关于“V”形破囊术在白内障手术操作中的研究

目的 :探讨“V”形破囊技术在白内障手术操作中的优越性。方法 :对利用“V”形破囊所做的 84例白内障手术操作中的破囊时间、前囊切口状态、破囊中并发症的发生率、利用空气植入人工晶体入囊袋的成功率、术中后囊膜破裂发生率、人工晶体单悬吊的成功率进行回顾性总结。结果 :破囊操作时间 1～ 2min ,前囊膜切口呈“V”字形 ,边缘光滑整齐呈直线状、无须状附着物、无晶体脱位及睫状小带裂开致玻璃体脱出现象。破囊并发症发生率为 0 .81例 (占总数 96.4 % ) ,利用空气植入人工晶体入囊袋 ,成功率为 10 0 % ,3例 (占总数 3 .5 % )在抽吸皮质中后囊膜破裂 ,行人工晶体悬吊 ,成功率 10 0 %。结论 :“V”形破囊技术操作简单易学 ,能减少术中并发症的发生 ,尤其是特别适合利用空气植入人工晶体 ,降低手术成本 ,是解决贫困地区白内障的一个较好的手术方法 ,值得推广应用。

临兴区块浅层气藏压裂液破胶优化

为保证埋深较浅的临兴区块气藏储层压裂液的顺利返排,对改进的压裂液配方破胶效果进行了评价。探索了破胶剂加量对瓜尔胶压裂液体系破胶效果的影响,通过不同比例加量下的实验室评价,对其进行优化。后在两口井进行现场实验,对实验室结果进行验证,现场实验表明,在一定比例范围内,楔形加入破胶剂可以提高瓜尔胶压裂液体系的破胶性能。

Temperature effects on the failure of deep circular tunnel under true-triaxial compression

The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The failure process of the inner walls of fine-grained granite specimens at different temperatures(25–600℃)was analyzed using a true-triaxial test system.The failure process,peak intensity,overall morphology(characteristics after failure),rock fragment characteristics,and acoustic emission(AE)characteristics were analyzed.The results showed that for the aforementioned type of granite specimens,the trend of the failure stress conditions changed with respect to the critical temperature(200℃).When the temperature was less than 200℃,the initial failure stress increased,final failure stress increased,and failure severity decreased.When the temperature exceeded 200℃,the initial failure stress decreased,final failure stress decreased,and failure severity increased.When the temperature was 600℃,the initial and final failure stresses of the specimens decreased by 60.93%and 19.77%compared with those at 200℃,respectively.The numerical results obtained with the software RFPA3D-Thermal were used to analyze the effect of temperature on the specimen and reveal the mechanism of the failure process in the deep tunnel surrounding rock.

汉字·哲学·艺术——汉字对中华民族思维的影响

汉字在其独特的构造中积淀了极为丰富的感性因子与理性精神,从而使其具有了其他文字无法具有的认识功能与审美价值,并对中华民族的思维模式与文化心理产生了巨大影响。对中国哲学的影响主要表现在以形象论道的思维方式与得意忘象的思辨精神,对中国艺术的影响主要表现为书法与水墨画中的破形传神的思维方式与空灵自由的艺术品格。

Effect of induction unloading on weakening of rock mechanics properties

The effects of induction unloading such as drilling, blasting, lancing and water-infusion softening on weakening of rock mechanics properties were investigated. Three stress paths were chosen as test schemes corresponding to the triaxial compressive test, pre-peak and post-peak unloading the confining pressure tests. The results show that compression deformation is the main cause of rock failure under loading condition. However, the strong dilatation leads to the rock failure along unloading direction. Rock failure happens even under little axial stress with confining pressure unloading. Poisson ratio increases with the decrease of confining pressure during the process of unloading. Elastic modulus increases slowly along with the decline of confining pressure, but decreases rapidly when unloaded to yielding strength. It shows that the weakening rate of rock intensity tends to be faster with easily failure under the unloading condition.

