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Crawler combine harvesters are mostly used in paddy field operation in South China. The field operation load is complex and variable, which leads to fatigue fracture and other accidents of gearboxes under the impact of variable loads and seriously affects the trouble-free working time of the whole machine. In order to solve the problem of high fault rate of gearboxes of crawler combine harvesters, the single HST hydro-mechanical differential steering gearbox developed by the team is taken as the test object, this study designs and builds the gearbox assembly fatigue test bench, and then carries out the fatigue test of differential steering gearboxes. The test results show that the test bench can well test the comprehensive working performance and durability of differential steering gearboxes, and has advantages of simple structure, convenient installation, etc. This is of great significance to study the fatigue damage rule of differential steering gearboxes, optimize and improve the mechanical structure of gearboxes and reduce the fault rate of its internal parts in the future.

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.

The paper analyzed development status of automation technology for fully mechanized coal face of thin seam at home and abroad, introduced structure of automation system of fully mechanized coal face of thin seam, and automation control technology for shearer, electro-hydraulic control technology for hydraulic support, automation control technology for scraper conveyor and visualized monitoring technology of mining space environment. It pointed out development trend of automation technology for fully mechanized coal face of thin seam, that is to use advanced technique to improve working reliability of devices such as shearer and hydraulic support; to improve automation degree of automation system of fully mechanized coal face of thin seam, perfect control system and fault diagnosis system and improve adaptability for mining environments; to develop from chain traction to no-chain traction and electric traction; to further study visualized monitoring system of fully mechanized coal face.

In the present work, the uniaxial compressive behavior of aluminum alloy processed by equal channel angular pressing (ECAP) for 1–8 passes are investigated experimentally under both quasi-static and dynamic loading conditions via an electronic universal testing machine with a maximum load capacity of 10KN and the split Hopkinson pressure bar (SHPB). The strain hardening rate as well as strain rate sensitivity the ECAPed with different passes have been determined and compared with annealed coarse grained counterpart. The experimental results show a continuously increase of both flow stress and strain rate sensitivity for the aluminum alloy subjected to ECAP process as the pressing pass number increasing. It is proposed that the reduction in grain size plays an important role in the enhancement of flow stress and strain rate sensitivity. However, the strain hardening rate of the ECAPed materials decreases remarkably. Meanwhile, compressive experiments at elevated temperatures indicate the temperature sensitivity of the material increases as the grain size is refined into fine grain regime. Based on thermal activation theory, it is proposed that the enhanced temperature and strain rate sensitivity of ECAPed aluminum alloy can be related to the reduction in activation volume due to grain refinement.

Abstract Background Although socioeconomic status (SES) has been focused on as a key determinant of cancer stage at diagosis in western countries, there has been no systemic study on the relationship of SES and breast cancer stage at diagnosis in China. Methods The medical charts of 4,211 eligible breast cancer patients from 7 areas across China who were diagnosed between 1999 and 2008 were reviewed. Four area-based socioeconomic indicators were used to calculate area-based SES by cluster analysis. The associations between area-based SES and stage at diagnosis were analyzed by trend chi-square tests. Binary logistic regression was performed to estimate odds ratios for individual demographic characteristics' effects on cancer stages, stratified by area-based SES. Results The individual demographic and pathologic characteristics of breast cancer cases were significantly different among the seven areas studied. More breast cancer cases in low SES areas (25.5%) were diagnosed later (stages III & IV) than those in high (20.4%) or highest (14.8%) SES areas (χ2 for trend = 80.79, P < 0.001). When area-based SES is controlled for, in high SES areas, cases with less education were more likely to be diagnosed at later stages compared with more educated cases. In low SES areas, working women appeared to be diagnosed at earlier breast cancer stages than were homemakers (OR: 0.18-0.26). Conclusions In China, women in low SES areas are more likely to be diagnosed at later breast cancer stages than those in high SES areas.

