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Though the component of threshing drum is pre-balancing on the factory, the drum after assembly still has the problem of unbalanced vibration. In this study, the unbalance mechanism produced by assembly are introduced and the centroid propagation model in the series rotation system was established. The influence of the eccentricity and assembly phase on the assembly unbalance was studied. It is shown that there was a superposition effect between the initial centroid eccentricity caused by the machining error and the centroid eccentricity caused by assembly error, the unbalance amount under the in-phase assembly was larger than that of the anti-phase assembly. Moreover, the unbalance variation was experimentally investigated using in-field balancing detection on the test rig and combine harvester. The experiment results showed the excellent vibration reduction effect of in-field balancing, which showed a reduction of 83.0% and 85.8%. In order to increase the range of in-field balance detection and reduce the calculation error, the double-speed influence coefficient method was proposed. The proposed method adopted the way of first low-speed pre-balancing, and then high-speed precision balance, taking advantage of vibration information at two speeds and avoids nonlinear vibration conditions caused by high unbalanced vibration. Finally, the doublespeed influence coefficient method was verified on the test rig. The vibration reduction effect of proposed method was better than the traditional method. [ABSTRACT FROM AUTHOR]

In order to study the influence of the side drive on the balance state of the threshing drum, this paper used the side eccentric load chain drive as the power on the threshing drum dynamic balance test bench. By analyzing the influence of different radial phases, different axial distances, and spiral combinations of the threshing drum on the counterweight, this paper studies the law of the effect of side partial load chain drive on the dynamic balance of the threshing drum and finds that the side chain drive has obvious influence on the unbalance phase of the threshing drum and the change of the axial distance of unbalance has little effect on the equilibrium state of the threshing drum. And from this, a vibration balance method based on the equivalent unbalance of the chain drive is proposed, which can predict and calculate the unbalance of the threshing drum. The unbalance of the threshing drum predicted by this method is smaller than the actual measured unbalance. The maximum error is 32.64% and the minimum error is 4.6%. In the two tests, the predicted unbalance is 1.24 mm/s in amplitude and 270 degrees in phase and amplitude 1.4 mm/s and phase 120 degrees, respectively. The measured unbalance is amplitude 1.587 mm/s and phases 286 degrees. The error between prediction and actual measurement is less than 32.64%, and the unbalance amplitudes that can be reduced by one-time dynamic balance are 0.856 mm/s and 0.674 mm/s, respectively. The research results in this paper provide an effective method for the balance state of the multidrum side chain transmission. [ABSTRACT FROM AUTHOR]

As to analyze the effects of friction pendulum bearings (FPB) on the responses of simply supported bridges on a high-speed railway under longitudinal earthquakes, a spatially integrated track-bridge model with a CRTS II slab ballastless track and FPB was established by using the OpenSEES software. The seismic responses under different ground motions were calculated and compared with those using common spherical steel bearings. The comparison results show that the combination of FPB and the CRTS II slab ballastless track is more reasonable. Namely, using FPB can effectively protect the bridge and track structures. Moreover, the rails, fasteners, CA layer and piers are perfectly protected by multi-layer isolation mechanics, induced by FPB and sliding layer, even under strong earthquakes. Finally, 0.05 is identified to be the best value for the friction coefficient of FPB under longitudinal earthquakes. [ABSTRACT FROM AUTHOR]

The benefit of adjuvant hysterectomy after definitive concurrent chemoradiotherapy (CCRT) for locally-advanced cervical cancer (LACC) is controversial. The purpose of the present study was to systematically search the literature and perform a meta-analysis to compare overall survival (OS) and disease-free survival (DFS) between patients subjected to CCRT with hysterectomy and those who underwent CCRT alone. T he P ubMed, S copus, E mbase a nd G oogle s cholar databases were searched. A meta-analysis to determine hazard ratios (HRs) and odds ratios (ORs) with meta-regression was performed for the following moderators: Disease stage, histology and proportion of radical hysterectomy. Data from 14 studies were included. The results indicated that patients who received CCRT with hysterectomy had significantly better OS (HR, 0.72; 95% CI, 0.56 to 0.91; I2=19%; P=0.007) and DFS (HR, 0.72; 95% CI, 0.56 to 0.93; I2=27%; P=0.01) than those treated with CCRT alone. However, in a subgroup analysis by study type, the results were significant only for retrospective studies but not for randomized controlled trials (RCTs). However, only 2 RCTs were included with small sample size, heterogeneity and low overall quality. Subgroup analyses based on the use of brachytherapy in the CCRT with hysterectomy group demonstrated no difference in OS and DFS between the two groups. Regarding the absolute numbers of death and recurrence events, no significant difference in mortality (OR, 0.91; 95% CI, 0.62 to 1.33; I2=0%; P=0.64) was determined between the two groups, but a significantly reduced incidence of recurrence was observed in the CCRT with hysterectomy group (OR, 0.61; 95% CI, 0.47-0.79; I2=29%; P=0.0002). The meta-regression results point to a significant influence of the proportion of stage II patients on OS. Despite the overall analysis indicating improved OS and DFS with the use of adjuvant hysterectomy after CCRT, subgroup analysis based on similar treatment protocols failed to demonstrate any significant benefit of hysterectomy in LACC. However, the results indicated that the recurrence rate may be higher in patients undergoing CCRT without hysterectomy. The limited quality of the studies included and selection bias from retrospective studies restrict the possibility to draw strong [ABSTRACT FROM AUTHOR]