营销企划中字体设计的研究

本文先介绍传统文字广告词设计的谋划应用,接着引申重点探讨如何从文字本身形美着手,提出从三方面破形、以及从多方面重组、升华到立新,让字体设计在营销中发挥出最大效用。

论西画中的抒情色彩——绘画抒情色彩研究

原始人的艺术中,色彩有象征的意味。进入文明社会后,直到19世纪,艺术是以写实为主的,其色彩也是为造型服务的写实性色彩。随着照相、录像术的问世与快速发展,艺术不再以精确描绘对象为能事。于是有些画家突破了写实性色彩的局限,提出了用新的抒情色彩传达自己的感情,并通过色与形的脱离及改变,创造主观的动力性色彩来体现抒情性色彩语言。

Experimental study on mechanical properties of dowel bar embedded in concrete under fatigue loads

To investigate the mechanical properties of a dowel action under fatigue loads, nine reinforced concrete specimens were fabricated, and the monotonic and fatigue loadings were performed on these specimens, respectively. All of these specimens were divided into two series. Six specimens in SeriesⅠwith different bar diameters of 12, 20 and 25 mm were subjected to monotonic loads and were used to confirm the ultimate bearing capacity. The remaining three specimens in Series Ⅱ were subjected to fatigue loads and were designed to investigate the attenuation character of dowel action and the fatigue failure modes. The test results show that the accumulated fatigue damage due to fatigue loads can reduce the ultimate bearing capacity of specimens. With the increase in fatigue loads, the failure mode can transform to fatigue rupture of the dowel bar under the serviceability loading state,i. e. 55% of the monotonic capacity. The fatigue life is determined by the fatigue properties of steel and concrete.Based on the test data, the failure process of dowel action can be divided into two stages： the accumulation of fatigue damage and the fatigue rupture of dowel bar.

Mechanical performance of the mixed post-installed connection in low-strength concrete

Due to inadequate bearing capacity of the chemically-planted steel bar in low-strength concrete, a new mixed post-installed connection is proposed using small diameter anchoring steel bars and grouting materials together to anchor the main steel bar. To investigate the feasibility of the proposed post-installed connections, a series of pull-out tests with different anchors were conducted for comparison,including fully adhesive anchors, partially adhesive anchors,grouting material anchoring connection and the new mixed post-installed connection. The experimental results of the single steel bar pull-out test show that the mixed post-installed connection can effectively enhance the bearing capacity of post-installed steel bars in low-strength concrete. The bearing capacity is increased by nearly two times with no cone-type concrete failure compared with the fully adhesive anchor. The results show that adopting the new mixed post-installed connection can ensure that joint performance meets the requirements if the space dimension is available.

Strength calculation methodology for internally ring- stiffened DT- joints

In order to obtain the strength design equations for internally ring-stiffened circular hollowsection tubular DT（ double tee）-joints subjected to brace axial compression or tension, theoretical and numerical studies on 800 stiffened joints were conducted. Based on the failure mechanism of the stiffened joints, four theoretical models and corresponding equations for predicting the strength of the stiffeners are proposed. Combined with existing unstiffened DT-joint design equations, a design equation for the stiffened joints is proposed. The finite element analysis shows that the failure of the stiffened joints under brace axial loads can be characterized by plastic hinges forming in the stiffener and chord wall yielding in the vicinity of the brace-chord intersection. The reliability of the proposed stiffener strength equations is demonstrated by a reliability analysis. Good agreement is achieved between the stiffened joint strength calculated from the proposed joint strength equation and that obtained from finite element analysis.

Analysis of Dynamic Failure of Plastic Spherical Shells Under Local Impact

Aim To study the dynamic failure of the plastic spherical shell impacted by a missile. Methods The deformation mode of spherical shells was given by introducing isometric transformation. The governing equation of motion of the rigid plastic spherical shell was given by energy balance. This equation was solved by using Runge Kutta method. Results The relationships between the impact force, dimple radius, central point deflection and time were obtained. The response time initial velocity, the maximal impact force permanent initial velocity, the central point deflection initial velocity and the dimple radius initial velocity characteristics were respectively plotted. Conclusion A comparison made between the theoretical results and the experimental ones indicates that the two groups of results are in conformity with each other.

Screening and Breeding of Sweetpotato Varieties Suitable for Mechanical Harvesting

The lower degree of mechanical harvesting is a bottleneck hindering the healthy development of sweetpotato industry in China, while the mismatching be- tween agricultural machinery and agronomy is one of the main factors for poor me- chani.cal harvesting. In this study, total five sweetpotato varieties were selected, and the effects of different shapes and sizes on mechanical harvesting of sweetpotato were investigated. The results showed that the breakage rate of Xuzishu 5 was lowest, so it is more suitable for mechanical harvesting in field. At the same time, the correlations between sweetpotato shape, breakage rate and exposure rate were analyzed. It was found that there was a significant linear correlation between sweet- potato shape and breakage rate （P〈0.01）; the higher the flat rate is, the higher the breakage rate is; and sweetpotato shape had no significant effect on exposure rate. Therefore, tuberous root with lower flat rate, as well as better agronomic characters should be selected in the breeding process of new sweetpotato varieties.

