patients who underwent this surgery between January 2018 and December 2018. The survey was conducted using a uniform electronic questionnaire to collect information, including clinical and pathological data on these patients. Results:. Overall, 4459 breast-conserving surgeries were performed in 34 member units of CSBrS, accounting for 14.6% of all breast cancer surgeries performed in these units during the study period. In patients who underwent breast-conserving surgery with information on tumor size available, more than half (61.2%) of the tumors were smaller than 2 cm in diameter, and only 87 (3.2%) tumors were larger than 4 cm in diameter. Among patients who underwent breast-conserving surgeries, 457 (10.2%) patients received neoadjuvant therapy before the surgery. Among patients with a reported margin width, 34 (2.0%) patients had a margin of ≤2 mm, and 1530 (88.2%) of them had a margin of >5 mm. Conclusions:. This study demonstrated the rates of breast-conserving surgery in member units of the CSBrS, and introduced the characteristics and surgical margins of patients who underwent this surgery. This information helps describe the real-world status of breast-conserving surgery in China. Trial registration. chictr.org.cn, ChiCTR1900026841; http://www.chictr.org.cn/showproj.aspx?proj=42783

Determination of the physicochemical properties of solutions is important for industrial applications. Geometrical models, specifically the “mass triangle model” and a new model, have been utilized to calculate the viscosity and surface tension of CaO–SiO2–CaF2 slags based on the corresponding ternary system boundary data within the partially soluble region. The two models are validated with available experimental data in terms of viscosity and surface tension. Results reveal that the models are capable of estimating the physicochemical properties of the ternary system with limited solubility with high accuracy. The new model predicts the viscosity better, but the mass triangle model may perform better for the surface tension predictions. It is expected that these two solution models could be applied to the calculation of physicochemical properties of more ternary systems with limited solubility, especially when the systems are with high melting points or/and volatile components and/or easily oxidized or reduced components.

The Rashba splitting in hybrid organic–inorganic lead–halide perovskites (HOIP) is particularly promising and yet controversial, due to questions surrounding the presence or absence of inversion symmetry. Here we utilize two-photon absorption spectroscopy to study inversion symmetry breaking in different phases of these materials. This is an all-optical technique to observe and quantify the Rashba effect as it probes the bulk of the materials. In particular, we measure two-photon excitation spectra of the photoluminescence in 2D, 3D, and anionic mixed HOIP crystals, and show that an additional band above, but close to the optical gap is the signature of new two-photon transition channels that originate from the Rashba splitting. The inversion symmetry breaking is believed to arise from ionic impurities that induce local electric fields. The observation of the Rashba splitting in the bulk of HOIP has significant implications for the understanding of their spintronic and optoelectronic device properties., Understanding of spin-orbit effects in hybrid organic–inorganic perovskites underlies their applications in spintronics and optoelectronics. Here, the authors demonstrate the use of the two-photon absorption spectroscopy to characterize inversion-symmetry breaking and Rashba effect in the bulk of these materials.

The introduction of chiral organic ligands into hybrid organic-inorganic perovskites (HOIPs) results in chiral perovskites, which exhibit natural optical activities (NOAs) such as circularly polarized luminescence (CPL). CPL can be observed in achiral HOIPs under a magnetic field as well. Here, we systematically study the temperature- and magnetic field-dependence of both circular polarization and total intensity in chiral HOIPs. Pronounced CPL polarization is observed in polycrystalline films of chiral HOIPs, which can be further tuned by an applied magnetic field. The magnetic field also modifies the total intensity of CPL, giving rise to magneto-PL in chiral HOIPs, which is observable even at room temperature. The observed field and temperature-dependence of polarization can be well accounted for by a recently developed theory of chiral HOIPs, where the materials' helicity gives rise to a novel spin-orbit coupling (SOC). The observed MPL can be quantitatively accounted for by the interplay of exciton fine structures and the magnetic field. Our study suggests that the magnetic field provides an effective means to manipulate both the polarization and intensity of CPL in chiral HOIPs, which can be exploited for novel device applications.

Two-dimensional (2D) van der Waals materials and related heterostructures have shown a wide variety of novel electronic and optoelectronic properties. However, a key challenge in fully realizing th...

The hybrid organic–inorganic perovskite (HOIP) CH3NH3PbI3 exhibits a long spin coherence despite its strong spin–orbit coupling. Elucidation of the spin relaxation mechanism is a prerequisite to ha...

Magnetic field can influence photoluminescence, electroluminescence, photocurrent, injection current, and dielectric constant in organic materials, organic–inorganic hybrids, and nanoparticles at r...

