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The Ge-film-based photon-counting imaging detector is a key component of optical payload in space weather observation. It’s important to study the space temperature adaptability of Ge film since the performances of Ge film are extremely sensitive to the temperature. Herein, the in-situ tests are proposed to measure the resistance and stress of the Ge film at the operating temperature. It is demonstrated that the resistance decreases from 520 MΩ/□ to 124 MΩ/□ linearly between -20 °C and 80 °C, which can meet the requirement of the imaging system well. And the stress gradually releases in the thermal cycle. The ex-situ test is adopted to investigate the limited temperature adaptability and the intrinsic mechanism of performance variations. When the temperature increased to 600 °C, Ge film failed and cracked because of resistance reducing to 30 KΩ/□ and stress increasing to 504 Mpa. Meanwhile, methods were proposed to enhance the temperature adaptability of Ge film by analyzing crystal phase and optical band gap. Thus, the resistance and stress changes of Ge film in space have little effect on the performances of imaging system. The Ge film with high temperature adaptability and low stress we prepared is promising in the space observation.

Inflammatory myofibroblastic tumor (IMT) is a rare tumor with an indolent course. It is less often reported as a second tumor that occurs after treatment of malignant tumors in pediatric patients. Here, we report a case of IMT following Wilms tumor (WT), and conduct a literature review concerning IMTs and WT to evaluate the diagnostic possibility of IMT as a second tumor. The coexistence of the 2 tumors may cause confusion as to whether they share genetic links or that IMTs may appear as late effects of the treatment of WT.

In this perspective, we outline that a space borne gravitational wave detector network combining LISA and Taiji can be used to measure the Hubble constant with an uncertainty less than 0.5% in ten years, compared with the network of the ground based gravitational wave detectors which can measure the Hubble constant within a 2% uncertainty in the next five years by the standard siren method. Taiji is a Chinese space borne gravitational wave detection mission planned for launch in the early 2030 s. The pilot satellite mission Taiji-1 has been launched in August 2019 to verify the feasibility of Taiji. The results of a few technologies tested on Taiji-1 are presented in this paper. Gravitational wave astronomy has opened the door to test general relativity and the effect of gravity in the Universe. The authors present the capabilities of an overlap between space gravitational wave detectors LISA and Taiji to constrain the Hubble constant to 0.5%, in 10 years, and what can be learned from the satellite pilot Taiji-1 launched in 2019.

Vegetation in slopes can effectively improve slope stability. However, it is difficult to estimate the effects of vegetation on slope stability because of variations in plant species and environmental conditions. Moreover, influences of plant growth on slope stability change with time, resulting in changes in the safety factor. This study was conducted to evaluate the stability of vegetated slopes with time and investigate the effects of different layouts of plant species on slope stability. Here, we used a plant growth model and slope stability analysis to build an evaluation model. To accomplish this, one species of tree, shrub and grass was chosen to set six layout patterns. A slope with no vegetation served as a control. The safety factors of the seven slopes were then calculated using the developed evaluation model and differences in the safety factors of slopes were compared and discussed. The slope vegetated with Platycladus orientalis reached the most stable state at the age of 60 years. Shrub slope (Vitex negundo) had the maximum safety factor after 20 years. Overall, the safety factor of vegetated slopes increased from 12.1% to 49.6% compared to the slope with no vegetation. When wind force was considered, the safety factor value of the slope changed from 3.5% to 43.5%. Vegetation mixtures of trees and grasses resulted in the best slope stability. Planting grasses on slopes can improve slope stability of trees to a greater degree than that of slopes with shrubs in the early stage of growth.

