Test Research on the Knock of a Common-Rail Diesel Engine Fueled with Diesel-Methanol Dual-Fuel

Experiments were conducted on a diesel-methanol dual-fuel(DMDF)engine modified by a six-cylinder,turbocharged,inter-cooled diesel engine.According to the number of diesel injection,the experiments are divided to two parts:the single injectionmode and double injectionmode.The results show that,at the double injectionmode,themaximumof pressure rise rate is small and the engine runs smoothly,however,knock still occurswhen the cocombustion ratio(CCR)is big enough.Under knock status,the power density of the block vibration concentrating at some special frequencies rises dramatically,and the special frequency of single injection mode(about 4.1 kHz)is lower than that of double injection mode(7–9 kHz).The cylinder pressure oscillations of knock status are very different fromthe non-knock status.Under knock status,cylinder pressure oscillations become more concentrated and fiercer at some special frequencies,and the same as the block vibration.The special frequency of single injection mode(3–6 kHz)is lower than that of double injection mode(above 9 kHz).

The Effect of Ignition Parameters on the Combustion Characteristics of an Aviation Piston Engine

A cylinder combustion simulation model was established for a two-stroke aviation piston engine used in a small unmanned aerial vehicle. The influence of different ignition system parameters on the combustion process of aviation kerosene was studied using this model. The research results showed that under the working conditions of 5500 r/min and 50% throttle opening, as the ignition energy increased, the peak values of average cylinder pressure and average temperature increased, and the combustion duration shortened, The advance of the combustion center of gravity increases the tendency of the engine to knock. Under the same operating conditions, as the ignition timing advances, the peak values of average pressure and average temperature in the cylinder increase, gradually approaching the top dead center, and the tendency of engine detonation increases more significantly.

Simulation Research on the Effect of Cooled EGR, Supercharging and Compression Ratio on Downsized SI Engine Knock

Knock in spark-ignition（SI） engines severely limits engine performance and thermal efficiency. The researches on knock of downsized SI engine have mainly focused on structural design, performance optimization and advanced combustion modes, however there is little for simulation study on the effect of cooled exhaust gas recirculation（EGR） combined with downsizing technologies on SI engine performance. On the basis of mean pressure and oscillating pressure during combustion process, the effect of different levels of cooled EGR ratio, supercharging and compression ratio on engine dynamic and knock characteristic is researched with three- dimensional KIVA-3V program coupled with pressure wave equation. The cylinder pressure, combustion temperature, ignition delay timing, combustion duration, maximum mean pressure, and maximum oscillating pressure at different initial conditions are discussed and analyzed to investigate potential approaches to inhibiting engine knock while improving power output. The calculation results of the effect of just cooled EGR on knock characteristic show that appropriate levels of cooled EGR ratio can effectively suppress cylinder high-frequency pressure oscillations without obvious decrease in mean pressure. Analysis of the synergistic effect of cooled EGR, supercharging and compression ratio on knock characteristic indicates that under the condition of high supercharging and compression ratio, several times more cooled EGR ratio than that under the original condition is necessarily utilized to suppress knock occurrence effectively. The proposed method of synergistic effect of cooled EGR and downsizing technologies on knock characteristic, analyzed from the aspects of mean pressure and oscillating pressure, is an effective way to study downsized SI engine knock and provides knock inhibition approaches in practical engineering.

