轧辊快速拆装式三辊定径机孔型错位的控制

为了解决轧辊快速拆装式三辊定径机孔型错位问题,通过分析该类定径机轧辊机架的结构特点及孔型错位产生的原因,提出了防止孔型错位的方法及措施。分析认为:通过控制轧辊各部件的公差,使轧辊机架间隙配合时的间隙值在规定范围内,并尽可能地减小孔型中心位置偏差,可较好地控制孔型错位。

Study on viscoelastic performance of asphalt mixture based on CAM model

In order to study the viscoelastic characteristics of asphalt mixtures in the whole-frequency range, a dynamic shearing rheometer is used to carry out dynamic frequency sweeps for asphalt mixtures, which obtains the three-dimensional relationships among G^＊, temperature and frequency. Then the time-temperature shift principle is used to translate the relationships from three dimensions to two dimensions, so master curves are obtained regarding dynamic modules changing along with the frequency over 15 amount levels. The Christensen- Anderson-Marasteanu （CAM） model, a kind of the rheological model, is used to analyze and compare rheological performances of several asphalt mixtures based on the obtained master curves. The results indicate that the dynamic theological test is an effective method for obtaining the master curve. Besides, the CAM model can describe well the viscoelastic deformation characteristics of asphalt mixtures.

Experimental study on dynamic modulus of thermosetting epoxy asphalt mixture for steel deck pavement

In order to study the dynamic performance of the thermosetting epoxy asphalt mixture（EAM）, an experimental program on the dynamic modulus E is conducted. First, E of the EAM under different temperatures and frequencies are tested through the simple performance test（SPT）, and the effects of temperatures and frequencies on the dynamic modulus of the EAM are analyzed. Secondly, the static modulus of the EAM and the dynamic modulus of other two ordinary mixtures are tested and compared to E of the EAM. Finally the dynamic modulus master curve is constructed using the time-temperature superposition principle. The results show that the E values increase with the increase in the test frequency while on the other hand, the E values decrease with the increase in the test temperature. It also can be seen from the results that the dynamic modulus corresponding to the actual vehicle mode is significantly greater than the static modulus, and the dynamic modulus of the EAM is greater than that of SBS mixtures and the common hot mixed asphalt （HMA）. The study results can provide a theoretical basis for the design and mechanical analysis of the steel deck pavement.

Prediction Model of Secondary Substances in Anthocyanins Synthesis of Purple Corn

The aim of this study was to assay the polyphenols,flavonoid,polyphenol oxidase and phenylalnine ammonialyase which were relative to the anthocyanins synthesis of purple corn. The optimization of multiple linear regression model of anthocyanins synthesis was y=4.383 86-0.205 45x1＋5.479 638x2＋0.195 575x4. According to standard partial regression coefficient testing,the result indicated that polyphenols content was negatively correlated with anthocyanins and the relative influence to anthocyanins synthesis was-42.7%; flavonoid content and activity of polyphenol oxidase were positively correlated with anthocyanins of purple corn and the relative influence to anthocyanins synthesis were 71.45% and 73.32% respectively. There was no positive correlation between the activity of phenylalnine ammonialyase and anthocyanins of purple corn. The establishment of multiple linear regression model of anthocyanins synthesis was to provide theory foundation of producing anthocyanins in laboratory.

Strain H_2-419-4 of Haematococcus pluvialis induced by ethyl methanesulphonate and ultraviolet radiation