Objective To investigate the effect and mechanism of total paeony glycosides (TPG) on spinal cord apoptosis in rats with spinal cord injury (SCI). Methods A total of 18 SD rats were randomly divided into control group, SCI group and TPG group (6 each). The SCI rat model was established using Allen method. For rats in control group, the spinal cord was sutured directly after laminectomy without spinal cord injury; those in TPG group were intraperitoneally injected with 25 mg/kg TPG every 24 hours after the establishment of SCI model, while those in SCI group and control group were intraperitoneally injected with the same volume of normal saline for 28 days. The rats' behavioral score were evaluated using Basso-Beattie-Bresnahan (BBB) method. The apoptosis of spinal cord cells was measured by flow cytometry. Western blotting was performed to detect the expression levels of cell apoptotic protein cleaved caspase-3 and cleaved caspase-9. The contents of MDA, SOD and LDH in the supernatant of spinal fluid were quantified with corresponding kits. Results Compared to those in control group, the BBB score decreased significantly, while the apoptosis rate of spinal cord cells and the expression levels of cleaved caspase-3 and cleaved caspase-9 were obviously elevated, and the contents of MDA and LDH increased, SOD decreased in the supernatant of spinal fluid in the rats of SCI group (P

Members of Fusarium graminearum species complex (FGSC) are the major pathogens that cause Fusarium head blight (FHB) in cereals worldwide. Symptoms of FHB on rice, including dark staining or browning of rice glumes, were recently observed in Jiangsu Province, China. To improve our understanding of the pathogens involved, 201 FGSC isolates were obtained from freshly harvested rice samples and identified by phylogenetic analyses. Among the 201 FGSC isolates, 196 were F. asiaticum and the remaining 5 were F. graminearum. Trichothecene chemotype and chemical analyses showed that 68.4% of the F. asiaticum isolates were the 3-acetyldeoxynivalenol (3ADON) chemotype and the remainder were the nivalenol (NIV) chemotype. All of the F. graminearum isolates were the 15-acetyldeoxynivalenol chemotype. Pathogenicity assays showed that both the 3ADON and NIV chemotypes of F. asiaticum could infect wheat and rice spikes. FHB severity and trichothecene toxin analysis revealed that F. asiaticum with the NIV chemotype was less aggressive than that with the 3ADON chemotype in wheat, while the NIV-producing strains were more virulent than the 3ADON-producing strains in rice. F. asiaticum isolates with different chemotypes did not show significant differences in mycelial growth, sporulation, conidial dimensions, or perithecial production. These findings would provide useful information for developing management strategies for the control of FHB in China.

Background To analyze the relationship between tumor viability in specimens retrieved at second-look procedures (SLPs) and clinical outcomes in patients with bladder/prostate rhabdomyosarcoma (BP RMS). Methods We retrospectively analyzed patients` characteristics, times between diagnoses and SLPs, types of SLPs, the pathological findings, and clinical outcomes between January 2003 and May 2014. Results A total of 29 patients underwent at least one SLP before completing chemotherapy, including 24 boys and 5 girls. The mean age was 36 months. No patients with clinical/radiographic complete responses (CRs) had viable tumor cells and 7/18 patients (38.9%) without CR had no viable tumor cells. Seven patients experienced tumor relapse, progression, and metastasis, and three of these survived. Five-year event-free survival (EFS) rates were 88.5% in 18 patients without viable tumor at SLPs and 54.5% in 11 patients with viable tumor (Cox proportional hazards adjusted P=0.045). The respective five-year overall survival (OS) rates were 94.1% and 72.7% (Cox proportional hazards adjusted P=0.175). Conclusions EFS was increased in patients with BP RMS having no viable tumor cells; however, OS was comparable in patients with and without viable tumor cells. Patients who achieved CR during the treatment generally had no viable tumor cells.

