This prospective observational study examined changing trends of excess self-protective behavior (EPB), and their association with perceived risk, perceived severity, and irrational beliefs about prevention during the Chinese COVID-19 epidemic. Participants were recruited for an online panel survey. There are 150 participants for the baseline and 102 for the final survey. There were 5 waves of interviews. Perceptions of risk and disease severity were measured by single items. Irrational beliefs about prevention and EPB comprised 5 common prevention misconceptions. Descriptive statistics and the CATMOD program were used for data analysis. The prevalence of participants perceiving personal risk of contracting COVID-19 and severe consequences of the disease was 18.6% and 25.5%, respectively, at baseline, and declining to 4.9% and 17.6% at final observation. The 5 selected EPB also showed a diminishing trend. Belief in COVID-19 prevention myths trended upwards. Perceived risk was positively associated with each EPB, and perceived severity with disinfection of clothes and hoarding of products. Myth adherence was positively associated with disinfection of clothes and both hand washing and sanitization. This study yields new information about EPB among the Chinese public. Policy modifications and public education interventions are essential for minimizing the adverse health effects of subscribing to irrational beliefs.

In the few weight loss studies assessing diet quality, improvements have been minimal and recommended calculation methods have not been used. This secondary analysis of a parallel group randomised trial (regsitered: https://clinicaltrials.gov/ct2/show/NCT03367936) assessed whether self-monitoring with feedback (SM + FB) v. self-monitoring alone (SM) improved diet quality. Adults with overweight/obesity (randomised: SM n 251, SM + FB n 251; analysed SM n 170, SM + FB n 186) self-monitored diet, physical activity and weight. Real-time, personalised feedback, delivered via a study-specific app up to three times daily, was based on reported energy, fat and added sugar intake. Healthy Eating Index 2015 (HEI-2015) scores were calculated from 24-hour recalls. Higher scores represent better diet quality. Data were collected August 2018 to March 2021 and analysed spring 2022. The sample was mostly female (78·9 %) and white (85·4 %). At baseline, HEI-2015 total scores and bootstrapped 95 % CI were similar by treatment group (SM + FB: 63·11 (60·41, 65·24); SM: 61·02 (58·72, 62·81)) with similar minimal improvement observed at 6 months (SM + FB: 65·42 (63·30, 67·20); SM: 63·19 (61·22, 64·97)) and 12 months (SM + FB: 63·94 (61·40, 66·29); SM: 63·56 (60·81, 65·42)). Among those who lost ≥ 5 % of baseline weight, HEI-2015 scores improved (baseline: 62·00 (58·94, 64·12); 6 months: 68·02 (65·41, 71·23); 12 months: 65·93 (63·40, 68·61)). There was no effect of the intervention on diet quality change. Clinically meaningful weight loss was related to diet quality improvement. Feedback may need to incorporate more targeted nutritional content.

Suicides are prone to misclassification during death-ascertainment procedures. This problem has generated frequent criticism of the validity of suicide mortality statistics. The study aim was to employ an external measure of the validity of cause-of-death statistics, national autopsy rates, to examine potential misclassification of suicide across 35 countries. Data for the time period 1979–2007, were employed to analyze the association between suicide rates and autopsy rates and death rates of undetermined and ill-defined causes, respectively. Autopsy rates among nations were associated with suicide rates. These respective associations were robust with adjustment for unemployment, degree of urbanization, and the rate of undetermined or ill-defined deaths. Associations strengthened when analyses were confined to 19 EU member countries. Based on these results, we conclude that autopsy rates may impact the validity of suicide mortality statistics. Therefore, caution should be exercised in comparing international suicide rates and evaluating interventions that target suicide rate reduction.