Two strains H2-410 and H2-419 were obtained from the chemically mutated survivors of wild Haematococcus pluvialis 2 by using ethyl methanesulphonate (EMS). Strains H2-410 and H2-419 showed a fast cell growth with 13% and 20% increase in biomass compared to wild type, respectively. Then H2-419-4, a fast cell growth and high astaxanthin accumulation strain, was obtained by exposing the strain H2-419 to ultraviolet radiation (UV) further. The total biomass, the astaxanthin content per cell, astaxanthin production of H2-419-4 showed 68%, 28%, and 120% increase compared to wild H. pluvialis 2, respectively. HPLC (High Performance Liquid Chromatography) data showed also an obvious proportional variation of different carotenoid compositions in the extracts of H2-419-4 and the wild type, although no peak of carotenoids appeared or disappeared. Therefore, the main compositions in strain H2-419-4, like its wild one, were free of astaxanthin, monoester, and diester of astaxanthin. The asexual reproduction in survivors after exposed to UV was not synchronous, and different from the normal synchronous asexual reproduction as the mother cells were motile instead of non-motile. Interestingly, some survivors from UV irradiation produced many mini-spores (or gamete?), the spores moved away from the mother cell gradually 4 or 5 days later. This is quite similar to sexual reproduction described by Elliot in 1934. However, whether this was sexual reproduction remains questionable, as no mating process has been observed.

Nematode Diversity of Qingdao Coast Inferred from the 18S Ribosomal RNA Gene Sequence Analysis

The 18S ribosomal DNA gene （18S rDNA） sequences （approxtmately 1300 bp in length） were amplified from the DNA extracted from the free-living marine nematodes collected from the inter-tidal sediment of Qingdao coast in bulk with nematode specific primers. The PCR products were cloned, re-amplified, digested with Rsa I and Hin61 restriction endonucleases and separated in agarose gel. Among 17 restriction fragment length types, types 1, 2 and 6 covered 61.2%, 14.4% and 9.3% of the clones analyzed, respectively, while the remaining 14 only covered 21 clones, which accounted for 15.1% of the total. Twenty-four representative clones were sequenced and phylogenetically analyzed by referring to those currently available in RDP and GenBank databases. Although it was hard to assign these sequences to known species or genera due to the lack of the 18S rDNA sequence data of known marine free-living nematodes, the obtained sequences were assigned to the nematodes of Adenophorea. Among them, twelve sequences were close to Pontonema vulgate and Adoncholaimus sp., four to Daptonema procerus and two （identical） to Enoplus brews. Our results showed that free-living marine nematode diversities could be determined by PCR retrieving and analysis of the 18S rDNA sequences and an 18S rDNA sequence could be assigned to a species or a genus only if the 18S rDNA sequences of the free-living marine nematodes were accumulated to some extent.

Synergistic effect of pinellia total alkaloids and uncaria total alkaloids on anticonvulsant action in mice and rats

Aim To investigate the synergistic effect of the combination of pinellia total alkaloid （PTA） and uncaria total alkaloid （UTA）, and explore the mechanism of anticonvulsant action. Methods Anticonvulsant and toxic effect profiles of combinations of PTA with UTA, alone and at three fixed ratios of 1：4, 1 ：1, 4：1, were evaluated in maximal electroshock （MES）-induced seizures and acute toxicity test in mice. Respective ED50 and LD50 were calculated with Bliss＇s method. Their synergistic effect were evaluated by isobolographic analysis and allowed the determination of benefit indices （BI） for respective combinations. The model of convulsive rats kindled by penicillin topically injected into cortex was used to investigated the content of Glu, Asp, Gly and GABA in hippocampus using high performance liquid chromatography （HPLC）. Results Combinations of PTA and UTA at the ratio of 4：1 were synergistic in MES test and antagonistic in acute toxicity test, showing the best profile for combinations of PTA with UTA. In contrast, the ratios of 1 ：4 and 1 ： 1, despite synergistic in MES test, were additive in acute toxicity test. The 4：1 combination and two drugs alone significantly decreased Glu level and increased GABA level in the hippocampus, but the GABA level in the 4：1 combination group was higher than that in the two drugs alone groups. They did not have significant influence on the levels of ASp and Gly. Conclusion Combinations of PTA and UTA at 4：1 ratio demonstrated synergistic effect in anticonvulsant action and antagonistic effect in toxicity. The anticonvulsant mechanism might be related to decreasing the excitability of Glutamatergic neurons and increasing the inhibition of GABAergic neurons.