Piperine (PIP) exerts numerous pharmacological effects and its involvement in endoplasmic reticulum (ER) stress (ERS)-led apoptosis has garnered attention. The present study focused on whether PIP played protective effects on hypoxia/reoxygenation (H/R)-induced cardiomyocytes by repressing ERS-led apoptosis. The potential molecular mechanisms in association with the PI3K/AKT signaling pathway were investigated. Primary neonatal rat cardiomyocytes (NRCMs) were isolated and randomized into four groups: Control + vehicle group, control + PIP group, H/R + vehicle group and H/R + PIP group. The H/R injury model was constructed by 4 h of hypoxia induction followed by 6 h of reoxygenation. A total of 10 µM PI3K/AKT inhibitor LY294002 was supplemented to the cells during the experiments. Cell viability and myocardial enzymes were detected to evaluate myocardial damage. A flow cytometry assay was performed to assess apoptotic response. Western blot analysis was performed to detect the expression of related proteins including PI3K, AKT, CHOP, GRP78 and cleaved caspase-12. The results showed that H/R markedly promoted myocardial damage as shown by the increased release of lactate dehydrogenase and creatine kinase levels, but a reduction in cell viability. In addition, ERS-induced apoptosis was markedly promoted by H/R in NRCMs, as shown by the increased apoptotic rates and expression of C/EBP-homologous protein, endoplasmic reticulum chaperone BiP and caspase-12. PIP administration reversed cell injury and ERS-induced apoptosis in H/R. Mechanistic studies concluded that the apoptosis-inhibitory contributions and cardio-favorable effects of PIP were caused partly by the activation of the PI3K/AKT signaling pathway, which was verified by LY294002 administration. To conclude, PIP can reduce ERS-induced apoptosis by activating the PI3K/AKT signaling pathway during the process of H/R injury, which could be a potential therapeutic target for the treatment of myocardial ischemia/reperfusion injury.

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Purpose To present the clinicopathological characteristics and outcome of children with bladder and ureteral inflammatory myofibroblastic tumors (IMTs) in our center. Methods We reviewed the medical records of patients with bladder and ureteral IMTs from 2010 to 2018. We recorded patients’ demographic data, presentation, hemoglobin level, presence of hydronephrosis, tumor size, treatment, and outcomes. Results Eight patients with bladder IMTs and 3 with ureteral IMTs were treated at our center during this period. The mean age was 7.1 years. Four patients presented with anemia at diagnosis with the mean hemoglobin level 84.5 g/L. Among patients with bladder IMTs, 5 were male and 3 were female. The most common symptom was lower urinary symptoms in 6 patients, followed by hematuria in 4 patients. 2 patients had complications of hydronephrosis and hydroureter. Among patients with ureteral IMTs, 2 were male and one was female. The most common symptom was abdominal pain, and 3 patients presented with upper urinary tract dilation. All patients underwent surgery. A total of 81.8% were positive for anaplastic lymphoma kinase. Cytokeratin (CK) expression was present in all patients with bladder IMTs, while it was negative in 2 patients with ureteral IMTs. During mean follow-up of 43.4 months, all patients survived event-free. Conclusion The presence of hydronephrosis and hydroureter is rare in patients with bladder IMTs. Anemia caused by hematuria should be raised the index of suspicion for IMTs. Children with bladder and ureteral IMTs had excellent prognosis. The expression pattern of CK varied between bladder and ureteral IMTs.

A disposable surface-enhanced Raman scattering (SERS) substrate was prepared by successively spraying silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) onto commercial filter paper using an inexpensive consumer sprayer. The strong surface enhancement of AgNPs and chemical stability of AuNPs can be advantageously combined. The substrate exhibited excellent SERS activity for malachite green (MG), methylene blue (MB), and crystal violet (CV) under 785-nm excitation, with limits of detection (LODs) of 4.3 × 10−9, 2.0 × 10−8, and 8.1 × 10−8 M, respectively. The substrate exhibited long-term stability, and it can be stored under ambient conditions for 4 weeks with a relative standard deviation of less than 3% among peak intensities. The substrate also showed good reproducibility with a relative standard deviation of 7.1% among different substrate peak intensities. The substrates enable on-site determination of residual fishery drugs and distinguish MG, MB, and CV mixtures in spiked fish within 5 min, and the average recoveries in fish scales and fish meat were better 90.1% and 76.9%, respectively. The method exhibited rapidity, simplicity, and high sensitivity and is expected to be used for the screening of additives in food.