Differential scanning calorimetry experiments on mixed Cu2-xS, ZnS, and SnS2 precursors were conducted to better understand how Cu2ZnSnS4 (CZTS) and Cu2SnS3 form. The onset temperatures of Cu2SnS3 reactions and CZTS suggest that the ZnS phase may mediate Cu2SnS3 formation at lower temperatures before a final CZTS phase forms. We also found no evidence of a stable Cu2ZnSn3S8 phase. The major diffraction peaks associated with Cu2ZnSnS4, and Cu2SnS3 (overlaps with ZnS, as well) began to grow around 380 °C, although the final reaction to form Cu2ZnSnS4 probably did not occur until higher temperatures were reached. An exothermic reaction was observed corresponding to formation of this phase. There was some variability in the onset temperature for reactions to form Cu2SnS3. At least 5 steps are involved in this reaction and several segments of the reaction had relatively reproducible energies.

Device quality CdS/CdTe heterostructures and completed solar cells (∼12% efficient) have been studied using photoluminescence (PL) as a function of temperature and laser excitation power. The CdS/CdTe junctions were grown on transparent conducting oxide covered soda lime glass using radio frequency sputter deposition. In the current work we found that the PL spectra of sputtered and thermally evaporated CdTe absorber films share common features. It was found that the luminescence shifts from being dominated by sub-gap defect-mediated emission at lower excitation powers to near band edge excitonic emission at higher excitation powers. It was found that the presence of Cu suppresses the sub-band gap PL emissions. This effect was concluded to be due either to Cu occupying cadmium vacancies (VCd) or forming acceptor complexes with them. This points to a potential role of Cu in eliminating sub-band gap recombination routes and hence increasing the charge separation ability of the device.

The role of intrinsic point defects on radiative recombination in Cu(In,Ga)Se2 thin films was investigated by photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. Experiments were performed on device-grade polycrystalline layers and single crystal thin films. PL transitions identified by others as indicating a shallow state with an ionization energy of ∼16 meV is proposed to be a transition into band tail states rather than a distinct shallow defect. The presence of deep levels contributing to radiative recombination does not necessarily preclude the material from producing a high efficiency device and may suggest the absence of dominant non-radiative recombination pathways. The band edge width as measured by PLE and the separation of this edge from defect states are suggested to be potentially effective indicators of the quality of a material. Luminescence that appears to be connected with the absence of Na in the growth process persists in high Ga alloy, Na containing materials, suggesting that Na may become ineffective in passivating or eliminating certain defects in high Ga material.

The linear polarisation of luminescence light allows conclusions on the symmetry of defects in semiconductors with non-cubic symmetry, like chalcopyrites, for which three shallow acceptors have been identified by photoluminescence. The polarisation dependent photoluminescence allows to determine the symmetry of the defects relative to the c-axis of the crystal. A simple geometrical model implies that chalcogen sites show a predominant direction perpendicular to the c-axis, while metal sites show a predominant direction parallel to the c-axis. Since all three shallow acceptors show polarization parallel to the c-axis, it can be concluded that they are situated on a metal site

An analysis of the fluid flow and mass transfer induced by ventilation systems in containership holds was carried out. The result of the work was used to support the U.S. position before a committee of the International Convention on Safety to Life at Sea. The analysis consists of a detailed calculation of the forced motion through an interconnected set of narrow, stably stratified, vertical air passages, which represent an idealized containership hold. The results of this calculation were then used to predict the vapour concentration of spilled volatile material assumed to lie at the bottom of the vertical air passages. The result is a set of formulae which determine the rate of extraction of volatile material as a function of hold geometry, ventilation parameters, and ambient stratification. A variety of computed results are presented. The results indicate the crucial importance of locating the extractor as close to the hold bottom as technically possible.

An experimental study was made of the steady-state natural convection induced in enclosures by a small hot spot centrally located on the floor. Enclosures of rectangular and circular floor plan were employed, with height equal to one-half the major dimension of the floor plan. The movement of air within the chambers was made visible by adding metaldehyde dust particles and illuminating them with an intense light beam. The Grashof number (Gr) based on hot-spot temperature and enclosure height ranged from 8 × 105 to 1 × 1010. Laminar flows were observed for Gr [lsim ] 1.2 × 109. The experimental flows in the circular chamber are compared in a companion paper with theoretically calculated flows (Torrance & Rockett 1969). In the region of laminar flows the agreement was excellent. The present paper notes certain similarities in the flows in rectangular and circular geometries. The disturbing effect of a slight heating of one wall of the rectangular enclosure was also investigated. Measurements were made of heat transfer from the hot spot to the air in the chamber.