Mechanical and energy dissipation characteristics of granite under cyclic impact loading

This study investigated the effect of repeated blasting on the stability of surrounding rock during the construction of a tunnel or city underground engineering.The split Hopkinson pressure bar(SHPB)was used to carry out cyclic impact tests on granite samples,each having a circular hole,under different axial pressures,and the cumulative specific energy was proposed to characterize the damage characteristics of the rock during the cyclic impact.The mechanical properties and the energy absorbed by the granite samples under cyclic impact loads were analyzed.The results showed that under different axial pressures,the reflected waveform from the samples was characterized by“double-peak”phenomenon,which gradually changed to“single-peak”wi th the increase in damage value.The dynamic peak stress of the sample first increased and then decreased with an increase in impact times.The damage value criterion established based on the energy dissipation could well characterize the relationship between the damage and the number of impacts,which showed a slow increase,steady increase,and high-speed increase,and the damage value depended mainly on the last impact.Under the action of different axial pressures,all the failure modes of the samples were axial splitting failures.As the strain rate increased,with an increase in the dimension of the block,the sizes of the rock fragments decreased,and the fragmentation became more severe.

诊断骨转移性伴破骨样巨细胞反应的梭形细胞肺癌1例并结合文献分析

目的对骨转移性伴破骨样巨细胞反应的梭形细胞肺癌进行诊断分析,旨在提高临床病理医师对该病特殊形态的认识,避免误诊、漏诊。方法回顾性分析2020年我院收治的1例骨转移性伴破骨样巨细胞反应的梭形细胞肺癌的临床资料,经过病理组织学及免疫表型观察进行诊断,并复习相关文献进行分析。结果骨转移性肺癌与肺原发腺癌组织像不同,光学显微镜下呈现骨转移性肺癌中伴破骨样巨细胞反应的梭形细胞癌形态,经免疫组织化学证实和详细询问患者病史,最终确诊为肺腺癌骨转移。结论骨转移性肺癌临床较常见,但转移性癌出现伴破骨样巨细胞反应的梭形细胞肺癌临床非常少见。临床病理诊断容易误诊为富巨细胞肉瘤,确诊要依靠免疫组织化学染色及详细询问患者病史。

Stability control of surrounding rocks for a coal roadway in a deep tectonic region

In order to effectively control the deformation and failure of surrounding rocks in a coal roadway in a deep tectonic region, the deformation and failure mechanism and stability control mechanism were studied. With such methods as numerical simulation and field testing, the distribution law of the displacement, stress and plastic zone in the surrounding rocks was analyzed. The deformation and failure mechanisms of coal roadways in deep tectonic areas were revealed: under high tectonic stress, two sides will slide along the roof or floor; while the plastic zone of the two sides will extend along the roof or floor,leading to more serious deformation and failure in the corner of two sides and the bolt supporting the corners is readily cut off by the shear force or tension force. Aimed at controlling the large slippage deformation of the two sides, serious deformation and failure in the corners of the two sides and massive bolt breakage, a ‘‘controlling and yielding coupling support'' control technology is proposed. Firstly, bolts which do not pass through the bedding plane should be used in the corners of the roadway, allowing the two sides to have some degree of sliding to achieve the purpose of ‘‘yielding'' support, and which avoid breakage of the bolts in the corner. After yielding support, bolts in the corner of the roadway and which pass through the bedding plane should be used to control the deformation and failure of the coal in the corner. ‘‘Controlling and yielding coupling support'' technology has been successfully applied in engineering practice, and the stability of deep coal roadway has been greatly improved.