Objectives The present work evaluated preventive effect of curcumin on cisplatin-induced bladder cystopathy. Methods Fifteen female rats were divided into (i) Control group administered with physiological saline solution for 5 days; (ii) Cis-P group injected with cisplatin (6 mg/kg); and (iii) Cis-Cur group given cisplatin (6 mg/kg) with curcumin for 5 consecutive days. The function of bladder was measured by means of urodynamic analysis. Furthermore, hematoxylin-eosin staining and Masson trichrome staining were performed for morphological analysis. The cell apoptosis was evaluated through terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay and flow cytometry. The expression of nerve growth factor (NGF), NF-E2-related factor 2, and hemeoxygenase-1 (HO-1) levels were measured through Western blotting. Results Urodynamic assay and histopathological manifestations revealed that curcumin ameliorated the bladder dysfunction induced by cisplatin. The level of cisplatin-induced apoptosis in the bladder decreased following curcumin treatment. Also, the increased protein expression of NGF indicated that the curcumin could offer neuroprotection for bladder against cisplatin. Curcumin also activated NRF2, and elevated the expression of HO-1, but curcumin could not rescue cisplatin-induced apoptosis in the cell lines with knockdown of NRF2. Conclusions Taken together, the results of this paper showed that curcumin could ameliorate cisplatin-induced cystopathy and inhibit the apoptosis of bladder cell in cisplatin-treated rats. This may be attributed to curcumin's broad biological functions, particularly antioxidant effect, and to its ability to activate the NRF2 protein.

Hyperbilirubinemia refers to an increase in bilirubin (BR) levels and is a serious health concern; in severe cases, hyperbilirubinemia can lead to the death of newborns infants within the first month. Traditional analytical technologies normally involve complex sample pretreatment procedures yet present unsatisfactory detection limits for BR levels. In this study, we developed a recyclable surface-enhanced Raman scattering (SERS) substrate by modifying functional boron nitride (M-BN) monolayer nanosheets on silver nanoarrays (Ag NRs/M-BN) for label-free detection of BR in complex biological samples. Modification of M-BN to silver nanoarrays (Ag NRs) significantly improved the detection sensitivity and long-term stability of the substrate due to the strong surface adsorption ability and thermal stability of M-BN. The limit of detection (LOD) of BR in blood obtained from the Ag NRs/M-BN was as low as 2.5 × 10−8 M, which was attributed to its superior affinity for hydrophobic BR molecules. The spiked blood samples were practically tested with recovery values of around 80 %, and relative standard deviations (RSD) were less than 15 %. The results, combined with the excellent reusability of the as-developed substrates, indicated that the Ag NRs/M-BN substrate provides a simple yet promising platform for nondestructive detection of BR.

Taiji-1 satellite was successfully launched on 31 August 2019, and it has been operating normally in orbit until now. A series of in-orbit experiments were carried out with the inertial sensor, which included the micro-thrust test, drag-free control test and laser interferometer test. Comprehensive performance simulations and tests of the inertial sensor were also carried out prior to the launch of Taiji-1, including the calibration and drop-tower tests. These tests were one of the preconditions for the success of these experiments. The calibration experiments were conducted in a cave-lab using the gravity-inclination method and the scale factors of the inertial sensor along Y- and Z-axis were measured. In addition, 20 drop-tower tests were carried out in the National Microgravity Laboratory of China (NMLC) drop tower and the control stability of all the axes was tested and optimized. A simulation model was used before each test, and the results showed that an accurate simulation prior to each experiment had an important role in ensuring the efficiency and accuracy of the experiment. The circuit-gain switch was realized for the first time during the drop-tower tests. The test results indicated that the microgravity level of the NMLC drop tower could reach about 13 [Formula: see text]g0 along the horizontal axes, offering an important reference for researchers planning to conduct microgravity experiments in the NMLC drop tower.