Effects of SIRT1 Gene Knock-Out via Activation of SREBP2 Protein-Mediated PI3K/AKT Signaling on Osteoarthritis in Mice

This study investigated the effects of SIRT1 gene knock-out on osteoarthritis in mice, and the possible roles of SREBP2 protein and the PI3K/AKT signaling pathway in the effects. Mice were randomly divided into a normal group and a SIRT1 gene knock-out group（6 mice in each group）. In these groups, one side of the knee anterior cruciate ligament was traversed, and the ipsilateral medial meniscus was cut to establish an osteoarthritis model of knee joint. The countralateral synovial bursa was cut out, serving as controls. The knee joint specimens were then divided into four groups： SIRT1^（＋/＋） control group（group A, n=6）; SIRT1^（＋/＋） osteoarthritis group（group B, n=6）; SIRT1^（–/–） control group（group C, n=6）; SIRT1^（–/–） osteoarthritis group（group D, n=6）. HE staining, Masson staining, Safranin O-Fast Green staining and Van Gieson staining were used to observe the morphological changes in the articular cartilage of the knee. Immunohistochemical staining was employed to detect the expression of SIRT1, SREBP2, VEGF, AKT, HMGCR and type Ⅱ collagen proteins. SA-β-gal staining was utilized to evaluate chondrocyte aging. The results showed clear knee joint cartilage destruction and degeneration in the SIRT1^（–/–） osteoarthritis group. The tidal line was twisted and displaced anteriorly. Type Ⅱ collagen was destroyed and distributed unevenly. Compared with the SIRT1^（＋/＋） osteoarthritis group and SIRT1^（–/–） control group, SIRT1 protein expression was not obviously changed in the SIRT1^（–/–） osteoarthritis group（P〉0.05）, while the expression levels of the SREBP2, VEGF and HMGCR proteins were significantly increased（P〈0.05） and the levels of AKT and type Ⅱ collagen proteins were significantly decreased（P〈0.05）. SIRT1 gene knock-out may aggravate cartilage degeneration in osteoarthritis by activating the SREBP2 protein-mediated PI3K/AKT signalling pathway, suggesting that SIRT1 gene may play a protective role against osteoarthritis.

Theoretical Analysis of Noise of Piston Knocking Cylinder Wall in Automotive Engines

Based on the loading conditions of engine, applying difference method to solve the hydrodynamic lubrication equation of piston skirt movement, the force acting on piston skirt and the moment on wrist pin were obtained. A computer program for simulating the piston second order motion was conducted to calculate the lateral motion of the upper part and the bottom part of piston skirts of the engine of automotive model CA1091. From the simulated result, the maximal impacting phase and the maximal impacting region of the piston were obtained. The result can be used for designing engine, diagnosing the noise of piston knocking cylinder wall and explaining many practical fault phenomena in theory.

论海上拖航合同中的Knock for Knock条款

海上拖航合同中的Knock For Knock条款的效力在实践中一直存在争议。本文通过分析《海商法》第162条,结合Knock For Knock条款的性质进行讨论,得出结论《海商法》第162条可以作为订立Knock For Knock条款的依据,但是不能作为该条款在任何情形下均有效的依据。并且通过对Knock For Knock条款效力的进一步探讨,可知海上拖航中的承拖方不得以该条款对抗被拖方提出的由于承拖方的故意或重大过失行为造成其损失的赔偿请求。除此之外,本文将借鉴国外判例,结合我国国情,提出减少Knock For Knock条款实践纠纷的建议。

Interference with the C-terminal structure of MARF1 causes defective oocyte meiotic division and female infertility in mice

Meiosis-arrest female 1（MARF1） is a recently identified key oogenic regulator essential for the maintenance of female fertility and genome integrity in mice. However, the detailed functions and the underlying mechanisms of MARF1 remain elusive. Here, in an attempt to create a mouse model expressing fluorescent protein-tagged MARF1 to facilitate further exploration of the roles of MARF1 in oocytes, we produced a Marf1-eGFP knockin（KI） mouse line in which the C-terminal structure and function of MARF1 were interfered by its fusing eGFP peptide. Using these Marfl-eGFP-KI mice, we revealed, unexpectedly, the functions of MARF1 in the control of oocyte meiotic division.We found that the Marfl-eGFP-KI females ovulated mature oocytes with severe meiotic and developmental defects,and thus were infertile. Moreover, meiotic reinitiation was delayed while meiotic completion was accelerated in the KI-oocytes, which was coincident with the increased incidence of oocyte aneuploidy. Therefore, MARF1 is indispensable for maintaining the fidelity of homolog segregation during oocyte maturation, and this function relies on its C-terminal domains.