A method to prepare novel organic-inorganic hydrophobic nanocomposite films was proposed by a site-specific polymerization process. The inorganic part, the core of the nanocomposite, is a ternary SiO2-Al2O3-TiO2 nanoparticles, which is grafted with methacryloxy propyl trimethoxyl silane (KH570), and wrapped by fluoride and siloxane polymers. The synthesized samples are characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrscopy, X-ray diffractometry (XRD), contact angle meter (CA), and scanning electron microscope (SEM). The results indicate that the novel organic-inorganic hydrophobic nanocomposite with a core-shell structure was synthesized successfully. XRD analysis reveals the nanocomposite film has an amorphous structure, and FTIR analysis indicates the nanoparticles react with a silane coupling agent (methacryloxy propyl trimethoxyl silane KH570). Interestingly, the morphology of the nanoparticle film is influenced by the composition of the core. Further, comparing with the film synthesized by silica nanoparticles, the film formed from SiO2-Al2O3-TiO2 nanoparticles has higher hydrophobic performance, i.e., the contact angle is greater than 101.7°. In addition, the TEM analysis reveals that the crystal structure of the particles can be changed at high temperatures. [ABSTRACT FROM AUTHOR]

An experimental study of 22 concrete-filled round-ended steel tubular (CFRT) stub columns under axial compression is conducted compared with 4 circular concrete-filled steel tubular (CFT) stub columns. The influences of width–thickness ratio, concrete strength, steel yield strength and wall-thickness of steel tube on the ultimate bearing capacity of the CFRT columns are discussed. The 3D finite element (FE) model is also developed to analyze the behavior of the CFRT columns under axial compression. From the results, local buckling of the round-ended steel tube associated with shear failure of in-filled concrete could be observed. With the increasing width–thickness ratio, the corresponding load–strain curves have a shorter elastic–plastic stage. The parametric studies indicate that the concrete strength, tube thickness and width–thickness ratio of the steel tube also have a great effect on the ultimate bearing capacity. The numerical results also show that the confinement effect of the stub columns decreases with the increasing width–thickness ratio. A practical calculation formula for the bearing capacity of the CFRT stub columns is proposed, which is well in agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Abstract: The effect of introducing water molecules into a Cxb7;·O complex on the interaction between the methyl hydrogen atom of dimethylsulfoxide (DMSO) and the oxygen atom of H2O has been investigated using the MP2/6-311++G(d,p) method to explore how the binding strength of the weak hydrogen-bond Cxb7;·O interaction changes during hydration. The calculations in gas phase, including the interaction energies, binding distances, stretching frequencies, isotropic shielding constants, natural population analysis (NPA) charges, and stabilization energies, on the DMSO–H2O complex showed that the Cxb7;·O interaction is enhanced by introducing water molecules into the system, and the effect of first water molecule is more prominent than that of the second. The results obtained in liquid media support these conclusions. The cooperativity between Oxb7;·O and Cxb7;·O hydrogen-bonds was also evaluated. The results demonstrate that both such cooperativity and solvation play important roles in enhancing the Cxb7;·O hydrogen bond in DMSO–H2O complex. The results are helpful to better understand the role of water molecules in biological processes involving Cxb7;·O interactions. [Copyright &y& Elsevier]

• A novel silicone waterproof material and waterbased capillary inorganic waterproofer were prepared. • The improvement of waterproof performance of CCCW was studied. • Contact angle of specimen coating with silicone waterproof material and waterbased capillary inorganic waterproofer was tested, respectively. • Water absorption test of silicone waterproof material and waterbased capillary inorganic waterproofer were proceeded. • Optimal content of silicone waterproof material and waterbased capillary inorganic waterproofer were proposed. The silicone waterproof material and waterbased capillary inorganic waterproofer possess the advantages of rapid film formation and significant hydrophobic effect. In this study, the material composition and mixing ratio of the silicone waterproofing material and waterbased capillary inorganic waterproofing were investigated by multiple performance tests. The results indicated that a white coating was formed on the surface when the mixing ratio of isobutyl-triethoxy-silane and isooctyl-triethoxy-silane was more than 69 %. When the content of sodium and potassium methyl silicate exceeded 0.5 %, respectively, there was an upward trend of contact angle while the reduction in water absorption gradually decreased. Meanwhile, the contact angle and water absorption height of silicone waterproof material were tested. The results showed that the coating performance and hydrophobicity were the best when the mixing ratio of isobutyl-triethoxy-silane, isooctyl-triethoxy-silane, sodium methyl silicate, and potassium methyl silicate was 1.5:0.2:1:0.5. When the matrix mortar specimen was made of Cementitious Capillary Crystalline Waterproofing Materials (CCCW), the lowest water absorption height and water absorption of the experimental group consisted of sodium silicate, sodium tetraborate, sodium phosphate, and sodium hydroxyethyl cellulose were 316.7 % and 39%, respectively. The lowest water absorption height and water absorption of the experimental group consisted of sodium silicate, sodium tetraborate, nano-silica, and sodium hydroxyethyl cellulose were 215.4 % and 28 %, respectively. The results showed that CCCW combined with the experimental group consisted of sodium silicate, sodium tetraborate, sodium phosphate, and sodium hydroxyethyl cellulose had better waterproofing effect. [ABSTRACT FROM AUTHOR]