Detection of target analytes with high sensitivity and reproducibility remains a challenge for surface-enhanced Raman scattering (SERS) due to the lack of cost-effective and highly sensitive substrates. In this study, a hydrophobic SERS substrate capable of concentrating nanoparticles and analytes was prepared by spin-coating lubricating liquid onto commercial paper. The condensation effect of the paper-based hydrophobic substrate induced aggregation of gold nanoparticles (Au NPs) to generate ‘‘hot spots’’ for SERS and to drive analytes to the hot-spot areas for more sensitive detection. The obtained SERS signal intensity was 5-fold higher than that obtained using common paper, and a detection limit (LOD) of 4.3 × 10−10 M for rhodamine 6G (R6G) was achieved. Randomly selected points on the substrate and different batches of substrates all exhibited high reproducibility, and the relative standard deviation (RSD) at 1362 cm−1 is approximately 11%. A further application of the hydrophobic substrate was demonstrated by the detection of cytochrome C within a linear detection range of 3.90 × 10−8 M–1.25 × 10−6 M. In addition, the prepared substrate can obtain identifiable SERS spectra of cancer cells and non-cancer cells because a large number of AuNP or Au NPs clusters can adhere to cells, resulting in the construction of a 3D hotspot matrix. The disposable hydrophobic paper substrate eliminates the problem of solution diffusion, and also provides an effective platform for biomolecular screening detection.

A large number of artificial or natural vegetation grow on the both sides of expressway, which play an important role in automobile gas purification and environmental protection. With the development of transportation, more and more reconstruction and extension projects spread up all over the country. However, those valuable biological resources are usually handled by rough means, which cause a waste of resources and damage of environment. Based on this, this paper intends to carry out roadside vegetation protection research in combination with the actual reconstruction and extension project of expressway. Evaluations of the roadside vegetation value are discussed and proposed. Results could provide reference for the roadside vegetation protection for reconstruction and extension project of expressway.

When studying the wavelength response to the temperature of the single mode fiber interference laser spectrum, a three layer BP neural network model is built to solve the problem of high complexity and low accuracy of temperature measurement system. With the Discussion of the parameters of network model, we obtain the optimal network structure by comparing the data acquisition which is the laser wavelength corresponding to its temperature trained by BP neural network. With network training completed and the wavelength of input laser reached the specified value, the corresponding temperature prediction can be obtained from the output layer. In conclusion, it shows a clear correlation between the predictive value and the actual value, i.e. the former is approximately equal to the latter. The correlation coefficients of the calibration and prediction are 0.999 61 and 0.979 27, respectively; while the standard errors of the calibration and prediction are 0.017 5 and 0.144 0, respectively, and the average relative error of prediction set is 0.17%. The residual predictive deviation (RPD), obtained theoretically, is 5.258 3. RPD3. It indicates that the calibration effect is good, and the model can be used for practical testing. In addition, the algorithm is also applied to the system of double coupled structure with single-mode core-offset fiber and correction for the temperature measurement. The results show that BP neural network method can deal with the nonlinear relationship between the laser spectral data and the temperature in the optical fiber temperature measurement system. The correlation and the average relative error between the predicted temperature and the true temperature are 0.996 58 and 0.63%, respectively. The precision and stability of the fiber optic temperature sensor are significantly improved. At the same time, the feasibility of the proposed algorithm is verified in the fiber optical sensor system. It also provides a new way for the accurate measurement of pressure, curvature and other physical quantities of the core-offset fiber.

It has been previously suggested that cytokeratins (CKs) are important diagnostic and prognostic biomarkers for urothelial lesions. Hence it is imperative to understand the expression pattern of cytokeratins during formation of papillary bladder cancer, which was the objective of the current study. Expression pattern of CK14 and CK18 were examined using immunohistochemical staining in a mice model of papillary bladder cancer. Twenty female mice were divided into two groups—group 1 (NT) and group 2, which received N-butyl- N-(4-hydroxybutyl) nitrosamine (BBN) for 20 weeks plus one week without treatment. Following histological classification of bladder lesions, CK14 and CK18 immunostaining was assessed according to its distribution and intensity. In NT animals, both basal cells and umbrella cells showed sporadic positive staining for CK14 and CK18, respectively. In BBN group, hyperplastic lesions showed significantly more CK14 and significantly less CK18 staining ( P Impact statement Studies have shown that expression of cytokeratins (CKs) or their altered distribution affects the bladder cancer pathogenesis and disease outcome, while the underlying mechanisms are not clear. The present study aims to explore the expression pattern of CK14 and CK18 during formation of papillary bladder cancer. The results showed that hyperplastic lesions showed significantly more CK14 and significantly less CK18 staining and invasive carcinomas showed increased CK14 immunostaining in all epithelial layers in N-butyl- N-(4-hydroxybutyl)nitrosamine (BBN)-induced mouse model. The results indicate that altered CK14 (high) and CK18 (low) expression is perhaps an early event in bladder cancer tumorigenesis and is characteristic of both urothelial superficial pre-neoplastic and neoplastic lesions, which may provide the early diagnosis index.