An analytical study was made of the natural convection induced in an enclosure by a small hot spot centrally located on the floor. The enclosure was a circular cylinder, vertically oriented, with height equal to radius. A Prandtl number of 0.7 (air) was assumed; the Grashof number (Gr) was based on cylinder height and hot spot temperature. The equations of fluid flow in axisymmetric cylindrical co-ordinates were simplified with the Boussinesq approximation. The equations were solved numerically with a computationally stable, explicit method. The computation, starting from quiescent conditions, proceeded through the initial transient to the fully developed flow. Solutions were obtained for Gr from 4 × 104 to 4 × 1010. The theoretical flows are in excellent agreement with experimentally observed laminar flows (Gr [lsim ] 1.2 × 109) which are discussed in a companion paper, Torrance, Orloff & Rockett (1969). Turbulence was observed experimentally for Gr [gsim ] 1.2 × 109. When the theoretical calculations were extended to Gr = 4 × 1010, a periodic vortex shedding developed, suggestive of the onset of laminar instability. The theoretical results reveal a √Gr scaling for the initial flow transients and, at large Gr, the velocities and heat transfer rates.

Analytical TEM techniques have been used to characterize the structure and chemistry of chalcopyrite solar cell devices produced by elemental evaporation using a bi-layer process at Ts=400°C and Ts=550°C. Dislocations, stacking faults, twins and voids exist in both materials but at a reduced density at the higher deposition temperature. The higher processing temperature also improved the density and structure of the grain boundaries and created a less rough surface. The CdS layer coats the surface conformally, although the roughness impacts the structure. CdS fills the grooves in the surface and infiltrates lower density grain boundaries to significant depths. The chemistry of the grain boundaries does not appear to be significantly impacted by the presence of the Cd and S.

The surface chemical composition of Cu(In, Ga)Se2 (CIGS) alloys and CIGS/CdS interfaces are characterized by photoelectron emission spectroscopy. The results show that there is a severe but shallow (1-2 atomic layers) Cu depletion at {112} surfaces of CuInSe2 epitaxial films, consistent with earlier results. The depletion is not due to the existence of ordered defect compounds, but likely a result of the reconstruction of polar CIGS surfaces. Cd was found incorporated into the top 1-2 atomic layers of Cu-poor surfaces of CIGS, which may explain the n-type surface inversion in finished devices. These results and others formed the basis of a numerical model of CIGS solar cells. It is argued from the experimental and simulation results that the performance of devices based on high Ga content alloys may be reduced by failure to dope the surface of CuGaSe2 sufficiently n-type. The effect of observed defect states on the energy gap is considered, in particular with respect to pinning of the Fermi level near the heterojunction. By contrast, devices based on high In-content alloys show strong surface inversion in CIGS/CdS heterojunctions, which is suggestive of an effect of Cd incorporation in the CIGS surface.

The microstructure and microchemistry of Cu(In, Ga)Se2 (CIGS) films have been analyzed by means of transmission electron microscopy (TEM). Specimens were obtained from a number of groups producing high-performance solar cells from these materials. Both plan-view and cross-sectional TEM samples were prepared by mechanical grinding and ion milling. Twins can be found easily within the films while dislocations are present only in a few grains and with low density. No extended structural defects such as stacking faults were discovered. X-ray energy dispersive spectroscopy was used to study the chemical composition of grains and grain boundaries. Experimental results showed no difference between the composition in the grain interiors and the grain boundary. In addition, there is no obvious enhancement of oxygen and sodium at grain boundaries. Structural depth dependences were also not found.