Single perovskite nanocrystals have attracted great research attention very recently due to their potential quantum-information applications, which critically depend on the development of powerful optical techniques to resolve delicate exciton photophysics. Here we have realized resonant and near-resonant excitations of single perovskite CsPbI3 nanocrystals, with the scattered laser light contributing to only ~10% of the total collected signals. This allows us to estimate an ultranarrow photoluminescence excitation linewidth of ~11.32 µeV for the emission state of a single CsPbI3 nanocrystal, corresponding to an exciton dephasing time of ~116.29 ps. Meanwhile, size-quantized acoustic phonons can be resolved from a single CsPbI3 nanocrystal, whose coupling with the exciton is proposed to arise from the piezoelectric potential. The ability to collect resonance fluorescence from single CsPbI3 nanocrystals, with the subsequent revelation of exciton-acoustic phonon coupling, has marked a critical step towards their steady advancement into superior quantum-light sources., In order to develop perovskite nanocrystals as a single-photon source, there is a need to understand the complex exciton photo-physics. Here, the authors employ resonant and near-resonant excitation technique to study single CsPbI3 nanocrystal that allows them to probe the continuous and size-quantised acoustic-phonon modes.

Hybrid organic-inorganic perovskites (HOIPs) with chiral organic ligands exhibit highly spin-dependent transport and strong natural optical activity (NOA). Here we show that these remarkable features can be traced to a chirality-induced spin-orbit coupling (SOC), Hso = ατkzσz, which connects the carrier's spin (σz), its wave vector (kz), and the material's helicity (τ) along the screw direction with strength α controlled by the geometry of the organic ligands. This SOC leads to a macroscopic spin polarization in the presence of an electrical current and is responsible for the observed spin-selective transport. NOA originates from a coupling between the exciton's center-of-mass wave vector Kz and its circular polarization jzex, Hso' = α'τKzjzex, contributed jointly from the electron's and the hole's SOCs in an exciton. Our model provides a roadmap to achieve a strong and tunable chirality in HOIPs for novel applications utilizing carrier spin and photon polarization.

Lead halide perovskite nanocrystals (NCs) have emerged as novel semiconductor nanostructures possessing great potential for optoelectronic, photovoltaic, and quantum information processing applications. Success in these applications requires a comprehensive understanding of the perovskite NCs' electronic structures, which mysteriously exhibit either doublet or triplet peaks of exciton luminescence at the single-particle level. Here we show that the transition from doublet- to triplet-exciton peaks can be triggered in single CsPbI3 NCs from the same batch of samples when they are stored in the ambient environment. We propose theoretically that the doublet-exciton peaks originate from two in-plane dipole moments, while the optical transition arising from the out-of-plane dipole moment becomes prominent only after the crystal-field splitting is strongly reduced by the structural transformation in the deterioration process. Furthermore, the quantum-confinement effect is strongly reinforced in the single CsPbI3 NCs with a triplet-exciton configuration, leading to enhanced Auger recombination and allowing us to extract the emission-energy dependence of the exciton-energy-level fine structure.

Background: Breast cancer is the most common cancer among women in China. Hence, how best to live with and improve the health-related quality of life (HRQoL) of this growing population of women is thus becoming of great public health importance. The aim of the study was to evaluate the relationship of lifestyle habits to HRQoL among younger and older women who were initially diagnosed with breast cancer within the first two weeks, determine the contribution of lifestyle habits factors on HRQoL.Methods: A multi-center, hospital-based, case control study was conducted among breast cancer women from 22 hospitals in 11 provinces or municipalities in northern and eastern China from April 2012 to April 2013. The Functional Assessment of Cancer Therapy-Breast Cancer (FACT-B) simplified Chinese version 4 was used to measure HRQoL. Chi-square test, ANOVA and Multivariable generalized linear models were conducted to verify differences in HRQoL between two groups and to evaluate the contribution of lifestyle habits factors ( including smoking, passive smoking, alcohol intake, Tea, Coffee, Sleep satisfaction, Current life satisfaction, Physical activity, BMI) on HRQoL of breast cancer patients.Results: 1199 eligible breast cancer patients were used for analysis. Younger women (age Conclusion: The relationship of the nine lifestyle habit items to HRQoL were different between younger and older women. Associated variable of low HRQoL can help clinicians take intervention early in order to improve the prognosis of breast cancer patients.