The status evaluation of the permafrost environment along the Chaida'er-Muli Railway in southern Qilian Mountains in northern Qinghai Province,China

Engineering construction has major influence on the permafrost environment.This paper analyzes the interaction between engineering construction and permafrost environment along the Chaidaer-Muli Railway(simply,CMR) based on the press-state-response(PSR) framework.The permafrost environmental system is divided into three subsystems,consisting of permafrost thermal stability,proneness to the freeze-thawing erosion and permafrost ecological fragility.Each subsystem considers its most important influencing factors.Catastrophe Progression Method(CPM) is applied to calculate the current environment condition along the railway.The result indicates that:(1) as far as the thermal stability is concerned,most sections along the CMR are mainly concentrated in rank Ⅲ(fair situation),and a few in Ⅱ(good situation) and Ⅳ(bad situation),respectively;(2) for the proneness tothe freeze-thawing erosion,the entire railway route falls largely in rank Ⅱ(good situation);(3) along the CMR,the ecological fragility of the permafrost environment is in rank Ⅱ(good situation),or slightly fragile;(4) overall,the permafrost environments along the CMR are in rank Ⅲ(fair situation) or Ⅱcondition(good situation).In general,the permafrost environment along the CMR is fair.It is mainly because a series of active measures of protecting permafrost were taken for stabilizing the CMR foundation soils.On the one hand,we should try our best to minimize the influences that engineering activities have exerted on ecology and environment,on the other hand,the positive measures have made improvements to prevent the permafrost environment from deterioration.

Soil Organic Matter Fractions under Different Vegetation Types in Permafrost Regions along the Qinghai-Tibet Highway, North of Kunlun Mountains, China

As a key attribute of soil quality, soil organic matter(SOM) and its different fractions play an important role in regulating soil nutrient cycling and soil properties.This study evaluated the soil carbon(C) and nitrogen(N) concentrations in different SOM fractions(light– and heavy fractions,microbial biomass) under different vegetation types and analyzed their influencing factors in continuous permafrost regions along the Qinghai-Tibet Highway in the North of Kunlun Mountains, China.Soil samples were collected in pits under four vegetation types — Alpine swamp meadow(ASM), Alpine meadow(AM), Alpine steppe(AS) and Alpine desert(AD) — at the depth of 0-50 cm.The vegetation coverage was the highest at ASM and AM, followed byAS and AD.The results indicated that the concentrations of light fraction carbon(LFC) and nitrogen(LFN), and microbial biomass carbon(MBC)and nitrogen(MBN) decreased as follows: ASM > AM >AS > AD, with the relatively stronger decrease of LFC,whereas the heavy fraction carbon(HFC) and nitrogen(HFN) concentrations were lower in AS soils than in the AD soils.The relatively higher proportions of LFC/SOC and MBC/SOC in the 0-10 cm depth under the ASM soils are mainly resulted from its higher substrate input and soil moisture content.Correlation analysis demonstrated that aboveground biomass, soil moisture content, soil organic carbon(SOC) and total nitrogen(TN) positively correlated to LFC, LFN, HFC, HFN, MBC and MBN, while p H negatively correlated to LFC, LFN, HFC, HFN, MBC and MBN.There was no relationship between active layer thickness and SOM fractions, except for the LFC.Results suggested that vegetation cover, soil moisture content, and SOC and TN concentrations were significantly correlated with the amount and availability of SOM fractions, while permafrost had less impact on SOM fractions in permafrost regions of the central Qinghai–Tibet Plateau.

STATISTICAL PROPERTIES OF HIGH-FREQUENCY INTERNAL WAVES IN QINGDAO OFFSHORE AREA OF THE YELLOW SEA

Densely-sampled thermistor chain data obtained from a shallow-water acoustics experiment in the Yellow Sea off the coast of Qingdao were analyzed to examine the statistical properties of the 6 to 520 cpd frequency band internal waves observed. The negative skewness coefficients and the greater-than-3 kurtosis coefficients indicated non-Gaussianity of the internal waves. The probability distributions were negatively skewed and abnormally high peaks. Nonlinear properties, as exemplified by the asymmetric waveshapes of the internal waves in the offshore area are described quantitatively.

