A new coumarin dye (see figure) for use in dye‐sensitized solar cells (DSSCs) is reported. It exhibits near‐unity light harvesting efficiency and incident photon‐to‐electron conversion efficiency ...(see figure) over a wide spectral region in 6 μm transparent TiO2 films. DSSCs based on this metal‐free organic dye show long‐term stability and power‐conversion efficiencies of around 6 % under continuous light‐soaking stress for up to 1000 h.
•A sorption thermal energy storage device for domestic heating is presented.•The new design scenario with valve-less adsorber and separate reservoir is adopted.•The newly developed composite sorbent ...of zeolite 13X/MgSO4/ENG-TSA is used.•The temperature lift is 65–69 °C at 25 °C adsorption and evaporating temperatures.•The impregnated MgSO4 dramatically accelerates the temperature rising rate.
A sorption thermal energy storage (TES) device for domestic heating is presented in this article. The TES device adopts the new design scenario with valve-less adsorber and separate reservoir to eliminate the large-diameter vacuum valve for vapor flow, which decreases the cost, reduces the vapor flow resistance, and improves the system reliability. The device is charged by electric heater, which can add much flexibility to the building energy system as well as contribute to the valley filling and peak shaving from the demand side management. The newly developed composite sorbent of zeolite 13X/MgSO4/ENG-TSA (expanded natural graphite treated with sulfuric acid) with the salt mass fraction of 15% in the zeolite 13X/MgSO4 mixture is tested and used in the TES device (denoted as XM15/ENG-TSA). Experimental results show that the TES device with XM15/ENG-TSA has the energy storage density of 120.3 kWh m−3 at 250 °C charging temperature and 25–90 °C discharging temperature. The temperature lift is as high as 65–69 °C under the adsorption and evaporating temperatures of 25 °C. The impregnated MgSO4 dramatically improves the temperature rising rate during the adsorption heat recovery process, but the specific energy storage capacity of XM15/ENG-TSA is similar to that of zeolite 13X/ENG-TSA. The effect of the impregnated MgSO4 suggests that MgSO4 can be used for low-temperature TES to relieve the self-hindrance of the hydration reaction.
Despite the utmost importance and decades of experimental studies on fatigue in metallic glasses (MGs), there has been so far little or no atomic-level understanding of the mechanisms involved. Here ...we perform molecular dynamics simulations of tension–compression fatigue in Cu50Zr50 MGs under strain-controlled cyclic loading. It is shown that the shear band (SB) initiation under cyclic loading is distinctly different from that under monotonic loading. Under cyclic loading, SB initiation takes place when aggregates of shear transformation zones (STZs) accumulating at the MG surface reach a critical size comparable to the SB width, and the accumulation of STZs follows a power law with rate depending on the applied strain. It is further shown that almost the entire fatigue life of nanoscale MGs under low cycle fatigue is spent in the SB-initiation stage, similar to that of crystalline materials. Furthermore, a qualitative investigation of the effect of cycling frequency on the fatigue behavior of MGs suggests that higher cycling frequency leads to more cycles to failure. The present study sheds light on the fundamental fatigue mechanisms of MGs that could be useful in developing strategies for their engineering applications.
Free-electron lasers have been successfully operated with ultrahigh brightness and excellent transverse coherence at X-ray wavelengths. One of the next goals for further improvements is full ...coherence. An obvious approach is to seed the free-electron laser interaction using a conventional source that has good temporal coherence. Here, we show the first lasing of a free-electron laser with an echo-enabled harmonic generation scheme, which shows great promise for producing coherent lasing at short wavelengths, even in the X-ray regime. The experiment was conducted at a test facility that combines a 135.4 MeV electron accelerator with an amplifier consisting of a series of undulator magnets. Lasing was achieved at the third harmonic of the seed with a gain of ∼100,000 over spontaneous radiation. The measurements show typical exponential growth and excellent spectral characteristics, as well as good intensity stability.
The composite sorbents of MgSO4-impregnated zeolite 13X and activated alumina are developed for thermal energy storage (TES) with different temperature ranges. The sorption and desorption ...characteristics of raw and MgSO4-impregnated activated alumina are studied, and the performances of the selected sorbents are tested in a closed-system TES device. The results are compared with those of raw and MgSO4-impregnated zeolite 13X. It is shown that the impregnated MgSO4 improves the overall TES performances of zeolite 13X and activated alumina. Compared to the raw host matrices, the impregnated MgSO4 remarkably accelerates the temperature-rising rate of zeolite 13X to about three times and improves the temperature lift of activated alumina by 32.5%. The experimental energy storage densities of MgSO4-impregnated zeolite 13X and activated alumina are 123.4 kWh m−3and 82.6 kWh m−3, respectively. The sorption temperature region of activated alumina is more aligned with the preferred hydration temperature of MgSO4 in comparison with zeolite 13X. The hydration characteristics of MgSO4 can resolve the solution leakage issue of open systems. Thermodynamic analysis is conducted to evaluate the performances of the TES device with different sorbents. It is found that entransy can be used to assess thermally and electrically driven TES systems reasonably.