Amorphous germanium (a-Ge) films in the thickness range of 5.2–370.7 nm were prepared by radio frequency magnetron sputtering. Spectroscopic ellipsometry analysis shows that less than 3% of medium-range order exists in a-Ge under the reported deposition conditions.

Background Concerns regarding the use of selected bone marrow stem cells (BMSCs) in the field of cardiac repair after acute ischemic events have been raised. The current meta-analysis aimed to assess the efficacy and safety of selected BMSC transplantation in patients with acute myocardial infarction (AMI) based on published randomized controlled trials (RCTs). Methods A systematic literature search of PubMed, Ovid LWW, BIOSIS Previews, and the Cochrane library from 1990 to 2014 was conducted. Results from RCTs involving subjects with AMI receiving selected BMSC therapy and followed up for at least 6months were pooled. Results Eight trials with a total of 262 participants were included. Data were analyzed using a random effects model. Overall, selected BMSC therapy improved left ventricular ejection fraction (LVEF) by 3.17% (95% confidence interval [CI] 0.57–5.76, P=0.02), compared with the controls. There were trends toward reduced left ventricular end-systolic volume (LVESV) and fewer major adverse cardiac events (MACEs). Subgroup analysis revealed a significant difference in LVEF in favor of selected BMSC therapy with bone marrow mesenchymal stem cells (BMMSCs) as the cell type. Conclusions Transplantation of selected BMSCs for patients with AMI is safe and induces a significant increase in LVEF with a limited impact on left ventricular remodeling.

For the engine maintenance enterprises, the test of aeroengine test can detect the performance of the product more accurately, but the engine testing work is a weak link. Conventional piston aircraft engine test system is the simulation instrument, according to the observed by human eyes, manual way to complete data collection work, this test system is inefficient. The engine bench test automatic measurement and control and monitoring system based on computer control is the inevitable trend of its development. Data acquisition module transmits the real-time data from the engine sensor installed on the different parts to the PC through CAN bus and display on the PC. The engine test bed control system and data acquisition system simplifies the system structure and obviously improves the test level and efficiency of the system.

A spectrum-folded Hadamard Transform spectrometer in near-infrared band has been proposed and designed to widen the spectral range of measurement as well as to improve the spectral resolution. The full spectral region of 800 nm to 2000 nm is divided into two bands of 800 nm to 1400 nm and 1400 nm to 2000 nm and dispersed by two sub-gratings. The optimal incident angles of 12.6 degrees and 6.7 degrees respectively for two sub-gratings are chosen to achieve the highest diffraction efficiency. The results show that the spectral resolution of the system is better than 6 nm. The stray light from sub-gratings and DMD are suppressed to minimize the effect on the measurement results. (C) 2014 Elsevier B.V. All rights reserved.