The article presents a study on the formation of hydrogen bond in dimethyl sulfoxide (DMSO)-methanol mixtures. The excess spectroscopy approach was used to examine the interaction between species at molecular and submolecular level. The term "excess spectrum" denotes the difference between the spectrum of a real solution and that of the corresponding ideal solution under the same condition. The evidence from Fourier Transform Infrared spectroscopy and Nuclear Magnetic Resonance spectroscopy suggest that the methyl groups of methanol and DMSO serve as electron-withdrawing and -donating groups in the mixture to rebalance the charge distribution.

Rational control of the cooperativity of multiple noncovalent interactions often plays an important role in the design and construction of supramolecular self-assemblies and materials, especially in precision supramolecular engineering. However, it still remains a challenge to control the cooperativity of multiple noncovalent interactions through tuning the hydrophobic effect. In this work, we demonstrate that the binding cooperativity of cucurbit[8]uril(CB[8])-mediated homoternary complexes is strongly influenced by the amphiphilicity of guest molecule side groups on account of an interplay between both classical (entropy-driven) and nonclassical (enthalpy-driven) hydrophobic effects. To this end, we rationally designed and prepared a series of guest molecules bearing a benzyl group as the CB[8] homoternary binding motif with various hydrophilic and hydrophobic side groups for cooperative control. By gradually tuning side groups of the guest molecules from hydrophilic to hydrophobic, we are able to control the binding from positive to negative cooperativity. An advanced molecular recognition process and self-assembling system can be developed by adjusting the positive and negative cooperativity. The ability to regulate and control the binding cooperativity will enrich the field of supramolecular chemistry, and employing cooperativity-controlled multiple noncovalent interactions in precision supramolecular engineering is highly anticipated. [ABSTRACT FROM AUTHOR]

Capsid proteins binding cell surface proteoglycans is a key early event in human papillomavirus (HPV) infection. The positively charged sequences at the C-terminus of the L1 protein and the N- and C-termini of the L2 protein of HPV-16 can efficiently bind to heparin receptors, which were characterized in the present study by quantitative isothermal titration calorimetry experiments primarily, fluorescence spectroscopy, and static right-angle light scattering. The binding constant, K, was at an order of magnitude of 107M−1for the two peptides at the N- and C-termini of HPV-16 L2 and segment b at the C-terminus of HPV-16 L1, while that for other L1 analogues were of a smaller order, illustrating that the heparin binding is a typical sequence-specific and -dependent phenomenon. These results suggest that, in addition to L1, the L2 protein may participate in cell surface attachment during HPV infection. Furthermore, the calorimetry results demonstrated that hydrophobic interactions and hydrogen bonding are involved in peptide binding to heparin in addition to the essential electrostatic interactions. Meanwhile, circular dichroism spectroscopy revealed that binding to heparin does not induce obvious secondary structural changes in the peptides. [ABSTRACT FROM AUTHOR]

The effect of androsterol, whose structure resembles that of cholesterol but without the alkyl side chain, on the phase behavior of aqueous dispersions of dipalmitoylphosphatidylcholine has been studied to understand the role of the side chain played in the formation of ordered phases of the type observed in membrane rafts. Thermotropic changes in the structure of mixed dispersions and transition enthalpies have been examined by synchrotron X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry. From these results a partial phase diagram of the binary system has been constructed. The three-phase line is determined to be 34.5 °C, which is 3−5 °C lower than that observed in binary mixtures of cholesterol, ergosterol, or stigmasterol with dipalmitoylphosphatidylcholine. The proportions of androsterol in mixtures representing the “left end point” and “right end point” of the three-phase line are 11.1 and 30.9 mol %, respectively. These proportions are greater than that seen in phase diagrams of other sterols codispersed with dipalmitoylphosphatidylcholine. We conclude that androsterol is less effective in promoting the formation of an ordered phase, and furthermore, this ordered phase is less compact than the normal lamellar liquid-ordered phase. [ABSTRACT FROM AUTHOR]

Excess infrared (IR) absorption spectroscopy, a new concept brought forward by applying the idea of excess thermodynamic functions to infrared spectroscopy, is shown to be a potential method to study hydrogen bonds. It can be applied to enhance spectral resolution of complexed IR bands, to evaluate nonideality of liquid mixtures, and to estimate selective molecular interactions. The sign of the excess infrared absorption coefficient is also of importance in providing information on molecular interactions. The results demonstrate that excess infrared absorption spectroscopy can unveil new information on hydrogen bonding in condensed phases. [ABSTRACT FROM AUTHOR]