Stratospheric balloon-based dropsonde technology:Development and preliminary assessment over the Tibetan Plateau

To complement the atmospheric profile measurements under complex geographical environments and extreme weather conditions,a stratospheric balloon-based dropsonde technology,which is carried by a stratospheric balloon platform from the Earth's surface to the upper troposphere and lower stratosphere(UTLS)to release the dropsonde for measurements,is independently developed and preliminarily assessed over the Tibetan Plateau(TP)in this study.The dropsonde system is mainly composed of the dropsonde chamber,dropsonde with a parachute,data receiving and communication antennas,dropsonde-releasing device,and GPS(Global Positioning System)modules.The dropsonde measurements can be sent in real time through satellite communication links and by radio signals to a data receiver at the ground control center for storage and processing.A total of eight dropsondes aboard the stratospheric balloon were successfully released during the TP campaign in 2020.A preliminary assessment was conducted based on a case comparison between the dropsonde and radiosonde measurements,which indicated that the dropsonde technology we developed can generally provide reasonable atmospheric profiles.However,further efforts are still required to improve the detection performance of the dropsonde sensors after long-term locating in the UTLS and to assess the accuracy and precision of the detection technology more carefully.

Field measurement of strain response for typical asphalt pavement

In order to reveal the changing law of the mechanical response of asphalt pavements under the action of vehicle load and provide references for the design of durable pavements,three typical asphalt pavement structures with flexible base(S1),combined base(S2),and semi-rigid base(S3)were selected to perform field strain tests under static and dynamic load using the fiber Bragg grating optical sensing technology.The changing characteristics of the strain field along the horizontal and depth directions of pavements were analyzed.The results indicate that the most unfavorable asphalt pavement layers were the upper-middle surface layer and the lower base layer.In addition,the most unfavorable loading positions on the surface layer and the base layer were the center of wheel load and the gap center between two wheels,respectively.The most unfavorable layer of the surface layers gradually moved from the lower layer to the upper layer with the increase of base layer modulus.The power function relationships between structural layer strain and vehicle speed were revealed.The semi-rigid base asphalt pavement was the most durable pavement type,since its strain value was lower compared to those of the other structures.

Snowline and Snow Cover Monitoring at High Spatial Resolution in a Mountainous River Basin Based on a Timelapse Camera at a Daily Scale

Snowline change and snow cover distribution patterns are still poorly understood in steep alpine basins of the Qilian Mountainous region because fast changes in snow cover cannot be observed by current sensing methods due to their short time scale. To address this issue of daily snowline and snow cover observations, a ground- based EOS 7D camera and four infrared digital hunting video cameras （LTL5210A） were installed around the Hulugou river basin （HRB） in the Qilian Mountains along northeastern margin of the Tibetan Plateau （38°15′54″N, 99°52′53″E） in September 2011. Pictures taken with the EOS 7D camera were georeferenced and the data from four LIL521oA cameras and snow depth sensors were used to assist snow cover estimation. The results showed that the time-lapse photography can be very useful and precise for monitoring snowline and snow cover in mountainous regions. The snowline and snow cover evolution at this basin can be precisely captured at daily scale. In HRB snow cover is mainly established after October, and the maximum snow cover appeared during February and March. The consistent rise of the snowline and decrease in snow cover appeared after middle part of March. This melt process is strongly associated with air temperature increase.