Abstract Background According to the very limited cancer registry, incidence and mortality rates for female breast cancer in China are regarded to be increasing especially in the metropolitan areas. Representative data on the breast cancer profile of Chinese women and its time trend over years are relatively rare. The aims of the current study are to illustrate the breast cancer profile of Chinese women in time span and to explore the current treatment approaches to female breast cancer. Methods This was a hospital-based nation-wide and multi-center retrospective study of female primary breast cancer cases. China was divided into 7 regions according to the geographic distribution; from each region, one tertiary hospital was selected. With the exception of January and February, one month was randomly selected to represent each year from year 1999 to 2008 at every hospital. All inpatient cases within the selected month were reviewed and related information was collected based on the designed case report form (CRF). The Cancer Hospital/Institute, Chinese Academy of Medical Sciences (CICAMS) was the leading hospital in this study. Results Four-thousand two-hundred and eleven cases were randomly selected from the total pool of 45,200 patients and were included in the analysis. The mean age at diagnosis was 48.7 years (s.d. = 10.5 yrs) and breast cancer peaked in age group 40-49 yrs (38.6%). The most common subtype was infiltrating ductal carcinoma (86.5%). Clinical stage I & II accounted for 60.6% of 4,211 patients. Three-thousand five-hundred and thirty-four cases had estrogen receptor (ER) and progestin receptor (PR) tests, among them, 47.9% were positive for both. Two-thousand eight-hundred and forty-nine cases had human epidermal growth factor receptor 2(HER-2) tests, 25.8% of them were HER-2 positive. Among all treatment options, surgery (96.9% (4,078/4,211)) was predominant, followed by chemotherapy (81.4% (3,428/4,211). Much less patients underwent radiotherapy (22.6% (952/4,211)) and endocrine therapy (38.0% (1,599/4,211)). Conclusions The younger age of breast cancer onset among Chinese women and more advanced tumor stages pose a great challenge. Adjuvant therapy, especially radiotherapy and endocrine therapy are of great unmet needs.

Abstract Background MicroRNAs (miRNAs) are a large group of RNAs that play important roles in regulating gene expression and protein translation. Several studies have indicated that some miRNAs are specifically expressed in human, mouse and zebrafish tissues. For example, miR-1 and miR-133 are specifically expressed in muscles. Tissue-specific miRNAs may have particular functions. Although previous studies have reported the presence of human, mouse and zebrafish tissue-specific miRNAs, there have been no detailed reports of rat tissue-specific miRNAs. In this study, Home-made rat miRNA microarrays which established in our previous study were used to investigate rat neural tissue-specific miRNAs, and mapped their target genes in rat tissues. This study will provide information for the functional analysis of these miRNAs. Results In order to obtain as complete a picture of specific miRNA expression in rat neural tissues as possible, customized miRNA microarrays with 152 selected miRNAs from miRBase were used to detect miRNA expression in 14 rat tissues. After a general clustering analysis, 14 rat tissues could be clearly classified into neural and non-neural tissues based on the obtained expression profiles with p values < 0.05. The results indicated that the miRNA profiles were different in neural and non-neural tissues. In total, we found 30 miRNAs that were specifically expressed in neural tissues. For example, miR-199a was specifically expressed in neural tissues. Of these, the expression patterns of four miRNAs were comparable with those of Landgraf et al., Bak et al., and Kapsimani et al. Thirty neural tissue-specific miRNAs were chosen to predict target genes. A total of 1,475 target mRNA were predicted based on the intersection of three public databases, and target mRNA's pathway, function, and regulatory network analysis were performed. We focused on target enrichments of the dorsal root ganglion (DRG) and olfactory bulb. There were four Gene Ontology (GO) functions and five KEGG pathways significantly enriched in DRG. Only one GO function was significantly enriched in the olfactory bulb. These targets are all predictions and have not been experimentally validated. Conclusion Our work provides a global view of rat neural tissue-specific miRNA profiles and a target map of miRNAs, which is expected to contribute to future investigations of miRNA regulatory mechanisms in neural systems.