Exciton transport plays a central role in optoelectronic and photonic devices. In quasi-two-dimensional (2D) hybrid organic–inorganic perovskites (HOIPs), tightly bound excitons are found to diffuse within 2D layers rapidly with a non-monotonic temperature dependence. Surprisingly, the interlayer exciton diffusion is quite effective as well despite the large interlayer distance. This is in sharp contrast to electron transport, where the interlayer mobility is several orders of magnitude smaller than the intralayer one. Here, we show that the unusual exciton diffusion behaviors can be systematically modeled via the excitonic band structure arising from a long-range dipolar coupling. Coherent exciton motion is interrupted by scattering of impurities at low temperatures and of acoustic/optical phonons at high temperatures. Acoustic and optical phonons modulate the dipole–dipole distance and the dipole orientation, respectively. The ratio of intralayer and interlayer diffusion constants, D xx/ D zz, is comparable to a z/ a x with a z and a x being the interlayer and intralayer lattice constants of 2D HOIPs, respectively. The efficient and omnidirectional exciton diffusion suggests a great potential of 2D HOIPs in novel excitonic and polaritonic applications.

Calculating physicochemical property within a ternary system based on three corresponding binary systems with only limited solubility is a meaningful subject and never been solved before. In this paper we are going to raise a method to solve this problem and give couple of examples to show how this method works in the practical systems. The satisfactory agreement between the experimental data and the predicted results of viscosity, electrical conductivity and density of some ceramic melts proves the important role of this new model for estimating physicochemical properties of ternary systems.

The Rashba effect (RE), caused by concurrent spin–orbit coupling and structural inversion asymmetry (SIA), has been invoked to explain outstanding optoelectronic properties of hybrid organic inorganic perovskites (HOIPs). The SIA in HOIPs also manifests itself in second harmonic generation (SHG). Here, we establish a quantitative relation between the RE strength and the low-frequency SHG value in two-dimensional (2D) and three-dimensional (3D) HOIPs using a newly developed effective-mass model. The calculated SHG, which exhibits one- and two-photon resonances between the valence and conduction bands, approaches a finite value at low frequencies. Using the measured SHG values in literature, the estimated RE strength is 10–3 eV A for 3D CH3NH3PbI3 and 4 × 10–2 eV A for 2D (C4H9NH3)2PbI4. Our results facilitate a simple and reliable determination of the RE strengths of 2D and 3D HOIPs and help quantify the impact of RE on various properties in HOIPs.

We study the anharmonic phonon interactions in the single-crystal semiconducting (α) and metal-like (β) van der Waals In2Se3 layers, through the determination and analysis of temperature-dependent Raman spectra and thermal conductivities, supported by first-principles calculations of phonon band structures. Our results indicate strong lattice anharmonicity in β-In2Se3 giving rise to significant phonon peak broadening and a suppressed lattice thermal conductivity and reveal that the anharmonic phonon interactions are the main thermal transport-limiting mechanism in both phases. The low thermal conductivity combined with a large electrical conductivity makes the metal-like β-In2Se3 a potential efficient thermoelectric material.

Chiral nanostructures have been attracting extensive interest in recent years primarily because of the unique materials properties that can be exploited for diverse applications. In this study, gold Janus nanoparticles, with hexanethiolates and 3-mercapto-1,2-propanediol segregated on the two hemispheres of the metal cores (dia. 2.7 ± 0.4 nm), self-assembled into vesicle-like, hollow nanostructures in both water and organic media, and exhibited apparent plasmonic circular dichroism (PCD) absorption in the visible range. This was in contrast to individual Janus nanoparticles, bulk-exchange nanoparticles where the two ligands were homogeneously mixed on the nanoparticle surface, or nanoparticles capped with only one kind of ligand. The PCD signals were found to become intensified with increasing coverage of the 3-mercapto-1,2-propanediol ligands on the nanoparticle surface. This was accounted for by the dipolar property of the structurally asymmetrical Janus nanoparticles, and theoretical simulations based on first principles calculations showed that when the nanoparticle dipoles self-assembled onto the surface of a hollow sphere, a vertex was formed which gave rise to the unique chiral characteristics. The resulting chiral nanoparticle vesicles could be exploited for the separation of optical enantiomers, as manifested in the selective identification and separation of d-alanine from the l-isomer.