Adsorption behavior of petroleum asphaltenc Adsorption model

Asphaltene is one of the most heavy components, asphaltene adsorption is a serious problem in oil production and processing. In this paper, the progress in the investigation of asphaltene adsorption from the aspects of adsorption model and adsorption behavior is reviewed. Asphaltene of adsorption model include the Langmuir, Freundlich, Langmuir-Freundlich, Rcdlich-Pctcrson, BET adsorption isothcrm. The adsorption behavior of asphaltene was characterized by a variety of structure-probing methods such as N：-adsorption, X-ray diffraction （XRD）, small-angle X-ray scattering （SAXS） measurements, and FT-IR spectroscopy. To understand better the adsorption progress of petroleum, asphaltene must understand the whole adsorption behavior of asphaltene.

Kinetics Study on Reaction between Dihydroartemisinic Acid and Singlet Oxygen: An Essential Step to Photochemical Synthesis of Artemisinin

Artemisinin is an excellent antimalarial drug widely used in clinical medicine.However,due to the limitation of natural source of artemisinin,the chemical synthesis of artemisinin has achieved substantial attention.Dihydroartemisinic acid is a key precursor for the synthesis of artemisinin.The reaction of dihydroartemisinic acid with singlet oxygen to form peroxide is a pivotal step in the photochemical preparation of artemisinin.Nevertheless,the reaction kinetics of dihydroartemisinic acid with singlet oxygen has not been investigated previously.Herein,we report the rate constants of the reaction between dihydroartemisinic acid and singlet oxygen.By directly detecting the luminescence decay kinetics of singlet oxygen at 1270 nm at room temperature,the reaction rate constants of singlet oxygen and dihydroartemisinic acid in different solvents are obtained to be 1.81×10^5(mol/L)^-1·s^-1 in CCl4,5.69×10^5(mol/L)^-1·s^-1 in CH3CN,and 3.27×10^6(mol/L)^-1·s^-1 in DMSO,respec-tively.It is found that the reaction rate constants of dihydroartemisinic acid with singlet oxygen increase as polarity of the solvent increases among the three solvents.These results provide fundamental knowledge to optimize experiment conditions of photochemical synthesis of artemisinin for improving the yields of artemisinin.

Online Supervision of Penicillin Cultivations Based on Rolling MPCA

To reduce the variations of the production process in penicillin cultivations, a rolling multivariate statis-tical approach based on multiway principle component analysis (MPCA) is developed and used for fault diagnosis of penicillin cultivations. Using the moving data windows technique, the static MPCA is extended for use in dy-namic process performance monitoring. The control chart is set up using the historical data collected from the past successful batches, thereby resulting in simplification of monitoring charts, easy tracking of the progress in each batch run, and monitoring the occurrence of the observable upsets. Data from the commercial-scale penicillin fer-mentation process are used to develop the rolling model. Using this method, faults are detected in real time and the corresponding measurements of these faults are directly made through inspection of a few simple plots (t-chart, SPE-chart, and T2-chart). Thus, the present methodology allows the process operator to actively monitor the data from several cultivations simultaneously.

Low temperature J-resistance curve determination of asphalt concrete using wavelet-Radon transform

A single specimen test using the three point single edge notched beam configuration at low temperatures for obtaining hot mix asphalt （HMA） resistance curves is developed.Resistance curves are obtained for mixtures at six temperature levels of＋5,0,-5,-10,-15,and-20 ℃ and three binder contents of 4％,4.5％,and 5％.Crack extension increments during the test are measured by means of an image processing technique using Radon transform and feature extraction.All the specimens exhibit a rising R-curve,indicating ductility and toughening mechanisms in the ductile-quasi brittle fracture of the mixture.It is observed that the reduction of temperature results in a further tendency of the mixture for unstable crack growth and less subcritical crack length.It is also shown that using the binarization process,an automatic index can be developed that can represent the extent of brittleness and extent of the low temperature in which the cracking has occurred.