•MgSO4-impregnated zeolite 13X and activated alumina are developed and tested.•The impregnated MgSO4 improves the overall performances of the host matrices.•Sorption temperature of activated alumina is more suitable for hydration of MgSO4.•Hydration characteristics of MgSO4 can resolve solution leakage of open systems.•Entransy can assess thermally and electrically driven TES systems reasonably.
One of the most promising approaches to reach a high gain in inertial confinement fusion is the fast ignition scheme. In this scheme, a relativistic electron beam is generated; this passes through ...the imploded plasma and deposits parts of its energy in the core. However, the large angular spread of the relativistic electron beam and the poorly controlled compression of the target affect realization of the fast ignition technique. Here, we demonstrate that indirectly driven (that is, driven by X-rays generated inside a gold hohlraum) implosions with a ‘high-foot’ and a short-coast time of less than 200 ps allow us to tightly compress the shell. Furthermore, we show the ability to optimize the symmetry of the imploding shell by changing the hohlraum length, successfully tuning a suitable tube-shaped shell to compensate for the large angular spread of the relativistic electron beam and to enhance the electron-to-core coupling efficiency via resistive magnetic fields. Benefiting from those experimental techniques, a significant enhancement in neutron yield was achieved in our indirectly driven fast ignition experiments. These results pave the way towards high-coupling fast ignition experiments with indirectly driven targets similar to those at the National Ignition Facility.Experiments realizing the indirect-drive fast ignition scheme for inertial confinement fusion are reported. Enabled by a tightly compressed target, an increase of neutron yield is observed.
•A facile route was developed to fabricate Co3O4@NMC OER/ORR catalysts.•Co3O4@NMC (1:3) exhibits a considerable ORR/OER activity and stability.•Accelerated kinetic charge transfer process is the main ...reason for catalysis.
A nanocomposite with mesoporous Co3O4 loaded on nitrogen-doped mesoporous carbon (Co3O4@NMC) has been constructed by a facile post-grinding process. The electro-catalytic experimental results show that Co3O4@NMC (1:3) can be regarded as the low-cost alternative ORR/OER bi-functional catalyst compared with commercial noble Pt/C + IrO2 catalysts. The potential difference (ΔE) between between E1/2 and Ej10 for Co3O4@NMC (1:3) sample is only 21 mV larger. Moreover, we observed no obvious degeneration in both ORR and OER activity during ADT tests. The enhancement of electro-catalytic activity can be attributed to the effective charge transfer process as suggested by the Tafel analysis due to the synergistic effect.
MicroRNA (miRNA) and long non-coding RNA (lncRNA) have been demonstrated to participate in the progression of many cancers. Hepatocellular carcinoma (HCC) is one of the most common and aggressive ...malignant tumors worldwide, while the molecular mechanisms underlying HCC tumorigenesis are not completely clear. In this study, we showed that miR-92b was significantly upregulated in tumor tissue and plasma of HCC patients, and its expression level was highly correlated with gender and microvascular invasion. Functionally, miR-92b could promote cell proliferation and metastasis of HCC in vitro and in vivo. Mechanistic investigations suggested that Smad7, which exhibited an inverse relationship with miR-92b expression in HCC, was a direct target of miR-92b and could reverse its effects on HCC tumorigenesis. Furthermore, long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) and miR-92b could directly interact with and repress each other, and XIST could inhibit HCC cell proliferation and metastasis by targeting miR-92b. Taken together, our study not only revealed for the first time the importance of XIST/miR-92b/Smad7 signaling axis in HCC progression but also suggested the potential value of miR-92b as a biomarker in the clinical diagnosis and treatment of HCC.
The rates for endoscopic detection of pancreas divisum at routine endoscopic retrograde cholangiopancreatography (ERCP) vary worldwide, and the sample sizes in the reported studies on endoscopy and ...surgery for pancreas divisum are very small and variable. The aim of this study was to systematically analyze the pooled data and determine endoscopic detection rates for pancreas divisum and pain relief rates in patients with pancreas divisum after endotherapy or surgery.
A search for published data was performed by using the Medline database (1950 to 1st May 2008) with "pancreas divisum" as the keyword. Publications, mainly on endoscopic detection rate, endotherapy, or surgery for pancreas divisum, were deemed relevant, and were further fully reviewed and analyzed.
A total of 615 abstracts were retrieved from Medline; 17 articles on endoscopic detection rate, 15 articles on endotherapy, and 13 articles on surgery were included in the review and analysis. The overall endoscopic detection rate for pancreas divisum was 2.9% (899/31,413), with the rate being significantly higher in the United States (5.8%) and Europe (6.0%) than in Asia (1.5%) (both P < 0.001). The pooled overall response rates (i. e. complete and partial pain relief rates after treatment) to endotherapy (69.4%, 361/520) and surgery (74.9%, 203/271) were similar (P = 0.106). In addition, there were significant differences in the combined response rates (for endotherapy and for surgery) between patients with pancreas divisum of acute recurrent pancreatitis (ARP)-type (81.2 %) compared with chronic pancreatitis-type (68.8%), and between ARP-type and pain-type (53.1%) (both P < 0.05).
The endoscopic detection rate for pancreas divisum is much higher in western countries than in Asian countries. The pooled response rates of patients with pancreas divisum to endotherapy and surgery are similar in the reported series. Patients with ARP-type pancreas divisum respond better to endotherapy or surgery than those with chronic pancreatitis-type and pain-type.
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