This study aimed to investigate risk factors associated with breast cancer among Han Chinese women in northern and eastern China. A matched case-control study involving 1489 patients with breast cancer and 1489 controls was conducted across 21 hospitals in 11 provinces in China, from April 2012 to April 2013. We developed a structured questionnaire to record information from face-to-face interviews with participants. Student's t-tests, Pearson's chi-square tests, and univariate and multivariate conditional logistic regression analyses were used to identify variables with significant differences between the case and control groups. Ten variables were identified (P

Hybrid organic–inorganic perovskites have emerged as a new class of semiconductors that exhibit excellent performance as active layers in photovoltaic solar cells. These compounds are also highly promising materials for the field of spintronics due to their large and tunable spin–orbit coupling, spin-dependent optical selection rules, and their predicted electrically tunable Rashba spin splitting. Here we demonstrate the optical orientation of excitons and optical detection of spin-polarized exciton quantum beating in polycrystalline films of the hybrid perovskite CH3NH3PbClxI3−x. Time-resolved Faraday rotation measurement in zero magnetic field reveals unexpectedly long spin lifetimes exceeding 1 ns at 4 K, despite the large spin–orbit couplings of the heavy lead and iodine atoms. The quantum beating of exciton states in transverse magnetic fields shows two distinct frequencies, corresponding to two g-factors of 2.63 and −0.33, which we assign to electrons and holes, respectively. These results provide a basic picture of the exciton states in hybrid perovskites, and suggest they hold potential for spintronic applications. Hybrid perovskites are known to have excellent optoelectronic properties, but the observation of exciton states with long spin lifetimes suggests that they may also have potential spintronics applications.

The structural response of a novel, insensitive energetic crystal—dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50)—was examined under high pressure. Using synchrotron single-crystal X-ray diffraction measurements, details of molecular, intermolecular, and crystal changes were determined to ∼10 GPa to understand its structural stability. The experimental results showed that TKX-50 exhibits highly anisotropic compression and significantly lower volume compressibility than currently known energetic crystals. These results are found to be in general agreement with our previous predictions from the DFT calculations. Additionally, the experimental data revealed anomalous compression—an expansion of the unit cell along the a axis (negative linear compressibility, NLC) upon compression to ∼3 GPa. The structural analyses demonstrated that this unusual effect, the first such observation in an energetic crystal, is a consequence of the highly anisotropic response of 3D motifs, comprised of two parallel ani...

The small exciton binding energy Eb in hybrid organic–inorganic perovskites (HOIPs) enables their extraordinary photovoltaic performance. The measured Eb in MAPbI3 (MA = CH3NH3), the most studied HOIP, is 50% smaller in the orthorhombic phase than estimated from the high-frequency dielectric constant and drops an additional 25% in the tetragonal phase. Here we show that these puzzling exciton behaviors can be quantitatively explained by incomplete screening arising from polar optical phonons (POPs) and randomly oriented MA ions. Emission/absorption of POPs introduces a virtual radius of electron (hole), within which the screening due to POPs is ineffective. Randomly oriented dipoles of MA ions in the tetragonal phase mediate an extra long-range coupling between the electron and hole. The exciton Hamiltonian is accurately solved by using variational hydrogenic wave functions as the basis set. Our results consistently account for the observed exciton properties and reveal the impact of polar coupling on exc...

The Rashba effect, which shifts the conduction band extremum from wavevector k = 0 to |k| = k0 ≠ 0 with an energy gain of ER, has been frequently invoked to explain outstanding optoelectronic properties in hybrid organic-inorganic perovskites (HOIPs). For two-dimensional (2D) layered HOIPs, the only direct experimental evidence of the Rashba effect to date is resonant free-carrier absorption (FCA), which has been attributed to direct optical transition between the Rashba subbands at |k| = k0 ≠ 0 with photon energy ℏω = 4ER. Here, we show that in layered perovskites, small polarons induced by a strong short-range coupling between electrons and optical phonons can also give rise to a resonant FCA at ℏω = 4Eb, with Eb being the polaron binding energy. The Rashba effect- and small-polaron-induced resonant FCA responses can be distinguished via an applied electric field, which moves the resonance peak to a higher or lower photon energy in the former but splits the peak into two in the latter, suggesting that electric-field-modulated FCA can help prove and quantify the Rashba effect and/or small polarons in layered perovskites.

Carrier scattering processes are studied in CH

Self-trapped excitons (STEs) in two-dimensional (2D) hybrid organic–inorganic perovskites (HOIPs) emit broadband white light, suggesting the great potential of 2D HOIPs in low-cost lighting and display applications. A prerequisite for understanding STEs' properties is a correct identification of the underlying interaction that leads to the STEs. Here, we show that the long-range polar coupling between electrons and optical phonons is quenched in 2D HOIPs' tightly bound excitons and cannot effect STEs. Rather, the STEs are induced by a short-range optical deformation potential (ODP) arising from the phonon-modulated Pb–X quantum-well thickness. Interaction between transition dipoles in adjacent PbX6 (X = Br or I) octahedra gives rise to highly anisotropic intra- and inter-layer exciton bandwidths. In flat (001) 2D HOIPs, both the ODP and the exciton bandwidths are susceptible to out-of-plane PbX6 tilting but not to the in-plane one, and their interplay can quantitatively account for the observed temperature and structure dependences of luminescence associated with STEs. In corrugated (011) 2D HOIPs, the exciton bandwidth is further reduced and the resultant STEs have a stronger lattice distortion and broader luminescence spectrum. Our results reveal the mechanism of STE formation and suggest ways of tuning STEs and associated broadband luminescence in 2D HOIPs.