Application of retardation time spectra of asphalt

To improve the performance of asphalt pavement, the dynamic and static tests of asphalt were used to measure its viscoelastic properties under different time. Based on the obtained data of static creep compliances and dynamic compliances according to the static creep test and dynamic test of asphalt using the dynamic shear rheometer, the discrete retardation time spectra were attained using the non-linear regression method. All viscoelastic functions are mathematically equivalent and belong to the same retardation time spectra, so the dynamic compliances of asphalt were converted to the static creep compliance using the retardation time spectra. Good correlations were found between calculation results and measurement results. In accordance to these findings, the retardation time spectra can accurately transform static and dynamic viscoelastic functions. Therefore, we can obtain viscoelastic properties over much larger time or frequency region than measurement results.

Correlated Features of Horizontal Movement-Deformation on the North and East Margins of the Qinghai-Xizang Block before the Kunlun Earthquake with M_S=8.1

The high-precision GPS data observed from the northeast margin of the Qinghai-Xizang （Tibet） block and the Sichuan-Yunnan GPS monitoring areas in 1991 （1993）, 1999 and 2001 revealed that： before the Kunlun earthquake with Ms =8.1 on November 14, 2001, the dynamic variation features of horizontal movement-deformation field in the north and east marginal tectonic areas of the Qinghai-Xizang （Tibet） block had some correlated features. That is to say, under the general background of inherited movement, the movement intensifies in the two areas weakened synchronously and the state of deformation changed when the great earthquake was impending. Analysis and study in connection with geological structures showed that before the Kunlun Ms8.1 earthquake, the correlated variations of movement-deformation on the boundaries of Qinghai-Xizang （Tibet） block were related to the disturbing stress field caused by the extensive and rapid stress-strain accumulation in the late stage of large earthquake preparation. Owing to the occurrence of large earthquake inside the block, the release of large amount of strain energy, and the adjustment of tectonic stress field, in relevant structural positions （especially zones not penetrated by historical strong earthquake ruptures） in boundary zones where larger amount of strain energy was accumulated, stress-strain may be further accumulated or else released through rupture.

Some Transition Metal Complexes Bearing Artemisinin Derivatives and （N-N-O） Tridentate Chromium （Ⅲ） Complexes Ligated by 2-benzolmidazo-yl-6-acetyl. pyridines for Catalytic Behaviour towards Ethylene

Interventions of metal complexes in the area of metallopharrneceutical and polymer sciences play a great economic importance to human challenges. Complexation behavior of some artemisinin derivatives with late transition metals and chromium-benzoimidazoylpyridine analogues have been investigated. The Fe（Ⅲ）, Zn（Ⅱ） and Cd（Ⅱ） complexes of artesunate and artemether and that of chromium-benzimidazoyl pyridine were synthesized with molar ratio of metal to ligand between 1：1 and 1：2. Structural elucidation using X-ray analysis and other characterization of the complexes （AAS, IR, UV, E.A, NMR） were carried out to explore the coordination affinity of them viz-a viz bonding, geometries and elemental composition. The IR absorption revealed that artesunate acts as monodentate specie through carbonyl group on coordination. However, its bidentate mode was also observed with carboxylic group acting as C=O and C-O bonding when deprotonation happened. Artemether （L2） was synthesized using artesunate and its structure was confirmed by single crystal X-ray crystallography as well as its Zn（Ⅱ） complex exhibiting a square planar geometry. A series of 2-benzoimidazoylpyridine derivates （L3-L6） and their chromium complexes were synthesized and characterized. In the presence of methylaluminoxane （MAO）, all chromium complexes show good activity for ethylene oligomerization and polymerization whereas with diethylaluminium chloride （Et2AlCl2） the complexes show moderate activity. The distribution of oligomers obtained follows Schulz- Flory rules with high selectivity for α-olefins. The combined productivity （meaning both activities of ethylene oligomerization and polymerization） are improved with increasing ethylene pressure. The results show that the reaction conditions greatly affect the properties of the polymer such as molecular weight distribution and melting point（Tm） with extremely broad molecular weight distributions. With elevating reaction temperature from 0 to 60 ℃, the melting point （Tin） of resultant polyethylene decreased rapidly from 134 ℃ to 70 ℃.