Calculation on Cylinder Pressure Fluctuation by Using the Wave Equation in KIVA Program

Cylinder pressure fluctuation during combustion process of internal combustion engine is closely related to combustion noise and knock.The current studies are based on cylinder pressure test to obtain information on combustion noise and knock,but there is little for simulation of combustion pressure fluctuation.Based on effects of combustion process in the combustion chamber on cylinder pressure by using wave equation,the mechanism of pressure fluctuation during combustion is researched with three-dimensional acoustic wave equation and flow field model of KIVA program.The cylinder pressure fluctuation curve,temperature field and acoustic field are obtained from the coupled calculation of the wave equation and KIVA program.The frequency spectrum analysis is taken with the cylinder pressure oscillation of cylinder pressure measured and calculated.The calculation result is consistent with the experimental result.This indicates that the cylinder pressure fluctuation can be correctly calculated with the wave equation.Analysis of calculation results of temperature field and acoustic field shows that sound field changes faster than flame propagates,and distribution of sound field is more complicated.Combustion pressure oscillation in the diesel engine is under highly unstable condition.This indicates that the combination of cylinder pressure fluctuation model and combustion model is an effective method to study the pressure oscillations and a new method to study the combustion noise and knock.

Loss of epithelial FAM20A in mice causes amelogenesis imperfecta, tooth eruption delay and gingival overgrowth

FAM20A has been studied to a very limited extent. Mutations in human FAM20A cause amelogenesis imperfecta, gingival fibromatosis and kidney problems. It would be desirable to systemically analyse the expression of FAM20A in dental tissues and to assess the pathological changes when this molecule is specifically nullified in individual tissues. Recently, we generated mice with a Fam2OA-floxed allele containing the beta-galactosidase reporter gene. We analysed FAM20A expression in dental tissues using X-Gal staining, immunohistochemistry and in situ hybridization, which showed that the ameloblasts in the mouse mandibular first molar began to express FAM20A at 1 day after birth, and the reduced enamel epithelium in erupting molars expressed a significant level of FAM2OA. By breeding K14-Cre mice with Fam20An^x/fl^x mice, we created K14-Cre;Fam20Af/flox/flox （conditional knock out, cKO） mice, in which Fam20A was inactivated in the epithelium. We analysed the dental tissues of cKO mice using X-ray radiography： histology and immunohistochemistry. The molar enamel matrix in cKO mice was much thinner than normal and was often separated from the dentinoenamel junction. The Fam2OA-deficient ameloblasts were non-polarized and disorganized and were detached from the enamel matrix. The enamel abnormality in cKO mice was consistent with the diagnosis of amelogenesis imperfecta. The levels of enamelin and matrix metalloproteinase 20 were lower in the ameloblasts and enamel of cKO mice than the normal mice, The cKO mice had remarkable delays in the eruption of molars and hyperplasia of the gingival epithelium. The findings emphasize the essential roles of FAM20A in the development of dental and oral tissues.

THEORY AND APPLICATION OF WAVELET ANALYSIS INSTRUMENT LIBRARY

Some new theory and algorithms on wavelet analysis are proposed, including continuous wavelet transform （CWT）, discrete wavelet transform （DWT）, wavelet package transform （WPT）, wavelet denosing and mother wavelet selection, etc. Using the component-based hierarchy mode, the platform for virtual instrument （VI） is constructed, and the functions such as data sampling, data analysis and data present, etc are provided. Subsequently, the wavelet analysis library is designed and developed. The library consists of expert system, experienced database, development platform and abundant wavelet analysis functional module, which together implement general and special wavelet analysis in the field of mechanical engineering, energy source, transportation and biomedicine, etc. Finally, the wavelet analysis virtual instrument library is applied to detect fault called engine knock. Experimental result indicates that the wavelet analysis virtual instrument library can efficiently solve the engineering problem such as detecting engine knock.

