大功率履带推土机的差速转向技术

对大功率推土机的差速转向技术做了介绍,并对该机构的组成、工作原理及使用特点进行了讨论分析。     

The pseudo-resonant-nuclide subgroup method based global–local self-shielding calculation scheme

The pseudo-resonant-nuclide subgroup method (PRNSM) based global–local self-shielding calculation scheme is proposed to simultaneously resolve the local self-shielding effects (including spatial self-shielding effect and the resonance interference effect) for large-scale problems in reactor physics calculations. This method splits self-shielding calculation into global calculations and local calculations. The global calculations obtain the Dancoff correction factor for each pin cell by neutron current method. Then an equivalent one-dimensional (1D) cylindrical problem for each pin cell is isolated from the lattice system by preserving Dancoff correction factor. The local calculation is to perform self-shielding calculations of the equivalent 1D cylindrical problem by the PRNSM. The numerical results show that PRNSM obtains accurate spatial dependent self-shielded cross sections and improves the accuracy of dealing with the resonance interference over the conventional Bondarenko iteration method and the resonance interference factor method. Furthermore, because both global and local calculation is linearly proportional to the size of problems, the global–local calculation scheme could be applied to large-scale problems.     

Biochemical,microbiological and sensory changes in shrimp (Panaeus aztecus) dipped in different solutions using face‐centred central composite design

Biochemical, microbiological and sensory changes during shelf‐life at ?1 °C were determined in shrimp (Panaeus aztecus) previously dipped in ascorbic acid, citric acid, potassium sorbate and 4‐hexyl resorcinol solutions using face‐centred central composite design. Microbiological count, trimethylamine and hypoxantine production were measured. The lowest level of the total psychrotrophic bacteria, hypoxantine and trimethylamine were found in samples dipped in all containing chemicals solutions comparing to control treatment. Sensory studies showed that treatment A (ascorbic acid 4.50, citric acid 0.12, potassium sorbate 18.60 and 4‐hexyl resorcinol 0.25, all g L^?1) and B (ascorbic acid 4.37, citric acid 1.26, potassium sorbate 7.03 and 4‐hexyl resorcinol 0.25, all g L^?1) did not alter the typical sensory features of shrimp and were effective at delaying the bitter off‐flavour formation for 26 days. This study constitutes a promising alternative to extent shelf‐life of shrimp kept at ?1 °C without freezing.     

Self‐Assembled Aptamer‐Nanomedicine for Targeted Chemotherapy and Gene Therapy

Chemotherapy is the mainstream treatment of anaplastic large cell lymphoma (ALCL). However, chemotherapy can cause severe adverse effects in patients because it is not ALCL‐specific. In this study, a multifunctional aptamer‐nanomedicine (Apt‐NMed) achieving targeted chemotherapy and gene therapy of ALCL is developed. Apt‐NMed is formulated by self‐assembly of synthetic oligonucleotides containing CD30‐specific aptamer and anaplastic lymphoma kinase (ALK)‐specific siRNA followed by self‐loading of the chemotherapeutic drug doxorubicin (DOX). Apt‐NMed exhibits a well‐defined nanostructure (diameter 59 mm) and stability in human serum. Under aptamer guidance, Apt‐NMed specifically binds and internalizes targeted ALCL cells. Intracellular delivery of Apt‐NMed triggers rapid DOX release for targeted ALCL chemotherapy and intracellular delivery of the ALK‐specific siRNA induced ALK oncogene silencing, resulting in combined therapeutic effects. Animal model studies reveal that upon systemic administration, Apt‐NMed specifically targets and selectively accumulates in ALCL tumor site, but does not react with off‐target tumors in the same xenograft mouse. Importantly, Apt‐NMed not only induces significantly higher inhibition in ALCL tumor growth, but also causes fewer or no side effects in treated mice compared to free DOX. Moreover, Apt‐NMed treatment markedly improves the survival rate of treated mice, opening a new avenue for precision treatment of ALCL.     

太阳能供热采暖系统研究现状及思考

太阳能供热采暖系统是以太阳能作为热源,供给建筑物冬季采暖和全年其他用热的系统。本文介绍了太阳能供热采暖系统国内外现状,在此基础上分析了存在的问题及改进的措施。     

Contraceptive Efficacy and Local Effects of Bioceramic IUD in Rat

The contraceptive efficacy and local effects of bioceramw IUD in rat were studied. The experiment was divided into four groups ： bioceramic IUD group ; stainless steel IUD group ; operation control group ; normal control group. All IUD samples were put into uterus of rats, The experimental results show that the alumina bioceramic has a strong contraceptive effect for those rats. In bioceramic IUD group the endometrial inflammation reaction was as mild as that in stainless IUD group during the.early days （ 30 days ） and gradually abated with time during the late days （60 days ）. The experiments show that the alumina bioceramic has a good biocompatibility and contraceptive effects and hint at the alumina bioceramw IUD may become a more safety reproduction family planning IUD.     

对提高PLC控制系统可靠性的研究

由于行程开关这类有触点的检测元件在实际使用过程中常常发生故障 ,影响了PLC控制系统的正常运行 ,本文作者提出了利用PLC程序中的一些功能以及一些无触点的检测元件来替代行程开关的作用 ,以提高控制系统的稳定性     

4,4′-二氨基二苯醚的快速分析法

在生产工艺稳定的条件下聚酰亚胺薄膜的性能与原材料的质量密切相关。4，4′－二氨基二苯醚是生产均苯型聚酰亚胺的主要原材料之一，论文介绍了一种对其纯度进行快速、简便测定的方法。该方法的准确性、重复性都较好。     

晋城矿区东部9号煤层及其顶底板岩性的研究

通过对 9号煤层及其顶底板岩性的研究 ,得出如下结论 :9号煤层煤层厚度变化很大 ,但层位稳定 ,在现代开采技术条件下应属大部可采煤层 ;9号煤层顶板K4灰岩厚度不稳定、相变大 ,须注意小于 0 .5m厚度顶板范围及相变部位的顶板管理 ;9号煤层底板为高岭石粘土岩 ,遇水易膨胀底鼓 ,对综采机械化生产可造成影响     

新型减速器优化设计

通过对摆线针轮行星减速器设计的过程分析 ,进行了多目标优化设计 ,建立了摆线针轮行星减速器优化设计的数学模型 ,经实例计算表明 ,该方案是可行的