Mechanism of rock deformation and failure and monitoring analysis in water-rich soft rock roadway of western China

Aiming to get the strata behavior and stability rules of surrounding rock of the main return airway of Yushujing Coal Mine, convergence deformation of two sides and force of U-shaped steel yieldable support and bolt were monitored, and deformation of surrounding rock and mechanical characteristics of support structure were timely obtained to guide the informa- tion construction and optimize supporting parameters in water-rich soft rock roadway. The field monitoring results indicate the following. （1） Convergence displacement of rock surface increases with time continuity and shows surrounding rock＇s intense theological behavior. The original support scheme cannot control the large deformation and strongly theological behavior; （2） Without backfilling, the U-shaped steel support begins to bear load after erecting for 4-7 days and increases rapidly in the first 30 days. The U-shaped steel support at the right shoulder and top of roadway bears a larger force and the left side and shoulder bears a smaller force; （3） The stress of bolt increasing over time and at the right shoulder of roadway has larger growth and value. The mechanism of rock deformation and the failure and strata behavior in water-rich soft rock roadway are revealed based on the results of the measured relaxation zone of surrounding rock, measured stresses, and the rock mechanics tests.

Comprehensive health assessment of shield tunnel structure based on prototype experiment

Health state of shield tunnels is one of the most important parameters for structure maintenance.Usually,the shield tunnel is extremely long in longitude direction and composed by many segments.It is difficult to quantify the relationship between the structure damage state and shield tunnel structure deformation by the model test because of unpredictable effects of different scales between model test and prototype tunnel structure.Here,an in-situ monitoring project was conducted to study the excavation induced shield tunnel structure damage,which could be considered a prototype test on the tunnel deformation.The disaster performance of tunnel leakage,segment crack,segment dislocation and segment block drop-off during longitude deformation and cross-section ovality developments was analyzed.The results indicate that instead of the longitude deformation,the ovality value has the strongest correlation to the rest disease performance,which could be used as the assessment index of the tunnel health.For this tunnel,it is in health state when the ovality is less than 0.5%,and the serious damage could be found when the ovality value is higher than 0.77%.The research results provide valuable reference to shield tunnel health assessment and help complete the standard of shield tunnel construction.

Finite Element Optimization of Vee-ring Factor in Fine-blanking Process

The vee-ring is one of the most characteristic features of the fine-blanking process which is derived from the conventional blanking. With the vee-ring, a counter plate and some other working parameters, a component with a precise geometry and smoothly blanked surface can be produced without any major secondary operations. However, these working parameters are always empirically determined or determined by trial-and-error method, which is time-consuming and expensive. In this study, a numerical simulation method was used to analyze the el- feet of vee-ring factors on product quality, such as distance between vee-ring and punch, vee-ring height and blank holder force, so as to obtain as high clean cut ratio as possible. During the simulation, the model was assumed as axisymmetric one and the workpiece was considered as rigid plastic material, meanwhile the tools were defined as rigid bodies so as to shorten the computational time. A damage model taking into account the influence of hydro- static stress was used to simulate material fracture in fine-blanking. The result obtained from the simulation indi- cated that with the help of vee-ring, the metal material near the shear band does not flow with the punch penetra- tion and high compressive stress in the shear band tained with a vee-ring model than the one obtained distance between vee-ring and punch is, the higher is generated. Consequently, higher clean cut ratio can be ob- with a plane blank holder model. Furthermore, the longer the the height of roll-over becomes.

Capacities and Failure Modes of Suction Bucket Foundation with Internal Bulkheads

Suction bucket foundations can be divided into four compartments by cruciform internal bulkheads,thereby yielding better capacity in certain conditions than those without internal bulkheads.As yet,no systematic study has been conducted regarding the effects of cruciform internal bulkheads on the capacities of suction bucket foundations.In this study,we established a large number of finite element models of suction bucket foundations with and without cruciform internal bulkheads and of solid embedded circular foundations.We found the uniaxial capacities and failure modes of suction bucket foundations with various depth ratios to remain basically unaffected by internal bulkheads in uniform clays.However,in inhomogeneous clay with high strength heterogeneity,we observed the uniaxial moment and horizontal capacities and corresponding failure modes of suction bucket foundations with a low depth ratio to be obviously affected by internal bulkheads.In this case,the uniaxial moment capacities,in particular,as well as the horizontal capacities of suction bucket foundations with cruciform internal bulkheads become obviously greater than those without internal bulkheads.Under combined loading,we found the failure envelopes of suction bucket foundations with and without cruciform internal bulkheads and of solid circular foundation to also be basically consistent in uniform clays.However,in inhomogeneous clay with high strength heterogeneity,cruciform internal bulkheads can obviously change the shapes of the failure envelopes of bucket foundations with a small depth ratio.We conclude that when the acting vertical load or foundation depth is relatively small,suction bucket foundations with cruciform internal bulkheads can be subjected to larger moment and horizontal loads in soft clays with high strength heterogeneity.