Thalidomide ameliorates portal hypertension via nitric oxide synthase independent reduced systolic blood pressure

AIM: Portal hypertension is a common complication of liver cirrhosis and significantly increases mortality and morbidity.Previous reports have suggested that the compound thalidomide attenuates portal hypertension(PHT).However, the mechanism for this action is not fully elucidated.One hypothesis is that thalidomide destabilizes tumor necrosis factor α(TNFα) mR NA and therefore diminishes TNFα induction of nitric oxide synthase(NOS) and the production of nitric oxide(NO).To examine this hypothesis, we utilized the murine partial portal vein ligation(PVL) PHT model in combination with endothelial or inducible NOS isoform gene knockout mice.METHODS: Wild type, inducible nitric oxide synthase(i NOS)-/- and endothelial nitric oxide synthase(e NOS)-/-mice received either PVL or sham surgery and were given either thalidomide or vehicle.Serum nitrate(total nitrate, NOx) was measured daily for 7 d as a surrogate of NO synthesis.Serum TNFα level was quantified by enzyme-linked immunosorbent assay.TNFα m RNA was quantified in liver and aorta tissue by reverse transcription-polymerase chain reaction.PHT was determined by recording splenic pulp pressure(SPP) and abdominal aortic flow after 0-7 d.Response to thalidomide was determined by measurement of SPP and mean arterial pressure(MAP).RESULTS: SPP, abdominal aortic flow(Qao) and plasma NOx were increased in wild type and i NOS-/-PVL mice when compared to sham operated control mice.In contrast, SPP, Qao and plasma NOx were not increased in e NOS-/- PVL mice when compared to sham controls.Serum TNFα level in both sham and PVL mice was below the detection limit of the commercial ELISA used.Therefore, the effect of thalidomide on serum TNFα levels was undetermined in wild type, e NOS-/-or i NOS-/- mice.Thalidomide acutely increased plasma NOx in wild type and e NOS-/- mice but not i NOS-/-mice.Moreover, thalidomide temporarily(0-90 min) decreased mean arterial pressure, SPP and Qao in wild type, e NOS-/- and i NOS-/- PVL mice, after which time levels returned to the respective baseline.CONCLUSION: Thalidomide does not reduce portalpressure in the murine PVL model by modulation of NO biosynthesis.Rather, thalidomide reduces PHT by decreasing MAP by an undetermined mechanism.

Observation on behavior of adult oriental white stork in nesting period

Based on the field observation on the parental behavior of Oriental White Stork (Ciconia boyciana) during their brooding period, this paper describes the breeding style, feeding behavior, water chicks, protect chicks, etc. A Ritual “behavior—Culmen Knocking/bill clattering” was observed and which is divided into three styles with deferent meanings. This behavior plays an important role during this season.

运用Mask Pro和Knock Out进行指纹等痕迹物证图像处理的尝试

如何滤除复杂背景,以获取清晰的痕迹物证图像,除应用计算机进行图像处理外,还应借用Photo shop作为平台,尝试运用Mask Pro和Knock Out两款特效插件对指纹图像进行处理,效果会更加理想。

EBNA3C combines with Gemin3 and up-regulates its expression

Objective To investigate the combination of Epstein-Barr virus nuclear protein 3C (EBNA3C) with Gemin3 and its effect on Gemin3 expression. Methods Co-immunoprecipitation, GST pull-down and immunofluorescent assay were used to determine the combination of EBNA3C and Gemin3 and their combining domain. Stable EBNA3C knockdown cell lines were made by lentivirus-delivered small hairpin RNA and then puromycin selection. Western blot was used to check the effect of EBNA3C on Gemin3 expression. Results EBNA3C and Gemin3 combined with each other in vivo and in vitro through their C-terminals. EBNA3C up-regulated Gemin3 gene expression. Conclusion EBNA3C forms complex with Gemin3 and up-regulates its expression.