To observe the retention time and effect of acellular porcine pericardium (APP) in bone regeneration for rabbit femoral bone defects.APP was prepared as follows: fresh porcine pericardium was chosen, high and low osmotic NaCl solution were used to soak the specimen alternately, trypsin+EDTA were used for digest, and then immersed with TritonX-100, cross-linked by using glutaraldehyde. 24 New Zealand rabbits were selected, and the area of bone defect was created 8 mm×8 mm×5 mm in size on bilateral distal femur. Stochastic method was used for grouping. One side of bone defect was covered with APP (experimental group); and the other side was covered without APP (control group). General observation, X-ray examination, histological examination, and bone mineral density (BMD) were performed 4 weeks, 8 weeks and 12 weeks after operation. SPSS18.0 software package was used for statistical analysis.After surgery, all wounds healed without complications. Under general observation, there were some fibrous cysts covered on the surface of APP. BMD (P0.05) in the experimental group was significantly greater than that in the control group. On histological examination, the rate of osteogenesis in the experimental group was faster than that in the control group.Bone regeneration can be achieved using APP in the repair of rabbit bone defects. The retention time of APP can meet the needs of osteogenesis.

To investigate the environmental adaptability of the Mo/Si multilayers on lunar surface, we studied the stability and stress of Mo/Si multilayers under the low and high temperature environment. The in-situ X-ray diffraction (XRD) and the ex-situ intrinsic stress are measured in the temperature range from - 135 degrees C to 600 degrees C and from 190 degrees C to 600 degrees C, respectively. The results demonstrate that the periodic structure of Mo/Si multilayers is stable between 135 degrees C and 300 degrees C. The stress is unaffected under low temperature and it gradually increases from 260 MPa to 1G MPa when the temperature changes from room temperature to 600 degrees C. Above 600 degrees C, large tensile stress leads to folds and cracks in the film. Thus, the large temperature range on lunar surface has little effect on the structure, performance and stress of the Mo/Si multilayers and the high temperature in lunar day releases the stress of the multilayer mirror. (C) 2014 Elsevier B.V. All rights reserved.

Performance test of the engine fueled with DME-methanol blends was conducted on a 4102BQ diesel engine. The results show that: by increasing the fuel pump plunger diameter, delaying injection timing, and reducing nozzle-opening pressure, the rated power of the engine, fueled with DM90 blends (Mass ratio of DME and methanol is 9:1), descended 13.97% relative to the original diesel engine, but the soot emissions did not appeared in all test conditions. In full load condition, NOx emissions declined by 55.1%, CO emissions fell by 65.8%, but HC emissions increased by 21.6%.

To further study the performance of the engine fueled with DME-diesel blends, the indicator diagrams of a two-cylinder four-stroke engine are recorded at 1700r/min and 2300r/min under different load, the heat release rate and the rate of pressure rise are calculated. The results show that: when fueled the engine with D20 blend (Mass ratio of DME and diesel oil is 2:10) and optimizing the fuel supply advance angle, the maximum cylinder pressure decreases by 10% averagely and its corresponding crank angle delays 2°CA, the maximum rate of pressure rise is relatively lowers about 20%, the beginning of heat release delays，but combustion duration do not extend, and the centroid of heat release curves is closer to TDC (Top Dead Center), maximum combustion temperature drops 70-90K. These results indicate that the mechanical efficiency will be improved and, NOx emissions and mechanical noise will be reduced when an engine fueled with DME-diesel blends.

The use of clean alternative fuel and new combustion mode is one of the most effective methods of further reduction of NOx and smoke emissions at diesel engine. High thermal efficiency and ultra-low NOx and PM emission of engine in HCCI combustion mode can be realized at low and medium load. However, some problems such as hard control of ignition timing and narrow operating range still exist.For the sake of expanding the operating range of HCCI (Homogeneous Charge Compression Ignition) engines and explore the scientific methods to realize the ultra-low emission with DME (Dimethyl Ether) as alternative fuel. Experimental Research on the characteristics of PCCI-DI (Partial Premixed Charge Compression Ignition – Direct Injection) combustion is carried out on a single cylinder and naturally aspirated direct injection diesel engine. Results indicate that PCCI-DI DME engine has lower peak cylinder pressure and lesser rise rate of pressure. The engine also shows up an obvious two-stage heat-release characteristic. Compared with HCCI DME engine, peak value of two heat-releases reduces, the position of the first peak almost has no change and the position of the second peak shifts to the position later than TDC (Top Dead Center).