The guiding ideas of our “ecological” education should have a turning transformation, that is, endowing “ecological” education with new contents and higher goal with the orientation of positive psychology. in the visual field of “ecological” education, it is suggested that strengthening ecological education should inject positive psychological factors into it, in the new mode of education, active teachers, students and classroom need to stimulate students' interest in learning, respect for students' unique personality, and inspire students with an appreciative view, eventually forming a positive educational concept to achieve the goal for the growth of physical and mental health, and it should, under the guidance of new ideas of education, regard the positive psychological factors as the breakthrough point of enhancing the “ecological” education development of professional courses so as to cultivate positive emotion, positive learning behavior, harmonious and healthy people.

The understanding of magnetoresistance (MR) in organic spin valves (OSVs) based on molecular semiconductors is still incomplete after its demonstration more than a decade ago. Although carrier concentration may play an essential role in spin transport in these devices, direct experimental evidence of its importance is lacking. We probed the role of the charge carrier concentration by studying the interplay between MR and multilevel resistive switching in OSVs. The present work demonstrates that all salient features of these devices, particularly the intimate correlation between MR and resistance, can be accounted for by the impurity band model, based on oxygen migration. Finally, we highlight the critical importance of the carrier concentration in determining spin transport and MR in OSVs and the role of interface-mediated oxygen migration in controlling the OSV response.

High-pressure structural response of an insensitive energetic crystal—1,1-diamino-2,2-dinitroethene (FOX-7)—was examined to gain insight into its structural and chemical stability and to obtain isothermal compression data. Using synchrotron single-crystal X-ray diffraction measurements, details of pressure-induced structural changes to 12.8 GPa were determined across three FOX-7 phases: α (P21/n), α′ (P21/n), and e (P1). We found that the C–NO2 bond is the most compressible chemical bond, and high pressure significantly reduces and homogenizes the length of H bonds in the hydrogen-bond network. The α′−e phase transition, at 4.5 GPa, significantly affects all molecular and crystal properties, whereas the α–α′ transition, at 2 GPa, is associated with subtle molecular and intermolecular changes. Anisotropic compressibility was observed over the entire pressure range, consistent with the layered structure of the crystal. The equation-of-state parameters were obtained using the third-order Birch–Murnaghan equa...

We have developed a hybrid method that can be applied to study isolated defects in semiconductor compounds and superlattices. The method is a combination of (1) a long-range tight-binding (TB) Hamiltonian, (2) a first-principles Hamiltonian, and (3) a Green’s function (GF) formalism. The calculation of the GF requires accurate energy band structure, wave functions, and defect potentials. The TB Hamiltonian with sp3 orbitals basis ensures accurate band gaps and band masses while providing the functional form for the wave functions. We calculated the band gaps of InAs/GaSb and InAs/InAsSb strained-layer superlattices and found them to agree well with measurements. The change in potentials caused by native point defects (NPDs) was obtained from a first-principles method using Spanish Initiative for Electronic Simulations with Thousands of Atoms, which also uses sp3 basis. We describe the method of calculating NPD energy levels in compounds and superlattices, obtain some defect levels in GaAs, InAs, InSb, and GaSb compounds, and provide details of the NPD-level calculations.

Understanding the insensitivity/stability of insensitive high explosive crystals requires detailed structural information at high pressures and high temperatures of interest. Synchrotron single-crystal X-ray diffraction experiments were used to determine the high-pressure structures of 1,1-diamino-2,2-dinitroethene (FOX-7), a prototypical insensitive high explosive. The phase transition around 4.5 GPa was investigated and the structures were determined at 4.27 GPa (α′ phase) and 5.9 GPa (e phase). The α′ phase (monoclinic, P21/n), structurally indistinguishable from the ambient α phase, transforms to the new e phase (triclinic, P1). The most notable features of the e phase, compared to those of the α′ phase, are formation of planar layers and flattening of molecules. Density functional theory (DFT-D2) calculations complemented the experimental results. The results presented here are important for understanding the molecular and crystalline attributes governing the high-pressure insensitivity/stability of ...