综合ChIP-chip数据、基因敲除数据和表达谱数据重构基因调控网络

揭示生物体内在的调控机制是生物信息学的一项重要研究内容.各种高通量生物数据的涌现,为从基因组的尺度上重构基因调控网络提供了可能.由于单数据源仅能提供关于调控关系的片面信息且存在噪声,因此整合多种生物学数据的方法有望得到可靠性较高的调控网络.提出了一种综合ChIP-chip数据、knock out(敲除)数据和各种条件下的表达谱数据来推断调控关系的新方法.ChIP-chip数据和knock out数据能分别提供转录因子和目标基因对关系的直接物理结合和功能关系的证据,这两类数据的整合有望获得较高的识别准确率.但这两类数据的重合性通常较低,基于共调控的基因通常具有较高的表达相似性这一假设,在一定程度上降低了这两类数据重合性较低所带来的影响.算法所识别的大部分调控关系都被YEASTRACT,高质量ChIP-chip数据和文献所验证,从而证明了该方法在调控关系的预测上具有较高的准确性.与其他方法的比较,也表明了该方法具有较高的预测性能.

Improvement of engine performance with high compression ratio based on knock suppression using Miller cycle with boost pressure and split injection

In theory,high compression ratio has the potential to improve the thermal efficiency and promote the power output of the SI engine.However,the application of high compression ratio is substantially limited by the knock in practical working process.The objective of this work is to comprehensively investigate the application of high compression ratio on a gasoline engine based on the Miller cycle with boost pressure and split injection.In this work,the specific optimum strategies for CR10 and CR12 were experimentally investigated respectively on a single cylinder DISI engine.It was found that a high level of Miller cycle with a higher boost pressure could be used in CR12 to achieve an effective compression ratio similar to CR10,which could eliminate the knock limits at a high compression ratio and high load.To verify the advantages of the high compression ratio,the fuel economy and power performance of CR10 and CR12 were compared at full and partial loads.The result revealed that,compared with CR10,a similar power performance and a reduced fuel consumption of CR12 at foil load could be achieved by using the strong Miller cycle and split injection.At partial load,the conditions of CR12 had very superior fuel economy and power performance compared to those of CR10.

Heat Transfer,Knock Modeling and Cyclic Variability in a “Downsized”Spark-Ignition Turbocharged Engine

In the present paper a combined procedure for the quasi-dimensional modelling of heat transfer,combustion and knock phenomena in a “downsized”Spark Ignition two-cylinder turbocharged engine is presented.The procedure is extended to also include the effects consequent the Cyclic Variability.Heat transfer is modelled by means of a Finite Elements model.Combustion simulation is based on a fractal description of the flame front area.Cyclic Variability(CV)is characterized through the introduction of a random variation on a number of parameters controlling the rate of heat release(air/fuel ratio,initial flame kernel duration and radius,laminar flame speed,turbulence intensity).The intensity of the random variation is specified in order to realize a Coefficient Of Variation(COV)of the Indicated Mean Effective Pressure(IMEP)similar to the one measured during an experimental campaign.Moreover,the relative importance of the various concurring effects is established on the overall COV.A kinetic scheme is then solved within the unburned gas zone,characterized by different thermodynamic conditions occurring cycle-by-cycle.In this way,an optimal choice of the “knock-limited”spark advance is effected and compared with experimental data.Finally,the CV effects on the occurrence of individual knocking cycles are assessed and discussed.

Knocking on Asia’s Door

U.S. Secretary of State Hillary Clinton visits Asia on her first overseas trip, showing Asia’s growing importance in American foreign policy Traditionally, the U.S. secretary of state heads to Europe first, but on her first foreign trip Hillary Clinton flew across the Pacific to visit four Asian countries: Japan, Indonesia,